klayout/Changelog

0.25            (2017-10-31):
* Enhancement: Menu items can be disabled or enabled
      now. The former "Key Bindings" configuration page
      has been turned into "Menu Customization". Check 
      boxes allow enabling or disabling of menu items.
* Enhancement: The cell tree no longer is collapsed on edits
      or when the sorting order changes.
* Enhancement: Using a special menu path, macros can be
      configured to appear in submenus now.
* Enhancement: KLAYOUT_HOME environment variable to 
      control the location of the application folder.
      The application folder is the place where KLayout
      keeps the configuration, macros, packages and
      other things.
* Enhancements: Major overhaul of the build environment
      - Qt5 supported now
      - Employs qmake as build system
      - Reorganisation of the sources
      - Continuous integration enabled (unit tests
        integrated in .pro files, JUnit output etc.)
      - Compatible with the clang compiler
* Enhancements: Buddy tools: KLayout now comes with a set of 
      additional executables that provide some functionality
      subset in a lean way. These binaries are named "strm..."
      and are installed along with KLayout. 
      - strm2cif: converts any format to CIF
      - strm2dxf: converts any format to DXF
      - strm2gds: converts any format to GDS2
      - strm2gdstxt: converts any format to GDS2/text
      - strm2oas: converts any format to OASIS
      - strm2txt: converts any format to plain text (internally)
      - strmclip: creates a clip from a file
      - strmcmp: compares two files (logically)
      - strmxor: compares two files (geometrically)
      For more information, use the "-h" or "--help" option.
* Enhancements: HTTPS support for loading files from URL's directly
* Enhancements: Numerous enhancements and optimizations in the RBA/pya
      area and in the debugger.
* Enhancements: KLayout notifies the user when a file was changed and 
      asks whether to reload.
* Enhancements: "File cell or layer": type into the cell or layer list to jump to the 
      cell name typed.
* Enhancements: Advanced search features in the filter entry box 
      for the cell selection form: Case sensitive/insensitive, 
      glob pattern, clear button.
* Enhancements: Tree expansion icons have a better contrast now on Windows
      with dark background.
* Enhancements: Forward and backward navigation buttons in the main window.
      These buttons jump to the previous or next display state:
      zoom window, hierarchy depth, etc..
* Enhancements: A Package manager is provided. Packages are add-ons for
      KLayout and can include macros, script libraries, fonts
      for the TEXT PCell, technologies, DRC scripts etc.
      Packages can be published on GitHub or any server 
      supporting WebDAV. After registering a package, users
      can install or update packages with a few clicks.
      For more information see https://github.com/klayoutmatthias/klayout/wiki
      or "About Packages" in the "Various Topics" area of the main 
      documentation. The package manager is found in the "Tools"
      menu under "Manage Packages".
* Enhancements: LEF/DEF reader:
       - Compatibility fixes with version 5.8
       - Regions and Groups are supported now
       - LEF/DEF is a standare format now and 
         can be used with "File/Open" for example.
* Enhancement: DXR reader supports variable path widths now
* Enhancement: XOR provides graphical progress
* Enhancements: Libraries can be associated with a technology. Only libraries
      associated with the selected technology are shown in the selection
      dialog. 
* Enhancements: Overlapping instances are easier to select now (instance 
      selection cycling).
* Enhancements: Many more methods in RBA/pya. For example:
       - Ability to directly insert "D" types (such as DBox
         into layouts and cells.
       - RBA::RecursiveShapeIterator now supports complex (non-rectangular)
         search regions
       - A more consistent type framework (consistent complex transformation
         types, vectors)
       - More intuitive interface in certain objects (i.e. CellView,
         LayerPropertiesNode, Annotation etc.). Changing an attribute 
         usually has an immediate effect on the respective property now
         ("live objects")
       - Hash functions for certain objects - Box, Edge, Trans, Polygon,
         and other objects can be used as dictionary keys now.
       - New import methods for Region, EdgePairs and Edges
       - New features for LayerMapping and CellMapping
       - Multiple selected cells in LayoutView
       - RBA::TextGenerator to supply the Basic.TEXT PCell's 
         functionality as static feature
       - Receivers can be added to signals and removed from 
         signals now.
       - Individual instance iterator for CellInstArray
       - ...
* Enhancements: Enhanced layout statistics form with detailed shape 
      statistics.
* Enhancements: Line styles (dashed, dotted etc.) available now.
      Works best with manhattan layouts.
* Enhancements: "Marked box mode": boxes are drawn with a cross.
* Enhancements: Arbitrary pattern size for custom fill pattern (no 
      limited to multiples of 8). Max size is 32x32.
      Enhanced annotations: 
       - Ellipses
       - Position markers
       - Text alignment
       - "Auto measure" rulers (place a ruler measuring the 
         distances between adjacent objects with a single 
         click)
* Enhancements: DRC enhancements:
       - Text support
       - "smoothed" function
       - "layers" function delivers all layers read
       - Polygon with edge interactions
       - middle and extent_refs methods for center point and other
         references
       - "corners" function
       - "collect...", "select" and "each" methods
* Enhancements: GDS2 paths can now use the MultiXY extension too.
* Enhancements: X2 Support for Gerber import.
* Enhancements: A function to reset the window state after the
      window has been misconfigured (i.e. detaching or closing
      the dockable windows). This feature is found in 
      View/Restore Window.

0.24.10         (2016-04-01):
* Enhancements: New method CellView#is_dirty?
       This method indicates that a cell view needs saving
* Bugfix: DEF reader was not able to read routing 
       Routed segments with vias plus continued wiring 
       were not read. Instead an error message was shown
       saying "Invalid orientation specification"
* Bugfix: Setting "technology-data" configuration property did not work
       Reading or writing the "technology-data" configuration
       property is the only way to access technology data from
       a script. Hence it's important that this property can
       be set. With this patch, "technology-data" can be set
       to an XML string which has the same format than the 
       one stored within the configuration file.
* Bugfix: Reader issues with some RVE files
       The RVE reader could not read files with cell names
       containing hyphens (like "A-B").
* Bugfix: Inplace operators are now working in Python too
       For example "r1 += r2" was not working where r1 and r2
       were pya.Region objects.

0.24.9          (2016-11-28):
* Enhancements: The RBA::Region#smooth function was enhanced to 
       give somewhat better results
* Enhancements: DXF's circle approximation can now also specified 
       through an "accuracy" parameter: if less than the number of 
       specified points is required to achieve the given accuracy, the
       number is reduced accordingly. This also applies to the polygon
       interpolation of spline and arc curves.
* Enhancement: RBA integration now is compatible with Ruby 2.3 
       which allows building on Ubuntu 16 as well.
* Enhancement: OASIS files with instance angles >360 were rejected
       before. Now, this has turned into a warning.
* Bugfix: DEF reader was failing to read MASK/via combinations.
* Bugfix: The marker browser's "show only rules with errors" option
       was enabled again on sorting of errors.
* Bugfix: Using Layout objects for inputs didn't work
* Bugfix: Copying Hierarchy treets containing PCell's made the 
       PCell's being turned into static cells.

0.24.8          (2016-06-19):
* Bugfix: XOR and different or big database units:
       With tiling, XOR between two layouts with different database
       units was still not working correctly. Also, when the database unit
       was larger than 1nm, the XOR feature was dropping results sometimes
       when tiling was on.
* Enhancements: progress bar shown also for "-z" mode scripts:
       The solution of 0.24.7 has been modified to avoid annoying
       progress bar windows popping up in background-window mode:
       Now, progress bar windows will only pop up if an active main
       window is present. This will enable progress bars for scripts that
       open their own main windows but still keep the application GUI-less
       when the script does not do so.
* Bugfix: Crash on empty panel:
       When "New/Panel" is used a view without a layout is created.
       An attempt to create layout on such panels crashed the application.
* Bugfix: LEF reader now can read PIN statements including VIA
* Bugfix: Polygon smoothing was not working properly in some cases
       Previously the smoothing function was sometimes dropping vertexes
       from the polygons.
       Smoothing now does also guarantee not to exceed the given 
       distance.
* Bugfix: Sorting cells by area now sorts cells by name as second choice
       In the previous version, cells with identical area were 
       grouped but the order was arbitrary. Now the name is used as
       the second-level sorting criterion which keeps such cells
       sorted by name.

0.24.7          (2016-05-01):
* Bugfix: XOR and different database units:
       With tiling, XOR between two layouts with different database
       units was not working correctly.
* Enhancements: progress bar shown also for "-z" mode scripts:
       Scripts running in KLayout with the "-z" option (don't
       show main window) were not experiencing progress reporting
       before. Now a small modal window is shown during long-running
       operations that indicates the progress and provides a Cancel
       button to abort the operation.
* Bugfix: Crash on using "Edit/Make cell":
       This happened sometimes if the selected objects contained
       instances.
* Bugfix: Invalid behavior of paths with reflecting segments:
       For example a path made of the points (0, 0), (0, 1000)
       and (0, 0) had a reflecting segment which cause some 
       computations (for example the bounding box) to return
       invalid results.

0.24.6          (2016-03-22):
* Bugfix: Early delete of plugin object when returning a new object
       from PluginFactory#create_plugin. The returned object was 
       not held, so in Ruby the GC could destroy the object. This 
       could lead to crashes in applications employing the Plugin API.
* Bugfix: It was possible to edit read-only macros. 
       For example, it was possible to enter new lines in macros 
       marked as read-only. However, these changes were not saved.
* Bugfix: Shift+Tab not working in macro editor. 
       On some platforms, Shift+Tab was not working as expected. 
       This key combinations was supposed to left-shift a selected
       block an undo indents.
* Bugfix: Wrong scaling of layers when doing XOR's with layouts
       with different database units.
       This happened when the layouts had different layers and 
       "summarize missing layers" was disabled.
* Bugfix: "Search & Replace" was not working properly if named 
       layers were present. Specifically the shape search was not
       working due to an incorrectly formed query.       
* Bugfix: Sizing produced incorrect results in case of slowly
       varying polygon contours. The effect was a contour with 
       spiky distortions where two "almost parallel" edges 
       connected.
* Bugfix: The diff tool was not reporting differences correctly when
       layers were present in one layout while they were not present
       in the other. This happened specficially when "Summarize 
       missing layers" was disabled.
* Enhancement: New context mode in marker browser: "Current or Any".
       In this mode, the markers are displayed in the context of the
       current cell. If that is not possible because the markers are
       given for cells outside the cell tree of the current cell, the
       fallback is to show the markers in the current cell as in "Any"
       mode.
* Enhancement: More consistent behaviour of cell and category filters
       in the marker browser. For example, the category filter is 
       now also applied when selecting a node for a certain cell in 
       the cell branch and if nested categories are present, the 
       category filter is applied smarter - not just on each category.

