Another fix for drawing bitmaps through an SkGPipe that share pixelrefs.

In addition to checking the offset, also check to ensure that the width
and height match, so that a subset which includes the upper left corner
will be handled properly as well.

Review URL: https://codereview.appspot.com/6352066

git-svn-id: http://skia.googlecode.com/svn/trunk@4448 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 32 insertions, 9 deletions

diff --git a/gm/extractbitmap.cpp b/gm/extractbitmap.cpp
index 67657968ae..050d7e7834 100644
--- a/gm/extractbitmap.cpp
+++ b/gm/extractbitmap.cpp
@@ -45,13 +45,33 @@ protected:
         create_bitmap(&bitmap);
         int x = bitmap.width() / 2;
         int y = bitmap.height() / 2;
-        SkBitmap subset;
-        bitmap.extractSubset(&subset, SkIRect::MakeXYWH(x, y, x, y));
 
         canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
 
         canvas->drawBitmap(bitmap, 0, 0);
-        canvas->drawBitmap(subset, 0, 0);
+
+        {
+            // Do some subset drawing. This will test that an SkGPipe properly
+            // handles the case where bitmaps share a pixelref
+            // Draw the bottom right fourth of the bitmap over the top left
+            SkBitmap subset;
+            bitmap.extractSubset(&subset, SkIRect::MakeXYWH(x, y, x, y));
+            canvas->drawBitmap(subset, 0, 0);
+            // Draw the top left corner over the bottom right
+            bitmap.extractSubset(&subset, SkIRect::MakeWH(x, y));
+            canvas->drawBitmap(subset, SkIntToScalar(x), SkIntToScalar(y));
+            // Draw a subset which has the same height and pixelref offset but a
+            // different width
+            bitmap.extractSubset(&subset, SkIRect::MakeWH(x, bitmap.height()));
+            SkAutoCanvasRestore autoRestore(canvas, true);
+            canvas->translate(0, SkIntToScalar(bitmap.height() + 20));
+            canvas->drawBitmap(subset, 0, 0);
+            // Now draw a subet which has the same width and pixelref offset but
+            // a different height
+            bitmap.extractSubset(&subset, SkIRect::MakeWH(bitmap.height(), y));
+            canvas->translate(0, SkIntToScalar(bitmap.height() + 20));
+            canvas->drawBitmap(subset, 0, 0);
+        }
 /*
         // Now do the same but with a device bitmap as source image
         SkRefPtr<SkDevice> primaryDevice(canvas->getDevice());
diff --git a/src/pipe/SkGPipeWrite.cpp b/src/pipe/SkGPipeWrite.cpp
index 066159f10a..5734a27800 100644
--- a/src/pipe/SkGPipeWrite.cpp
+++ b/src/pipe/SkGPipeWrite.cpp
@@ -85,16 +85,19 @@ public:
         const uint32_t genID = orig.getGenerationID();
         SkPixelRef* sharedPixelRef = NULL;
         for (int i = fBitmaps.count() - 1; i >= 0; i--) {
+            SkBitmap* storedBitmap = fBitmaps[i].fBitmap;
             if (genID == fBitmaps[i].fGenID) {
-                if (orig.pixelRefOffset() != fBitmaps[i].fBitmap->pixelRefOffset()) {
+                if (orig.pixelRefOffset() != storedBitmap->pixelRefOffset()
+                    || orig.width() != storedBitmap->width()
+                    || orig.height() != storedBitmap->height()) {
                     // In this case, the bitmaps share a pixelRef, but have
-                    // different offsets. Keep track of the other bitmap so that
-                    // instead of making another copy of the pixelRef we can use
-                    // the copy we already made.
-                    sharedPixelRef = fBitmaps[i].fBitmap->pixelRef();
+                    // different offsets or sizes. Keep track of the other
+                    // bitmap so that instead of making another copy of the
+                    // pixelRef we can use the copy we already made.
+                    sharedPixelRef = storedBitmap->pixelRef();
                     break;
                 }
-                return fBitmaps[i].fBitmap;
+                return storedBitmap;
             }
         }
         SkBitmap* copy;