From ae46712f4582b8527432a738a9dcfe0cb4544082 Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@klayout.de>
Date: Mon, 11 May 2026 23:48:55 +0200
Subject: [PATCH] WIP on density map feature

---
 src/img/img/imgObject.cc                      |  8 +++
 src/img/img/imgObject.h                       | 17 ++++++
 .../lay_plugin/layDensityMapDialog.cc         | 55 ++++++++++++-------
 3 files changed, 60 insertions(+), 20 deletions(-)

diff --git a/src/img/img/imgObject.cc b/src/img/img/imgObject.cc
index 6642ccdcb..4f6d97cf3 100644
--- a/src/img/img/imgObject.cc
+++ b/src/img/img/imgObject.cc
@@ -1009,6 +1009,7 @@ Object::operator= (const img::Object &d)
 
     m_trans = d.m_trans;
     m_filename = d.m_filename;
+    m_tag = d.m_tag;
 
     mp_data = d.mp_data;
     if (mp_data) {
@@ -1963,6 +1964,7 @@ void
 Object::swap (Object &other)
 {
   m_filename.swap (other.m_filename);
+  m_tag.swap (other.m_tag);
   std::swap (m_trans, other.m_trans);
   std::swap (mp_data, other.mp_data);
   std::swap (m_id, other.m_id);
@@ -1979,6 +1981,12 @@ Object::swap (Object &other)
   std::swap (m_updates_enabled, other.m_updates_enabled);
 }
 
+void
+Object::set_tag (const std::string &tag)
+{
+  m_tag = tag;
+}
+
 size_t 
 Object::width () const
 {
diff --git a/src/img/img/imgObject.h b/src/img/img/imgObject.h
index a48e72551..6658d2ae9 100644
--- a/src/img/img/imgObject.h
+++ b/src/img/img/imgObject.h
@@ -581,6 +581,22 @@ public:
     return d;
   }
 
+  /**
+   *  @brief Sets the tag string
+   *
+   *  The tag string is an arbitrary string that can be used to identify
+   *  the image. It is not persisted and it not considered for equality or sorting.
+   */
+  void set_tag (const std::string &tag);
+
+  /**
+   *  @brief Gets the tag string
+   */
+  const std::string tag () const
+  {
+    return m_tag;
+  }
+
   /**
    *  @brief Accessor to the width property
    */
@@ -1036,6 +1052,7 @@ protected:
 
 private:
   std::string m_filename;
+  std::string m_tag;
   db::Matrix3d m_trans;
   DataHeader *mp_data;
   size_t m_id;
diff --git a/src/plugins/tools/density_map/lay_plugin/layDensityMapDialog.cc b/src/plugins/tools/density_map/lay_plugin/layDensityMapDialog.cc
index 909ecc788..8d926a011 100644
--- a/src/plugins/tools/density_map/lay_plugin/layDensityMapDialog.cc
+++ b/src/plugins/tools/density_map/lay_plugin/layDensityMapDialog.cc
@@ -135,27 +135,33 @@ DensityMapDialog::~DensityMapDialog ()
   //  .. nothing yet ..
 }
 
-// @@@@
-class TileRec
-  : public db::TileOutputReceiver
+namespace
 {
-public:
-  TileRec (img::Object *img)
-    : mp_img (img)
-  {
-    //  .. nothing yet ..
-  }
 
-  virtual void put (size_t ix, size_t iy, const db::Box &tile, size_t /*id*/, const tl::Variant &obj, double /*dbu*/, const db::ICplxTrans & /*trans*/, bool /*clip*/)
+  class DensityMapTileReceiver
+    : public db::TileOutputReceiver
   {
-    tl::info << "@@@ " << ix << "," << iy << " -> " << obj.to_string () << " -- " << tile.to_string ();
-    mp_img->set_pixel (ix, iy, obj.to_double ());
-  }
+  public:
+    DensityMapTileReceiver (img::Object *img)
+      : mp_img (img)
+    {
+      //  .. nothing yet ..
+    }
 
-private:
-  img::Object *mp_img;
-};
-// @@@
+    virtual void put (size_t ix, size_t iy, const db::Box &tile, size_t /*id*/, const tl::Variant &obj, double /*dbu*/, const db::ICplxTrans & /*trans*/, bool /*clip*/)
+    {
+      if (tl::verbosity () >= 30) {
+        tl::info << "Density map value: " << ix << "," << iy << " " << tile.to_string () << " -> " << obj.to_string ();
+      }
+
+      mp_img->set_pixel (ix, iy, obj.to_double ());
+    }
+
+  private:
+    img::Object *mp_img;
+  };
+
+}
 
 void 
 DensityMapDialog::accept ()
@@ -326,8 +332,7 @@ BEGIN_PROTECTED
   img::Service *img_service = view ()->get_plugin <img::Service> ();
   if (img_service) {
 
-    //  TODO: we could selectively clear all images that are used for density maps (-> needs a property that identifies them)
-    img_service->clear_images ();
+    const std::string img_tag = "density-map-image";
 
     img::DataMapping dm;
     dm.false_color_nodes.clear ();
@@ -337,15 +342,25 @@ BEGIN_PROTECTED
     dm.false_color_nodes.push_back (std::make_pair (0.0, std::make_pair (0x0000ff, 0x0000ff)));
     dm.false_color_nodes.push_back (std::make_pair (1.0, std::make_pair (0xff0000, 0xff0000)));
 
+    for (auto i = img_service->begin_images (); ! i.at_end (); ++i) {
+      if (i->tag () == img_tag) {
+        //  inherit data mapping from previous image
+        dm = i->data_mapping ();
+        img_service->erase_image_by_id (i->id ());
+        break;
+      }
+    }
+
     img::Object img (nx, ny, db::DCplxTrans (pixel_size, 0.0, false, region.center () - db::DPoint ()), false, false);
     img.set_data_mapping (dm);
+    img.set_tag (img_tag);
 
     img_object = img_service->insert_image (img);
 
   }
 
   tl_assert (img_object);
-  tp.output ("dens", 0, new TileRec (img_object), db::ICplxTrans ());
+  tp.output ("dens", 0, new DensityMapTileReceiver (img_object), db::ICplxTrans ());
 
   //  Execute the tiling processor