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doc: Brush up QPaintEngine documentation for Qt 5

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The paint engine story has changed drastically in Qt 5,
and we no longer need the reference to Qt 3.

Change-Id: I66090582e5c66d2a3cd9de355c34b33a94b67dfe
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
This commit is contained in:
Eskil Abrahamsen Blomfeldt 2012-10-04 14:58:32 +02:00 committed by The Qt Project
parent 3f6122a692
commit f884a73fcb
1 changed files with 10 additions and 13 deletions
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23
src/gui/painting/qpaintengine.cpp
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@ -152,14 +152,16 @@ QFont QTextItem::font() const
\brief The QPaintEngine class provides an abstract definition of how
QPainter draws to a given device on a given platform.
Qt 4.0 provides several premade implementations of QPaintEngine for the
different painter backends we support. We provide one paint engine for each
window system and painting framework we support. This includes X11 on
Unix/Linux and CoreGraphics on Mac OS X. In addition we provide QPaintEngine
implementations for OpenGL (accessible through QOpenGLWidget) and PostScript
(accessible through QPSPrinter on X11). Additionally there is a raster-based
paint engine that is a fallback for when an engine does not support a certain
capability.
Qt provides several premade implementations of QPaintEngine for the
different painter backends we support. The primary paint engine
provided is the raster paint engine, which contains a software
rasterizer which supports the full feature set on all supported platforms.
This is the default for painting on QWidget-based classes in e.g. on Windows,
X11 and Mac OS X, it is the backend for painting on QImage and it is
used as a fallback for paint engines that do not support a certain
capability. In addition we provide QPaintEngine implementations for
OpenGL (accessible through QGLWidget) and printing (which allows using
QPainter to draw on a QPrinter object).
If one wants to use QPainter to draw to a different backend,
one must subclass QPaintEngine and reimplement all its virtual
@ -169,11 +171,6 @@ QFont QTextItem::font() const
QPaintEngine is created and owned by the QPaintDevice that created it.
The big advantage of the QPaintEngine approach opposed to
Qt 3's QPainter/QPaintDevice::cmd() approach is that it is now
possible to adapt to multiple technologies on each platform and take
advantage of each to the fullest.
\sa QPainter, QPaintDevice::paintEngine(), {Paint System}
*/