Fix merge crop rect computation.

src/effects/SkMergeImageFilter.cpp

Index: src/effects/SkMergeImageFilter.cpp
diff --git a/src/effects/SkMergeImageFilter.cpp b/src/effects/SkMergeImageFilter.cpp
index d6f0eaa794bcacaa7801d993bb15fe3cece0e98b..8782f89a6ef416f3c07c8a2fad0416a339655da5 100755
--- a/src/effects/SkMergeImageFilter.cpp
+++ b/src/effects/SkMergeImageFilter.cpp
@@ -63,7 +63,32 @@ bool SkMergeImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
     }
 
     SkIRect bounds;
-    if (!this->applyCropRect(ctx, src, SkIPoint::Make(0, 0), &bounds)) {
+

[robertphillips, 2015/11/24 20:58:16]

this->countInputs() ?

// Basically move the CL's description in here ?

[Stephen White, 2015/11/24 21:15:53]

Done (here and elsewhere).
Done.

+    int inputCount = countInputs();
+    SkAutoTDeleteArray<SkBitmap> inputs(new SkBitmap[inputCount]);
+    SkAutoTDeleteArray<SkIPoint> offsets(new SkIPoint[inputCount]);
+    bool didProduceResult = false;
+    for (int i = 0; i < inputCount; ++i) {
+        inputs[i] = src;
+        offsets[i].setZero();
+        if (!this->filterInput(i, proxy, src, ctx, &inputs[i], &offsets[i])) {
+            inputs[i].reset();
+            continue;
+        }
+        SkIRect srcBounds;
+        inputs[i].getBounds(&srcBounds);
+        srcBounds.offset(offsets[i]);
+        if (!didProduceResult) {
+            bounds = srcBounds;
+            didProduceResult = true;
+        } else {
+            bounds.join(srcBounds);
+        }
+    }
+    if (!didProduceResult) {
+        return false;
+    }
+    if (!this->getCropRect().applyTo(bounds, ctx, &bounds)) {
         return false;
     }
 
@@ -77,27 +102,15 @@ bool SkMergeImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src,
     SkCanvas canvas(dst);
     SkPaint paint;
 
-    bool didProduceResult = false;
-    int inputCount = countInputs();
     for (int i = 0; i < inputCount; ++i) {

[robertphillips, 2015/11/24 20:58:16]

if (!inputs[i]) {
   continue;
}

?

[Stephen White, 2015/11/24 21:15:53]

canvas.drawBitmap() does this as its first line; I think it's redundant here.

-        SkBitmap tmp;
-        SkBitmap input = src;
-        SkIPoint pos = SkIPoint::Make(0, 0);
-        if (!this->filterInput(i, proxy, src, ctx, &input, &pos)) {
-            continue;
-        }
         if (fModes) {
             paint.setXfermodeMode((SkXfermode::Mode)fModes[i]);
         } else {

[robertphillips, 2015/11/24 20:58:16]

Do we actually need this else clause ?

[Stephen White, 2015/11/24 21:15:53]

Good point. Fixed.

             paint.setXfermode(nullptr);
         }

[robertphillips, 2015/11/24 20:58:16]

\n somewhere ?

[Stephen White, 2015/11/24 21:15:53]

Done.

-        canvas.drawBitmap(input, SkIntToScalar(pos.x() - x0), SkIntToScalar(pos.y() - y0), &paint);
-        didProduceResult = true;
+        canvas.drawBitmap(inputs[i], SkIntToScalar(offsets[i].x() - x0), SkIntToScalar(offsets[i].y() - y0), &paint);
     }
 
-    if (!didProduceResult)
-        return false;
-
     offset->fX = bounds.left();
     offset->fY = bounds.top();
     *result = dst->accessBitmap(false);