We need to adjust the bounds of clip ops with SaveLayer paints too.

gm/imageblurtiled2.cpp

Index: gm/imageblurtiled2.cpp
diff --git a/gm/imageblurtiled2.cpp b/gm/imageblurtiled2.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..82d148d795562d2e5c020555e1535d87c998c488
--- /dev/null
+++ b/gm/imageblurtiled2.cpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkDropShadowImageFilter.h"
+#include "SkPictureRecorder.h"
+
+#define TILE   128
+#define WIDTH  200
+#define HEIGHT 400
+#define DX     4
+#define DY     4
+#define SIGMA  3
+#define OFFSET (WIDTH + 10)
+
+// This GM is a regression test for http://skbug.com/2957 and http://crbug.com/415468.

[robertphillips, 2014/09/23 16:36:38]

// It draws a clipped rect in a layer which, in turn, has an exceedingly offset
drop shadow.
// This exercises the bounding box bloating effects of a saveLayer's paint in
the face of a clip.
?

+struct ImageBlurTiled2GM : public skiagm::GM {

[robertphillips, 2014/09/23 16:36:38]

SK_OVERRIDE on these two ?

+    virtual SkString onShortName() { return SkString("imageblurtiled2");  }

[Stephen White, 2014/09/23 16:03:51]

Nit: this GM should probably be renamed dropshadowtiled (or
dropshadowimagefiltertiled, but maybe that's redundant), since it's not a blur.

Also, we should consider making this a unit test instead.

[mtklein, 2014/09/23 17:43:13]

Very good idea.  Done.

+    virtual SkISize onISize() {
+        return SkISize::Make(WIDTH + OFFSET + DX + 3 * SIGMA, HEIGHT + DY + 3 * SIGMA);
+    }
+

[robertphillips, 2014/09/23 16:36:38]

Just make this "const SkPicture* create_picture();" ?

+    void drawInto(SkCanvas* canvas) const {
+        SkPaint layerPaint;
+        layerPaint.setImageFilter(
+                SkDropShadowImageFilter::Create(OFFSET, DX, DY, SIGMA, SK_ColorBLACK))->unref();
+
+        SkPaint green;
+        green.setColor(SK_ColorGREEN);
+
+        canvas->saveLayer(NULL, &layerPaint);
+            canvas->clipRect(SkRect::MakeWH(WIDTH, HEIGHT));
+            canvas->drawRect(SkRect::MakeWH(WIDTH, HEIGHT), green);
+        canvas->restore();
+    }
+

[robertphillips, 2014/09/23 16:36:38]

SK_OVERRIDE ?

+    virtual void onDraw(SkCanvas* canvas) {
+        SkPictureRecorder recorder;
+        const SkTileGridFactory::TileGridInfo info = { { TILE, TILE }, {0, 0}, {0, 0} };
+        SkTileGridFactory factory(info);
+
+        this->drawInto(recorder.beginRecording(WIDTH + OFFSET, HEIGHT, &factory));
+        SkAutoTUnref<const SkPicture> pic(recorder.endRecording());
+
+        SkRect bounds = { 0, 0, 0, 0 };
+        SkAssertResult(canvas->getClipBounds(&bounds));
+
+        for (SkScalar y = bounds.top() ; y < bounds.bottom(); y += TILE) {

[robertphillips, 2014/09/23 16:36:38]

indent here?

+        for (SkScalar x = bounds.left(); x < bounds.right() ; x += TILE) {
+            canvas->save();
+                canvas->clipRect(SkRect::MakeXYWH(x, y, TILE, TILE));
+                canvas->drawPicture(pic);
+            canvas->restore();
+        }
+        }
+    }

[robertphillips, 2014/09/23 16:36:38]

    private:
        typedef GM INHERITED;
?

+};

[robertphillips, 2014/09/23 16:36:38]

virtual uint32_t onGetFlags() const SK_OVERRIDE { return kSkipTiled_Flag; }

since it tiles internally?

+DEF_GM(return new ImageBlurTiled2GM);