0.24.5          (2016-02-26):
* Bugfix: Instance browser was messing up array instances sometimes.
       After browsing instances, in some cases array instances got
       messed up. This specifically happened with OASIS files.
* Enhancement: Diff tool does not care about text alignment and
       font properties unless in "exact" mode. Previously alignment
       flags and font properties were compared in non-exact mode too
       causing some confusion for example when comparing OASIS vs. 
       GDS.
* Enhancement: XOR on layouts with different database units.
       Previously, the XOR tool refused to run on layouts with
       different database units.
* Bugfix: The OASIS writer's S_TOP_CELL standard property now will 
       correctly use an "n-string" value in strict mode.
* Bugfix: The OASIS writer bailed out on 1x1 cell arrays.
       Now these pseudo arrays are written as single instances.
* Bugfix: GUI type support for QVariant.
       RBA/pya did not provide constructors for QVariant from 
       GUI types like QColor and QFont. These have been added now.
       The corresponding conversion functions to QColor, QFont etc.
       are provided as well.
* Bugfix: Problems with QVariant constructor: some feature were not
       usable. For example, a double value could not be passed to
       the constructor. Disambiguators have been provided to solve
       these issues.
* Enhancement: Cell/Category filter for marker browser. The marker
       browser now has a filter entry box to select specific cells
       or categories.
* Enhancement: Images are cached now for faster image update. 
       Specifically the "fit" image will be cached and if "fit" is 
       selected again, the image is restored rather quickly (provided
       the window is not resized). The cache depth can be configured 
       in "Setup/Display/Optimization".
* Bugfix: "Read all other layers" option in LEF/DEF reader was
       potentially assigning GDS layers which have been defined in
       the layer mapping. Now, layers used in the layer map for 
       targets are blocked and not used for automatic assignment.
* Enhancement: The database unit can be configured now in LEF/DEF
       import options. Previously it was fixed to 1 nm.
* Bugfix: RBA::LayerProperties#id was not always unique as stated
       by the documentation. Specifically not after a file was loaded.

0.24.4          (2015-12-17):
* Enhancement: Layer colors are iterated for named layers without
       layer numbers as well. Such layers are created when reading
       DXF files for example and all layers had the same color 
       initially. Now, these layers will be assigned different colors.
* Bugfix: RBA::TilingProcess#threads was not working properly 
       when assigning a value of 1.
* Bugfix: The perimeter computation now has changed to 64 bit numerics
       reducing the risk of numerical overflow. In earlier versions, 
       the perimeter computation of integer type shapes (polygons, 
       boxes, regions) was performed with 32 bit length which is 
       not sufficient to represent total perimeters of full layouts.
* Bugfix: The OASIS writer's S_TOP_CELL standard property now is 
       set to the correct value when using "Save cell as".
* Bugfix: Some patches are provided for enhanced compatibility with
       MacOS. One MacOS-only bug was related to a crash when re-registering
       of PCell's while developing then.
* Bugfix: PCell guiding shape parts could not be selected in partial
       editing mode using a drawn selection box.
* Enhancement: The color of the guiding shapes can now be configured
       individually.
* Bugfix: OASIS reader was not properly associating CELLNAME properties 
       with cells as the standard requires. Instead CELLNAME properties were
       ignored. 
* Bugfix: Strict mode compatibility issues in OASIS writer:
       File level PROPERTY records were not put right at the beginning of the file, 
       empty tables were not listed with 0 position, property value strings were
       not referenced by ID and the property modal variables were referenced 
       sometimes after name records (specifically CELLNAME with standard 
       properties enabled). According to the specification, the name records 
       reset these variables so this is not correct. Other readers may report 
       errors for such files.
* Enhancement: OASIS writer file size reduction. Now, the OASIS writer
       will opimize the arrangement of cell array instances so that 
       modal variables can be used for a better compaction.
* Enhancement: During script debugging now the Assistant window is active
       even while the debugger is executing a script. The main window is
       still inactive however to avoid fatal cross-interactions between 
       the debugger and the user interface.
* Bugfix: The Python PCell sample was broken.
* Bugfix: slowly bending paths have not been displayed correctly.
* Bugfix: coordinates might have been swapped in the box properties
       page when switching from local to absolute coordinates and 
       back.
* Bugfix: certain ruler styles with independent x and y axis have not
       been displayed properly when using a global transformation.
* Enhancement: the performance of "Flatten cell" is enhanced significantly
       in cases of many instances. 
* Bugfix: DRC output was producing new layers with an empty layer name
       selector (no major issue, but confusing).

0.24.3          (2015-11-05):
* Enhancement: PYTHONPATH does not mess up the Windows installation any
       longer. If you want to set the PYTHONPATH for KLayout, use 
       KLAYOUT_PYTHONPATH. 
* Bugfix: The oasis_write_std_properties attribute of RBA::SaveLayoutOptions
       did not work as described. To maintain backward compatibility and
       enable the cell bounding box feature, a new attribute called 
       oasis_write_cell_bounding_boxes was introduced.
* Bugfix: "Hide all" only hides the top level layer properties, not the
       members of layer groups.
* Bugfix: S_BOUNDING_BOX standard properties now appear after CELLNAME
       records in OASIS files as required by the OASIS specification.
* Bugfix: The unintuitive behavior of the "Writer Options" has been changed.
       Now, the writer options are applied to the saved layout always, not
       just on the first save. Previously, the program remembered the options
       and reused the previous options on following saves. This was quite
       unintuitive since changing the properties did not necessarily affect 
       the way files were written.
* Enhancement: The starting directory for files dialogs is the "Documents"
       folder on Windows now. Not the current directory which is the 
       installation directory usually.
* Bugfix: Signal names are property set for RBA::QListWidget and other 
       objects. This enables the use of "indexesChanged" signals and eliminates
       Qt runtime warnings.
* Bugfix: Library cells were not properly loaded again after reloading
       a layout which used libraries which itself referred to other libraries.
* Bugfix: The program crashed sometimes when using report databases with
       properties.
* Bugfix: Layers with a single box rendered wrong results in the DRC's 
       size function with strong undersize. The boxes did not vanish as
       expected but instead were inverted.
* Enhancement: The build now is compatible with Python 2.6.
* Bugfix: Reading OASIS files in strict mode with cell names consisting
       of a "$" character followed by an integer number (like "$1") sometimes
       messed up the cells.
* Bugfix: RBA::TilingProcessor could not be used both with tile size and
       tile count set since setting the tile size was resetting the tile
       count and vice versa.

0.24.2          (2015-10-02):
* Bugfix: Flip and Rotate function did not work as expected when the view 
       was descended into the hierarchy.
* Enhancement: RBA::BrowserDialog now also accepts a parent parameter
       which are important to better integrate such dialogs into the
       application.
* Bugfix/enhancement: "klayout_vo.exe" now is a pure viewer application
       again. By calling this executable, the edit functions cannot be
       enabled and the save functions are disabled as well. Under Linux,
       renaming the binary to "klayout_vo" switches KLayout into this
       mode as well.
* Bugfix: The zoom and selection rectangle can now be dragged outside the
       visible area and still define the zoom or selection rectangle.
* Bugfix: expressions were not coercing floating-point values consistently:
       The expression "to_i(2)+1.4" rendered 3 instead of 3.4 as expected.
       The sum was treated as an integer sum because the first operand is
       an integer. Now the integer is converted into a floating-point value
       as expected.

0.24.1          (2015-08-26):
* Enhancement: switched to -O2 instead of -O3 to avoid issues with certain
       gcc versions for which -O3 appears to be broken.
* Bugfix: fixed a backward compatibility issue in scripting. Specifically
       "view.each_object_selected { |s| s.shape }" will work again.
* Bugfix: the layer matching algorithm in the .lyp file layer assignment
       is compatible with the previous version again. This specifically applies
       to "wildcard" specifications. In 0.24, named and unnamed layers were 
       considered different even if GDS layer and datatype numbers were identical.
       The effect was that if a named layer was present, a .lyp file specification
       without that name was not matching the named layer and with "add other layers"
       the named layer was produced again.
* Enhancement: "Apply all" in the object properties dialog behaves somewhat
       more intuitive now. Specifically changing the path endcap styles now
       works as expected. For the other properties, a choice was provided 
       between applying changes in a relative or absolute way. For example,
       when the left edge of a box is changed, the left edges of all selected
       boxes are shifted by the same amount in relative mode. In absolute mode,
       the left edge will be set to the specified position for all selected boxes.
* Bugfix: Python iterators will keep a reference to the source object now. 
       This avoids problems when fetching iterated properties (typically "each..." methods)
       from short-living objects.
* Bugfix: Python's StopIteration exception does no longer appear in the debugger 
       now. This is an exception used internally to mark the end of an iteration 
       sequence.
* Bugfix: "Path#width=" does no longer reset the round end flag.
* Enhancement: the "Show All" mode of the marker browser is persisted now. 

