Create an SkAndroidCodec API separate from SkCodec

dm/DMSrcSink.cpp

Index: dm/DMSrcSink.cpp
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index 394b84fa7bd568a6a44a0235cff6bfb08a1201f7..85c4b29784b71362714eb67a06bea278e814a28b 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -249,18 +249,7 @@ Error CodecSrc::draw(SkCanvas* canvas) const {
     if (!encoded) {
         return SkStringPrintf("Couldn't read %s.", fPath.c_str());
     }
-    SkAutoTDelete<SkCodec> codec(NULL);
-    if (kScaledCodec_Mode == fMode) {
-        codec.reset(SkScaledCodec::NewFromData(encoded));
-        // TODO (msarett): This should fall through to a fatal error once we support scaled
-        //                 codecs for all image types.
-        if (nullptr == codec.get()) {
-            return Error::Nonfatal(SkStringPrintf("Couldn't create scaled codec for %s.",
-                    fPath.c_str()));
-        }
-    } else {
-        codec.reset(SkCodec::NewFromData(encoded));
-    }
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(encoded));
     if (nullptr == codec.get()) {
         return SkStringPrintf("Couldn't create codec for %s.", fPath.c_str());
     }
@@ -323,7 +312,6 @@ Error CodecSrc::draw(SkCanvas* canvas) const {
     }
 
     switch (fMode) {
-        case kScaledCodec_Mode:
         case kCodec_Mode: {
             switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes(), nullptr,
                     colorPtr, colorCountPtr)) {
@@ -585,14 +573,7 @@ Error CodecSrc::draw(SkCanvas* canvas) const {
 
 SkISize CodecSrc::size() const {
     SkAutoTUnref<SkData> encoded(SkData::NewFromFileName(fPath.c_str()));
-    SkAutoTDelete<SkCodec> codec(nullptr);
-
-    if (kScaledCodec_Mode == fMode) {
-        codec.reset(SkScaledCodec::NewFromData(encoded));
-    } else {
-        codec.reset(SkCodec::NewFromData(encoded));
-    }
-
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(encoded));
     if (nullptr == codec) {
         return SkISize::Make(0, 0);
     }
@@ -608,6 +589,183 @@ Name CodecSrc::name() const {
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
+AndroidCodecSrc::AndroidCodecSrc(Path path, Mode mode, CodecSrc::DstColorType dstColorType,
+        int sampleSize)
+    : fPath(path)
+    , fMode(mode)
+    , fDstColorType(dstColorType)
+    , fSampleSize(sampleSize)
+{}
+
+bool AndroidCodecSrc::veto(SinkFlags flags) const {
+    // No need to test decoding to non-raster or indirect backend.
+    // TODO: Once we implement GPU paths (e.g. JPEG YUV), we should use a deferred decode to
+    // let the GPU handle it.
+    return flags.type != SinkFlags::kRaster
+        || flags.approach != SinkFlags::kDirect;
+}
+
+Error AndroidCodecSrc::draw(SkCanvas* canvas) const {
+    SkAutoTUnref<SkData> encoded(SkData::NewFromFileName(fPath.c_str()));
+    if (!encoded) {
+        return SkStringPrintf("Couldn't read %s.", fPath.c_str());
+    }
+    SkAutoTDelete<SkAndroidCodec> codec(SkAndroidCodec::NewFromData(encoded));
+    if (nullptr == codec.get()) {
+        return SkStringPrintf("Couldn't create android codec for %s.", fPath.c_str());
+    }
+
+    // Choose the color type to decode to
+    SkImageInfo decodeInfo = codec->getInfo();

[msarett, 2015/10/16 18:42:16]

Much of this code is shared with CodecSrc.  I'm looking at refactoring it.

