Test scanline decoding in DM.

BUG=skia:3475

Review URL: https://codereview.chromium.org/999173010

dm/DM.cpp

@@ -25,7 +25,7 @@
 #include "Test.h"
 #include "Timer.h"
 
-DEFINE_string(src, "tests gm skp image subset codec", "Source types to test.");
+DEFINE_string(src, "tests gm skp image subset codec scanline", "Source types to test.");
 DEFINE_bool(nameByHash, false,
             "If true, write to FLAGS_writePath[0]/<hash>.png instead of "
             "to FLAGS_writePath[0]/<config>/<sourceType>/<name>.png");
@@ -187,7 +187,8 @@ static void gather_srcs() {
                     push_src("image", new ImageSrc(path));     // Decode entire image.
                     push_src("subset", new ImageSrc(path, 2)); // Decode into 2 x 2 subsets
                     if (codec_supported(exts[j])) {
-                        push_src("codec", new CodecSrc(path));     // Decode with SkCodec.
+                        push_src("codec", new CodecSrc(path, CodecSrc::kNormal_Mode));
+                        push_src("scanline", new CodecSrc(path, CodecSrc::kScanline_Mode));
                     }
                 }
             }
@@ -195,7 +196,8 @@ static void gather_srcs() {
             // assume that FLAGS_images[i] is a valid image if it is a file.
             push_src("image", new ImageSrc(flag));     // Decode entire image.
             push_src("subset", new ImageSrc(flag, 2)); // Decode into 2 x 2 subsets
-            push_src("codec", new CodecSrc(flag));     // Decode with SkCodec.
+            push_src("codec", new CodecSrc(flag, CodecSrc::kNormal_Mode));
+            push_src("scanline", new CodecSrc(flag, CodecSrc::kScanline_Mode));
         }
     }
 }

dm/DMSrcSink.cpp

@@ -19,6 +19,7 @@
 #include "SkPictureData.h"
 #include "SkPictureRecorder.h"
 #include "SkRandom.h"
+#include "SkScanlineDecoder.h"
 #include "SkSVGCanvas.h"
 #include "SkStream.h"
 #include "SkXMLWriter.h"
@@ -51,7 +52,7 @@ Name GMSrc::name() const {
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
-CodecSrc::CodecSrc(Path path) : fPath(path) {}
+CodecSrc::CodecSrc(Path path, Mode mode) : fPath(path), fMode(mode) {}
 
 Error CodecSrc::draw(SkCanvas* canvas) const {
     SkImageInfo canvasInfo;
@@ -83,20 +84,43 @@ Error CodecSrc::draw(SkCanvas* canvas) const {
                               decodeInfo.width(), decodeInfo.height());
     }
 
-    SkAutoLockPixels alp(bitmap);
-    switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes())) {
-        case SkImageGenerator::kSuccess:
-        // We consider incomplete to be valid, since we should still decode what is
-        // available.
-        case SkImageGenerator::kIncompleteInput:
-            canvas->drawBitmap(bitmap, 0, 0);
-            return "";
-        case SkImageGenerator::kInvalidConversion:
-            return Error::Nonfatal("Incompatible colortype conversion");
-        default:
-            // Everything else is considered a failure.
-            return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
+    switch (fMode) {
+        case kNormal_Mode:
+            switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes())) {
+                case SkImageGenerator::kSuccess:
+                    // We consider incomplete to be valid, since we should still decode what is
+                    // available.
+                case SkImageGenerator::kIncompleteInput:
+                    break;
+                case SkImageGenerator::kInvalidConversion:
+                    return Error::Nonfatal("Incompatible colortype conversion");
+                default:
+                    // Everything else is considered a failure.
+                    return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
+            }
+            break;
+        case kScanline_Mode: {
+            SkScanlineDecoder* scanlineDecoder = codec->getScanlineDecoder(decodeInfo);
+            if (NULL == scanlineDecoder) {
+                return Error::Nonfatal("Cannot use scanline decoder for all images");
+            }
+            for (int y = 0; y < decodeInfo.height(); ++y) {
+                const SkImageGenerator::Result result = scanlineDecoder->getScanlines(
+                        bitmap.getAddr(0, y), 1, 0);
+                switch (result) {
+                    case SkImageGenerator::kSuccess:
+                    case SkImageGenerator::kIncompleteInput:
+                        break;
+                    default:
+                        return SkStringPrintf("%s failed after %d scanlines with error message %d",
+                                              fPath.c_str(), y-1, (int) result);
+                }
+            }
+            break;
+        }
     }
+    canvas->drawBitmap(bitmap, 0, 0);
+    return "";
 }
 
 SkISize CodecSrc::size() const {

dm/DMSrcSink.h

@@ -90,13 +90,18 @@ private:
 
 class CodecSrc : public Src {
 public:
-    explicit CodecSrc(Path path);
+    enum Mode {
+        kNormal_Mode,
+        kScanline_Mode,
+    };
+    CodecSrc(Path, Mode);
 
     Error draw(SkCanvas*) const SK_OVERRIDE;
     SkISize size() const SK_OVERRIDE;
     Name name() const SK_OVERRIDE;
 private:
     Path fPath;
+    Mode fMode;
 };