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| author | Jason Barron <jbarron@trolltech.com> | 2010-04-13 15:37:06 (GMT) |
|---|---|---|
| committer | Jason Barron <jbarron@trolltech.com> | 2010-04-14 07:32:22 (GMT) |
| commit | 779123b79cc27599f73a61b2f2055a32cc15230a (patch) | |
| tree | 176d78d8c18308c57f4b8e20d968cf30f2e0fd85 /doc/src | |
| parent | 67f6618f887b3c524f9da58de8136d474881d29f (diff) | |
| download | Qt-779123b79cc27599f73a61b2f2055a32cc15230a.zip Qt-779123b79cc27599f73a61b2f2055a32cc15230a.tar.gz Qt-779123b79cc27599f73a61b2f2055a32cc15230a.tar.bz2 | |
Implement OpenVG buffer scrolling and enable it on Symbian.
Add support for accelerated scrolling in the "direct" window surface
implementation. Using vgCopyPixels(), the already rasterized content on
the surface can be shifted to a new location such that only a portion
of the suqsequent frame needs to be repainted instead of the entire
frame.
This only works when the "preserved" EGL swap behavior is enabled and
the impact on performance is highly dependant on the specific hardware
platform in use.
Task-number: QT-2972
Reviewed-by: Rhys Weatherley
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/howtos/openvg.qdoc | 10 | ||||
| -rw-r--r-- | doc/src/platforms/emb-openvg.qdocinc | 6 |
2 files changed, 16 insertions, 0 deletions
diff --git a/doc/src/howtos/openvg.qdoc b/doc/src/howtos/openvg.qdoc index 9c805bb..f70ed54 100644 --- a/doc/src/howtos/openvg.qdoc +++ b/doc/src/howtos/openvg.qdoc @@ -295,6 +295,16 @@ Convolution, colorize, drop shadow, and blur filters are accelerated using OpenVG operations. + \section2 Scrolling + + By default, accelerated scrolling is not enabled because the impact on + performance is very much tied to the hardware platform. To enable + accelerated scrolling, you should ensure that QVG_BUFFER_SCROLLING is + defined when compiling the QtOpenVG module. + + You should only enable this feature if vgCopyPixels() is known to be + efficient on your hardware platform. + \section1 Known issues Performance of copying the contents of an OpenVG-rendered window to the diff --git a/doc/src/platforms/emb-openvg.qdocinc b/doc/src/platforms/emb-openvg.qdocinc index 37ccb9c..2f9cc21 100644 --- a/doc/src/platforms/emb-openvg.qdocinc +++ b/doc/src/platforms/emb-openvg.qdocinc @@ -259,6 +259,12 @@ at present. \o Convolution, colorize, drop shadow, and blur filters are accelerated using OpenVG operations. + \row + \o Scrolling + \o Accelerated scrolling is implemented but disabled by default +unless QVG_BUFFER_SCROLLING is defined. This should only be enabled on +OpenVG engines where vgCopyPixels() is known to be efficient. + \endtable \section2 Known issues |