explictly fail to draw unpremul, as this is buggy, incomplete, tricky, and unused

BUG=skia:

Change-Id: Ie9da6015cc4955c0f27f6db53fc6ae532e0132f4
Reviewed-on: https://skia-review.googlesource.com/7304
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 0375ab738d..367a348f51 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -53,6 +53,12 @@
 
 #define RETURN_ON_NULL(ptr)     do { if (nullptr == (ptr)) return; } while (0)
 
+#define RETURN_ON_UNPREMUL_IMAGE(image) \
+    do { if (as_IB(image)->onAlphaType() == kUnpremul_SkAlphaType) return; } while (0)
+
+#define RETURN_ON_UNPREMUL_BITMAP(bitmap) \
+    do { if (bitmap.alphaType() == kUnpremul_SkAlphaType) return; } while (0)
+
 /*
  *  Return true if the drawing this rect would hit every pixels in the canvas.
  *
@@ -1909,12 +1915,14 @@ void SkCanvas::drawPath(const SkPath& path, const SkPaint& paint) {
 
 void SkCanvas::drawImage(const SkImage* image, SkScalar x, SkScalar y, const SkPaint* paint) {
     RETURN_ON_NULL(image);
+    RETURN_ON_UNPREMUL_IMAGE(image);
     this->onDrawImage(image, x, y, paint);
 }
 
 void SkCanvas::drawImageRect(const SkImage* image, const SkRect& src, const SkRect& dst,
                              const SkPaint* paint, SrcRectConstraint constraint) {
     RETURN_ON_NULL(image);
+    RETURN_ON_UNPREMUL_IMAGE(image);
     if (dst.isEmpty() || src.isEmpty()) {
         return;
     }
@@ -1924,12 +1932,14 @@ void SkCanvas::drawImageRect(const SkImage* image, const SkRect& src, const SkRe
 void SkCanvas::drawImageRect(const SkImage* image, const SkIRect& isrc, const SkRect& dst,
                              const SkPaint* paint, SrcRectConstraint constraint) {
     RETURN_ON_NULL(image);
+    RETURN_ON_UNPREMUL_IMAGE(image);
     this->drawImageRect(image, SkRect::Make(isrc), dst, paint, constraint);
 }
 
 void SkCanvas::drawImageRect(const SkImage* image, const SkRect& dst, const SkPaint* paint,
                              SrcRectConstraint constraint) {
     RETURN_ON_NULL(image);
+    RETURN_ON_UNPREMUL_IMAGE(image);
     this->drawImageRect(image, SkRect::MakeIWH(image->width(), image->height()), dst, paint,
                         constraint);
 }
@@ -1937,6 +1947,7 @@ void SkCanvas::drawImageRect(const SkImage* image, const SkRect& dst, const SkPa
 void SkCanvas::drawImageNine(const SkImage* image, const SkIRect& center, const SkRect& dst,
                              const SkPaint* paint) {
     RETURN_ON_NULL(image);
+    RETURN_ON_UNPREMUL_IMAGE(image);
     if (dst.isEmpty()) {
         return;
     }
@@ -1950,6 +1961,7 @@ void SkCanvas::drawImageNine(const SkImage* image, const SkIRect& center, const
 void SkCanvas::drawImageLattice(const SkImage* image, const Lattice& lattice, const SkRect& dst,
                                 const SkPaint* paint) {
     RETURN_ON_NULL(image);
+    RETURN_ON_UNPREMUL_IMAGE(image);
     if (dst.isEmpty()) {
         return;
     }
@@ -1972,6 +1984,7 @@ void SkCanvas::drawBitmap(const SkBitmap& bitmap, SkScalar dx, SkScalar dy, cons
     if (bitmap.drawsNothing()) {
         return;
     }
+    RETURN_ON_UNPREMUL_BITMAP(bitmap);
     this->onDrawBitmap(bitmap, dx, dy, paint);
 }
 
@@ -1980,6 +1993,7 @@ void SkCanvas::drawBitmapRect(const SkBitmap& bitmap, const SkRect& src, const S
     if (bitmap.drawsNothing() || dst.isEmpty() || src.isEmpty()) {
         return;
     }
+    RETURN_ON_UNPREMUL_BITMAP(bitmap);
     this->onDrawBitmapRect(bitmap, &src, dst, paint, constraint);
 }
 
@@ -1999,6 +2013,7 @@ void SkCanvas::drawBitmapNine(const SkBitmap& bitmap, const SkIRect& center, con
     if (bitmap.drawsNothing() || dst.isEmpty()) {
         return;
     }
+    RETURN_ON_UNPREMUL_BITMAP(bitmap);
     if (SkLatticeIter::Valid(bitmap.width(), bitmap.height(), center)) {
         this->onDrawBitmapNine(bitmap, center, dst, paint);
     } else {
@@ -2011,6 +2026,7 @@ void SkCanvas::drawBitmapLattice(const SkBitmap& bitmap, const Lattice& lattice,
     if (bitmap.drawsNothing() || dst.isEmpty()) {
         return;
     }
+    RETURN_ON_UNPREMUL_BITMAP(bitmap);
 
     SkIRect bounds;
     Lattice latticePlusBounds = lattice;
@@ -2030,10 +2046,10 @@ void SkCanvas::drawAtlas(const SkImage* atlas, const SkRSXform xform[], const Sk
                          const SkColor colors[], int count, SkBlendMode mode,
                          const SkRect* cull, const SkPaint* paint) {
     RETURN_ON_NULL(atlas);
+    RETURN_ON_UNPREMUL_IMAGE(atlas);
     if (count <= 0) {
         return;
     }
-    SkASSERT(atlas);
     SkASSERT(tex);
     this->onDrawAtlas(atlas, xform, tex, colors, count, mode, cull, paint);
 }