Use new jpeg_crop_scanlines() API to optimize jpeg subset decodes

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 221 matching lines @@
     switch (mode) {
         case CodecSrc::kCodec_Mode:
             folder.append("codec");
             break;
         case CodecSrc::kCodecZeroInit_Mode:
             folder.append("codec_zero_init");
             break;
         case CodecSrc::kScanline_Mode:
             folder.append("scanline");
             break;
-        case CodecSrc::kStripe_Mode:
-            folder.append("stripe");
+        case CodecSrc::kTile_Mode:
+            folder.append("tile");
             break;
         case CodecSrc::kSubset_Mode:
             folder.append("codec_subset");
             break;
         case CodecSrc::kGen_Mode:
             folder.append("gen");
             break;
     }
 
     switch (dstColorType) {
@@ skipping 85 matching lines @@
         SkDebugf("Couldn't create codec for %s.", path.c_str());
         return;
     }
 
     // Native Scales
     // TODO (msarett): Implement scaling tests for SkImageDecoder in order to compare with these
     //                 tests.  SkImageDecoder supports downscales by integer factors.
     // SkJpegCodec natively supports scaling to: 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875
     const float nativeScales[] = { 0.125f, 0.25f, 0.375f, 0.5f, 0.625f, 0.750f, 0.875f, 1.0f };
 
-    const CodecSrc::Mode nativeModes[] = { CodecSrc::kCodec_Mode, CodecSrc::kCodecZeroInit_Mode,
-            CodecSrc::kScanline_Mode, CodecSrc::kStripe_Mode, CodecSrc::kSubset_Mode,
-            CodecSrc::kGen_Mode };
+    CodecSrc::Mode nativeModes[5];

[scroggo, 2016/02/22 15:55:03]

nit: As long as you're rewriting this code, why not use an SkTArray like
alphaModes does, down below. Then you don't need to worry about using the
correct index/size.

[msarett, 2016/02/22 17:38:15]

Agreed that's better.  I'll fix the color types as well.

+    nativeModes[0] = CodecSrc::kCodec_Mode;
+    nativeModes[1] = CodecSrc::kCodecZeroInit_Mode;
+    nativeModes[2] = CodecSrc::kGen_Mode;
+    uint32_t numNativeModes;
+    switch (codec->getEncodedFormat()) {
+        case SkEncodedFormat::kJPEG_SkEncodedFormat:
+            nativeModes[3] = CodecSrc::kScanline_Mode;
+            nativeModes[4] = CodecSrc::kTile_Mode;
+            numNativeModes = 5;
+            break;
+        case SkEncodedFormat::kWEBP_SkEncodedFormat:
+            nativeModes[3] = CodecSrc::kSubset_Mode;
+            numNativeModes = 4;
+            break;
+        default:
+            nativeModes[3] = CodecSrc::kScanline_Mode;
+            numNativeModes = 4;
+            break;
+    }
 
     CodecSrc::DstColorType colorTypes[3];
     uint32_t numColorTypes;
     switch (codec->getInfo().colorType()) {
         case kGray_8_SkColorType:
             colorTypes[0] = CodecSrc::kGetFromCanvas_DstColorType;
             colorTypes[1] = CodecSrc::kGrayscale_Always_DstColorType;
             if (kWBMP_SkEncodedFormat == codec->getEncodedFormat()) {
                 colorTypes[2] = CodecSrc::kIndex8_Always_DstColorType;
                 numColorTypes = 3;
@@ skipping 12 matching lines @@
             break;
     }
 
     SkTArray<SkAlphaType> alphaModes;
     alphaModes.push_back(kPremul_SkAlphaType);
     alphaModes.push_back(kUnpremul_SkAlphaType);
     if (codec->getInfo().alphaType() == kOpaque_SkAlphaType) {
         alphaModes.push_back(kOpaque_SkAlphaType);
     }
 
-    for (CodecSrc::Mode mode : nativeModes) {
+    for (uint32_t j = 0; j < numNativeModes; j++) {
         // SkCodecImageGenerator only runs for the default colorType
         // recommended by SkCodec.  There is no need to generate multiple
         // tests for different colorTypes.
         // TODO (msarett): Add scaling support to SkCodecImageGenerator.
-        if (CodecSrc::kGen_Mode == mode) {
+        if (CodecSrc::kGen_Mode == nativeModes[j]) {
             // FIXME: The gpu backend does not draw kGray sources correctly. (skbug.com/4822)
             if (kGray_8_SkColorType != codec->getInfo().colorType()) {
-                push_codec_src(path, mode, CodecSrc::kGetFromCanvas_DstColorType,
+                push_codec_src(path, CodecSrc::kGen_Mode, CodecSrc::kGetFromCanvas_DstColorType,
                                codec->getInfo().alphaType(), 1.0f);
             }
             continue;
         }
 
         for (float scale : nativeScales) {
             for (uint32_t i = 0; i < numColorTypes; i++) {
                 for (SkAlphaType alphaType : alphaModes) {
-                    push_codec_src(path, mode, colorTypes[i], alphaType, scale);
+                    push_codec_src(path, nativeModes[j], colorTypes[i], alphaType, scale);
                 }
             }
         }
     }
 
     // https://bug.skia.org/4428
     bool subset = false;
     // The following image types are supported by BitmapRegionDecoder,
     // so we will test full image decodes and subset decodes.
     static const char* const exts[] = {
@@ skipping 862 matching lines @@
                                                            Reporter* reporter,
                                                            GrContextFactory* factory);
 } // namespace skiatest
 
 #if !defined(SK_BUILD_FOR_IOS)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return dm_main();
 }
 #endif