Add support for webp lossless compression

Bug: 713862
Change-Id: I8dcc6506338f3c54fb14a78620e7daaadadfedde
Reviewed-on: https://skia-review.googlesource.com/17073
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>

1 files changed, 11 insertions, 6 deletions

diff --git a/src/images/SkWebpEncoder.cpp b/src/images/SkWebpEncoder.cpp
index 5c26111040..b6c6212314 100644
--- a/src/images/SkWebpEncoder.cpp
+++ b/src/images/SkWebpEncoder.cpp
@@ -124,8 +124,7 @@ static int stream_writer(const uint8_t* data, size_t data_size,
   return stream->write(data, data_size) ? 1 : 0;
 }
 
-static bool do_encode(SkWStream* stream, const SkPixmap& pixmap, const SkWebpEncoder::Options& opts)
-{
+bool SkWebpEncoder::Encode(SkWStream* stream, const SkPixmap& pixmap, const Options& opts) {
     if (!SkPixmapIsValid(pixmap, opts.fUnpremulBehavior)) {
         return false;
     }
@@ -168,6 +167,16 @@ static bool do_encode(SkWStream* stream, const SkPixmap& pixmap, const SkWebpEnc
         return false;
     }
 
+    // The choice of |webp_config.method| currently just match Chrome's defaults.  We
+    // could potentially expose this to the client.
+    if (Compression::kLossy == opts.fCompression) {
+        webp_config.lossless = 0;
+        webp_config.method = 3;
+    } else {
+        webp_config.lossless = 1;
+        webp_config.method = 0;
+    }
+
     WebPPicture pic;
     WebPPictureInit(&pic);
     SkAutoTCallVProc<WebPPicture, WebPPictureFree> autoPic(&pic);
@@ -236,8 +245,4 @@ static bool do_encode(SkWStream* stream, const SkPixmap& pixmap, const SkWebpEnc
     return true;
 }
 
-bool SkWebpEncoder::Encode(SkWStream* dst, const SkPixmap& src, const Options& opts) {
-    return do_encode(dst, src, opts);
-}
-
 #endif