diff options
| -rw-r--r-- | src/gui/effects/qgraphicseffect.cpp | 54 |
1 files changed, 30 insertions, 24 deletions
diff --git a/src/gui/effects/qgraphicseffect.cpp b/src/gui/effects/qgraphicseffect.cpp index fbd53b0..3274f4d 100644 --- a/src/gui/effects/qgraphicseffect.cpp +++ b/src/gui/effects/qgraphicseffect.cpp @@ -41,23 +41,24 @@ /*! \class QGraphicsEffect - \brief The QGraphicsEffect class is the base class for all graphics effects. + \brief The QGraphicsEffect class is the base class for all graphics + effects. \since 4.6 \ingroup multimedia \ingroup graphicsview-api Effects alter the appearance of elements by hooking into the rendering - pipeline and operating between the source (e.g., a QGraphicsPixmapItem), + pipeline and operating between the source (e.g., a QGraphicsPixmapItem) and the destination device (e.g., QGraphicsView's viewport). Effects can be - disabled by calling setEnabled(); if the effect is disabled, the source is - rendered directly. + disabled by calling setEnabled(false). If effects are disabled, the source + is rendered directly. - If you want to add a visual effect to a e.g. a QGraphicsItem, you can either use - one of the standard effects, or create your own effect by making a subclass - of QGraphicsEffect. The effect can then be installed on the item by calling - QGraphicsItem::setGraphicsEffect. + To add a visual effect to a QGraphicsItem, for example, you can use one of + the standard effects, or alternately, create your own effect by creating a + subclass of QGraphicsEffect. The effect can then be installed on the item + using QGraphicsItem::setGraphicsEffect(). - Qt provides several standard effects, including: + Qt provides the following standard effects: \list \o QGraphicsGrayScaleEffect - renders the item in shades of gray @@ -69,19 +70,24 @@ \o QGrahicsShaderEffect - renders the item with a pixel shader fragment \endlist - If all you want is to add an effect to an item, you should visit the - documentation for the specific effect to learn more about how each effect - can be used. - If you want to create your own custom effect, you can start by creating a - subclass of QGraphicsEffect (or any of the existing effects), and - reimplement the virtual function draw(). This function is called whenever - the effect needs to redraw. draw() has two arguments: the painter, and a - pointer to the source (QGraphicsEffectSource). The source provides extra - context information, such as a pointer to the item that is rendering the - effect, any cached pixmap data, and the device rect bounds. See the draw() - documentation for more details. You can also get a pointer to the current - source by calling source(). + For more information on how to use each effect, refer to the specific + effect's documentation. + + To create your own custom effect, create a subclass of QGraphicsEffect (or + any other existing effects) and reimplement the virtual function draw(). + This function is called whenever the effect needs to redraw. The draw() + function accepts two arguments: the painter and a pointer to the source + (QGraphicsEffectSource). The source provides extra context information, + such as a pointer to the item that is rendering the effect, any cached + pixmap data, or the device rect bounds. For more information, refer to the + documenation for draw(). To obtain a pointer to the current source, simply + call source(). + + If your effect changes, use update() to request for a redraw. If your + custom effect changes the bounding rectangle of the source, e.g., a radial + glow effect may need to apply an extra margin, + If your effect changes, you can call update() to request a redraw. If your custom effect changes the bounding rectangle of the source (e.g., a radial @@ -107,11 +113,11 @@ QT_BEGIN_NAMESPACE /*! \class QGraphicsEffectSource - \brief The QGraphicsEffectSource represents the source of which a QGraphicsEffect - is installed on. + \brief The QGraphicsEffectSource represents the source on which a + QGraphicsEffect is installed on. \since 4.6 - When a QGraphicsEffect is installed on e.g. a QGraphicsItem, this class will act as + When a QGraphicsEffect is installed on a QGraphicsItem, for example, this class will act as a wrapper around QGraphicsItem. E.g. calling update() is effectively the same as calling QGraphicsItem::update(). |