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author | Eirik Aavitsland <eirik.aavitsland@qt.io> | 2018-05-28 15:05:13 +0200 |
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committer | Eirik Aavitsland <eirik.aavitsland@qt.io> | 2018-05-30 07:35:48 +0000 |
commit | 9749e824a53afd1490a85ea42dddeda696a4f90e (patch) | |
tree | 3638c32dec9d694354f8231b1d1ed590f7e6289e /src | |
parent | b9ba2217566531b51f3c5c5158bfcc386539d810 (diff) | |
download | qtimageformats-9749e824a53afd1490a85ea42dddeda696a4f90e.tar.gz |
webp handler: improve quality-level handling
In lossless mode, libwebp interpretes the quality setting as a
compression-effort setting instead. The code used to set it to 100
(maximum), which could lead to unreasonable compression times (several
seconds for a small image). Instead set it to libweb's own default value.
Also, since the alpha channel compression has its own quality setting,
make sure it follows the main quality/effort setting.
Change-Id: I595d42c61f61c9932b27b185745bde6e7cfb3526
Reviewed-by: Liang Qi <liang.qi@qt.io>
Diffstat (limited to 'src')
-rw-r--r-- | src/plugins/imageformats/webp/qwebphandler.cpp | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/plugins/imageformats/webp/qwebphandler.cpp b/src/plugins/imageformats/webp/qwebphandler.cpp index 12c4001..578a701 100644 --- a/src/plugins/imageformats/webp/qwebphandler.cpp +++ b/src/plugins/imageformats/webp/qwebphandler.cpp @@ -248,8 +248,15 @@ bool QWebpHandler::write(const QImage &image) return false; } - config.quality = m_quality < 0 ? 75 : qMin(m_quality, 100); - config.lossless = (config.quality >= 100); + int reqQuality = m_quality < 0 ? 75 : qMin(m_quality, 100); + if (reqQuality < 100) { + config.lossless = 0; + config.quality = reqQuality; + } else { + config.lossless = 1; + config.quality = 70; // For lossless, specifies compression effort; 70 is libwebp default + } + config.alpha_quality = config.quality; picture.writer = pictureWriter; picture.custom_ptr = device(); |