Fix Qt.tint() algorithm

QT-2424

3 files changed, 9 insertions, 13 deletions

diff --git a/src/declarative/qml/qdeclarativeengine.cpp b/src/declarative/qml/qdeclarativeengine.cpp
index 1e60df4..41d55d7 100644
--- a/src/declarative/qml/qdeclarativeengine.cpp
+++ b/src/declarative/qml/qdeclarativeengine.cpp
@@ -1234,17 +1234,13 @@ QScriptValue QDeclarativeEnginePrivate::tint(QScriptContext *ctxt, QScriptEngine
     else if (a == 0x00)
         finalColor = color;
     else {
-        uint src = tintColor.rgba();
-        uint dest = color.rgba();
+        qreal a = tintColor.alphaF();
+        qreal inv_a = 1.0 - a;
 
-        uint res = (((a * (src & 0xFF00FF)) +
-                    ((0xFF - a) * (dest & 0xFF00FF))) >> 8) & 0xFF00FF;
-        res |= (((a * ((src >> 8) & 0xFF00FF)) +
-                ((0xFF - a) * ((dest >> 8) & 0xFF00FF)))) & 0xFF00FF00;
-        if ((src & 0xFF000000) == 0xFF000000)
-            res |= 0xFF000000;
-
-        finalColor = QColor::fromRgba(res);
+        finalColor.setRgbF(tintColor.redF() * a + color.redF() * inv_a,
+                           tintColor.greenF() * a + color.greenF() * inv_a,
+                           tintColor.blueF() * a + color.blueF() * inv_a,
+                           a + inv_a * color.alphaF());
     }
 
     return qScriptValueFromValue(engine, qVariantFromValue(finalColor));
diff --git a/tests/auto/declarative/qdeclarativeqt/data/tint.qml b/tests/auto/declarative/qdeclarativeqt/data/tint.qml
index da8afe2..478245f 100644
--- a/tests/auto/declarative/qdeclarativeqt/data/tint.qml
+++ b/tests/auto/declarative/qdeclarativeqt/data/tint.qml
@@ -3,7 +3,7 @@ import Qt 4.6
 QtObject {
     property color test1: Qt.tint("red", "blue");
     property color test2: Qt.tint(Qt.rgba(1, 0, 0), Qt.rgba(0, 0, 0, 0));
-    property color test3: Qt.tint("red", Qt.rgba(0, 0, 1, 0.5)); // XXX - what should this be?
+    property color test3: Qt.tint("red", Qt.rgba(0, 0, 1, 0.5));
     property color test4: Qt.tint("red", Qt.rgba(0, 0, 1, 0.5), 10);
     property color test5: Qt.tint("red")
 }
diff --git a/tests/auto/declarative/qdeclarativeqt/tst_qdeclarativeqt.cpp b/tests/auto/declarative/qdeclarativeqt/tst_qdeclarativeqt.cpp
index 90afd4e..b70011b 100644
--- a/tests/auto/declarative/qdeclarativeqt/tst_qdeclarativeqt.cpp
+++ b/tests/auto/declarative/qdeclarativeqt/tst_qdeclarativeqt.cpp
@@ -254,8 +254,8 @@ void tst_qdeclarativeqt::tint()
 
     QCOMPARE(qvariant_cast<QColor>(object->property("test1")), QColor::fromRgbF(0, 0, 1));
     QCOMPARE(qvariant_cast<QColor>(object->property("test2")), QColor::fromRgbF(1, 0, 0));
-    QEXPECT_FAIL("", "QT-2424",Continue);
-    QCOMPARE(qvariant_cast<QColor>(object->property("test3")), QColor::fromRgbF(1, 0, 0)); 
+    QColor test3 = qvariant_cast<QColor>(object->property("test3"));
+    QCOMPARE(test3.rgba(), 0xFF7F0080);
     QCOMPARE(qvariant_cast<QColor>(object->property("test4")), QColor());
     QCOMPARE(qvariant_cast<QColor>(object->property("test5")), QColor());