0.24            (2015-07-25):
* Enhancement: Python support: Scripts and PCells can now be coded in Python as well. Python and Ruby
       scripts may coexist in the same application and they can be debugged together. The macro
       IDE features a Python tab in which Python scripts can be managed. 
       The language features of Python and Ruby are very similar, so the features of the 
       integration are highly comparable and easy to translate. The Python module 
       name is "pya".
* Bugfix: When using a layer with special hierarchy level settings (i.e. #*), the ruler did not snap to that shapes.
* Bugfix: Qt item ownership is now transferred on some methods. For example, "QTreeWidget#insertItem" now will 
       transfer ownership of the item to the tree widget. Hence, when the variable holding the item goes out of scope,
       the tree item will not be destroyed.
* Enhancement: The shape selection can now be manipulated through scripts (new LayoutView methods "object_selection=",
       "select_object" etc.)
* Enhancement: New edge vs. region operations are supported (edge AND region and edge MINUS region)
* Enhancement: RBA/pya objects now in general feature a "_manage" and "_unmanage" method will allows releasing
       the ownership over an object in cases where object lifetime control is important (specifically when passing
       objects around in Qt applications).
* Enhancement: Many new RBA methods, i.e. 
       - Annotation#id
       - Cell#change_pcell_parameters
       - Cell#pcell_parameters_by_name
       - DPolygon#assign_hull (raw argument)
       - DPolygon#assign_hole (raw argument)
       - DPolygon#each_edge (with contour argument)
       - DPolygon#insert_hole (raw argument)
       - DPolygon#transform 
       - DSimplePolygon#initialize (raw parameter) 
       - DSimplePolygon#initialize (raw parameter) 
       - DSimplePolygon#set_points
       - DSimplePolygon#transform 
       - EdgePairs#+ 
       - Edges#& (with Region)
       - Edges#&= (with Region)
       - Edges#- (with Region)
       - Edges#-= (with Region)
       - Edges#inside_part
       - Edges#select_inside_part
       - Edges#outside_part
       - Edges#select_outside_part
       - Instance#change_pcell_parameter
       - Instance#change_pcell_parameters
       - Instance#convert_to_static
       - Instance#flatten
       - Instance#is_pcell?
       - Instance#pcell_declaration
       - Instance#pcell_parameters
       - Instance#pcell_parameters_by_name
       - Layout#begin_shapes (with cell ref)
       - Layout#begin_shapes_overlapping (with cell ref)
       - Layout#begin_shapes_touching (with cell ref)
       - Layout#create_cell (with PCell parameters and/or lib name)
       - Layout#delete_property
       - Layout#flatten_into
       - Layout#has_prop_id?
       - Layout#pcell_ids
       - Layout#pcell_names
       - Layout#prop_id
       - Layout#prop_id=
       - LayoutView#clear_object_selection
       - LayoutView#object_selection
       - LayoutView#object_selection=
       - LayoutView#replace_annotation
       - LayoutView#select_object
       - LayoutView#unselect_object
       - MainWindow#cm_close_all
       - MainWindow#cm_save_all
       - MainWindow#cm_sel_move_to
       - MainWindow#instance
       - MainWindow#manager
       - ObjectInstPath#==
       - ObjectInstPath#!=
       - ObjectInstPath#<
       - ObjectInstPath#append_path
       - ObjectInstPath#clear_path
       - ObjectInstPath#cv_index=
       - ObjectInstPath#layer=
       - ObjectInstPath#seq=
       - ObjectInstPath#shape=
       - ObjectInstPath#top
       - ObjectInstPath#top=
       - RdbItemValue#initialize (with float argument)
       - RdbItemValue#float
       - RdbItemValue#is_float?
       - RdbItemValue#tag_id
       - RdbItemValue#tag_id=
       - SaveLayoutOptions#gds_write_file_properties
       - SaveLayoutOptions#gds_write_file_properties=
       - SaveLayoutOptions#oasis_write_std_properties
       - SaveLayoutOptions#oasis_write_std_properties=
       - Shape#each_edge (with contour argument)
* Enhancement: Qt API is aligned better with C++ Qt notation. Several bug fixes, new features and stability enhancements.
       For example:
         New: RBA::Qt::white or RBA::Qt::GlobalColor::white
         Old: RBA::Qt_GlobalColor::white
* Enhancement: the debugger can now be disabled in the macro editor IDE for enhanced 
       script execution performance with IDE window open and less interactions between
       Qt code and Macro IDE
* Bugfix: DRC crashed when outputting shapes to a layer that was used as an input
       in further parts of the script but has been declared as input befor the layer
       was output.
* Bugfix: ".lyp wildcard replacement" now honors transformations as well
* Bugfix: Gerber import issues fixed: Zero-diameter circular apertures moves are translated into lines,
       Zero-length moves must not be clear for G1 and circular apertures.
* Bugfix: The technology button now applies the technology even if the technology did not change.
* Enhancement: Polygons with holes are better supported now (for example in partial editing). Such
       polygons cannot be written to GDS or OASIS (they will be converted to ones without holes), but
       they may be created in DRC scripts.
* Bugfix: "Reload layout" now doesn't forget the technology that was attached to a layout.
* Bugfix: Box side setters now behave more consistently in scripting. Before this fix, it was not possible to
       assign the sides of a box this way: "b = Box::new; b.left = 100; b.right = 300".
* Bugfix: recursive library references (library referencing itself indirectly) made the application
       crash.
* Bugfix: Subclass mapping sometimes failed in certain cases. This was particular annoying in Qt's event
       handlers since "QKeyEvent" (or similar classes) only showed up "QEvent".
* Enhancement: "Move selection to" function available in "Edit/Selection/Move To". With this function, 
       the selection (shapes are instances) can be moved to a specific position. You can specify the 
       reference point to use. For example the center of the bounding box.
* Bugfix: Menu icon assignment was not working in some cases within scripts.
* Bugfix: Readonly (global) macros could be edited but not saved.
* Bugfix: Instances could be selected even if they had only invalid layers.
* Enhancement: The application now features a crash handler. This handler gives some debugging information
       about the crash which you can send together with a bug report. In some cases, the crash handler will 
       allow continuing to work with the application although it's highly advisable to save and close.
* Bugfix: Registering plugins through the script's plugin API sometimes disabled view features.
* Bugfix: The macro IDE is not automatically put in the foreground any more. This sometimes interfered with
       modal dialogs shown from a macro.
* Enhancement: The macro IDE now features watch expressions which are automatically evaluated when in a
       breakpoint.
* Enhancements: The "Save Layout" options are now separated from the save function. That means they can 
       be configured once and the dialog will not pop up always when saving. This way, "Save All" is provided
       which will save all open files with the current options.
* Enhancement: A "Close All" function to close all open layouts.
* Enhancement: In scripted layout loads, multiple files can be loaded into the same layout object. In that
       case, the content of the files are merged. This worked so far with GDS. Now this also works with OASIS.
* Bugfix: OASIS int-typed properties now as written as such. Before, they have been written as strings.
* Enhancement: sizing code and path to polygon translation now will better maintain 45-degree edges.
* Enhancement: DRC support for edge/polygon booleans ("edges AND polygons" will select the edges inside the polygons,
       "edges MINUS polygons" will remove the edges inside the polygons)
* Enhancement: Global layout properties supported as well. Layout properties can be edited by selecting
       "User Properties" in "File/Layout Properties". They are written to OASIS. Writing to GDS2 is optional since
       that may create compatibility issues with other tools.
* Enhancement: The OASIS writer will now produce some standard properties: "S_TOP_CELL", "S_BOUNDING_BOX",
       "S_CELL_OFFSET", "S_MAX_SIGNED_INTEGER_WIDTH", "S_MAX_UNSIGNED_INTEGER_WIDTH" and "S_BOUNDING_BOXES_AVAILABLE".
* Enhancement: User properties of cells are available in cell context menu too: this way there can be 
       browsed in non-editable mode too. 
* Enhancement: "Degenerated" polygons (one or two points) can be created in scripts now when using "raw" mode.
       Such polygons are useful in the context of Minkowsky sums for example.
* Bugfix: The application crashed when the macro currently running was deleted.
* Enhancement: "Search & replace" now is available in viewer mode too, but without the ability to replace or
       delete.
* Enhancement: In menu paths, appending a "+" to the path means to add something after that item.
* Bugfix: Guiding shapes are only selected if the PCell corresponding to them is visible.
* Enhancement: there is a clearer indication now that 'Show layers without fill' is on.
* Enhancement: a new mode is available in which PCell content can be selected too. When editing things inside
       PCells however, PCell recomputation may revert these edits.
       The mode is found in "File/Setup", "Application/Selection" page.
* Enhancement: Edge set boolean operations have been too selective with respect to almost-parallel edges. 
       Now a tolerance is applied allowing edges to deviate by ~1 dbu.
* Enhancement: Search & replace: texts, paths and boxes are exported into report databases. 
       Shapes and instances are shown in micron coordinates and as seen in top.
* Enhancement: "Apply all" in properties dialogs: with this function, a specific change is applied to 
       all shapes or instances of the same class. For example a path width change is applied to all other selected 
       paths. The change will be applied smartly (hopefully), so that the intention of the change is preserved.
       For example a left edge shift for a box will be turned into the same shift for all other selected boxes.
* Enhancement: multiple categories can be selected in the marker browser now.
* Enhancement: the instance properties page now shows the cell dimensions (which are not editable of course).
* Enhancement: box property editing is less tedious - the left and right coordinates will now swap if the order
       changes and the mode (width/center or coordinates) is maintained.
* Enhancement: Report databases now support "tagged values" (values with a name) which are shown in the marker 
       list. The markers can be sorted by these values, provided they are string or numerical values. 
       RVE properties are read as tagged values.

0.23.11         (2015-05-23):
* Bugfix: partial edit mode - a cell could be selected even if not visible
       With the new version, the selection behavior of normal selection
       and partial selection are somewhat more consistent.
* Bugfix: The CIF reader was not able to read CIF files with line breaks
       Commands with line breaks separating arguments were not read
       correctly.
* Bugfix: Printout now considers global transformation correctly
       Previously, the global transformation was ignored on printout
       and for screenshots.
* Enhancement: Partial edit mode now also supports polygons with holes
       Polygons with holes are rare since they cannot be represented
       in GDS or OASIS files. But they can be generated in DRC scripts.
       Now, such polygons can be edited in partial edit mode too.
* Bugfix: LEF/DEF reader now correctly uses half the path width for path extension
       Previously the default value was 0.
* Bugfix: Library update was not working properly for OASIS reader
       OASIS files with library references had as issue when updating
       the library cells: cell deleted in the library were not deleted
       in the layout.
* Enhancement: Warning, when drawing on invisible layers
       Previously there was not feedback: the shape was drawn, but not
       visible. Now, a warning pops up when trying to draw on invisible
       layers. This warning can be disabled.

0.23.10         (2015-03-07):
* Bugfix/Enhancement: CIF compatibility. The reader was not fully 
       compatible with the specification. For example, lower-case
       characters have not been ignored as specified. This has been
       fixed among other compatibility issues.
* Enhancement: The CIF writer now has an option to use blank characters
       as x/y separator. Some tools apparently don't like comma
       characters for separators (that is still the default).
* Enhancement: The CIF writer now has an option to emit dummy cell
       calls on top level to reference the top cells. The top-level
       entity is unnamed and does not correspond to a cell. Despite
       that some tools require these entities not to be empty and
       hold dummy references to the real top cells at least.
* Bugfix: Key bindings to default grid menu entries were not working
* Bugfix: When a layer was deleted and a shape on that layer was 
       selected, the application crashed
* Bugfix: Search and replace sometimes gave an internal error, for
       example with the following query:
       'with * do cell.name = "A" + cell.name'
* Bugfix: Search and replace was crashing when trying to delete 
       instances.
* Bugfix: Net tracer bug: the first selected shape was always taken as
       a whole even if parts were disabled through boolean NOT 
       operations.
* Bugfix: Net tracer was using the wrong origin when working in 
       "descend" mode.
* Bugfix/Enhancement: The technology setup now features "read all" and
       "add other layers" flags for the reader mapping table and 
       the layer properties. Before, the global flags were used
       causing some confusion. With the new options the behavior
       can be configured consistently.
* Enhancement: The file dialogs now remember the file type chosen.
* Bugfix: The application issues a error message when trying to 
       write very big images instead of crashing
* Enhancement: Two new Ruby methods to write image files. These new
       methods are LayoutView#save_image_with_options and LayoutView#
       get_image_with_options. These methods allow configuration of
       more features for the image generation like box to draw, 
       oversampling etc.
* Enhancement: DXF reader now converts ATTDEF entities to texts too.
* Bugfix: The application crashed when the top cell was deleted.

0.23.9          (2014-12-28):
* Bugfix: DEF reader: E and W pin orientation was swapped.
* Bugfix: DEF reader: PIN definitions are read correctly even if
       the PLACED statement comes before the LAYER statement.
* Enhancement: LEF reader: deprecated keyword TOPOPSTACKONLY is 
       ignored for VIA statements now instead of giving an error.
* Enhancement: DEF reader: the reader now is able to read BLOCKAGE
       definitions. Currently, routing and placement blockages are
       supported. The layers they appear on can be configured the 
       in the same fashion than for the other elements.
* Bugfix: Typing in the Macro Editor was slow if many macros were
       bound to menus.
* Enhancement: GDS AREF's with pitches not a multiple of the database
       unit are split into individual arrays rather than simply 
       rounding the pitch. The disadvantage of the rounding solution
       was an accumulation of rounding errors over the array instances
       leading to a substantial deviation from the target location.
* Bugfix: Paths have sometimes not been displayed properly, 
       specifically paths with a small segment length and sharp bends.
* Bugfix: DXF reader: bulges have not been ignored on the last vertex
       of a non-closed POLYLINE as they should.

