O2D:...

core/cross/cairo/renderer_cairo.cc

Index: core/cross/cairo/renderer_cairo.cc
===================================================================
--- core/cross/cairo/renderer_cairo.cc	(revision 71475)
+++ core/cross/cairo/renderer_cairo.cc	(working copy)
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010, Google Inc.
+ * Copyright 2011, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -95,32 +95,59 @@
   // Core process of painting.
   for (LayerList::iterator i = layer_list_.begin();
        i != layer_list_.end(); i++) {
-    // Put the state with no mask to the stack.
-    cairo_save(current_drawing);
+    Layer* cur = *i;
+    if (!cur->ShouldPaint()) continue;
 
-    // Preparing and updating the Layer.
-    Layer* cur = *i;
     Pattern* pattern = cur->pattern();
-    if (!pattern) {
-      // Skip layers with no pattern assigned.
-      continue;
-    }
 
-    // Masking areas for other scene.
+    // Save the current drawing state.
+    cairo_save(current_drawing);
+
+    // Clip areas that will be obscured anyway.
     LayerList::iterator start_mask_it = i;
     start_mask_it++;
-    MaskArea(current_drawing, start_mask_it);
+    ClipArea(current_drawing, start_mask_it);
 
+    // Define the region to fill.
+    cairo_rectangle(current_drawing,
+                    cur->x(),
+                    cur->y(),
+                    cur->width(),
+                    cur->height());
+
+    // Transform the pattern to fit into the fill region.
     cairo_translate(current_drawing, cur->x(), cur->y());
-
     cairo_scale(current_drawing, cur->scale_x(), cur->scale_y());
 
-    // Painting the image to the surface.
+    // Set source pattern.
     cairo_set_source(current_drawing, pattern->pattern());
 
-    cairo_paint_with_alpha(current_drawing, cur->alpha());
+    // Paint the pattern to the off-screen surface.
+    switch (cur->paint_operator()) {
+      case Layer::BLEND:
+        cairo_fill(current_drawing);
+        break;
 

[zhurunz, 2011/01/20 00:46:51]

Should we remove the blank line?

[Tristan Schmelcher 2, 2011/01/20 01:12:38]

I think putting a blank line here is typical.

-    // Restore to the state with no mask.
+      case Layer::BLEND_WITH_TRANSPARENCY:
+        {
+          cairo_pattern_t* mask = cairo_pattern_create_rgba(0.0,
+                                                            0.0,
+                                                            0.0,
+                                                            cur->alpha());
+          cairo_mask(current_drawing, mask);
+          cairo_pattern_destroy(mask);
+        }
+        break;
+
+      case Layer::COPY:
+      case Layer::COPY_WITH_FADING:  // TODO(tschmelcher): Not implemented yet.

[zhurunz, 2011/01/20 00:46:51]

The comment say it is Not implemented yet.
But there is some "implementation" below. 
Which is true?

[Tristan Schmelcher 2, 2011/01/20 01:12:38]

The below stuff is the code for COPY. I'm treating the _WITH_FADING version as
COPY for now until it's implemented. I had a comment about that before but I
took it out to make space for the TODO ... I guess I'll add it back.

+        // Set Cairo to copy the pattern's alpha content instead of blending.
+        cairo_set_operator(current_drawing, CAIRO_OPERATOR_SOURCE);
+        cairo_fill(current_drawing);
+        break;
+    }

[zhurunz, 2011/01/20 00:46:51]

Better adding a default. 
Even if just DCheck().

[Tristan Schmelcher 2, 2011/01/20 01:12:38]

Done.

+
+    // Restore to a clean state.
     cairo_restore(current_drawing);
   }
 
@@ -136,7 +163,7 @@
 
 void RendererCairo::PaintBackground(cairo_t* cr) {
   cairo_save(cr);
-  MaskArea(cr, layer_list_.begin());
+  ClipArea(cr, layer_list_.begin());
 
   cairo_rectangle(cr, 0, 0, display_width(), display_height());
   cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
@@ -144,19 +171,20 @@
   cairo_restore(cr);
 }
 
-void RendererCairo::MaskArea(cairo_t* cr,  LayerList::iterator it) {
+void RendererCairo::ClipArea(cairo_t* cr,  LayerList::iterator it) {
   cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
 
   for (LayerList::iterator i = it; i != layer_list_.end(); i++) {
     // Preparing and updating the Layer.
-    Layer* cur_mask = *i;
+    Layer* cur = *i;
+    if (!cur->ShouldClip()) continue;
 
     cairo_rectangle(cr, 0, 0, display_width(), display_height());
     cairo_rectangle(cr,
-                    cur_mask->x(),
-                    cur_mask->y(),
-                    cur_mask->width(),
-                    cur_mask->height());
+                    cur->x(),
+                    cur->y(),
+                    cur->width(),
+                    cur->height());
     cairo_clip(cr);
   }
 }