Add filter strength to QGraphics[Colorize,Grayscale]Effect.

Autotest: included
Reviewed-by: Bjørn Erik Nilsen

4 files changed, 126 insertions, 1 deletions

diff --git a/src/gui/effects/qgraphicseffect.cpp b/src/gui/effects/qgraphicseffect.cpp
index 683a98407f..26489c5d28 100644
--- a/src/gui/effects/qgraphicseffect.cpp
+++ b/src/gui/effects/qgraphicseffect.cpp
@@ -467,12 +467,44 @@ QGraphicsGrayscaleEffect::~QGraphicsGrayscaleEffect()
 {
 }
 
+
+/*!
+    \property QGraphicsGrayscaleEffect::strength
+    \brief the strength of the effect.
+
+    By default, the strength is 1.0.
+    A strength 0.0 equals to no effect, while 1.0 means full grayscale.
+*/
+qreal QGraphicsGrayscaleEffect::strength() const
+{
+    Q_D(const QGraphicsGrayscaleEffect);
+    return d->filter->strength();
+}
+
+void QGraphicsGrayscaleEffect::setStrength(qreal strength)
+{
+    Q_D(QGraphicsGrayscaleEffect);
+    if (qFuzzyCompare(d->filter->strength(), strength))
+        return;
+
+    d->filter->setStrength(strength);
+    d->opaque = !qFuzzyIsNull(strength);
+    update();
+    emit strengthChanged(strength);
+}
+
 /*!
     \reimp
 */
 void QGraphicsGrayscaleEffect::draw(QPainter *painter, QGraphicsEffectSource *source)
 {
     Q_D(QGraphicsGrayscaleEffect);
+
+    if (!d->opaque) {
+        source->draw(painter);
+        return;
+    }
+
     QPoint offset;
     if (source->isPixmap()) {
         // No point in drawing in device coordinates (pixmap will be scaled anyways).
@@ -546,6 +578,31 @@ void QGraphicsColorizeEffect::setColor(const QColor &color)
 }
 
 /*!
+    \property QGraphicsColorizeEffect::strength
+    \brief the strength of the effect.
+
+    By default, the strength is 1.0.
+    A strength 0.0 equals to no effect, while 1.0 means full colorization.
+*/
+qreal QGraphicsColorizeEffect::strength() const
+{
+    Q_D(const QGraphicsColorizeEffect);
+    return d->filter->strength();
+}
+
+void QGraphicsColorizeEffect::setStrength(qreal strength)
+{
+    Q_D(QGraphicsColorizeEffect);
+    if (qFuzzyCompare(d->filter->strength(), strength))
+        return;
+
+    d->filter->setStrength(strength);
+    d->opaque = !qFuzzyIsNull(strength);
+    update();
+    emit strengthChanged(strength);
+}
+
+/*!
     \fn void QGraphicsColorizeEffect::colorChanged(const QColor &color)
 
     This signal is emitted whenever the effect's color changes.
@@ -558,6 +615,12 @@ void QGraphicsColorizeEffect::setColor(const QColor &color)
 void QGraphicsColorizeEffect::draw(QPainter *painter, QGraphicsEffectSource *source)
 {
     Q_D(QGraphicsColorizeEffect);
+
+    if (!d->opaque) {
+        source->draw(painter);
+        return;
+    }
+
     QPoint offset;
     if (source->isPixmap()) {
         // No point in drawing in device coordinates (pixmap will be scaled anyways).
diff --git a/src/gui/effects/qgraphicseffect.h b/src/gui/effects/qgraphicseffect.h
index 5822d8cef3..506282602c 100644
--- a/src/gui/effects/qgraphicseffect.h
+++ b/src/gui/effects/qgraphicseffect.h
@@ -144,13 +144,22 @@ class QGraphicsGrayscaleEffectPrivate;
 class Q_GUI_EXPORT QGraphicsGrayscaleEffect: public QGraphicsEffect
 {
     Q_OBJECT
+    Q_PROPERTY(qreal strength READ strength WRITE setStrength NOTIFY strengthChanged)
 public:
     QGraphicsGrayscaleEffect(QObject *parent = 0);
     ~QGraphicsGrayscaleEffect();
 
+    qreal strength() const;
+
 protected:
     void draw(QPainter *painter, QGraphicsEffectSource *source);
 
