Fix SkImage::asLegacyBitmap() rowBytes assert

tests/SurfaceTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkData.h"
 #include "SkDevice.h"
@@ skipping 372 matching lines @@
     REPORTER_ASSERT(reporter, has_pixels(pixels, w*h - 1, notExpected));
 
     // partial bottom-right should succeed
     set_pixels(pixels, w*h, notExpected);
     REPORTER_ASSERT(reporter, image->readPixels(info, pixels, rowBytes,
                                                 image->width() - 1, image->height() - 1));
     REPORTER_ASSERT(reporter, pixels[0] == expected);
     REPORTER_ASSERT(reporter, has_pixels(&pixels[1], w*h - 1, notExpected));
 }
 
+static void check_legacy_bitmap(skiatest::Reporter* reporter, const SkImage* image,
+                                const SkBitmap& bitmap, SkImage::LegacyBitmapMode mode) {
+    REPORTER_ASSERT(reporter, image->width() == bitmap.width());
+    REPORTER_ASSERT(reporter, image->height() == bitmap.height());
+    REPORTER_ASSERT(reporter, image->isOpaque() == bitmap.isOpaque());
+
+    if (SkImage::kRO_LegacyBitmapMode == mode) {
+        REPORTER_ASSERT(reporter, bitmap.isImmutable());
+    }
+
+    SkAutoLockPixels alp(bitmap);
+    REPORTER_ASSERT(reporter, bitmap.getPixels());
+
+    const SkImageInfo info = SkImageInfo::MakeN32(1, 1, bitmap.alphaType());
+    SkPMColor imageColor;
+    REPORTER_ASSERT(reporter, image->readPixels(info, &imageColor, sizeof(SkPMColor), 0, 0));
+    REPORTER_ASSERT(reporter, imageColor == *bitmap.getAddr32(0, 0));
+}
+
 static void test_legacy_bitmap(skiatest::Reporter* reporter, const SkImage* image) {
     const SkImage::LegacyBitmapMode modes[] = {
         SkImage::kRO_LegacyBitmapMode,
         SkImage::kRW_LegacyBitmapMode,
     };
     for (size_t i = 0; i < SK_ARRAY_COUNT(modes); ++i) {
         SkBitmap bitmap;
         REPORTER_ASSERT(reporter, image->asLegacyBitmap(&bitmap, modes[i]));
+        check_legacy_bitmap(reporter, image, bitmap, modes[i]);
 
-        REPORTER_ASSERT(reporter, image->width() == bitmap.width());
-        REPORTER_ASSERT(reporter, image->height() == bitmap.height());
-        REPORTER_ASSERT(reporter, image->isOpaque() == bitmap.isOpaque());
+        // Test subsetting to exercise the rowBytes logic.
+        SkBitmap tmp;
+        REPORTER_ASSERT(reporter, bitmap.extractSubset(&tmp, SkIRect::MakeWH(image->width() / 2,
+                                                                             image->height() / 2)));
+        SkAutoTUnref<SkImage> subsetImage(SkImage::NewFromBitmap(tmp));
+        REPORTER_ASSERT(reporter, subsetImage);
 
-        bitmap.lockPixels();
-        REPORTER_ASSERT(reporter, bitmap.getPixels());
-
-        const SkImageInfo info = SkImageInfo::MakeN32(1, 1, bitmap.alphaType());
-        SkPMColor imageColor;
-        REPORTER_ASSERT(reporter, image->readPixels(info, &imageColor, sizeof(SkPMColor), 0, 0));
-        REPORTER_ASSERT(reporter, imageColor == *bitmap.getAddr32(0, 0));
-
-        if (SkImage::kRO_LegacyBitmapMode == modes[i]) {
-            REPORTER_ASSERT(reporter, bitmap.isImmutable());
-        }
+        SkBitmap subsetBitmap;
+        REPORTER_ASSERT(reporter, subsetImage->asLegacyBitmap(&subsetBitmap, modes[i]));
+        check_legacy_bitmap(reporter, subsetImage, subsetBitmap, modes[i]);
     }
 }
 
 static void test_imagepeek(skiatest::Reporter* reporter, GrContextFactory* factory) {
     static const struct {
         ImageType   fType;
         bool        fPeekShouldSucceed;
         const char* fName;
     } gRec[] = {
         { kRasterCopy_ImageType,    true,       "RasterCopy"    },
@@ skipping 564 matching lines @@
     // We expect the ref'd image to see the new color, but cpy'd one should still see the old color
     test_image_color(reporter, refImg, expected1);
     test_image_color(reporter, cpyImg, expected0);
 
     // Now exercise the release proc
     REPORTER_ASSERT(reporter, !releaseCtx.fIsReleased);
     refImg.reset(NULL); // force a release of the image
     REPORTER_ASSERT(reporter, releaseCtx.fIsReleased);
 }
 #endif