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author | Gareth Stockwell <ext-gareth.stockwell@nokia.com> | 2011-03-16 15:53:45 (GMT) |
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committer | Gareth Stockwell <ext-gareth.stockwell@nokia.com> | 2011-03-18 15:50:43 (GMT) |
commit | 31514ab488c610056973318f5a950d925155d480 (patch) | |
tree | bfc9c2082edc5e6e5dbe1978c7bb61ff659d5aca /src/gui/kernel/qwidget_p.h | |
parent | 59373dd338cb9428514b67c21d0e03b8dc189eef (diff) | |
download | Qt-31514ab488c610056973318f5a950d925155d480.zip Qt-31514ab488c610056973318f5a950d925155d480.tar.gz Qt-31514ab488c610056973318f5a950d925155d480.tar.bz2 |
Add flag for forcibly propagating backing store alpha to framebuffer
Previously, the following rules applies to the creation and blitting of
the Symbian raster backing store:
1. Creation of backing store with an alpha channel:
Backing store has an alpha channel only if !QWidget::isOpaque.
2. Pre-filling of backing store prior to paint loop:
Backing store is filled with transparent pixels if
!QWidget::isOpaque.
3. Blitting of backing store:
CGraphicsContext::EDrawModeWriteAlpha is used (meaning that backing
store alpha values are propagated into the frame buffer), if
QWidget::isOpaque.
In order for the direct camera viewfinder to be visible on DSA devices,
alpha=0 must be written into the framebuffer in the region where the
viewfinder will be displayed. This requires a backing store with an alpha
channel (1), use of CGraphicsContext::EDrawModeWriteAlpha (3), but not
pre-filling of the entire backing store (2).
This patch adds a new enum value, QWExtra::BlitWriteAlpha, which can be
used by camera backends to achieve the desired behaviour.
Task-number: QTMOBILITY-1278
Reviewed-by: Jani Hautakangas
Diffstat (limited to 'src/gui/kernel/qwidget_p.h')
-rw-r--r-- | src/gui/kernel/qwidget_p.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/gui/kernel/qwidget_p.h b/src/gui/kernel/qwidget_p.h index 5235dc4..13e2349 100644 --- a/src/gui/kernel/qwidget_p.h +++ b/src/gui/kernel/qwidget_p.h @@ -315,6 +315,11 @@ struct QWExtra { */ ZeroFill, + /** + * Blit backing store, propagating alpha channel into the framebuffer. + */ + BlitWriteAlpha, + Default = Blit }; |