0.23.8          (2014-11-15):
* Bugfix: DRC: "inside", "not_inside", "outside" and "not_outside" were
       broken
* Bugfix: LEF/DEF reader: VIA PATTERN support was broken
* Enhancement: LEF/DEF reader: Support for LEF/DEF Version 5.8 syntax
* Bugfix: The Tab order of certain dialogs was weired
* Bugfix: Multi-layout layer properties files in technology setups behaved
       strangely. Now, the behavior of layout properties files (.lyp) is
       the same in the technology context and the usual application context.

0.23.7          (2014-10-11):
* Bugfix: DRC was crashing on second run if it was overwriting an input file.
* Bugfix: RBA::InputDialog::ask_double was not accepting negative numbers.
* Bugfix: With a net highlighted in the net tracer, so view zoomed to show
       the whole net if a layer was shown or hidden.
* Bugfix: Ruler snapping was disabled for moderately complex hierarchies.
       The threshold has been increased. Now snapping of the ruler to objects
       also works for denser and more complex layouts.
* Bugfix: Some signals were not available to Ruby (i.e. QIODevice signals).
* Enhancement: When using "Hide empty layers", the layer list will scroll to 
       keep the selected layer visible (unless it is empty and hidden therefore).
* Enhancement: A "split view" for the cell trees. When multiple layouts are 
       loaded in a panel, you can choose split view (right mouse in cell list,
       check "Split View"). In split view, up to 5 cell trees are shown at the
       same time.

0.23.6          (2014-08-20):
* Bugfix: A DRC issue was fixed. Sometimes errors were reported too many times.
       This happened for big polygons wrapping smaller ones.
* Enhancement: Now, macro key bindings can be edited on the key binding page 
       of the setup dialog too if the macros are shown in the menu.
       Before, those changes were reset when the program was closed.
* Enhancement: The DXF reader now also considers thin (width = 0) POLYLINES 
       as mergable edge contributions in the "merge edge" modes if the 
       POLYLINES are closed ones too.
* Bugfix: The float function in the OASIS writer was fixed.
       This is a code cleanup, and did not have effect on functionality (yet).

0.23.5          (2014-07-04):
     * Bugfix: DXF polyline mode could not be set in reader options in Ruby. 
               A value of 3 and 4 was not allowed.
     * Enhancement: CIRCLE AND ELLIPSE objects are treated as thin lines in DXF reader's
               "merge edges" mode. Hence they participate in region formation.
     * Enhancement: A warning is displayed when an ambiguous keyboard shortcut is triggered
     * Bugfix: An assertion in the boolean processor was fixed.
     * Bugfix: The following command caused the program to crash on the Ruby console:
               "require 'net/http'; uri = URI('xyz')".
     * Bugfix: The "cell" function in DRC scripts was creating a new cell if is was not existing
               yet. In general, the DRC function is not supposed to change the layout's hierarchy.
     * Bugfix: The macro editor now can distinguish between the same file with different suffixes.
               Before, "test.rb" and "test.lym" were not presented as different files.
     * Enhancement: The marker browser now indicates if the number of markers exceeds the
               specified maximum and the list is shortened.
     * Bugfix: The "browser.rb" sample was not working any longer because of a backward
               compatibility issue.

0.23.4          (2014-03-15):
     * Bugfix: UTF8 encoding in XML was ignored - special characters have not been
               read properly. This in particular caused issues in the .lym macro files
               when UTF8 characters are employed.
     * Bugfix: Backward compatiblity issue: layout files with PCells written with 0.23
               could not be read with 0.22 and vice versa.
     * Bugfix: Label text centering and right-alignment was not working propertly
               with the default font.
     * Bugfix: A segmentation fault occuring when rerunning a PCell macro has been 
               fixed.
     * Bugfix: PCell layer parameters can be set to "no layer" now. This was possible
               before, but caused some issues - i.e. creation of dead layers.

0.23.3          (2014-02-23):
     * Bugfix: DRC bug fixed: "@x" notation was not working for layout, source and 
               target.
     * Bugfix: A boolean processor bug was fixed that cause an internal error in 
               some rare cases with certain edge configurations.
     * Bugfix: Image documentation was wrong about the offset meaning: it's the center,
               not the lower left corner.
     * Bugfix: Layer table tab names were lost when sorting or regrouping a layer 
               list.
     * Enhancement: The net tracer now can be configured to auto-color the nets with
               a set of predefined colors. 8 colors can be configured in the 
               configuration dialog or the net tracer setup page in the setup dialog.
     * Enhancement: The net tracer now has a "Redo" button which will trace all 
               nets in the list again using the original start and stop (for path
               tracing) locations.

0.23.2          (2014-01-26):
     * Bugfix: Build issues fixed for MacOS and some Qt versions.
     * Bugfix: DRC log to file was not working.
     * Bugfix: Ruby script was crashing when using ruby-implemented tiling
               processor receiver and multi-threaded tiling.
     * Bugfix: Layout move function was using database units instead of micron.
     * Bugfix: Search & replace markes where not shown in a reasonable context
               for search in "All cells", instance markers are not shown
               correctly.
     * Bugfix: DRC now also handles the case of different database units for
               multiple inputs. The database unit of output files is now taken
               from the input.
     * Enhancement: Search & replace layer selection combo boxes now show display
               string
     * Enhancement: Unexpected elements are ignored in XML files.
     * Enhancement: Options are provided for making boolean operations not
               optimize the "single empty input" case for XOR tool 
               and DRC (strict handling mode).

0.23.1          (2013-12-07):
     * Bugfix: RBA SimplePolygon#inside? and Polygon#inside? now work as expected
     * Bugfix: DRC output to marker browser now works as expected
     * Bugfix: HTTP URL's now are written as such into the MRU list
     * Bugfix: A net tracer crash was fixed
     * Bugfix: Net tracer connectivity setup: the move buttons now work as expected
     * Bugfix: a DRC issue was fixed when assigning the output of modifying operations (i.e. 
        "layer=layer.move(...)".
     * Enhancement: compatibility with clang 3.3 was established as well as compatibility
        with Ruby 2.0.
     * Bugfix: some memory and static code analysis issues have been fixed after
        analysis with valgrind, clang and Coverity.

0.23            (2013-11-24):
     * Enhancement: Net tracer: Nets can now be colored individually.
     * Enhancement: The OASIS writer now uses CBLOCK compression also for tables.
     * Enhancement: Transparency is now supported for images (as a mask only - not a real  
        alpha channel, but close to).
     * Enhancement: The layer/datatype assignment for purely named layers originating from 
        DXF or CIF has changed. It's now no longer done when reading DXF or CIF but when 
        writing the file. This solution is more general and allows some level of control, 
        i.e. by scripts.
     * Enhancement: "http:..." URLs are now allowed as file names - such files are loaded 
        from the URL instead. Such URL's can be used from the command line or within scripts 
        for example. Drag and drop of HTTP URLs is also support. This allows dropping of 
        URLs from the browser into KLayout.
     * Enhancement: Menus have been rearranged: 
        The "Tools" menu was split into "Tools" and "Macros", "Verification" menu has been 
        resolved into the "Tools" menu.
     * Enhancement: New command line options are available:
        "-nn" to load .lyt (technology file) on command line. "-b" for batch mode (implies some
        batch-mode specific options), "-zz" for display-less applications.
     * Enhancement: "Adjust cell origin" now adjusts the cell in their parents as well (optional).
     * Enhancement: Cells can have properties now: Cells can now have user properties as well. 
        However, writing these properties to files is subject to some constraints. Cell
        properties are fully supported on OASIS and optionally supported on GDS using
        an extension feature.
     * Enhancement: Transformations are now available for whole layout (applied to all cells).
        This is specifically useful for scaling layouts.
     * Enhancement: A function now is available to convert PCell's to normal (static) cells.
     * Enhancement: The printout now has a header and footer.
     * Enhancement: The XOR can now be confined to a region.
     * Enhancement: There is an option now to hide guiding shapes for PCell instances.
     * Enhancement: New option to pan/zoom or do nothing on paste - Option is in "Navigation/Zoom 
        and Pan" in setup dialog.
     * Enhancement: Cells can now be copied in "shallow copy" mode without creating copies of the 
        child cells.
     * Enhancement: A "Tap" function is provided now. The tap function selectes and changes to the 
        layer of the currently selected shape. New shapes will be put on that layer.
     * Enhancement: There now is a function to convert instance arrays to single instances.
     * Enhancement: The instantiation path of an object is now shown in the status bar.
     * Enhancement: An option is now provided for configuring the replacement character for 
        OASIS and GDS. The replacement character is used instead of illegal characters.
     * Enhancement: Some unicode support for texts in default font ("µ" now is available).
     * Enhancement: There is a GDS2 writer option now to eliminate zero-length paths.
     * Enhancement: There are new save options: disable or enable writing of PCell and library cell 
        contexts, drop hidden cells, keep instances even if cells are dropped.
     * Enhancement: Layers can now be made invalid. Invalid layers don't participate in selection or 
        snapping.
     * Enhancement: Multi-selection on 'open layout' allows to open many files at once.
     * Enhancement: DRC functionality: a rich DRC engine was integrated in the tool. The 
        implementation is flat, so performance is limited compared to hierarchical tools. A tiling 
        approach is available to distribute tasks on multiple CPU's to somewhat mitigate that issue.
     * Enhancement: Search and replace feature plus custom queries: the search & replace functionality 
        is just the tip of the iceberg. "custom queries" are a powerful feature to perform 
        queries and modifications using a SQL-like language.
     * Enhancement: Some enhancements on LEF/DEF import: i.e. proper default routing rule with octagon 
        ends implementedin DEF, NONDEFAULTRULES for LEF reader
     * Enhancement: Auto-import feature for technologies: technologies can now be imported from 
        the installation folder automatically.
     * Enhancement: RBA enhancements: Tiling processor, fill tool bindings, regions, edge collections, 
        edge pairs and edge pair collections, numerous new methods and classes.
     * Enhancement: More configuration options for macro IDE: stop on exception will ask whether to stop 
        in the debugger when an exception is thrown. The editor font can now be configured.
     * Enhancement: The diff tool now has an option to disable smart cell matching and enable
        name-only cell matching.
     * Enhancement: cells can now be dragged and dropped from the cell list to the canvas.
     * Bugfix: Layout diff reported texts as different which are not.
     * Bugfix: Instance editor options problem fixed: magnification could not be edited in some cases.
     * Bugfix: DXF reader: anisotropic scaling of block deletes subcells of that block, error messages 
        on coordinate overflow.
     * Bugfix: OASIS output files were corrupt when edge objects were written.
     * Bugfix: Problems with boxes having odd width are solved now.
     * Bugfix: Close function - "Cancel" now works properly on the "which view to close" dialog.
     * Bugfix: Closing the main window while layouts are loaded crashed the application.
     * Bugfix: Net tracer did not work properly with OASIS in viewer mode.
     * Bugfix: Diff tool was not matching cells propertly in some cases

0.22.9          (2013-09-19):
      * Bugfixes: LEF/DEF reader: NONDEFAULTRULES, TAPERRULE implemented now, 
        correct octagon style for default rules for non-rectangular routing, 
        POLYGON and RECT implemented for routing. 
      * Bugfix: DXF reader crash fixed for ARC objects with identical start and end angle,
                polygons have not been read in some cases.
      * Bugfix: It is possible again to use "Show as new top" after "Descend/Ascend hierarchy"
                without clicking at the cell list.

