Add the ability to decode a subset to SkCodec.

dm/DM.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 "CrashHandler.h"
 #include "DMJsonWriter.h"
 #include "DMSrcSink.h"
@@ skipping 201 matching lines @@
     const float scales[] = { 0.125f, 0.25f, 0.375f, 0.5f, 0.625f, 0.750f, 0.875f, 1.0f };
 
     for (float scale : scales) {
         if (scale != 1.0f && (path.endsWith(".webp") || path.endsWith(".WEBP"))) {
             // FIXME: skbug.com/4038 Scaling webp seems to leave some pixels uninitialized/
             // compute their colors based on uninitialized values.
             continue;
         }
         // Build additional test cases for images that decode natively to non-canvas types
         switch(codec->getInfo().colorType()) {
             case kGray_8_SkColorType:

[emmaleer, 2015/07/17 22:31:05]

Should run the Codec Subset test for Gray8 to Gray8 or Index8 to Index8 decodes?
Maybe we should add the Codec Subset test to the kGray_8_SkColorType case, and
the kIndex_8_SkColorType case in this switch statement, to test images which are
Index8 or Gray8.

[scroggo, 2015/07/20 14:25:42]

Good question. Currently WEBP is the only codec that supports subsets, and it
will never report gray or index8.

I've added a comment.

                 push_src("image", "codec_kGray8", new CodecSrc(path, CodecSrc::kNormal_Mode,
                         CodecSrc::kGrayscale_Always_DstColorType, scale));
                 push_src("image", "scanline_kGray8", new CodecSrc(path, CodecSrc::kScanline_Mode,
                         CodecSrc::kGrayscale_Always_DstColorType, scale));
                 push_src("image", "scanline_subset_kGray8", new CodecSrc(path,
                         CodecSrc::kScanline_Subset_Mode, CodecSrc::kGrayscale_Always_DstColorType,
                         scale));
                 push_src("image", "stripe_kGray8", new CodecSrc(path, CodecSrc::kStripe_Mode,
                         CodecSrc::kGrayscale_Always_DstColorType, scale));
                 // Intentional fall through
@@ skipping 17 matching lines @@
 
         // Decode all images to the canvas color type
         push_src("image", "codec", new CodecSrc(path, CodecSrc::kNormal_Mode,
                 CodecSrc::kGetFromCanvas_DstColorType, scale));
         push_src("image", "scanline", new CodecSrc(path, CodecSrc::kScanline_Mode,
                 CodecSrc::kGetFromCanvas_DstColorType, scale));
         push_src("image", "scanline_subset", new CodecSrc(path, CodecSrc::kScanline_Subset_Mode,
                 CodecSrc::kGetFromCanvas_DstColorType, scale));
         push_src("image", "stripe", new CodecSrc(path, CodecSrc::kStripe_Mode,
                 CodecSrc::kGetFromCanvas_DstColorType, scale));
+        push_src("image", "codec_subset", new CodecSrc(path, CodecSrc::kSubset_Mode,
+                CodecSrc::kGetFromCanvas_DstColorType, scale));
     }
 }
 
 static bool codec_supported(const char* ext) {
     // FIXME: Once other versions of SkCodec are available, we can add them to this
     // list (and eventually we can remove this check once they are all supported).
     static const char* const exts[] = {
         "bmp", "gif", "jpg", "jpeg", "png", "ico", "wbmp", "webp",
         "BMP", "GIF", "JPG", "JPEG", "PNG", "ICO", "WBMP", "WEBP",
     };
@@ skipping 556 matching lines @@
     }
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return dm_main();
 }
 #endif