Use SkPngEncoder and SkWebpEncoder in WebKit platform

third_party/WebKit/Source/platform/image-encoders/ImageEncoder.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ImageEncoder_h
 #define ImageEncoder_h
 
 #include "platform/PlatformExport.h"
 #include "platform/wtf/Vector.h"
 #include "third_party/skia/include/core/SkStream.h"
 #include "third_party/skia/include/encode/SkJpegEncoder.h"
 #include "third_party/skia/include/encode/SkPngEncoder.h"
+#include "third_party/skia/include/encode/SkWebpEncoder.h"
 
 namespace blink {
 
 class VectorWStream : public SkWStream {
  public:
   VectorWStream(Vector<unsigned char>* dst) : dst_(dst) {
     DCHECK(dst_);
     DCHECK_EQ(0UL, dst->size());
   }
 
@@ skipping 12 matching lines @@
 class PLATFORM_EXPORT ImageEncoder {
  public:
   static bool Encode(Vector<unsigned char>* dst,
                      const SkPixmap& src,
                      const SkJpegEncoder::Options&);
 
   static bool Encode(Vector<unsigned char>* dst,
                      const SkPixmap& src,
                      const SkPngEncoder::Options&);
 
+  static bool Encode(Vector<unsigned char>* dst,
+                     const SkPixmap& src,
+                     const SkWebpEncoder::Options&);
+
   static std::unique_ptr<ImageEncoder> Create(Vector<unsigned char>* dst,
                                               const SkPixmap& src,
                                               const SkJpegEncoder::Options&);
 
   static std::unique_ptr<ImageEncoder> Create(Vector<unsigned char>* dst,
                                               const SkPixmap& src,
                                               const SkPngEncoder::Options&);
 
   bool encodeRows(int numRows) { return encoder_->encodeRows(numRows); }
 
   /**
    *  If quality is in [0, 1], this will simply convert to a [0, 100]
    *  integer scale (which is what is used by libjpeg-turbo).
    *
    *  Otherwise, this will return the default value.
    */
   static int ComputeJpegQuality(double quality);
 
+  /**
+   *  Sets Skia encoding options based on the requested quality.
+   *
+   *  If quality is 1, this will signal a lossless encode.
+   *
+   *  Otherwise, this will use webp lossy encoding.
+   *  If quality is in [0, 1), this will simply convert to a [0, 100)
+   *  float scale (which is what is used by libwebp).  If the quality
+   *  is out of range, this will use the default value.

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

What is the default value? Will it be lossy or lossless?

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

Added comments.

+   */
+  static SkWebpEncoder::Options ComputeWebpOptions(
+      double quality,
+      SkTransferFunctionBehavior unpremulBehavior);
+
  private:
   ImageEncoder(Vector<unsigned char>* dst) : dst_(dst) {}
 
   VectorWStream dst_;
   std::unique_ptr<SkEncoder> encoder_;
 };
 };
 
 #endif