skia WIPjarred/canvas

1 files changed, 99 insertions, 0 deletions

diff --git a/src/deps/skia/include/encode/SkPngEncoder.h b/src/deps/skia/include/encode/SkPngEncoder.h
new file mode 100644
index 000000000..ccfa292f7
--- /dev/null
+++ b/src/deps/skia/include/encode/SkPngEncoder.h
@@ -0,0 +1,99 @@
+/*
+ * 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 SkPngEncoder_DEFINED
+#define SkPngEncoder_DEFINED
+
+#include "include/core/SkDataTable.h"
+#include "include/encode/SkEncoder.h"
+
+class SkPngEncoderMgr;
+class SkWStream;
+
+class SK_API SkPngEncoder : public SkEncoder {
+public:
+
+    enum class FilterFlag : int {
+        kZero  = 0x00,
+        kNone  = 0x08,
+        kSub   = 0x10,
+        kUp    = 0x20,
+        kAvg   = 0x40,
+        kPaeth = 0x80,
+        kAll   = kNone | kSub | kUp | kAvg | kPaeth,
+    };
+
+    struct Options {
+        /**
+         *  Selects which filtering strategies to use.
+         *
+         *  If a single filter is chosen, libpng will use that filter for every row.
+         *
+         *  If multiple filters are chosen, libpng will use a heuristic to guess which filter
+         *  will encode smallest, then apply that filter.  This happens on a per row basis,
+         *  different rows can use different filters.
+         *
+         *  Using a single filter (or less filters) is typically faster.  Trying all of the
+         *  filters may help minimize the output file size.
+         *
+         *  Our default value matches libpng's default.
+         */
+        FilterFlag fFilterFlags = FilterFlag::kAll;
+
+        /**
+         *  Must be in [0, 9] where 9 corresponds to maximal compression.  This value is passed
+         *  directly to zlib.  0 is a special case to skip zlib entirely, creating dramatically
+         *  larger pngs.
+         *
+         *  Our default value matches libpng's default.
+         */
+        int fZLibLevel = 6;
+
+        /**
+         *  Represents comments in the tEXt ancillary chunk of the png.
+         *  The 2i-th entry is the keyword for the i-th comment,
+         *  and the (2i + 1)-th entry is the text for the i-th comment.
+         */
+        sk_sp<SkDataTable> fComments;
+    };
+
+    /**
+     *  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 png 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);
+
+    ~SkPngEncoder() override;
+
+protected:
+    bool onEncodeRows(int numRows) override;
+
+    SkPngEncoder(std::unique_ptr<SkPngEncoderMgr>, const SkPixmap& src);
+
+    std::unique_ptr<SkPngEncoderMgr> fEncoderMgr;
+    using INHERITED = SkEncoder;
+};
+
+static inline SkPngEncoder::FilterFlag operator|(SkPngEncoder::FilterFlag x,
+                                                 SkPngEncoder::FilterFlag y) {
+    return (SkPngEncoder::FilterFlag)((int)x | (int)y);
+}
+
+#endif