0.22.8          (2013-06-21):
      * Enhancement: "gds2" now is recognized as extension of GDS files.
      * Bugfix: CIF reader was broken in some cases. Layers have not been assigned properly
        and sometimes, identical or no GDS layers were assigned. 
      * Bugfix: RecursiveShapeIterator (RBA) had an issue when iterating shape arrays.
        This was the case when working on OASIS files in viewer mode for example.
      * Bugfix: DEF reader had some issues (TAPER and RESISTANCE keywords have not been 
        supported properly).

0.22.7          (2013-03-22):
      * Bugfix: The output mode in the XOR tool dialog was not shown properly. Instead of
        "Report database", "Other layout" was shown etc.
      * Bugfix: When creating a third layout for output of the XOR tool, the database unit
        was not set to the input layout's database unit.
      * Bugfix: Layout numbering was not done correctly when multiple layouts were loaded
        with the same file name.
      * Bugfix: In viewer mode sometimes it was not possible to move to the next selected
        item in the shape properties dialog. A message appeared saying "Shape array members
        cannot be modified."
      * Enhancement: OASIS writer performance is significantly better now in cases where
        shape compression is relevant. Also, shape arrays are maintained as such which 
        avoids repeated compression.
      * Bugfix: A drawing bug was fixed which caused shape arrays to disappear on certain 
        zoom levels.
      * Bugfix: "Add missing layers" now adds all existing layers, not just the ones 
        present in the currently selected cell also in viewer mode.

0.22.6          (2013-03-03):
      * Bugfix: It was possible for example to add shapes to a PCell. This feature does
        not make sense since PCell's are updated when required. In that case, changes
        are lost. This feature has been disabled for PCell's.
      * Bugfix: RBA::Application#get_config was crashing in some cases (i.e. in -zz mode)
      * Bugfix: The "create cell variants" function was not working properly if a single
        instance array was present for a cell.
      * Bugfix: The radius was limited too strictly for end segments for the ROUND_PATH
        PCell of the Basic library.
      * Enhancement: Some additional RBA methods have been enabled which disambiguate
        various constructors for Qt objects (i.e RBA::QVariant#new_i allows to create
        a variant with "int" type)
      * Bugfix: the Ruby-less build was broken.
      * Bugfix: Copy & paste was not working for the layer list. This is an effect of the
        modified key handling in KLayout 0.22. New menu functions are provided in the layer
        list's context menu to resolve the ambiguities involved in that feature.
        These menu functions allow to copy, cut and paste parts of the layer list to other
        windows or tabs.
      * Bugfix: PCell's are now cleared before the production method is called. 
      * Enhancement: OASIS layer names are also recognized if the LAYERNAME record
        appears after the layout's body.
      * Bugfix: in previous versions it could happen that the layout panels got 
        locked and it was no longer possible to switch between different tabs.
      * Bugfix: a potential crash in the drawing engine was fixed.

0.22.5          (2013-02-02):
      * Bugfix: Layer properties file in technology definitions can be given as relative path 
        in which case KLayout uses the base path
      * Enhancement: Windows installer now provides a useful default installation path when 
        started as non-administrator.
      * Bugfix: GDS reader: a false warning was issued sometimes indicating that an 
        AREF might be off-grid.
      * Bugfix: Fixed build for MacOS and some Linux distributions.
      * Bugfix: Fixed a crash that happened when KLayout was closed while a instance 
        property form was still open.
      * Enhancement: PCell names are now shown in the status bar
      * Bugfix: Fixed a crash that happened when a macro was run that was already closed.
      * Bugfix: MRU list for macro editor's console was getting huge when the macro editor
        was closed and opened again in the same session.
      * RBA bugfixes: "destroyed?" was not working properly in some cases. Infinite 
        recursion happened for for PCell implementation without "get_layers".
      * Enhancement: Better error messages for RBA including class and method names.
      * Bugfix: PCell implementation issue. Some methods were passed a deep copy 
        of the layout object which first created a potential performance issue and 
        second made it impossible to modify the layout.
      * Enhancement: DXF writer now provides a header which enables some tools to 
        read the generated DXF files.
      * Bugfix: DXF reader: degenerated polygons for HATCH objects don't cause an 
        assertion now.

0.22.4          (2012-12-30):
     * Bugfix: a drawing problem was fixed which created invalid images in certain 
       cases.
     * Bugfix: multi-tab .lyp files could not be used correctly as default layer
       properties files.
     * Bugfix: the macro IDE crashed sometimes when adding a new location.
     * Bugfix: the application crashed when the net tracer window was open and a new
       layout was loaded into the same panel.
     * Bugfix: a memory leak was happening when a boolean operation (in particular
       inside the XOR tool) was cancelled.
     * Bugfix: when inserting an instance using the lower left corner of the bounding
       box as the reference point, rotations have not been handled correctly.
     * Enhancement: the "detailed" view of a net's properties in the net tracer now
       reports area and perimeter of the net's shapes (only available for nets up to 
       ~2000 shapes to avoid timeouts on computation). Thanks to Peter for providing 
       the raw version of that code.
     * DXF reader enhancements: 
       Support for "999" comment records. DIMENSION and SPLINE entities are supported
       now to some extent. "fit" formatting of TEXT objects supported now. 
       Holes are correctly formed now from multiple POLYLINE/LINE items when combining
       them into polygons.
     * DXF writer: HATCH entries are written in a compatible way now. Text formatting
       flags are fixed (top and bottom formatting was swapped).

0.22.3          (2012-11-25):
     * Bugfix: a segmentation fault sometimes happened in the drawing engine
     * DXF reader enhancements: 
       Anisotropic scaling of instances is supported. LWPOLYLINES with both common and 
       variable width are handled more gracefully. Closed polylines produce closed shapes
       now, not closed paths.
     * Selecting of instances with non-orthogonal transformations is easier now
     * The local config files now override the global one again like this was in 0.21.x.
     * A compile problem with older gcc's (namely gcc 4.4) was fixed.
     * Selection of cells in the cell tree now has been fixed (before that sometimes 
       cells were selected in addition to current ones instead of being the only
       one selected).
     * The RVE DB reader was enhanced to read error waivers and certain new forms of the
       RVE file.
     * The align operation now works also if there is not a primary and secondary
       selection (i.e. selection by box)
     * "Layer pollution" does not happen when instantiating a PCell or library cell 
       which is instantiated in another panel
     * PCell layer parameters now can be set to any layer which is present in the 
       layer list, not just the ones which are created already in the database
     * The round corners function has been fixed for certain cases. In particular 
       the limitations are less strict (for example it is possible now to create 
       a donut from a square with a hole). Changing of the radius later now works
       more reliably.
     * "Shallow copy mode" now works again for copy & paste of instances. Previously
       instances were always copies in deep copy mode which creates new cells.
     * Move of partial selection now works like the move function for other objects: 
       select a subset of edges, click on them to start dragging and click again to
       drop them.
     * Arrow keys don't interfere with move by mouse mode any longer. Previously using
       the arrow keys while moving objects with the mouse had strange effects.

0.22.2          (2012-11-01):
     * Copy & and paste of PCell or library instances across layouts did not work
       Instead, the cell was duplicated, but it's no longer a PCell or library cell.
     * "klayout -v" was segmentation faults
       The -v option is supposed to print the version number. After printing it, 
       the executable terminates with a segmentation fault.
     * 'Real' unicode file names could not be used
       Using Unicode filenames (i.e. Chinese) file names did not work properly. 
       In particular these files were not opened on Windows. Unicode file names were 
       not recorded properly in the "recently used" list.
       In version 0.22.2, unicode files names can be used in all places on Windows
       and Linux.
     * Some LEF import issues solved
       The outline layer was not always generated correctly. Pin labels were not generated 
       on pin shapes for LEF import.
     * KLayout was crashing on exit when the clipboard contained something
       The application issued a segmentation fault on exit (or "is not working" on Windows) 
       when the clipboard contained data.
     * Ruby debugger crashed in some cases
       In some cases (i.e. breakpoint in a widget callback) the debugger crashed with a 
       "Stack level too deep" message.
     * Instances of leaf cells were always copied "flat" to another layout
       There was no way to copy the instance plus cells before this was fixed.
     * Sometimes PCell variants remain as top level cells
       If the Instance function was cancelled and a PCell was active, a new top cell remained
       which held the PCell that was about to be placed. These cells could be deleted manually, 
       but that may be annoying.
     * Help index cache was growing large in some cases
       When switching between versions, the help index that KLayout creates once grew larger 
       every time a new program version was used. This increased startup times of the program.
     * An "abs" function was missing expressions
     * Experimental support for 64bit coordinates is provided.
       To enable 64bit coordinates, use "-with-64bit-coord" on the build script. This feature
       requires gcc >= 4.4 and a 64bit platform. 64bit coordinate support is "experimental" 
       because of some known issues (i.e. it is possible to write corrupt GDS files with such large
       coordinates). OASIS on the other hand supports 64bit coordinates.

0.22.1          (2012-10-09):
     * Edit/Select/Disable All was not working
       This function was supposed to disable all selectable items. Instead, an internal 
       error message was issued.
     * Build problems with gcc 4.0 were solved
     * GDS text size as based on micron instead of user units
       Because of this the text object size were not be correct if the user unit was not micron.
     * Arrow keys behaved differently
       This had annoying effects if one was used to a particular behavior. The operation of the 
       arrow keys was restored in some places but still moving with the keys in move mode is
       possible.
     * -z option worked differently
       "-z" is not a true "non-GUI" mode, in which no XServer connection is made on 
       Linux. The advantage of this is that KLayout can be used as a engine on display-less 
       servers. In 0.22, some user-interface related objects were not available in Ruby code.
       Some scripts depending on MainWindow or LayoutView objects were not working
       because these objects are no longer available. In 0.22.1 the original behavior of "-z" 
       was restored and instead, "-zz" was implemented as a different, true display-less mode 
     * KLayout was crashing when using custom key bindings on some platforms
       On some platforms, apparently Linux and recent Qt versions, KLayout crashed when 
       custom key bindings are defined and the respective key is pressed.
     * Some issues with the macro tree solved
       Drag & drop was not working correctly within the macro tree on Windows. KLayout 
       crashed when trying to open a macro file that is not writable.

