Fix SkTileImageFilter when srcRect is a superset of bitmap bounds.

src/effects/SkTileImageFilter.cpp

Index: src/effects/SkTileImageFilter.cpp
diff --git a/src/effects/SkTileImageFilter.cpp b/src/effects/SkTileImageFilter.cpp
index 8d158013879a7bf23097c75a2ce241f49816bad6..883efd4137912c3863340f32ca01898ea9dee085 100644
--- a/src/effects/SkTileImageFilter.cpp
+++ b/src/effects/SkTileImageFilter.cpp
@@ -54,15 +54,30 @@ bool SkTileImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
     srcRect.roundOut(&srcIRect);
     srcIRect.offset(-srcOffset);
     SkBitmap subset;
-    SkIRect bounds;
-    source.getBounds(&bounds);
+    SkIRect srcBounds;
+    source.getBounds(&srcBounds);
 
-    if (!srcIRect.intersect(bounds)) {
+    if (!SkIRect::Intersects(srcIRect, srcBounds)) {
         offset->fX = offset->fY = 0;
         return true;
-    } else if (!source.extractSubset(&subset, srcIRect)) {
-        return false;
     }
+    if (srcBounds.contains(srcIRect)) {
+        if (!source.extractSubset(&subset, srcIRect)) {
+            return false;
+        }
+    } else {

[robertphillips, 2016/01/11 13:31:54]

\n somewhere ?
Maybe "static bool kWillTiledResult = true;" ?

[Stephen White, 2016/01/11 16:20:30]

Done.

+        SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(srcIRect.width(), srcIRect.height(), true));
+        if (!device) {
+            return false;
+        }
+        SkCanvas canvas(device);
+        canvas.clear(0x0);

[reed1, 2016/01/10 02:25:02]

is the clear needed? I thought our devices were already cleared (but not sure)

[Stephen White, 2016/01/11 16:20:30]

I wasn't sure either. Removed and the tests seem ok.

+        canvas.drawBitmap(src, SkIntToScalar(srcOffset.x()),
+                               SkIntToScalar(srcOffset.y()));
+        subset = device->accessBitmap(false);
+    }
+    SkASSERT(subset.width() == srcIRect.width());
+    SkASSERT(subset.height() == srcIRect.height());
 
     SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(w, h));
     if (nullptr == device.get()) {
@@ -72,12 +87,8 @@ bool SkTileImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
     SkPaint paint;
     paint.setXfermodeMode(SkXfermode::kSrc_Mode);
 
-    SkMatrix shaderMatrix;
-    shaderMatrix.setTranslate(SkIntToScalar(srcOffset.fX),
-                              SkIntToScalar(srcOffset.fY));
     SkAutoTUnref<SkShader> shader(SkShader::CreateBitmapShader(subset,
-                                  SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode,
-                                  &shaderMatrix));
+                                  SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode));
     paint.setShader(shader);
     canvas.translate(-dstRect.fLeft, -dstRect.fTop);
     canvas.drawRect(dstRect, paint);