add dox for drawPath, describing how to interpret the prePathMatrix.
git-svn-id: http://skia.googlecode.com/svn/trunk@1006 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkDraw.h b/include/core/SkDraw.h
index 99ab342..76a9093 100644
--- a/include/core/SkDraw.h
+++ b/include/core/SkDraw.h
@@ -41,9 +41,15 @@
void drawPoints(SkCanvas::PointMode, size_t count, const SkPoint[],
const SkPaint&, bool forceUseDevice = false) const;
void drawRect(const SkRect&, const SkPaint&) const;
- /* To save on mallocs, we allow a flag that tells us that srcPath is
- mutable, so that we don't have to make copies of it as we transform it.
- */
+ /**
+ * To save on mallocs, we allow a flag that tells us that srcPath is
+ * mutable, so that we don't have to make copies of it as we transform it.
+ *
+ * If prePathMatrix is not null, it should logically be applied before any
+ * stroking or other effects. If there are no effects on the paint that
+ * affect the geometry/rasterization, then the pre matrix can just be
+ * pre-concated with the current matrix.
+ */
void drawPath(const SkPath& srcPath, const SkPaint&,
const SkMatrix* prePathMatrix, bool pathIsMutable) const;
void drawBitmap(const SkBitmap&, const SkMatrix&, const SkPaint&) const;