1 files changed, 98 insertions, 0 deletions
diff --git a/include/encode/SkJpegEncoder.h b/include/encode/SkJpegEncoder.h
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+++ b/include/encode/SkJpegEncoder.h
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+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkJpegEncoder_DEFINED
+#define SkJpegEncoder_DEFINED
+
+#include "SkEncoder.h"
+
+class SkJpegEncoderMgr;
+class SkWStream;
+
+class SK_API SkJpegEncoder : public SkEncoder {
+public:
+
+    enum class AlphaOption {
+        kIgnore,
+        kBlendOnBlack,
+    };
+
+    enum class Downsample {
+        /**
+         *  Reduction by a factor of two in both the horizontal and vertical directions.
+         */
+        k420,
+
+        /**
+         *  Reduction by a factor of two in the horizontal direction.
+         */
+        k422,
+
+        /**
+         *  No downsampling.
+         */
+        k444,
+    };
+
+    struct Options {
+        /**
+         *  |fQuality| must be in [0, 100] where 0 corresponds to the lowest quality.
+         */
+        int fQuality = 100;
+
+        /**
+         *  Choose the downsampling factor for the U and V components.  This is only
+         *  meaningful if the |src| is not kGray, since kGray will not be encoded as YUV.
+         *
+         *  Our default value matches the libjpeg-turbo default.
+         */
+        Downsample fDownsample = Downsample::k420;
+
+        /**
+         *  Jpegs must be opaque.  This instructs the encoder on how to handle input
+         *  images with alpha.
+         *
+         *  The default is to ignore the alpha channel and treat the image as opaque.
+         *  Another option is to blend the pixels onto a black background before encoding.
+         *  In the second case, the encoder supports linear or legacy blending.
+         */
+        AlphaOption fAlphaOption = AlphaOption::kIgnore;
+        SkTransferFunctionBehavior fBlendBehavior = SkTransferFunctionBehavior::kRespect;
+    };
+
+    /**
+     *  Encode the |src| pixels to the |dst| stream.
+     *  |options| may be used to control the encoding behavior.
+     *
+     *  Returns true on success.  Returns false on an invalid or unsupported |src|.
+     */
+    static bool Encode(SkWStream* dst, const SkPixmap& src, const Options& options);
+
+    /**
+     *  Create a jpeg encoder that will encode the |src| pixels to the |dst| stream.
+     *  |options| may be used to control the encoding behavior.
+     *
+     *  |dst| is unowned but must remain valid for the lifetime of the object.
+     *
+     *  This returns nullptr on an invalid or unsupported |src|.
+     */
+    static std::unique_ptr<SkEncoder> Make(SkWStream* dst, const SkPixmap& src,
+                                           const Options& options);
+
+    ~SkJpegEncoder() override;
+
+protected:
+    bool onEncodeRows(int numRows) override;
+
+private:
+    SkJpegEncoder(std::unique_ptr<SkJpegEncoderMgr>, const SkPixmap& src);
+
+    std::unique_ptr<SkJpegEncoderMgr> fEncoderMgr;
+    typedef SkEncoder INHERITED;
+};
+
+#endif