0.22            (2012-09-19):
     New available features:
     * A script (macro) development environment is now integrated into KLayout.
       It features a simple debugger, a syntax highlighting editor. For details
       see About Macro Development at http://www.klayout.de/doc/about/macro_editor.html.
     * KLayout now features an integrated help system (available through the "Help/Assistant" menu entry).
     * Support for libraries. See About Libraries for details.
       http://www.klayout.de/doc/about/about_libraries.html
     * KLayout now supports parametrized cells (PCells).
       There is a cool feature called "guiding shapes". Learn more about that here:
       About PCell's (http://www.klayout.de/doc/about/about_pcells.html).
     * A basic library is provided adding text generation for example to KLayout.
       See About The Basic Library for details.
     * The net tracer now allows to use layer combinations (derived by boolean operations)
       for the conductive and via layers. See The Net Tracing Feature for details.
     * A technology management is integrated into Klayout.
       That allows to switch various settings depending on the choosen technology.
       See About Technology Management for details about this feature.
     * The drawing can now be rotated or flipped without having to modify the layout.
       This function can be found in the "Display" menu under "Global Transformation".
     * The "background" combination mode allows to erase parts of existing shapes or
       add new parts to existing shapes. The background combination mode is available
       as a new drop-down button in the toolbar.
     * A "cell variant" generation function simplifies hiearchical editing.
       See Create Cell Variants for details about this feature. 
     * General performance improvement of the render.
       This has been achieved by bitmap caching of cells and various optimisation measures.
     * Images now can be aligned with a layout using landmark points.
       The possible image transformations now include shear and perspective distortions.
       See Using Landmarks To Align Images
     * Images can now be stacked and moved to the bottom and to the top.
       The configuration now is stored along with additional configuration data
       (i.e. libraries) in a per-user directory in "~/.klayout" on Linux and in the application
       data path on Windows. The configuration file now is found there and is called "klayoutrc".
       New locations can be added using $KLAYOUT_PATH.
     * The database unit of the layout can be changed now in the layout properties page
       (menu: "File/Layout Properties"). 
     * Most numeric input boxes now accept formulas,
       i.e. "1254+3221" instead of a single value.
     * By clicking a on single point multiple times you can now cycle the selection through all objects below the point.
     * Layers can be copied (menu: "Edit/Layer/Copy Layer").
     * The selection can be duplicated (menu: "Edit/Duplicate" or Ctrl+B).
     * The size of the default font can now be adjusted (choose between small (current),
       medium and large on the Display/General page of the setup dialog).
     * The number of points used for circle interpolation can now be adjusted
       on the Application/Circles page of the setup dialog.
     * Some changes to make the user interface more consistent, i.e. "Synchonized views"
       has been moved to "Display" where most users where expecting it to be.
     * The selection now can be moved with the cursor keys in move mode.
     * The cell selection dialog allows to specify glob pattern wildcards in the filter box now.
     * OASIS CBLOCK compression and strict mode writing is supported now.
     * Multiple cells now can be selected in the cell tree. Some functions operate on that set (i.e. delete, copy, hide).
     * KLayout now has a LEF/Def import feature. See About LEF/DEF Import for details.
     * This feature is somewhat experimental. Feedback is welcome about that feature.

    Solved bugs:
     * Edit/Select/Disable All not working
       This function is supposed to disable all selectable items. Instead, an internal error message is issued.
     * Build problems with gcc 4.0
     * GDS text size is based on micron instead of user units
       Because of this the text object size may not be correct if the user unit is not micron.
     * Arrow keys may behave differently
       This can be annoying effects if you are used to a particular behavior. On the other hand, moving with
       the arrow keys now is possible in move mode.
     * -z option works differently
       "-z" not is a true "non-GUI" mode, in which no XServer connection is made on Linux. The advantage of this
       is that KLayout can be used as a engine on display-less servers. But some scripts depending on MainWindow or
       LayoutView objects will not work because these objects are no longer available. The solution will be to
       restore the original behavior of "-z" and implement a different, true display-less mode (i.e. "-zz").
     * Crash when using custom key bindings on some platforms
       On some platforms, apparently Linux and recent Qt versions, KLayout crashes when custom key bindings
       are defined and the respective key is pressed.
     * Issues with the macro tree
       Drag & drop does not work correctly within the macro tree on Windows. KLayout crashes when trying to
       open a macro file that is not writable.

0.21.19         (2012-06-19):
     * Gerber file reader enhancements: Negative contrast layers supported now
       with an option to provide a background and 'real' inversion.
     * Gerber reader bugfix: SR command implemented correctly now also for
       negative contrast.
     * Enhancement: transient selection markers are drawn over other markers
       for better visibility.
     * Bugfix: XOR tool can be canceled without crash.
     * Fixed build problems with gcc 4.7.0.
     * Fixed a layout import bug (cells have been deleted which should have been kept).
     * OASIS writer bugfixes: don't accumulate rounding errors when writing type 0
       or type 1 pointlists. Avoid writing invalid type 0 and 1 pointlists in certain
       cases.

0.21.18         (2012-05-14):
     * Gerber file reader enhancements: SR (step-and-repeat) is supported now.
     * Gerber reader bugfix: AM macro expansion was not done correctly sometimes.
     * Gerber reader enhancements: removed some superfluous warnings.
     * CIF writer: convert OASIS circles correctly to "R" round flash primitives.
     * Bugfix: copy & paste of layers in the layers tree now works and the copied
       layers are pasted to the current position.

0.21.17         (2012-04-12):
     * The memory footprint of 8-bit images has been reduced significantly.
     * The "Save current cell as" bug (see here) has been fixed: this function now works as expected.

0.21.16         (2012-03-05):
     * GDS format readers and writers now support time stamps: by default, the
       current time is written to the files. This option can be turned off in the
       "Save Layout Options" to simplify comparison of binary files for example.
       In addition, the timestamp of the BGNLIB record is read and displayed in the
       "Layout Properties" page.
     * The GDS reader now is somewhat less strict and also accepts certain broken versions
       (i.e. missing ENDEL records).
     * Several bug fixes related to scripting applications: Proc objects are held by the
       application now, Application does not abort in non-GUI mode in operations that take
       some time and try to display a progress bar.
     * DXF bugfix: layer names now do no longer contain blanks which made files unreadable
       by other tools like AutoCad.
     * Bugfix: foreground objects (i.e. rulers) are now correctly rendered in printout.

0.21.15         (2012-01-22):
     * Bugfix: the correct initial cell now is selected. Formerly, the largest
       cell was selected even it is was not a top cell.
     * "Show only selected" in the layer panel does not clear the selection any longer.
     * GDS reader now is less strict with respect to record order of STRANS, MAG and ANGLE.
     * Excellon drill file reader is now conforming to the specification in many respects.
     * Instances are not selected if the cell does not contain shapes in visible layers.
     * Marker browser does now work correctly when layer view transformations are present.
     * DXF reader enhancements: read LAYER table and assign GDS layers in that order,
       except for layer which got a layer name through their name (i.e. L1D100).
       Bugfix: don't suppress INSERT's if the layer is not mapped. Write TEXT and
       MTEXT correctly (multi-line support, small chunks for MTEXT, character alignment).
       New option: keep all cells for DXF reader. Added elliptic interpolation edge type
       (not really tested yet). HATCH objects with bulges and various edge types are
       implemented now. MTEXT supported now. New option: convert text to polygon for
       unicode support.
     * Changed default sorting of layers: always sort by layer number first, even if there
       is a name. If there is no layer number, sort by name.

0.21.14         (2011-11-28):
     * "Synchonized views" and "Select top level only" configuration shortcuts
       added to the "Views" menu.
     * Gerber reader bugfixes and enhancements: less strict parsing of aperture
       definitions, rotation of aperture macro elements is not considered
       correctly. Enhanced drill file reader.
     * Disabled cell copy & paste in viewer mode (was not working correctly).
     * Bugfix: it was possible to create an invalid configuration when removing
       all default stipples (lead to a crash on the next KLayout start).
     * Bugfix: an error appeared when switching the tabs in the layer panel in
       certain configuration involving groups.
     * Correct initialization of ruby interpreter to support Ruby 1.9.2 and
       later.
     * Bugfix: marker browser was only partially reporting collected markers
       for certain categories.
     * XOR now has an option to make use of multiple cores using a configurable
       number of threads.
     * Bugfix: reset of configuration required a restart.
     * Bugfix: OASIS reader now is more robust against overflow for g-deltas.
     * GDS reader enhancement: An invalid angle (outside the range of -360 to
       360 degree) now is no longer an error and the angle is automatically
       restricted to the valid range.

0.21.13 	(2011-09-19):
     * A bug in the clip function was fixed which was related to empty cells
       (reported in the forum)
     * By default, the first level of hierarchy is shown now if a new layout
       is opened. That feature can be adjusted using the "Default levels of
       hierarchy" setting on the "General" page in the setup dialog.
     * For multiple top cells, the cell with the larges footprint is selected
       initially.
     * A simple print function (available in the "File" menu)
     * Support for command 93 in CIF (AREF)
     * Improved handling of single point paths. In particular with round ends.
       They now render a circle in OASIS. In reverse, OASIS circles now render
       single-point paths with round ends in GDS.
     * Ruby scripts now work more reliably under ruby 1.9 (i.e. Windows binary).
       Formerly, some operations failed due to improper initialization of the
       encoding system (i.e. Dir.glob).
     * Clean uninstaller under Windows (removes all registry entries).

0.21.12         (2011-07-29):
     * Bugfix: GDS2Text format was not recognized correctly in some cases.
     * Texts: strings with line breaks can be edited now (line breaks are shown
       as \n). Text size is shown more realistic now. Alignment flags are
       supported in GDS2 and can be edited now.
     * Layer and datatype is shown in addition to OASIS layer names in the layer
       list. The old behaviour can be configured by unchecking the "Always show
       layer and datatype" checkbox on the "Layers" page in the setup dialog.
     * For most file dialogs, the specific filter is the default now (i.e. 
       "*.lyp" is default instead of "All files" for the layer properties file
       dialogs.)
     * There is a "all layout files" filter for the layout file selection dialogs.

0.21.11 	(2011-06-26):
     * Bugfix: command line option -p was not working correctly.
     * Bugfix: writing layouts with large coordinates was producing invalid OASIS
       files in some cases.
     * The tarkit now contains the files necessary for a build with Visual Studio
       on Windows.

0.21.10 	(2011-05-07):
     * Bugfix: content of cell was not shown correctly when the cell was moved.
     * Bugfix: PCB import was not working properly (Bottom mounting mode was
       broken, top cell and dbu were not set correctly when a PCB project file
       was imported directly).
     * Bugfix: RVE reader was not correctly handling check names with a dot.

0.21.9		(2011-04-20):
     * Bugfix: Loading of layer files with tabs was not working properly: the
       first tab's name was discarded.

0.21.8 		(2011-04-06):
     * Bugfix: navigator was broken. It was not functional if KLayout was closed
       with the navigator open.

0.21.7 		(2011-03-24):
     * DXF bugfixes (arc interpolation of polylines).
     * Performance enhancement of "test for shapes in view" feature of layer list.

0.21.6 		(2011-02-20):
     * DXF enhancements (support for bulges for polylines).
     * Bugfix: RBA::Edge.intersect? reports intersections correctly also if edges
       are collinear.
     * Performance bugfix: selection was slow for certain cases of hierarchy.