+public Q_SLOTS:
+    void setStrength(qreal strength);
+
+Q_SIGNALS:
+    void strengthChanged(qreal strength);
+
 private:
     Q_DECLARE_PRIVATE(QGraphicsGrayscaleEffect)
     Q_DISABLE_COPY(QGraphicsGrayscaleEffect)
@@ -161,17 +170,21 @@ class Q_GUI_EXPORT QGraphicsColorizeEffect: public QGraphicsEffect
 {
     Q_OBJECT
     Q_PROPERTY(QColor color READ color WRITE setColor NOTIFY colorChanged)
+    Q_PROPERTY(qreal strength READ strength WRITE setStrength NOTIFY strengthChanged)
 public:
     QGraphicsColorizeEffect(QObject *parent = 0);
     ~QGraphicsColorizeEffect();
 
     QColor color() const;
+    qreal strength() const;
 
 public Q_SLOTS:
     void setColor(const QColor &c);
+    void setStrength(qreal strength);
 
 Q_SIGNALS:
     void colorChanged(const QColor &color);
+    void strengthChanged(qreal strength);
 
 protected:
     void draw(QPainter *painter, QGraphicsEffectSource *source);
diff --git a/src/gui/effects/qgraphicseffect_p.h b/src/gui/effects/qgraphicseffect_p.h
index 47713844a8..e109790011 100644
--- a/src/gui/effects/qgraphicseffect_p.h
+++ b/src/gui/effects/qgraphicseffect_p.h
@@ -113,6 +113,7 @@ class QGraphicsGrayscaleEffectPrivate : public QGraphicsEffectPrivate
     Q_DECLARE_PUBLIC(QGraphicsGrayscaleEffect)
 public:
     QGraphicsGrayscaleEffectPrivate()
+        : opaque(true)
     {
         filter = new QPixmapColorizeFilter;
         filter->setColor(Qt::black);
@@ -120,16 +121,24 @@ public:
     ~QGraphicsGrayscaleEffectPrivate() { delete filter; }
 
     QPixmapColorizeFilter *filter;
+    quint32 opaque : 1;
+    quint32 padding : 31;
 };
 
 class QGraphicsColorizeEffectPrivate : public QGraphicsEffectPrivate
 {
     Q_DECLARE_PUBLIC(QGraphicsColorizeEffect)
 public:
-    QGraphicsColorizeEffectPrivate() { filter = new QPixmapColorizeFilter; }
+    QGraphicsColorizeEffectPrivate()
+        : opaque(true)
+    {
+        filter = new QPixmapColorizeFilter;
+    }
     ~QGraphicsColorizeEffectPrivate() { delete filter; }
 
     QPixmapColorizeFilter *filter;
+    quint32 opaque : 1;
+    quint32 padding : 31;
 };
 
 class QGraphicsPixelizeEffectPrivate : public QGraphicsEffectPrivate
diff --git a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
index 5363fd6fb3..d5205cd0d0 100644
--- a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
+++ b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
@@ -388,6 +388,26 @@ void tst_QGraphicsEffect::grayscale()
     painter.end();
 
     QCOMPARE(image.pixel(10, 10), qRgb(148, 148, 148));
+
+    effect->setStrength(0.5);
+
+    image.fill(0);
+    painter.begin(&image);
+    painter.setRenderHint(QPainter::Antialiasing);
+    scene.render(&painter);
+    painter.end();
+
+    QCOMPARE(image.pixel(10, 10), qRgb(135, 171, 107));
+
+    effect->setStrength(0.0);
+
+    image.fill(0);
+    painter.begin(&image);
+    painter.setRenderHint(QPainter::Antialiasing);
+    scene.render(&painter);
+    painter.end();
+
+    QCOMPARE(image.pixel(10, 10), qRgb(122, 193, 66));
 }
 
 void tst_QGraphicsEffect::colorize()
@@ -412,6 +432,26 @@ void tst_QGraphicsEffect::colorize()
     painter.end();
 
     QCOMPARE(image.pixel(10, 10), qRgb(191, 212, 169));
+
+    effect->setStrength(0.5);
+
+    image.fill(0);
+    painter.begin(&image);
+    painter.setRenderHint(QPainter::Antialiasing);
+    scene.render(&painter);
+    painter.end();
+
+    QCOMPARE(image.pixel(10, 10), qRgb(156, 203, 117));
+
+    effect->setStrength(0.0);
+
+    image.fill(0);
+    painter.begin(&image);
+    painter.setRenderHint(QPainter::Antialiasing);
+    scene.render(&painter);
+    painter.end();
+
+    QCOMPARE(image.pixel(10, 10), qRgb(122, 193, 66));
 }
 
 QTEST_MAIN(tst_QGraphicsEffect)