Direct2D QPA: Optimize Clipping

Use axis aligned clips when possible instead of layer-clipping. This can
be much faster when a lot of clipping operations take place.

Change-Id: I6865d69fc917a7da858033b4c362b307724d9006
Reviewed-by: Risto Avila <risto.avila@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Andrew Knight <andrew.knight@digia.com>

1 files changed, 27 insertions, 1 deletions

diff --git a/src/gui/painting/qvectorpath_p.h b/src/gui/painting/qvectorpath_p.h
index e97d6e1dce..ca95c32597 100644
--- a/src/gui/painting/qvectorpath_p.h
+++ b/src/gui/painting/qvectorpath_p.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the QtGui module of the Qt Toolkit.
@@ -167,6 +167,32 @@ public:
         return 0;
     }
 
+    template <typename T> static inline bool isRect(const T *pts, int elementCount) {
+        return (elementCount == 5 // 5-point polygon, check for closed rect
+                && pts[0] == pts[8] && pts[1] == pts[9] // last point == first point
+                && pts[0] == pts[6] && pts[2] == pts[4] // x values equal
+                && pts[1] == pts[3] && pts[5] == pts[7] // y values equal...
+                && pts[0] < pts[4] && pts[1] < pts[5]
+                ) ||
+               (elementCount == 4 // 4-point polygon, check for unclosed rect
+                && pts[0] == pts[6] && pts[2] == pts[4] // x values equal
+                && pts[1] == pts[3] && pts[5] == pts[7] // y values equal...
+                && pts[0] < pts[4] && pts[1] < pts[5]
+                );
+    }
+
+    inline bool isRect() const
+    {
+        const QPainterPath::ElementType * const types = elements();
+
+        return (shape() == QVectorPath::RectangleHint)
+                || (isRect(points(), elementCount())
+                    && (!types || (types[0] == QPainterPath::MoveToElement
+                                   && types[1] == QPainterPath::LineToElement
+                                   && types[2] == QPainterPath::LineToElement
+                                   && types[3] == QPainterPath::LineToElement)));
+    }
+
 
 private:
     Q_DISABLE_COPY(QVectorPath)