+    SkColorType canvasColorType = canvas->imageInfo().colorType();
+    switch (fDstColorType) {
+        case CodecSrc::kIndex8_Always_DstColorType:
+            decodeInfo = codec->getInfo().makeColorType(kIndex_8_SkColorType);
+            if (kRGB_565_SkColorType == canvasColorType) {
+                return Error::Nonfatal("Testing non-565 to 565 is uninteresting.");
+            }
+            break;
+        case CodecSrc::kGrayscale_Always_DstColorType:
+            decodeInfo = codec->getInfo().makeColorType(kGray_8_SkColorType);
+            if (kRGB_565_SkColorType == canvasColorType) {
+                return Error::Nonfatal("Testing non-565 to 565 is uninteresting.");
+            }
+            break;
+        default:
+            decodeInfo = decodeInfo.makeColorType(canvasColorType);
+            break;
+    }
+
+    // Scale the image if it is desired.
+    SkISize size = codec->getSampledDimensions(fSampleSize);
+
+    // Visually inspecting very small output images is not necessary.  We will
+    // cover these cases in unit testing.
+    if ((size.width() <= 10 || size.height() <= 10) && 1 != fSampleSize) {
+        return Error::Nonfatal("Scaling very small images is uninteresting.");
+    }
+    decodeInfo = decodeInfo.makeWH(size.width(), size.height());
+
+    // Construct a color table for the decode if necessary
+    SkAutoTUnref<SkColorTable> colorTable(nullptr);
+    SkPMColor* colorPtr = nullptr;
+    int* colorCountPtr = nullptr;
+    int maxColors = 256;
+    if (kIndex_8_SkColorType == decodeInfo.colorType()) {
+        SkPMColor colors[256];
+        colorTable.reset(new SkColorTable(colors, maxColors));
+        colorPtr = const_cast<SkPMColor*>(colorTable->readColors());
+        colorCountPtr = &maxColors;
+    }
+
+    // FIXME: Currently we cannot draw unpremultiplied sources.
+    if (decodeInfo.alphaType() == kUnpremul_SkAlphaType) {
+        decodeInfo = decodeInfo.makeAlphaType(kPremul_SkAlphaType);
+    }
+
+    SkBitmap bitmap;
+    if (!bitmap.tryAllocPixels(decodeInfo, nullptr, colorTable.get())) {
+        return SkStringPrintf("Image(%s) is too large (%d x %d)\n", fPath.c_str(),
+                              decodeInfo.width(), decodeInfo.height());
+    }
+
+    // Create options for the codec.
+    SkAndroidCodec::AndroidOptions options;
+    options.fColorPtr = colorPtr;
+    options.fColorCount = colorCountPtr;
+    options.fSampleSize = fSampleSize;
+
+    switch (fMode) {
+        case kFullImage_Mode: {
+            switch (codec->getAndroidPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes(),
+                    &options)) {
+                case SkCodec::kSuccess:
+                case SkCodec::kIncompleteInput:
+                    break;
+                case SkCodec::kInvalidConversion:
+                    return Error::Nonfatal("Cannot convert to requested color type.\n");
+                default:
+                    return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
+            }
+            canvas->drawBitmap(bitmap, 0, 0);
+            return "";
+        }
+        case kDivisor_Mode: {
+            const int width = codec->getInfo().width();
+            const int height = codec->getInfo().height();
+            const int divisor = 2;
+            if (width < divisor || height < divisor) {
+                return Error::Nonfatal("Divisor is larger than image dimension.\n");
+            }
+
+            // Rounding the size of the subsets may leave some pixels uninitialized on the bottom
+            // and right edges of the bitmap.
+            bitmap.eraseColor(0);
+            for (uint32_t x = 0; x < divisor; x++) {
+                for (uint32_t y = 0; y < divisor; y++) {
+                    // Calculate the subset dimensions
+                    int subsetWidth = width / divisor;
+                    int subsetHeight = height / divisor;
+                    const int left = x * subsetWidth;
+                    const int top = y * subsetHeight;
+
+                    // Increase the size of the last subset in each row or column, when the
+                    // divisor does not divide evenly into the image dimensions
+                    subsetWidth += (x + 1 == divisor) ? (width % divisor) : 0;
+                    subsetHeight += (y + 1 == divisor) ? (height % divisor) : 0;
+                    SkIRect subset = SkIRect::MakeXYWH(left, top, subsetWidth, subsetHeight);
+                    if (!codec->getSubset(&subset)) {
+                        return "Could not get subset to decode.\n";
+                    }
+                    options.fSubset = &subset;
+                    void* pixels = bitmap.getAddr(subset.left() / fSampleSize,
+                            subset.top() / fSampleSize);
+                    SkISize scaledSubsetSize = codec->getSampledSubsetDimensions(fSampleSize,
+                            subset);
+                    SkImageInfo subsetDecodeInfo = decodeInfo.makeWH(scaledSubsetSize.width(),
+                            scaledSubsetSize.height());
+
+                    switch (codec->getAndroidPixels(subsetDecodeInfo, pixels, bitmap.rowBytes(),
+                            &options)) {
+                        case SkCodec::kSuccess:
+                        case SkCodec::kIncompleteInput:
+                            break;
+                        case SkCodec::kInvalidConversion:
+                            return Error::Nonfatal("Cannot convert to requested color type.\n");
+                        default:
+                            return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
+                    }
+                }
+            }
+            canvas->drawBitmap(bitmap, 0, 0);
+            return "";
+        }
+        default:
+            SkASSERT(false);
+            return "Error: Should not be reached.\n";
+    }
+}
+
+SkISize AndroidCodecSrc::size() const {
+    SkAutoTUnref<SkData> encoded(SkData::NewFromFileName(fPath.c_str()));
+    SkAutoTDelete<SkAndroidCodec> codec(SkAndroidCodec::NewFromData(encoded));
+    if (nullptr == codec) {

[scroggo, 2015/10/16 21:13:55]

Maybe this reproduces the old code, but is it necessary? Don't we only create
the Src if the trial run succeeded?

Oh, I think I'm confusing this with nanobench...

[msarett, 2015/10/19 16:06:10]

We'll create the AndroidCodecSrc before verifying that we can create an
AndroidCodec.

We check this in onDraw(), but size() will actually be called first to create
the SkCanvas.

Of course, we should always succeed when creating an AndroidCodec since this
test is only enabled for webp, jpeg, and png - but I think it's safer to check
than to seg fault.

That way we will fail when we fail to create an AndroidCodec in onDraw().

[scroggo, 2015/10/19 20:03:20]

sgtm

+        return SkISize::Make(0, 0);
+    }
+    return codec->getSampledDimensions(fSampleSize);
+}
+
+Name AndroidCodecSrc::name() const {
+    // We will replicate the names used by CodecSrc so that images can
+    // be compared in Gold.
+    if (1 == fSampleSize) {
+        return SkOSPath::Basename(fPath.c_str());
+    }
+    return get_scaled_name(fPath, get_scale_from_sample_size(fSampleSize));
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
 ImageSrc::ImageSrc(Path path, int divisor) : fPath(path), fDivisor(divisor) {}
 
 bool ImageSrc::veto(SinkFlags flags) const {