reland 6798 w/ fix for bitmap-as-mask pixel-locking
git-svn-id: http://skia.googlecode.com/svn/trunk@6806 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkShader.h b/include/core/SkShader.h
index 1286177..7edbe6f 100644
--- a/include/core/SkShader.h
+++ b/include/core/SkShader.h
@@ -139,12 +139,29 @@
/**
* Called once before drawing, with the current paint and device matrix.
* Return true if your shader supports these parameters, or false if not.
- * If false is returned, nothing will be drawn.
+ * If false is returned, nothing will be drawn. If true is returned, then
+ * a balancing call to endContext() will be made before the next call to
+ * setContext.
+ *
+ * Subclasses should be sure to call their INHERITED::setContext() if they
+ * override this method.
*/
virtual bool setContext(const SkBitmap& device, const SkPaint& paint,
const SkMatrix& matrix);
/**
+ * Assuming setContext returned true, endContext() will be called when
+ * the draw using the shader has completed. It is an error for setContext
+ * to be called twice w/o an intervening call to endContext().
+ *
+ * Subclasses should be sure to call their INHERITED::endContext() if they
+ * override this method.
+ */
+ virtual void endContext();
+
+ SkDEBUGCODE(bool setContextHasBeenCalled() const { return fInSetContext; })
+
+ /**
* Called for each span of the object being drawn. Your subclass should
* set the appropriate colors (with premultiplied alpha) that correspond
* to the specified device coordinates.
@@ -183,14 +200,6 @@
}
/**
- * Called before a session using the shader begins. Some shaders override
- * this to defer some of their work (like calling bitmap.lockPixels()).
- * Must be balanced by a call to endSession.
- */
- virtual void beginSession();
- virtual void endSession();
-
- /**
Gives method bitmap should be read to implement a shader.
Also determines number and interpretation of "extra" parameters returned
by asABitmap
@@ -355,7 +364,7 @@
uint8_t fPaintAlpha;
uint8_t fDeviceConfig;
uint8_t fTotalInverseClass;
- SkDEBUGCODE(SkBool8 fInSession;)
+ SkDEBUGCODE(SkBool8 fInSetContext;)
static SkShader* CreateBitmapShader(const SkBitmap& src,
TileMode, TileMode,