0.21.5 		(2011-02-03):
     * DXF enhancements (some polylines now have the correct width).
     * An option to select how instances are placed (at origin or lower left
       corner of bounding box).
     * Bugfix: when placing an instance at the lower left bounding box corner,
       it is guaranteed that the origin is on grid.
     * Stable operation on UTF-8 filesystems and with non-english locales on
       Linux (i.e. consistent use of dot as decimal point). However, UTF-8 file
       names are not correctly displayed although the file is opened correctly.
       This will be fixed in the next major release.

0.21.4 		(2011-01-19):
     * Correct installation of the image reader plugins for the Windows packages.
     * Bugfix: rotate counterclockwise was clockwise and vice versa.
     * Bugfix: "draw border instances of arrays" feature was broken.
     * Fixed a ruby crash on some systems (related to an initial 'require' on a
       ruby module loaded with -rm).
     * CIF reader enhancement: "DS" statements are now accepted with a single
       value also.
     * The Windows installation now also includes the standard Ruby modules.

0.21.3 		(2010-12-27):
     * DXF reader and writer enhancements. The reader now allows to specify how
       POLYLINE entities are read. In most cases, the "Automatic" mode will be
       appropriate. The writer was enhanced by providing an option which
       determines how to write polygons. The default method is POLYLINE. A
       comprehensive description of the DXF format, as KLayout understands it,
       together with a description of the modes, is given here.

0.21.2 		(2010-12-19):
     * RBA bugfix: RdbItem.each_value was not working on const references.
     * DXF reader and writer enhancements for improved interoperability with
       other tools.
     * Unit option for DXF input (to specify the units of the drawing).
     * Bugfix: layer mapping was not working correctly for DXF and CIF output.

0.21.1 		(2010-12-06):
     * Added cell margins for fill utility.
     * A couple of bugs fixed (related to Diff tool, marker database reader,
       Ruby scripting).
     * Source is compatible with earlier versions of Qt now (down to 4.2.3).
     * Bugfix: persistency of reader options was broken.
     * Enhanced DXF and CIF reader and writer functionality with improved
       compatibility with other systems.

0.21 		(2010-11-28):
     * Support for DXF format (reading and writing).
       ASCII and binary format are supported. There is an open issue how to
       represent layouts with multiple top cells. Currently, the ENTITY section
       is always empty and all cells are put into BLOCKS sections. DXF units
       will be micron and the database unit must be selected manually when
       layouts are read.
     * Support for CIF format (reading and writing).
       There is an open issue how to deal with paths. By default, CIF states
       that paths are supposed to have round ends. Obviously that interpretation
       is not commonly used. Options are provided which control how path objects
       are read and written.
     * Tabs for the layer panel. This feature is explained here.
     * Flat cell list and cell list sorting modes. The feature is explained here.
     * Dockable tool boxes.
       Layer list, cell list, layer toolbox and navigator are now dockable and
       can be dragged to another location, torn off the main window or closed
       with Qt's standard dockable window controls. The position and the state
       of the dockable windows is saved in the settings and session files.
     * A ruler embedded in the background image.
       Now, a small ruler is embedded into the background which shows the
       dimension scale similar to a map. It can be disabled in the setup dialog
       on the "Display/Background" page.
     * Image quality enhancement by oversampling. The feature is explained here.
     * The "Diff" tool. The Diff tool produces a marker database containing a
       description of the differences. A detailed description can be found here.
     * Snapping to objects is provided as an option for edit mode. In this mode,
       the mouse snaps to vertices and edges of visible objects. This mode can
       be enabled with the "Objects" checkbox on the "Editor Options" page (F3
       key or "Edit/Editor Options" menu).
     * The reference point for the placement of instances now is the lower left
       point of the placed cell's bounding box, not the origin.
     * Dialog geometry persistent now.
       Marker, shape and instance browsers now save their geometries and
       splitter pane configurations when the application exits.
     * Instance placement now uses bbox origin, not cell origin.
       This simplifies placement of cells with their origin not aligned with
       the content.
     * Fill (tiling) tool. The tool is found in "Edit/Utilities/Fill Tool". A 
       detailed description can be found here.
     * In some places, particular in the ruler display string, expressions can
       be used. For rulers, the previous display string placeholder scheme is
       replaced by the more powerful expression expansion scheme (see Ruler
       properties for details).
     * Build support for VC++ and Visual Studio 2010. The Windows 64bit build
       now is based on that environment. Note: Visual Studio 2010 no longer
       supports Windows 2000. To use KLayout on Windows 2000, a legacy build
       based on MinGW is provided.

0.20.2 		(2010-05-25):
     * Bugfix: marker browser crashed when opened from menu and the maximum
       number of markers was set differently from default.

0.20.1 		(2010-05-23):
     * Navigator now allows to drag a zoom box in the usual way.
     * Paths with odd width (in database units) are shown correctly.
     * Some bugfixes (for a list of fixed bugs see Known bugs in version 0.20)
       concerning the net tracer and the Gerber import feature.
     * Support for Ruby 1.9 (experimental).
     * Support for 64 bit Windows (experimental).

0.20 		(2010-05-01):
     * Import option for Gerber PCB data ("File/Import" menu entry). Details
       about this function can be found in the Importing Gerber PCB files
       section in the advanced features manual.
     * A function to import another stream file into the current file.
       This avoids having to use copy & paste and provides a couple of nice
       options. Details about this function can be found in the Importing other
       layout files section in the advanced features manual.
     * A simple XOR tool providing a flat XOR between two layouts. A tolerance
       can be set to suppress small deviations. A tiling option is provided to
       reduce memory requirements for large layouts. The flat approach probably
       limits the application to "almost flat", small to medium sized layouts.
       Details about this function can be found in the The XOR tool section in
       the advanced features manual.
     * A net tracing tool to trace single nets of conductive layers connected
       through via shapes. The function is intended for extracting single small
       nets and it's not performance optimized for the case of huge power nets.
       Details about this function can be found in the The net tracing feature
       section in the advanced features manual.
     * A navigator window that shows current view's rectangle and allows to
       control the rectangle by dragging or resizing it.
     * Multi threading support for drawing increases the drawing performance on
       multi-core CPU's by rendering different layers on different CPU's. The
       number of threads to use can be set in the setup dialog in the "Display"
       group under "Optimizations". By default, a single thread is used.
     * "Make array" method ("Edit/Selection" menu) to multiply the selection
       into an array arrangement.
     * A function to add a layout already loaded to a view ("File/Pull In
       Other Layout").
     * A function to scan a layer's geometry and create a marker database from
       that. The menu function is found in the "Tools/Verification" menu. It
       will scan all selected layers either flat or hierarchical and create a
       marker database containing the shapes as markers.
     * Layer mapping on input: the reader options now allow to specify a
       mapping together with a layer specification. In addition to specifying
       the layers to read, a target can be given which specifies which layer
       the shapes will be stored under (See "Reader Options" dialog found in
       the "File" menu).
     * A couple of new display options:
         o Abstract mode (shows only the outer interfacing shapes of child cells.
         o Child hierarchy level layout can be configured to be shown in different
           brightness, hollow fill or static neutral color to differentiate top
           level from bottom level layout.
         o Enhancements for the hierarchy level specifications in the layer source
           notation.
     * A log viewer is provided to catch warning messages. The menu entry to open
       the log viewer is found in the "File" menu.
     * The setup dialog has been reorganized to make room for more property pages.
     * Instances now show the cell's content when being moved instead just a
       rectangle. This feature can be disabled.
     * Various usability enhancements (i.e. mouse cursor now shows activity,
       status bar shows short shape statistics etc.).
     * An option to not write empty cells.
     * Support for missing cells in the input layout: those cells get marked and
       are not produced in the output unless they have received content. That
       allows to load and save layouts with missing cells without producing empty
       cells for those missing cells.
     * Some new functions in the layer list context menu ("Show All", "Hide All",
       "Show Only Selected").
     * Various bug fixes (i.e. for clip function).
     * A couple of new RBA methods.

0.19.3 		(2009-12-17):
     * Some bugfixes (for a list of fixed bugs see Known bugs in version 0.19.2).
     * To specify the installation path (where the ".rbm" files are looked up),
       a new environment variable "KLAYOUT_PATH" is provided. This variable
       currently supports a single entry only. In that sense it's not a "path"
       right now.

0.19.2	 	(2009-12-05):
     * Some bugfixes (for a list of fixed bugs see Known bugs in version 0.19.1).

0.19.1 		(2009-11-30):
     * Some bugfixes (for a list of fixed bugs see Known bugs in version 0.19).

0.19 		(2009-11-21):
     * Images: it is possible now to load image files (JPG, GIF, TIFF etc.) and
       display them below the drawn layout. The display of the images can be
       adjusted in many ways, i.e. placement, scaling, rotation, mirroring,
       color/contrast/brightness adjustments and false color mapping for gray
       level images. Images are fully supported by RBA. The feature is described
       in detail in Adding images.
     * Marker browser: the marker browser is based on the report database (RDB).
       This is a new concept that has been introduced as a container for report
       items, in particular marker objects but also for a number of additional
       annotations including screenshots for documentation. An import of Calibre
       DRC databases is provided. The RDB is fully supported by RBA.
       The feature is described in detail in The marker browser.
     * Some enhancements for the layer views: invisible layers are now shown
       differently in a "collapsed" way. Thus, the layer's colors and styles are
       still recognizable. The new features are described in detail in Telling
       used from unused layers.
     * In the layer list, unused layers can now be hidden and layers without
       shapes in view can be marked unused or hidden. The normal mode of marking
       layers unused when the cell does not contain any shapes at all is still
       available. Both modes are available as checkable items in the layer list's
       context menu.
     * A "View" menu has been added with fast access to certain display options,
       i.e. turn grid on an off. A number of default grids can be defined for
       quick selection in the "View" menu. On request, the tool bar can now be
       hidden as well as the layer and hierarchy lists.
     * A key binding editor is provided. This way, all menu functions can be
       assigned arbitrary key shortcuts in a more comfortable ways.
     * The mid mouse button can be used to pan (drag) the view window now.
     * Various RBA enhancements, i.e. a method to compute the intersection point
       between edges.

0.18.2 		(2009-11-05):
     * Enhancements for building with gcc 4.4.x and Qt 4.5.x.
     * OASIS reader now also supports text objects with forward references to
       text string definitions.

0.18.1 		(2009-08-02):
    * Some bugfixes (for a list of fixed bugs see Known bugs in version 0.18)
      in particular for MacOS users.

