Changeset 21035 for trunk/WebCore/platform/graphics/cairo/GraphicsContextCairo.cpp

Timestamp:

04/23/07 07:16:40 (21 months ago)

Author:

bdash

Message:

2007-04-23 Alp Toker <alp@atoker.com>

Reviewed by Mark.

Further implementation and checks. The opacity layer code is not so beautiful
but gets the job done with fewer complications than maintaining our own stack.

• platform/graphics/cairo/GraphicsContextCairo.cpp: (WebCore::GraphicsContext::translate): (WebCore::GraphicsContext::setPlatformStrokeThickness): (WebCore::GraphicsContext::beginTransparencyLayer): (WebCore::GraphicsContext::endTransparencyLayer): (WebCore::GraphicsContext::setCompositeOperation): (WebCore::GraphicsContext::rotate): (WebCore::GraphicsContext::scale):

Files:

• trunk/WebCore/platform/graphics/cairo/GraphicsContextCairo.cpp (modified) (6 diffs)

trunk/WebCore/platform/graphics/cairo/GraphicsContextCairo.cpp

@@ -66 +66 @@
 
     cairo_t* context;
+    cairo_user_data_key_t opacityKey;
 };
 
@@ -469 +470 @@
 void GraphicsContext::translate(float x, float y)
 {
+    if (paintingDisabled())
+        return;
     cairo_t* context = m_data->context;
     cairo_translate(context, x, y);
@@ -495 +498 @@
 void GraphicsContext::setPlatformStrokeThickness(float strokeThickness)
 {
+    if (paintingDisabled())
+        return;
     cairo_set_line_width(m_data->context, strokeThickness);
 }
@@ -565 +570 @@
 }
 
-void GraphicsContext::beginTransparencyLayer(float)
-{
-    notImplemented();
+void GraphicsContext::beginTransparencyLayer(float opacity)
+{
+    if (paintingDisabled())
+        return;
+
+    ASSERT(opacity >= 0 && opacity <= 1);
+
+    cairo_t* context = m_data->context;
+    cairo_push_group(context);
+    // We insert the opacity into a Cairo surface data slot.
+    // Rather than passing a pointer, we store the opacity value directly.
+    void* odata = reinterpret_cast<void*>(static_cast<unsigned int>(opacity * UINT_MAX));
+    cairo_surface_set_user_data(cairo_get_target(context), &m_data->opacityKey, odata, NULL);
 }
 
 void GraphicsContext::endTransparencyLayer()
 {
-    notImplemented();
+    if (paintingDisabled())
+        return;
+
+    cairo_t* context = m_data->context;
+    void* odata = cairo_surface_get_user_data(cairo_get_target(context), &m_data->opacityKey);
+    float opacity = static_cast<float>(reinterpret_cast<unsigned int>(odata)) / UINT_MAX;
+
+    ASSERT(opacity >= 0 && opacity <= 1);
+
+    cairo_pop_group_to_source(context);
+    cairo_paint_with_alpha(context, opacity);
 }
 
@@ -675 +700 @@
 void GraphicsContext::setCompositeOperation(CompositeOperator op)
 {
+    if (paintingDisabled())
+        return;
     cairo_set_operator(m_data->context, toCairoOperator(op));
 }
@@ -683 +710 @@
 }
 
-void GraphicsContext::rotate(float)
-{
-    notImplemented();
-}
-
-void GraphicsContext::scale(const FloatSize&)
-{
-    notImplemented();
+void GraphicsContext::rotate(float angle)
+{
+    if (paintingDisabled())
+        return;
+    cairo_rotate(m_data->context, angle);
+}
+
+void GraphicsContext::scale(const FloatSize& size)
+{
+    if (paintingDisabled())
+        return;
+    cairo_scale(m_data->context, size.width(), size.height());
 }