Fix two bugs when deciding to tile. Large images were always tiling.

usedTileBytes was actually usedTileTexels, so we underestimated how much
of the image we were using by a factor of 4.

Then, to determine if we were using more than 50% of the image, we wrote:
usedTileBytes < 2 * bmpSize;

That meant we were off by another factor of 4.

BUG=skia:

Change-Id: Iba2acc75c5e7603543f05e4473b73f76a2937d7a
Reviewed-on: https://skia-review.googlesource.com/8063
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 4068c2b102..6f8bad9d76 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -810,9 +810,10 @@ bool SkGpuDevice::shouldTileImageID(uint32_t imageID, const SkIRect& imageRect,
                                clippedSubset);
     *tileSize = kBmpSmallTileSize; // already know whole bitmap fits in one max sized tile.
     size_t usedTileBytes = get_tile_count(*clippedSubset, kBmpSmallTileSize) *
-                           kBmpSmallTileSize * kBmpSmallTileSize;
+                           kBmpSmallTileSize * kBmpSmallTileSize *
+                           sizeof(SkPMColor);  // assume 32bit pixels;
 
-    return usedTileBytes < 2 * bmpSize;
+    return usedTileBytes * 2 < bmpSize;
 }
 
 bool SkGpuDevice::shouldTileImage(const SkImage* image, const SkRect* srcRectPtr,