Avoid unnecessary color format conversion

If a color is not the rgb format, when QColor::red() QColor::blue()
QColor::green() is used continuously to obtain the values of different
channels, three times color conversions will occur. Therefore, use
QColor::toRgb() before that to ensure that only one conversion is
performed at most. Not only rgb, the conversion of other formats is the
same.

Change-Id: Ia969e1ca6f1524ad5d7e8dec915bcbc407875c66
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 6 insertions, 4 deletions

diff --git a/src/quickshapes/qquickshapegenericrenderer.cpp b/src/quickshapes/qquickshapegenericrenderer.cpp
index f5fcd72152..864d0f06d9 100644
--- a/src/quickshapes/qquickshapegenericrenderer.cpp
+++ b/src/quickshapes/qquickshapegenericrenderer.cpp
@@ -63,11 +63,13 @@ struct ColoredVertex // must match QSGGeometry::ColoredPoint2D
 
 static inline QQuickShapeGenericRenderer::Color4ub colorToColor4ub(const QColor &c)
 {
+    float r, g, b, a;
+    c.getRgbF(&r, &g, &b, &a);
     QQuickShapeGenericRenderer::Color4ub color = {
-        uchar(qRound(c.redF() * c.alphaF() * 255)),
-        uchar(qRound(c.greenF() * c.alphaF() * 255)),
-        uchar(qRound(c.blueF() * c.alphaF() * 255)),
-        uchar(qRound(c.alphaF() * 255))
+        uchar(qRound(r * a * 255)),
+        uchar(qRound(g * a * 255)),
+        uchar(qRound(b * a * 255)),
+        uchar(qRound(a * 255))
     };
     return color;
 }