[dia] [transform] handle matrix given to DrsRenderer::draw_object()

[Hans Breuer <hans src gnome org>]

commit 4dd36327dd59cc03ea73fa59fc13b6682e4c8906
Author: Hans Breuer <hans breuer org>
Date:   Sun Aug 25 15:58:13 2013 +0200

    [transform] handle matrix given to DrsRenderer::draw_object()
    
    special handling for group objects:
     - for the render branch use DiaTransformRenderer, but not it's draw_object,
       to see all the children's draw_object ourself
     - for the object branch we rely on this draw_object being called so need
       to inline group_draw here
     - to maintain the correct transform build our own queue of matrices like
       the DiaTransformRenderer would do through it's draw_object

 lib/libdia.def                            |    2 +
 plug-ins/drs/dia-render-script-renderer.c |   59 +++++++++++++++++++++++++++--
 plug-ins/drs/dia-render-script-renderer.h |    4 ++
 3 files changed, 61 insertions(+), 4 deletions(-)
---
diff --git a/lib/libdia.def b/lib/libdia.def
index 4242a39..d21a94f 100644
--- a/lib/libdia.def
+++ b/lib/libdia.def
@@ -380,6 +380,8 @@ EXPORTS
  dia_transform_coords
  dia_untransform_length
 
+ dia_transform_renderer_new
+
  dia_toggle_button_new_with_icons
 
  dia_sort_sheets
diff --git a/plug-ins/drs/dia-render-script-renderer.c b/plug-ins/drs/dia-render-script-renderer.c
index 87b1143..65645cf 100644
--- a/plug-ins/drs/dia-render-script-renderer.c
+++ b/plug-ins/drs/dia-render-script-renderer.c
@@ -37,6 +37,9 @@
 
 #include "dia-render-script-renderer.h"
 
+#include "diatransformrenderer.h"
+#include "group.h"
+
 static gpointer parent_class = NULL;
 
 /* constructor */
@@ -47,6 +50,7 @@ drs_renderer_init (GTypeInstance *self, gpointer g_class)
 
   renderer->parents = g_queue_new ();
   renderer->save_props = FALSE;
+  renderer->matrices = g_queue_new ();
 }
 
 /* destructor */
@@ -56,6 +60,7 @@ drs_renderer_finalize (GObject *object)
   DrsRenderer *renderer = DRS_RENDERER (object);
 
   g_queue_free (renderer->parents);
+  g_queue_free (renderer->matrices);
 
   G_OBJECT_CLASS (parent_class)->finalize (object);  
 }
@@ -99,6 +104,7 @@ draw_object(DiaRenderer *self,
            DiaMatrix   *matrix)
 {
   DrsRenderer *renderer = DRS_RENDERER (self);
+  DiaMatrix *m = g_queue_peek_tail (renderer->matrices);
   xmlNodePtr node;
 
   g_queue_push_tail (renderer->parents, renderer->root);
@@ -116,16 +122,61 @@ draw_object(DiaRenderer *self,
     props_node = xmlNewChild(node, NULL, (const xmlChar *)"properties", NULL);
     object_save_props (object, props_node);
   }
-  if (matrix)
-    g_warning ("DrsRender::draw_object ignored matrix!");
-  /* TODO: special handling for group object? */
+  if (matrix) {
+    DiaMatrix *m2 = g_new (DiaMatrix, 1);
+    if (m)
+      dia_matrix_multiply (m2, matrix, m);
+    else
+      *m2 = *matrix;
+    g_queue_push_tail (renderer->matrices, m2);
+    /* lazy creation of our transformer */
+    if (!renderer->transformer)
+      renderer->transformer = dia_transform_renderer_new (self);
+  }
+  /* special handling for group objects:
+   *  - for the render branch use DiaTransformRenderer, but not it's draw_object,
+   *    to see all the children's draw_object ourself
+   *  - for the object branch we rely on this draw_object being called so need
+   *    to inline group_draw here
+   *  - to maintain the correct transform build our own queue of matrices like
+   *    the DiaTransformRenderer would do through it's draw_object
+   */
   {
     g_queue_push_tail (renderer->parents, renderer->root);
     renderer->root = node = xmlNewChild(renderer->root, NULL, (const xmlChar *)"render", NULL);
-    object->ops->draw(object, DIA_RENDERER (renderer));
+    if (renderer->transformer) {
+      DiaMatrix *m = g_queue_peek_tail (renderer->matrices);
+
+      if (IS_GROUP (object)) {
+       /* reimplementation of group_draw to use this draw_object method */
+       GList *list;
+       DiaObject *obj;
+
+       list = group_objects (object);
+       while (list != NULL) {
+         obj = (DiaObject *) list->data;
+
+         DIA_RENDERER_GET_CLASS(self)->draw_object(self, obj, m);
+         list = g_list_next(list);
+       }
+      } else {
+       /* just the leaf */
+       DIA_RENDERER_GET_CLASS(renderer->transformer)->draw_object(renderer->transformer, object, m);
+      }
+    } else {
+      object->ops->draw(object, DIA_RENDERER (renderer));
+    }
     renderer->root = g_queue_pop_tail (renderer->parents);
   }
   renderer->root = g_queue_pop_tail (renderer->parents);
+
+  if (matrix)
+    g_queue_pop_tail (renderer->matrices);
+  /* one lost demand destruction */
+  if (renderer->transformer && g_queue_is_empty (renderer->matrices)) {
+    g_object_unref (renderer->transformer);
+    renderer->transformer = NULL;
+  }
 }
 
 static void
diff --git a/plug-ins/drs/dia-render-script-renderer.h b/plug-ins/drs/dia-render-script-renderer.h
index 41b6a5d..563208e 100644
--- a/plug-ins/drs/dia-render-script-renderer.h
+++ b/plug-ins/drs/dia-render-script-renderer.h
@@ -45,6 +45,10 @@ struct _DrsRenderer
   xmlNodePtr root;
   /* track the parents */
   GQueue *parents;
+  /* track transformation matrix */
+  GQueue *matrices;
+  /* to actually render transformed */
+  DiaRenderer *transformer;
 };
 
 struct _DrsRendererClass