skia2/include/encode/SkWebpEncoder.h
Mike Klein 940c3f136d add runtime registration for encoders
If we want to make these external dependencies mix-and-match in Google3,
we'll need to group together the encoders and decoders, everything that
dependends on each external library.

I was tempted to try to remove these generic encoder entrypoints and
replace them with calls to the direct equivalents, but I'm not sure
that's necessary.  I think we can just register encoders like decoders.

Change-Id: I41d2d1bb3ceb1daafa62c95d345eb6a70249be75
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/213880
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2019-05-15 18:52:43 +00:00

63 lines
2.1 KiB
C++

/*
* 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 SkWebpEncoder_DEFINED
#define SkWebpEncoder_DEFINED
#include "include/encode/SkEncoder.h"
class SkWStream;
namespace SkWebpEncoder {
enum class Compression {
kLossy,
kLossless,
};
struct SK_API Options {
/**
* |fCompression| determines whether we will use webp lossy or lossless compression.
*
* |fQuality| must be in [0.0f, 100.0f].
* If |fCompression| is kLossy, |fQuality| corresponds to the visual quality of the
* encoding. Decreasing the quality will result in a smaller encoded image.
* If |fCompression| is kLossless, |fQuality| corresponds to the amount of effort
* put into the encoding. Lower values will compress faster into larger files,
* while larger values will compress slower into smaller files.
*
* This scheme is designed to match the libwebp API.
*/
Compression fCompression = Compression::kLossy;
float fQuality = 100.0f;
};
/**
* 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|.
*/
SK_API bool Encode(SkWStream* dst, const SkPixmap& src, const Options& options);
inline bool Encode(SkWStream* dst, const SkPixmap& src, int quality) {
SkWebpEncoder::Options opts;
if (quality == 100) {
// fQuality acts as a signal for how much time to invest encoding a smaller file.
// This value matches blink::ImageEncoder::ComputeWebpOptions and WebPConfigInit.
opts.fQuality = 75;
opts.fCompression = SkWebpEncoder::Compression::kLossless;
} else {
opts.fQuality = quality;
opts.fCompression = SkWebpEncoder::Compression::kLossy;
}
return SkWebpEncoder::Encode(dst, src, opts);
}
}
#endif