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Revert "Treat kWEBP encode with quality=100 as lossless"

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This reverts commit e7f165be2e.

Reason for revert: doesn't compile in google3

Original change's description:
> Treat kWEBP encode with quality=100 as lossless
> 
> In SkEncodeImage and friends, treat quality of 100 as a lossless encode
> when using kWEBP. This seems a good fit for the intent - which is
> presumably to save the highest quality image. This also matches
> Chromium's blink::ImageEncoder::ComputeWebpOptions, which treats a
> quality of 1 (on a float scale from 0 to 1) as a lossless encode.
> 
> FWIW, Chromium has had this behavior since
> https://codereview.chromium.org/1937433002, in response to
> crbug.com/523098. The goal is to "maintain sharpness to
> match the JPEG encoder behavior (use WEBP lossless encoding)".
> 
> Add a test to verify the new behavior. This requires making tests
> depend on libwebp to use WebPGetFeatures, since the Skia API does not
> provide a way to determine whether an encoded webp file was encoded
> lossless-ly or lossily.
> 
> Bug: skia:8586
> Change-Id: Ie9e09c2f7414ab701d696c4ad9edf405868a716f
> Reviewed-on: https://skia-review.googlesource.com/c/175823
> Commit-Queue: Leon Scroggins <scroggo@google.com>
> Reviewed-by: Derek Sollenberger <djsollen@google.com>
> Reviewed-by: Mike Reed <reed@google.com>

TBR=djsollen@google.com,scroggo@google.com,reed@google.com

Change-Id: I91680f65a2a5e6f0a13b84e97c9541ebe0606b33
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:8586
Reviewed-on: https://skia-review.googlesource.com/c/176584
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
This commit is contained in:
Mike Reed 2018-12-11 17:12:39 +00:00 committed by Skia Commit-Bot
parent aa3b291717
commit 22170b3178
4 changed files with 4 additions and 72 deletions
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1
BUILD.gn
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@ -1560,7 +1560,6 @@ if (skia_enable_tools) {
"modules/skottie:tests",
"modules/sksg:tests",
"//third_party/libpng",
"//third_party/libwebp",
"//third_party/zlib",
]
public_deps = [

6
include/core/SkImageEncoder.h
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@ -27,8 +27,7 @@
* Will always return false if Skia is compiled without image
* encoders.
*
* For SkEncodedImageFormat::kWEBP, if quality is 100, it will use lossless compression. Otherwise
* it will use lossy.
* Note that webp encodes will use webp lossy compression.
*
* For examples of encoding an image to a file or to a block of memory,
* see tools/sk_tool_utils.h.
@ -57,8 +56,7 @@ inline bool SkEncodeImage(SkWStream* dst, const SkBitmap& src, SkEncodedImageFor
* Will always return nullptr if Skia is compiled without image
* encoders.
*
* For SkEncodedImageFormat::kWEBP, if quality is 100, it will use lossless compression. Otherwise
* it will use lossy.
* Note that webp encodes will use webp lossy compression.
*/
SK_API sk_sp<SkData> SkEncodePixmap(const SkPixmap& src, SkEncodedImageFormat format, int quality);

21
src/images/SkImageEncoder.cpp
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@ -48,25 +48,8 @@ bool SkEncodeImage(SkWStream* dst, const SkPixmap& src,
}
case SkEncodedImageFormat::kWEBP: {
SkWebpEncoder::Options opts;
if (quality == 100) {
opts.fCompression = SkWebpEncoder::Compression::kLossless;
// Note: SkEncodeImage treats 0 quality as the lowest quality
// (greatest compression) and 100 as the highest quality (least
// compression). For kLossy, this matches libwebp's
// interpretation, so it is passed directly to libwebp. But
// with kLossless, libwebp always creates the highest quality
// image. In this case, fQuality is reinterpreted as how much
// effort (time) to put into making a smaller file. This API
// does not provide a way to specify this value (though it can
// be specified by using SkWebpEncoder::Encode) so we have to
// pick one arbitrarily. This value matches that chosen by
// blink::ImageEncoder::ComputeWebpOptions as well
// WebPConfigInit.
opts.fQuality = 75;
} else {
opts.fCompression = SkWebpEncoder::Compression::kLossy;
opts.fQuality = quality;
}
opts.fCompression = SkWebpEncoder::Compression::kLossy;
opts.fQuality = quality;
return SkWebpEncoder::Encode(dst, src, opts);
}
default:

48
tests/EncodeTest.cpp
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@ -23,8 +23,6 @@
#include <string>
#include <vector>
#include "webp/decode.h"
static bool encode(SkEncodedImageFormat format, SkWStream* dst, const SkPixmap& src) {
switch (format) {
case SkEncodedImageFormat::kJPEG:
@ -288,52 +286,6 @@ DEF_TEST(Encode_PngOptions, r) {
REPORTER_ASSERT(r, almost_equals(bm0, bm2, 0));
}
DEF_TEST(Encode_WebpQuality, r) {
SkBitmap bm;
bm.allocN32Pixels(100, 100);
bm.eraseColor(SK_ColorBLUE);
auto dataLossy = SkEncodeBitmap(bm, SkEncodedImageFormat::kWEBP, 99);
auto dataLossLess = SkEncodeBitmap(bm, SkEncodedImageFormat::kWEBP, 100);
enum Format {
kMixed = 0,
kLossy = 1,
kLossless = 2,
};
auto test = [&r](const sk_sp<SkData>& data, Format expected) {
auto printFormat = [](int f) {
switch (f) {
case kMixed: return "mixed";
case kLossy: return "lossy";
case kLossless: return "lossless";
default: return "unknown";
}
};
if (!data) {
ERRORF(r, "Failed to encode. Expected %s", printFormat(expected));
return;
}
WebPBitstreamFeatures features;
auto status = WebPGetFeatures(data->bytes(), data->size(), &features);
if (status != VP8_STATUS_OK) {
ERRORF(r, "Encode had an error %i. Expected %s", status, printFormat(expected));
return;
}
if (expected != features.format) {
ERRORF(r, "Expected %s encode, but got format %s", printFormat(expected),
printFormat(features.format));
}
};
test(dataLossy, kLossy);
test(dataLossLess, kLossless);
}
DEF_TEST(Encode_WebpOptions, r) {
SkBitmap bitmap;
bool success = GetResourceAsBitmap("images/google_chrome.ico", &bitmap);