Provide a solution for #809 (density goes outside the area)

src/drc/drc/built-in-macros/_drc_engine.rb

@@ -102,6 +102,14 @@ module DRC
       DRCJoinFlag::new(true)
     end
     
+    def padding_zero
+      DRCDensityPadding::new(:zero)
+    end
+
+    def padding_ignore
+      DRCDensityPadding::new(:ignore)
+    end
+
     def diamond_limit
       DRCSizingMode::new(0)
     end

src/drc/drc/built-in-macros/_drc_layer.rb

@@ -3898,6 +3898,20 @@ CODE
     # low_density = input(1, 0).density(0.0 .. 0.1, tile_size(20.um), tile_origin(0.0, 0.0), tile_count(100, 150))
     # @/code
     #
+    # The "padding mode" indicates how the area outside the layout's bounding box is considered.
+    # There are two modes:
+    #
+    # @ul
+    #   @li @b padding_zero @/b: the outside area is considered zero density. This is the default mode. @/li
+    #   @li @b padding_ignore @/b: the outside area is ignored for the density computation. @/li
+    # @/ul
+    #
+    # Example:
+    #
+    # @code
+    # low_density = input(1, 0).density(0.0 .. 0.1, tile_size(20.um), padding_ignore)
+    # @/code
+    # 
     # The complementary version of "with_density" is \without_density.
     
     # %DRC%
@@ -3920,6 +3934,7 @@ CODE
       tile_origin = nil
       tile_count = nil
       tile_boundary = nil
+      padding_mode = :zero
 
       n = 1
       args.each do |a|
@@ -3933,6 +3948,8 @@ CODE
           tile_count = a.get
         elsif a.is_a?(DRCTileBoundary)
           tile_boundary = a.get
+        elsif a.is_a?(DRCDensityPadding)
+          padding_mode = a.value
         elsif a.is_a?(Float) || a.is_a?(1.class) || a == nil
           nlimits < 2 || raise("Too many values specified")
           limits[nlimits] = @engine._make_numeric_value_with_nil(a)
@@ -3977,11 +3994,15 @@ CODE
       tp.threads = (@engine.threads || 1)
       if tile_boundary
         tp.input("boundary", tile_boundary.data)
+      else
+        tp.input("boundary", RBA::Region::new(self.data.bbox))
       end
 
       tp.var("vmin", limits[0] || 0.0)
       tp.var("vmax", limits[1] || 1.0)
       tp.var("inverse", inverse)
+
+      if padding_mode == :zero
         tp.queue(<<"TP_SCRIPT")
           _tile && (
             var bx = _tile.bbox.enlarged(xoverlap, yoverlap);
@@ -3989,6 +4010,18 @@ CODE
             ((d > vmin - 1e-10 && d < vmax + 1e-10) != inverse) && _output(res, bx, false)
           )
 TP_SCRIPT
+      elsif padding_mode == :ignore
+        tp.queue(<<"TP_SCRIPT")
+          _tile && (
+            var bx = _tile.bbox.enlarged(xoverlap, yoverlap);
+            var ba = boundary.area(bx);
+            ba > 0 && (
+              var d = to_f(input.area(bx)) / to_f(ba);
+              ((d > vmin - 1e-10 && d < vmax + 1e-10) != inverse) && _output(res, bx, false)
+            )
+          )
+TP_SCRIPT
+      end
 
       @engine.run_timed("\"#{method}\" in: #{@engine.src_line}", self.data) do
         tp.execute("Tiled \"#{method}\" in: #{@engine.src_line}")

src/drc/drc/built-in-macros/_drc_tags.rb

@@ -20,6 +20,14 @@ module DRC
   class DRCBothEdges
   end
   
+  # A wrapper for the padding modes of with_density
+  class DRCDensityPadding
+    attr_accessor :value
+    def initialize(v)
+      self.value = v
+    end
+  end
+  
   # A wrapper for the sizing mode value
   class DRCSizingMode
     attr_accessor :value

src/lay/lay/doc/about/drc_ref_layer.xml

@@ -3382,6 +3382,20 @@ direction. With the "tile_origin" option this allows full control over the area
 low_density = input(1, 0).density(0.0 .. 0.1, tile_size(20.um), tile_origin(0.0, 0.0), tile_count(100, 150))
 </pre>
 </p><p>
+The "padding mode" indicates how the area outside the layout's bounding box is considered.
+There are two modes:
+</p><p>
+<ul>
+<li><b>padding_zero </b>: the outside area is considered zero density. This is the default mode. </li>
+<li><b>padding_ignore </b>: the outside area is ignored for the density computation. </li>
+</ul>
+</p><p>
+Example:
+</p><p>
+<pre>
+low_density = input(1, 0).density(0.0 .. 0.1, tile_size(20.um), padding_ignore)
+</pre>
+</p><p>
 The complementary version of "with_density" is <a href="#without_density">without_density</a>.
 </p>
 <a name="with_distance"/><h2>"with_distance" - Selects edge pairs by the distance of the edges</h2>

testdata/drc/drcSimpleTests_30.drc

@@ -9,10 +9,18 @@ b.output(0, 0)
 a.output(1, 0)
 
 a.with_density(0..0.1, tile_size(10.um), tile_boundary(b)).output(100, 0)
-a.without_density(0..0.1, tile_size(10.um)).output(101, 0)
+a.without_density(0..0.1, tile_size(10.um), padding_zero).output(101, 0)
 a.with_density(0.1, nil, tile_size(10.um), tile_origin(25.um, 10.um)).output(102, 0)
 a.with_density(0.1, nil, tile_size(10.um, 20.um)).output(103, 0)
 a.with_density(0.1, 1.0, tile_size(10.um), tile_step(10.um, 20.um)).output(104, 0)
 a.with_density(0.1, nil, tile_size(10.um), tile_origin(25.um, 10.um), tile_count(10, 15)).output(105, 0)
-a.with_density(0..0.1, tile_size(100.um), tile_step(10.um)).output(110, 0)
+a.with_density(0..0.1, tile_size(100.um), tile_step(10.um), padding_zero).output(110, 0)
+
+a.with_density(0..0.1, tile_size(10.um), tile_boundary(b), padding_ignore).output(200, 0)
+a.without_density(0..0.1, tile_size(10.um), padding_ignore).output(201, 0)
+a.with_density(0.1, nil, tile_size(10.um), tile_origin(25.um, 10.um), padding_ignore).output(202, 0)
+a.with_density(0.1, nil, tile_size(10.um, 20.um), padding_ignore).output(203, 0)
+a.with_density(0.1, 1.0, tile_size(10.um), tile_step(10.um, 20.um), padding_ignore).output(204, 0)
+a.with_density(0.1, nil, tile_size(10.um), tile_origin(25.um, 10.um), tile_count(10, 15), padding_ignore).output(205, 0)
+a.with_density(0..0.1, tile_size(100.um), tile_step(10.um), padding_ignore).output(210, 0)