add readPixels to SkImage

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 "SkDecodingImageGenerator.h"
@@ skipping 100 matching lines @@
             SkAutoTUnref<SkData> src(
                  SkImageEncoder::EncodeData(bitmap, SkImageEncoder::kPNG_Type, 100));
             return SkImage::NewFromGenerator(
                 SkDecodingImageGenerator::Create(src, SkDecodingImageGenerator::Options()));
         }
     }
     SkASSERT(false);
     return NULL;
 }
 
+static void set_pixels(SkPMColor pixels[], int count, SkPMColor color) {
+    sk_memset32(pixels, color, count);
+}
+static bool has_pixels(const SkPMColor pixels[], int count, SkPMColor expected) {
+    for (int i = 0; i < count; ++i) {
+        if (pixels[i] != expected) {
+            return false;
+        }
+    }
+    return true;
+}
+
+static void test_image_readpixels(skiatest::Reporter* reporter, SkImage* image,
+                                  SkPMColor expected) {
+    const SkPMColor notExpected = ~expected;
+
+    const int w = 2, h = 2;
+    const size_t rowBytes = w * sizeof(SkPMColor);
+    SkPMColor pixels[w*h];
+
+    SkImageInfo info;
+
+    info = SkImageInfo::MakeUnknown(w, h);
+    REPORTER_ASSERT(reporter, !image->readPixels(info, pixels, rowBytes, 0, 0));
+
+    // out-of-bounds should fail
+    info = SkImageInfo::MakeN32Premul(w, h);
+    REPORTER_ASSERT(reporter, !image->readPixels(info, pixels, rowBytes, -w, 0));
+    REPORTER_ASSERT(reporter, !image->readPixels(info, pixels, rowBytes, 0, -h));
+    REPORTER_ASSERT(reporter, !image->readPixels(info, pixels, rowBytes, image->width(), 0));
+    REPORTER_ASSERT(reporter, !image->readPixels(info, pixels, rowBytes, 0, image->height()));
+
+    // top-left should succeed
+    set_pixels(pixels, w*h, notExpected);
+    REPORTER_ASSERT(reporter, image->readPixels(info, pixels, rowBytes, 0, 0));
+    REPORTER_ASSERT(reporter, has_pixels(pixels, w*h, expected));
+
+    // bottom-right should succeed
+    set_pixels(pixels, w*h, notExpected);
+    REPORTER_ASSERT(reporter, image->readPixels(info, pixels, rowBytes,
+                                                image->width() - w, image->height() - h));
+    REPORTER_ASSERT(reporter, has_pixels(pixels, w*h, expected));
+
+    // partial top-left should succeed
+    set_pixels(pixels, w*h, notExpected);
+    REPORTER_ASSERT(reporter, image->readPixels(info, pixels, rowBytes, -1, -1));
+    REPORTER_ASSERT(reporter, pixels[3] == expected);
+    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 test_imagepeek(skiatest::Reporter* reporter, GrContextFactory* factory) {
     static const struct {
         ImageType   fType;
         bool        fPeekShouldSucceed;
         const char* fName;
     } gRec[] = {
         { kRasterCopy_ImageType,    true,       "RasterCopy"    },
         { kRasterData_ImageType,    true,       "RasterData"    },
         { kGpu_ImageType,           false,      "Gpu"           },
         { kCodec_ImageType,         false,      "Codec"         },
@@ skipping 21 matching lines @@
         REPORTER_ASSERT(reporter, gRec[i].fPeekShouldSucceed == success);
         if (success) {
             REPORTER_ASSERT(reporter, 10 == info.width());
             REPORTER_ASSERT(reporter, 10 == info.height());
             REPORTER_ASSERT(reporter, kN32_SkColorType == info.colorType());
             REPORTER_ASSERT(reporter, kPremul_SkAlphaType == info.alphaType() ||
                             kOpaque_SkAlphaType == info.alphaType());
             REPORTER_ASSERT(reporter, info.minRowBytes() <= rowBytes);
             REPORTER_ASSERT(reporter, pmcolor == *(const SkPMColor*)addr);
         }
+
+        test_image_readpixels(reporter, image, pmcolor);
     }
 }
 
 static void test_canvaspeek(skiatest::Reporter* reporter,
                             GrContextFactory* factory) {
     static const struct {
         SurfaceType fType;
         bool        fPeekShouldSucceed;
     } gRec[] = {
         { kRaster_SurfaceType,          true    },
@@ skipping 272 matching lines @@
                 TestSurfaceNoCanvas(reporter, kGpuScratch_SurfaceType, context, SkSurface::kDiscard_ContentChangeMode);
                 TestSurfaceNoCanvas(reporter, kGpu_SurfaceType, context, SkSurface::kRetain_ContentChangeMode);
                 TestSurfaceNoCanvas(reporter, kGpuScratch_SurfaceType, context, SkSurface::kRetain_ContentChangeMode);
                 TestGetTexture(reporter, kGpu_SurfaceType, context);
                 TestGetTexture(reporter, kGpuScratch_SurfaceType, context);
             }
         }
     }
 #endif
 }