Added support for drawing a pixmap multiple times in one call.

This is internal API.
It's possible to specify a horizontal and vertical scale, rotation,
opacity and source rectangle for each pixmap item.
Useful for particle effects.

Reviewed-by: Trond

4 files changed, 95 insertions, 3 deletions

diff --git a/src/gui/painting/qdrawutil.cpp b/src/gui/painting/qdrawutil.cpp
index ac3796a..4f17e59 100644
--- a/src/gui/painting/qdrawutil.cpp
+++ b/src/gui/painting/qdrawutil.cpp
@@ -45,6 +45,7 @@
 #include "qapplication.h"
 #include "qpainter.h"
 #include "qpalette.h"
+#include <private/qpaintengineex_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -1351,4 +1352,58 @@ void qDrawBorderPixmap(QPainter *painter, const QRect &targetRect, const QMargin
     }
 }
 
+/*!
+    \struct QDrawPixmapsData
+    \since 4.6
+    \internal
+
+    This structure is used with the qDrawPixmaps() function.
+
+    QPointF point:  Specifies the center of the target rectangle.
+    QRectF source:  Specifies the source rectangle in the pixmap passed into the qDrawPixmaps() call.
+    qreal scaleX:   Specifies the horizontal scale of the target rectangle.
+    qreal scaleY:   Specifies the vertical scale of the target rectangle.
+    qreal rotation: Specifies the rotation of the target rectangle in degrees.
+                    The target rectangle is rotated after scaling.
+    qreal opacity:  Specifies the opacity of the rectangle.
+*/
+
+/*!
+    \internal
+    \since 4.6
+
+    This function is used to draw \a pixmap, or a sub-rectangle of \a pixmap, at multiple positions
+    with different scale, rotation and opacity on \a painter. \a drawingData is an array of \a
+    dataCount elements specifying the parameters used to draw each pixmap instance.
+    This can be used for example to implement a particle system.
+*/
+void qDrawPixmaps(QPainter *painter, const QDrawPixmapsData *drawingData, int dataCount, const QPixmap &pixmap)
+{
+    QPaintEngine *engine = painter->paintEngine();
+    if (!engine)
+        return;
+
+    if (engine->isExtended()) {
+        static_cast<QPaintEngineEx *>(engine)->drawPixmaps(drawingData, dataCount, pixmap);
+    } else {
+        qreal oldOpacity = painter->opacity();
+        QTransform oldTransform = painter->transform();
+
+        for (int i = 0; i < dataCount; ++i) {
+            QTransform transform = oldTransform;
+            transform.translate(drawingData[i].point.x(), drawingData[i].point.y());
+            transform.rotate(drawingData[i].rotation);
+            painter->setOpacity(oldOpacity * drawingData[i].opacity);
+            painter->setTransform(transform);
+
+            qreal w = drawingData[i].scaleX * drawingData[i].source.width();
+            qreal h = drawingData[i].scaleY * drawingData[i].source.height();
+            painter->drawPixmap(QRectF(-0.5 * w, -0.5 * h, w, h), pixmap, drawingData[i].source);
+        }
+
+        painter->setOpacity(oldOpacity);
+        painter->setTransform(oldTransform);
+    }
+}
+
 QT_END_NAMESPACE
diff --git a/src/gui/painting/qdrawutil.h b/src/gui/painting/qdrawutil.h
index 22a57e9..98a36a7 100644
--- a/src/gui/painting/qdrawutil.h
+++ b/src/gui/painting/qdrawutil.h
@@ -158,6 +158,18 @@ inline void qDrawBorderPixmap(QPainter *painter,
     qDrawBorderPixmap(painter, target, margins, pixmap, pixmap.rect(), margins);
 }
 
+struct QDrawPixmapsData
+{
+    QPointF point;
+    QRectF source;
+    qreal scaleX;
+    qreal scaleY;
+    qreal rotation;
+    qreal opacity;
+};
+
+Q_GUI_EXPORT void qDrawPixmaps(QPainter *painter, const QDrawPixmapsData *drawingData, int dataCount, const QPixmap &pixmap);
+
 QT_END_NAMESPACE
 
 QT_END_HEADER
diff --git a/src/gui/painting/qpaintengineex.cpp b/src/gui/painting/qpaintengineex.cpp
index 60e4df6..2342b9d 100644
--- a/src/gui/painting/qpaintengineex.cpp
+++ b/src/gui/painting/qpaintengineex.cpp
@@ -932,6 +932,31 @@ void QPaintEngineEx::drawTiledPixmap(const QRectF &r, const QPixmap &pixmap, con
     fill(path, brush);
 }
 
+void QPaintEngineEx::drawPixmaps(const QDrawPixmapsData *drawingData, int dataCount, const QPixmap &pixmap)
+{
+    qreal oldOpacity = state()->opacity;
+    QTransform oldTransform = state()->matrix;
+
+    for (int i = 0; i < dataCount; ++i) {
+        QTransform transform = oldTransform;
+        transform.translate(drawingData[i].point.x(), drawingData[i].point.y());
+        transform.rotate(drawingData[i].rotation);
+        state()->opacity = oldOpacity * drawingData[i].opacity;
+        state()->matrix = transform;
+        opacityChanged();
+        transformChanged();
+
+        qreal w = drawingData[i].scaleX * drawingData[i].source.width();
+        qreal h = drawingData[i].scaleY * drawingData[i].source.height();
+        drawPixmap(QRectF(-0.5 * w, -0.5 * h, w, h), pixmap, drawingData[i].source);
+    }
+
+    state()->opacity = oldOpacity;
+    state()->matrix = oldTransform;
+    opacityChanged();
+    transformChanged();
+}
+
 void QPaintEngineEx::setState(QPainterState *s)
 {
     QPaintEngine::state = s;
diff --git a/src/gui/painting/qpaintengineex_p.h b/src/gui/painting/qpaintengineex_p.h
index 814a0f0..42c1ce9 100644
--- a/src/gui/painting/qpaintengineex_p.h
+++ b/src/gui/painting/qpaintengineex_p.h
@@ -70,7 +70,7 @@ QT_MODULE(Gui)
 class QPainterState;
 class QPaintEngineExPrivate;
 struct StrokeHandler;
-
+struct QDrawPixmapsData;
 
 struct QIntRect {
     int x1, y1, x2, y2;
@@ -133,8 +133,6 @@ public:
     qreal pts[8];
 };
 
-
-
 #ifndef QT_NO_DEBUG_STREAM
 QDebug Q_GUI_EXPORT &operator<<(QDebug &, const QVectorPath &path);
 #endif
@@ -198,6 +196,8 @@ public:
 
     virtual void drawTiledPixmap(const QRectF &r, const QPixmap &pixmap, const QPointF &s);
 
+    virtual void drawPixmaps(const QDrawPixmapsData *drawingData, int dataCount, const QPixmap &pixmap);
+
     virtual void updateState(const QPaintEngineState &state);
 
     virtual void setState(QPainterState *s);