Use SkPngEncoder and SkWebpEncoder in WebKit platform

third_party/WebKit/Source/platform/graphics/ImageBuffer.cpp

 /*
  * Copyright (c) 2008, Google Inc. All rights reserved.
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
@@ skipping 32 matching lines @@
 #include "platform/graphics/ImageBufferClient.h"
 #include "platform/graphics/RecordingImageBufferSurface.h"
 #include "platform/graphics/StaticBitmapImage.h"
 #include "platform/graphics/UnacceleratedImageBufferSurface.h"
 #include "platform/graphics/gpu/DrawingBuffer.h"
 #include "platform/graphics/gpu/Extensions3DUtil.h"
 #include "platform/graphics/paint/PaintImage.h"
 #include "platform/graphics/paint/PaintRecord.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "platform/image-encoders/ImageEncoder.h"
-#include "platform/image-encoders/PNGImageEncoder.h"
-#include "platform/image-encoders/WEBPImageEncoder.h"
 #include "platform/network/mime/MIMETypeRegistry.h"
 #include "platform/wtf/CheckedNumeric.h"
 #include "platform/wtf/MathExtras.h"
 #include "platform/wtf/PtrUtil.h"
 #include "platform/wtf/Vector.h"
 #include "platform/wtf/text/Base64.h"
 #include "platform/wtf/text/WTFString.h"
 #include "platform/wtf/typed_arrays/ArrayBufferContents.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebGraphicsContext3DProvider.h"
@@ skipping 474 matching lines @@
 }
 
 void ImageBuffer::SetNeedsCompositingUpdate() {
   if (client_)
     client_->SetNeedsCompositingUpdate();
 }
 
 bool ImageDataBuffer::EncodeImage(const String& mime_type,
                                   const double& quality,
                                   Vector<unsigned char>* encoded_image) const {
+  SkImageInfo info =
+      SkImageInfo::Make(Width(), Height(), kRGBA_8888_SkColorType,

[scroggo_chromium, 2017/05/22 13:35:04]

It seems weird to me that the color type and alpha type are hardcoded, but it
looks like there's an implicit contract about using ImageDataBuffer.

[msarett1, 2017/05/22 15:33:56]

Yeah that seems to be part of the implicit contract.  Now that the image encoder
supports SkImageInfos, this could become more flexible.

But that might be better for another change.

+                        kUnpremul_SkAlphaType, nullptr);
+  size_t rowBytes = Width() * SkColorTypeBytesPerPixel(kRGBA_8888_SkColorType);

[scroggo_chromium, 2017/05/22 13:35:04]

Should this be info.minRowBytes?

Also, nit: Could be const?

[msarett1, 2017/05/22 15:33:56]

Yeah, that's better.

+  SkPixmap src(info, Pixels(), rowBytes);

[scroggo_chromium, 2017/05/22 13:35:04]

This kind of seems like it should be in the constructor. That said, it seems
like we really just want two functions (one that encodes, and the other that
writes to DataUrl); the only callsites I saw use a temporary object.

No need to address in this CL, but I wonder if we should clean this up someday?

[msarett1, 2017/05/22 15:33:56]

I agree.  This could/should just be two methods.  Will consider a future
cleanup.

+
   if (mime_type == "image/jpeg") {
-    SkImageInfo info =
-        SkImageInfo::Make(Width(), Height(), kRGBA_8888_SkColorType,
-                          kUnpremul_SkAlphaType, nullptr);
-    size_t rowBytes =
-        Width() * SkColorTypeBytesPerPixel(kRGBA_8888_SkColorType);
-    SkPixmap src(info, Pixels(), rowBytes);
-
     SkJpegEncoder::Options options;
     options.fQuality = ImageEncoder::ComputeJpegQuality(quality);
     options.fAlphaOption = SkJpegEncoder::AlphaOption::kBlendOnBlack;
     options.fBlendBehavior = SkTransferFunctionBehavior::kIgnore;
     if (options.fQuality == 100) {
       options.fDownsample = SkJpegEncoder::Downsample::k444;
     }
     return ImageEncoder::Encode(encoded_image, src, options);
   }
 
   if (mime_type == "image/webp") {
-    int compression_quality = WEBPImageEncoder::kDefaultCompressionQuality;
-    if (quality >= 0.0 && quality <= 1.0)
-      compression_quality = static_cast<int>(quality * 100 + 0.5);
-    return WEBPImageEncoder::Encode(*this, compression_quality, encoded_image);
+    SkWebpEncoder::Options options = ImageEncoder::ComputeWebpOptions(
+        quality, SkTransferFunctionBehavior::kIgnore);
+    return ImageEncoder::Encode(encoded_image, src, options);
   }
 
   DCHECK_EQ(mime_type, "image/png");
-  return PNGImageEncoder::Encode(*this, encoded_image);
+  SkPngEncoder::Options options;
+  options.fFilterFlags = SkPngEncoder::FilterFlag::kSub;
+  options.fZLibLevel = 3;
+  options.fUnpremulBehavior = SkTransferFunctionBehavior::kIgnore;
+  return ImageEncoder::Encode(encoded_image, src, options);
 }
 
 String ImageDataBuffer::ToDataURL(const String& mime_type,
                                   const double& quality) const {
   DCHECK(MIMETypeRegistry::IsSupportedImageMIMETypeForEncoding(mime_type));
 
   Vector<unsigned char> result;
   if (!EncodeImage(mime_type, quality, &result))
     return "data:,";
 
   return "data:" + mime_type + ";base64," + Base64Encode(result);
 }
 
 }  // namespace blink