Implement clipRect with a transform, clipRegion & clipPath

Bug #7146141

When non-rectangular clipping occurs in a layer the render buffer
used as the stencil buffer is not cached. If this happens on a
View's hardware layer the render buffer will live for as long
as the layer is bound to the view. When a stencil buffer is
required because of a call to Canvas.saveLayer() it will be allocated
on every frame. A future change will address this problem.

If "show GPU overdraw" is enabled, non-rectangular clips are not
supported anymore and we fall back to rectangular clips instead.
This is a limitation imposed by OpenGL ES that cannot be worked
around at this time.

This change also improves the Matrix4 implementation to easily
detect when a rect remains a rect after transform.

Change-Id: I0e69fb901792d38bc0c4ca1bf9fdb02d7db415b9

1 files changed, 9 insertions, 1 deletions

diff --git a/libs/hwui/LayerRenderer.cpp b/libs/hwui/LayerRenderer.cpp
index 3484d411c130..ba59bb391f1d 100644
--- a/libs/hwui/LayerRenderer.cpp
+++ b/libs/hwui/LayerRenderer.cpp
@@ -100,13 +100,21 @@ bool LayerRenderer::suppressErrorChecks() {
 }
 
 ///////////////////////////////////////////////////////////////////////////////
-// Dirty region tracking
+// Layer support
 ///////////////////////////////////////////////////////////////////////////////
 
 bool LayerRenderer::hasLayer() {
     return true;
 }
 
+void LayerRenderer::ensureStencilBuffer() {
+    attachStencilBufferToLayer(mLayer);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Dirty region tracking
+///////////////////////////////////////////////////////////////////////////////
+
 Region* LayerRenderer::getRegion() {
     if (getSnapshot()->flags & Snapshot::kFlagFboTarget) {
         return OpenGLRenderer::getRegion();