0.18 		(2009-07-07):
     * Some bugfixes (for a list of fixed bugs see Known bugs in version 0.17.2).
     * Added support for the GDS2 text format. This is a contribution by
       Romain Gauci from Oscillated Recall Technology (http://www.or-tech.co.jp).
     * Session persistence: sessions (files, layers, bookmarks, setup) can be
       saved and restored. Details for this feature can be found here.
     * Reader options can be specified in a dialog now (File menu). Some GDS2
       specific reader options are available: allow multi XY, allow big records
       and several box record handling modes. Details for this feature can be
       found here.
     * GDS2 specific writer options (max vertex option, multi XY record option,
       max cell name length).
     * The stipple palette now is editable. A corresponding page has been added
       in the setup dialog.
     * Flatten cell function. A cell can be flattened which will remove the cell
       and all the subcells unless not specified otherwise. This function can be
       found in the cell's context menu. Details for this feature can be found
       here.
     * The 'Make Cell' operation provides a nice origin now. Before, the origin
       of the new cell was far off sometimes.
     * Accept drag & drop of .lyb, .lys, .lyp, .rb, .rbm and layout files.
     * Switched to standard file dialogs where this has not been the case yet.
       In particular on the Windows platform, the application will behave somewhat
       more consistent.
     * Added an option to draw only border instances of arrays. This option can be
       found on the 'Misc.' tab of the setup dialog.
     * Added the capability to define global ruby modules using the ".rbm"
       extension and putting them into the installation directory.
     * Full cell copy & paste functions can now be found in hierarchy panel
       context menu.
     * Enhancement of grid snapping in partial mode. Before, a offgrid vertex could
       not be brought on-grid because movement was confined to grid steps.
     * Number of points for polygons is shown now in the polygon property dialog.
     * Hole resolution for GDS2 and OASIS writer. Before, polygons with holes
       (which can be produced by scripts) were rejected.
     * Some bugfixes for clip, using booleans for clip to overcome some problems
       with hole connectors and spikes - slow but safe..
     * '#' character is not longer used when creating cell variants - instead '$'
       is used to enhance the compatibility with other tools which do not allow
       the "#" character as part of cell names.
     * On paste, a 'fit selection' is done to show what has been pasted.
     * Mouse wheel mode is configurable now (shift/ctrl modifier behaviour).
       The 'alternative mode' can be found on the 'Misc.' tab in the setup dialog.
     * Option to clear all rulers when cell is changed. This option can be found
       on the 'Misc.' tab in the setup dialog in the 'On Cell Change' group.

     RBA enhancements:
     * A new class: ICplxTrans and related functions.
     * A recursive shape iterator simplifies hierarchical region queries and
       "as if flat" traversal of cells.
     * Polygon: hull and hole can be assigned now, compress method, point accessors.
     * The installation path now is available.
     * Added a method which allows to display a message in the status bar.
     * The transient selection now is available for RBA procedures.
     * New events are generated if selection and transient selection changes.
     * Added a generic assign method for copyable objects.
     * Added new classes 'LayerMap' and 'LoadLayoutOptions'.
     * Added two 'read' methods to Layout class.
     * Added a couple of methods to 'LayerInfo' (constructors, compare, ...).
     * Added a 'load_layout' method to LayoutView.
     * Added more cm_* methods to MainWindow.

0.17.2 		(2009-04-20):
     * Some bugs are fixed now (for a list of fixed bugs see Known bugs in
       version 0.17.1).
     * The GDS2 writer now normalizes AREF records. This way compatibility with
       other EDA systems is enhanced.

0.17.1 		(2009-03-27):
     * The display freezing bug on Windows is fixed now (i.e. see Known bugs
       in version 0.17).

0.17 		(2009-03-23):
     * Various layer operations are now available: boolean operations (AND, XOR,
       NOT), layer merge and sizing. For a detailed description see Layer boolean
       operations and Layer sizing. These operations are also available in RBA
       (see RBA::EdgeProcessor and RBA::ShapeProcessor).
     * Boolean and sizing operations are also available Shapewise boolean
       operations and Shapewise sizing.
     * Objects can now be aligned. For a detailed description of the alignment
       function see Object alignment.
     * The cell origin can be adjusted relative to the cell's bounding box.
       For a detailed description see Cell origin adjustment.
     * A 'corner rounding' function has been implemented to support
       soft-cornered layout which is common in power applications. For a detailed
       description see Corner rounding.
     * Various layer operations are now implemented in edit mode: clear layer,
       delete layer and edit layer properties. For a detailed description see
       Layer operations: clear, delete, edit specification.
     * The selection can now be scaled (The "Scale" function is available in the
       "Selection" submenu of the "Edit" menu).
     * An option is available that allows to select all hierarchy levels
       automatically when a cell is opened (found in the "Misc." tab of the setup
       dialog: "Select all hierarchy levels" must be checked).
     * Various bug fixes (i.e. see Known bugs in version 0.16.1).

0.16.1 		(2009-01-07):
     * Various bug fixes (i.e. see Known bugs in version 0.16).

0.16 		(2008-12-27):
     * Some new editing capabilities: flatten, make cell, clear layer and a clip
       function.
     * Some RBA extensions, in particular the ability to modify layout by deleting
       shapes and instances, replacing and transforming them, changing property
       handles etc.
     * Support for global preset of configuration (through a file called "layviewrc"
       beside the executable binary) and a global RBA initialisation file (a file
       called "rbainit" beside the executable binary).
     * Transient selection: indicates by a faint selection marker what object is
       below the mouse (can be disabled).
     * The layer specification (layer, datatype, name) can be now be edited which
       allows to move a complete layer to a different one.
     * Undo buffering can now be disabled on the command line with the '-i' option.
       This saves the memory otherwise required for storing the replay information.
     * Directional constraints can be modified by using the Shift and Ctrl modifiers
       on various operations such as rulers, movement, drawing etc.
     * Now there is a 'most recently used' list ("Open Recent" in the "File" menu)
       which shows the last layouts opened for easy re-opening.
     * Reduced memory requirements for particular OASIS constructs (random repetitions)
     * The instance browser now has a "Choose cell" button where the cell can be
       chosen whose instances will be presented.
     * For most editing operations, the status bar will now indicate more detailed
       informations such as move distance.
     * Pasted shapes and instances now are selected initially.
     * Enhanced OASIS compression mode (can be chosen from the options dialog on
       saving). Reduces file size considerably by creating regular shape arrays if
       possible at the cost of higher memory consumption and longer writing times.
     * Various bug fixes (i.e. see Known bugs in version 0.15).

0.15 		(2008-08-16):
     * Editing capabilities. "klayout" in it's basic form still operates as pure
       viewer. However, a mode is available that enables editing capabilities.
       See Editor mode quickstart manual for a more detailed description
     * Some RBA extensions: i.e. conversion from "double" type polygons to "integer"
       type ones.
     * A default layer table can be configured in the "Application" tab of the
       setup dialog. This table will be loaded whenever a layout is opened or
       created.
     * A installer for Windows is provided now.
     * Properties are supported on instances now as well.
     * Code is compatible with gcc 4.3.0 now.
     * Enhanced compatibility with SunStudio 11 compiler (in particular in RBA).
     * Various bug fixes (i.e. in GDS reader and OASIS writer).

0.14 		(2008-04-04):
     * Several RBA extensions: i.e. alternative methods replacing different 'new'
       variants by one 'new'. Markers now can be filled.
     * Fixes for the bugs mentioned in the issues list.
     * OASIS and GDS writing capabilities. Menu functions are provided to save a
       layout and single cells as well as RBA extensions that allow to write a
       layout. See Saving a layout or parts of it for details.
     * Rulers and markers are drawn with a thin halo in background color to
       enhance their visibility. This can be switched off in the setup dialog if
       this is not desired. The screenshots illustrate the differences.

0.13 		(2008-01-16):
     * A couple of RBA extensions: API's for shape properties, rulers and geometry
       selections.
     * A bugfix for the OASIS reader (sometimes crashing the reader on
       CBLOCK-compressed input)
     * A function to descend into a cell in the hierarchy but keeping the context,
       which is shown in dimmed colors. This function can be found in the "Display"
       menu and is called "Descend". To use this function, select a shape or instance
       inside the cell into which to descend. "Descend" then enters the next cell
       along the path that leads to the selected shape or instance.
     * The mouse wheel can be used to zoom in and out.
     * Shift+right mouse button pressed now allows to "drag" layout in a "Google maps" fashion.
     * Copy & paste now is available for layers as well.
     * A ruby console is provided where ruby commands can be executed interactively.
     * The way how the selection is displayed can be configured now (color, line width
       and vertex size).
     * The interrupt signal now is enabled again even if Ruby is activated (Ctrl+C
       now works again).

0.12 		(2007-11-02):
     * Support for arbitrary angles on cell instances.
     * A bugfix for the OASIS reader (CTRAPEZOIDS have not been read in some
       cases). The OASIS reader now uses shape arrays to achieve are smaller
       memory footprint in some cases.
     * Multiple transformations are now allowed on layer source expressions
       (see Transforming views and property selectors for a detailed description).
     * Rulers now are configurable to a large extent. Multiple ruler templates may
       be defined from which a certain ruler type can be chosen. Some of the new
       ruler styles are no longer "rulers" but rather "annotations". See Ruler
       properties for a description of that feature.
     * Last, but not least: KLayout now can be scripted to some extend using Ruby
       as the scripting language. For more information about this feature, see
       RBA introduction.

0.11 		(2007-06-26):
     * Some bugs were fixed in the OASIS implementation. CBLOCK compression now
       is supported. Forward cell name references (numerical ID is used before
       being associated with a string) are supported as now. File global properties
       are now read correctly. A bug reading certain CTRAPEZOID objects was fixed.
       (Still, forward references are not allowed for text/property strings or
       property names).
     * A layout properties dialog has been added that shows basic properties of
       the layout such as top cells, layers and others.
     * The "Select Cell" dialog has been enhanced with the capability to hide
       and show multiple cells in the cell list.
     * A "zoom fit" mouse gesture was implemented: moving the mouse up and right
       with the right mouse button pressed now fits the current cell into the window.
       Moving up and left still zooms out.
     * A bug in the GDS2 reader, dropping polygon points in rare cases, was fixed

0.10 		(2007-05):
     * The build script has been enhanced and supports Qt installations with
       different locations for binaries, libraries and headers. See the Build
       section for details about this.
     * OASIS files can be read as well now. The reader automatically determines
       the kind of file. OASIS layer names are supported. Due to the complexity
       of the OASIS specification, or more precisely the effort required to test
       a reader for meeting the specification, OASIS support currently is regarded
       to be in "beta" state.
     * Layers can now be organized hierarchically. Layers can be grouped which
       allows to control visibility and other properties for the group as a whole.
       Layers can be removed from the layer view list or new layer views can be created.
     * The layout can be transformed (rotated, shifted, mirrored) now. This
       transformation is specified in the layer panel as a part of the layer
       source specification. An optional transformation can be applied per layer
       or layer group. This way for example, different layouts can be aligned
       over each other.
     * Shape properties now are supported. Each shape may carry optional
       properties that are read from GDS or OASIS files. A property selector
       can be applied per layer view, so that a layer only shows these shapes
       that match the given property selection. 
     * As an experimental feature, the inverse layout tree can be visualised
       by allowing the minimum hierarchy level to go into the negative range.
       The effect of this is, that a cell is shown in the context of all of
       it's direct parents, if the first hierarchy level is set to -1. If set
       to -2, the cell is shown in the context of all of it's parents and
       grandparents and so on. Since there is no particular optimization for
       this feature, performance may be poor, if a cell must be painted in a
       huge number of contexts. In addition, the context displayed does not
       participate in selection or ruler snapping.

0.9 		(2006-04):
     * This was the first official release