From 0b190b7114c816689eeb8478ea5151732bc7a5de Mon Sep 17 00:00:00 2001
From: Yoann Lopes <yoann.lopes@digia.com>
Date: Thu, 21 Mar 2013 16:34:38 +0100
Subject: [PATCH] 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>
---
 .../scenegraph/qsgdistancefieldglyphnode_p.cpp     | 24 ++++++++++++++++++----
 .../scenegraph/qsgdistancefieldglyphnode_p_p.h     |  6 ++++--
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp b/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp
index 45fc0f5..86c3356 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());
diff --git a/src/quick/scenegraph/qsgdistancefieldglyphnode_p_p.h b/src/quick/scenegraph/qsgdistancefieldglyphnode_p_p.h
index d6aa38a..7fea8f6 100644
--- a/src/quick/scenegraph/qsgdistancefieldglyphnode_p_p.h
+++ b/src/quick/scenegraph/qsgdistancefieldglyphnode_p_p.h
@@ -58,7 +58,7 @@ public:
     virtual QSGMaterialShader *createShader() const;
     virtual int compare(const QSGMaterial *other) const;
 
-    void setColor(const QColor &color) { m_color = color; }
+    virtual void setColor(const QColor &color);
     const QColor &color() const { return m_color; }
 
     void setGlyphCache(QSGDistanceFieldGlyphCache *a) { m_glyph_cache = a; }
@@ -92,7 +92,7 @@ public:
     virtual QSGMaterialShader *createShader() const = 0;
     virtual int compare(const QSGMaterial *other) const;
 
-    void setStyleColor(const QColor &color) { m_styleColor = color; }
+    void setStyleColor(const QColor &color);
     const QColor &styleColor() const { return m_styleColor; }
 
 protected:
@@ -130,6 +130,7 @@ class Q_QUICK_PRIVATE_EXPORT QSGHiQSubPixelDistanceFieldTextMaterial : public QS
 public:
     virtual QSGMaterialType *type() const;
     virtual QSGMaterialShader *createShader() const;
+    void setColor(const QColor &color) { m_color = color; }
 };
 
 class Q_QUICK_PRIVATE_EXPORT QSGLoQSubPixelDistanceFieldTextMaterial : public QSGDistanceFieldTextMaterial
@@ -137,6 +138,7 @@ class Q_QUICK_PRIVATE_EXPORT QSGLoQSubPixelDistanceFieldTextMaterial : public QS
 public:
     virtual QSGMaterialType *type() const;
     virtual QSGMaterialShader *createShader() const;
+    void setColor(const QColor &color) { m_color = color; }
 };
 
 QT_END_NAMESPACE
-- 
2.7.4