diff options
author | aavit <eirik.aavitsland@digia.com> | 2014-10-14 12:18:08 +0200 |
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committer | aavit <eirik.aavitsland@digia.com> | 2014-10-22 08:39:23 +0200 |
commit | ff98c440603e94ae284ad08d289418f4b5cca89e (patch) | |
tree | f119345bd48110bca2bf5b0afb4e18bc73b439a7 /src/gui/image/qimagereader.cpp | |
parent | d0402bed6f9a4f9943183720b13e941cc6b656b7 (diff) |
Doc: Improved explanation of quality setting in QImageReader/Writer
Explanation was somewhat inprecise and incomplete.
Task-number: QTBUG-41358
Change-Id: Iae52c30868ca48a49eac76d6979a9b02c24a7d49
Reviewed-by: Topi Reiniƶ <topi.reinio@digia.com>
Diffstat (limited to 'src/gui/image/qimagereader.cpp')
-rw-r--r-- | src/gui/image/qimagereader.cpp | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/src/gui/image/qimagereader.cpp b/src/gui/image/qimagereader.cpp index a1b9743209..a7a08a6fee 100644 --- a/src/gui/image/qimagereader.cpp +++ b/src/gui/image/qimagereader.cpp @@ -877,15 +877,22 @@ QString QImageReader::fileName() const /*! \since 4.2 - This is an image format specific function that sets the quality - level of the image to \a quality. For image formats that do not - support setting the quality, this value is ignored. + Sets the quality setting of the image format to \a quality. - The value range of \a quality depends on the image format. For - example, the "jpeg" format supports a quality range from 0 (low - quality, high compression) to 100 (high quality, low compression). + Some image formats, in particular lossy ones, entail a tradeoff between a) + visual quality of the resulting image, and b) decoding execution time. + This function sets the level of that tradeoff for image formats that + support it. - \sa quality() + In case of scaled image reading, the quality setting may also influence the + tradeoff level between visual quality and execution speed of the scaling + algorithm. + + The value range of \a quality depends on the image format. For example, + the "jpeg" format supports a quality range from 0 (low visual quality) to + 100 (high visual quality). + + \sa quality() setScaledSize() */ void QImageReader::setQuality(int quality) { @@ -895,7 +902,7 @@ void QImageReader::setQuality(int quality) /*! \since 4.2 - Returns the quality level of the image. + Returns the quality setting of the image format. \sa setQuality() */ |