Fixed distance field text when using non-opaque colors.

The alpha has to be premultiplied before passing the color to the
shader.

Change-Id: If22f0e0892eb4330d5f7398bea2710fce18c4dcb
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>

1 files changed, 20 insertions, 4 deletions

diff --git a/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp b/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp
index 45fc0f5c6d..86c3356d58 100644
--- a/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp
+++ b/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp
@@ -144,8 +144,8 @@ void QSGDistanceFieldTextMaterialShader::updateState(const RenderState &state, Q
     if (oldMaterial == 0
            || material->color() != oldMaterial->color()
            || state.isOpacityDirty()) {
-        QVector4D color(material->color().redF(), material->color().greenF(),
-                        material->color().blueF(), material->color().alphaF());
+        QColor c = material->color();
+        QVector4D color(c.redF(), c.greenF(), c.blueF(), c.alphaF());
         color *= state.opacity();
         program()->setUniformValue(m_color_id, color);
     }
@@ -204,6 +204,14 @@ QSGMaterialType *QSGDistanceFieldTextMaterial::type() const
     return &type;
 }
 
+void QSGDistanceFieldTextMaterial::setColor(const QColor &color)
+{
+    m_color = QColor::fromRgbF(color.redF() * color.alphaF(),
+                               color.greenF() * color.alphaF(),
+                               color.blueF() * color.alphaF(),
+                               color.alphaF());
+}
+
 QSGMaterialShader *QSGDistanceFieldTextMaterial::createShader() const
 {
     return new QSGDistanceFieldTextMaterialShader;
@@ -276,8 +284,8 @@ void DistanceFieldStyledTextMaterialShader::updateState(const RenderState &state
     if (oldMaterial == 0
            || material->styleColor() != oldMaterial->styleColor()
            || (state.isOpacityDirty())) {
-        QVector4D color(material->styleColor().redF(), material->styleColor().greenF(),
-                        material->styleColor().blueF(), material->styleColor().alphaF());
+        QColor c = material->styleColor();
+        QVector4D color(c.redF(), c.greenF(), c.blueF(), c.alphaF());
         color *= state.opacity();
         program()->setUniformValue(m_styleColor_id, color);
     }
@@ -292,6 +300,14 @@ QSGDistanceFieldStyledTextMaterial::~QSGDistanceFieldStyledTextMaterial()
 {
 }
 
+void QSGDistanceFieldStyledTextMaterial::setStyleColor(const QColor &color)
+{
+    m_styleColor = QColor::fromRgbF(color.redF() * color.alphaF(),
+                                    color.greenF() * color.alphaF(),
+                                    color.blueF() * color.alphaF(),
+                                    color.alphaF());
+}
+
 int QSGDistanceFieldStyledTextMaterial::compare(const QSGMaterial *o) const
 {
     Q_ASSERT(o && type() == o->type());