Avoided expensive image upload for GL pixmap backend for QPixmap::fill.

In the fill case we can simply set a flag saying the pixmap needs to be
filled, and then when painting on the pixmap we start by filling the
background using glClear via the existing
QGLDrawable::autoFillBackground interface.

4 files changed, 59 insertions, 11 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index a7c7426..aafa6de 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1095,7 +1095,13 @@ bool QGL2PaintEngineEx::begin(QPaintDevice *pdev)
     glDisable(GL_SCISSOR_TEST);
 
     QGLPixmapData *source = d->drawable.copyOnBegin();
-    if (source) {
+    if (d->drawable.autoFillBackground()) {
+        QColor color = d->drawable.backgroundColor();
+
+        float alpha = color.alphaF();
+        glClearColor(color.redF() * alpha, color.greenF() * alpha, color.blueF() * alpha, alpha);
+        glClear(GL_COLOR_BUFFER_BIT);
+    } else if (source) {
         d->transferMode(ImageDrawingMode);
 
         source->bind(false);
diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 62a592a..0be70d7 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -4525,6 +4525,8 @@ QColor QGLDrawable::backgroundColor() const
 {
     if (widget)
         return widget->palette().brush(widget->backgroundRole()).color();
+    else if (pixmapData)
+        return pixmapData->fillColor();
     return QApplication::palette().brush(QPalette::Background).color();
 }
 
@@ -4547,6 +4549,8 @@ bool QGLDrawable::autoFillBackground() const
 {
     if (widget)
         return widget->autoFillBackground();
+    else if (pixmapData)
+        return pixmapData->needsFill();
     else
         return false;
 }
diff --git a/src/opengl/qpixmapdata_gl.cpp b/src/opengl/qpixmapdata_gl.cpp
index c89b99b..85bcda5 100644
--- a/src/opengl/qpixmapdata_gl.cpp
+++ b/src/opengl/qpixmapdata_gl.cpp
@@ -103,6 +103,7 @@ QGLPixmapData::QGLPixmapData(PixelType type)
     , m_engine(0)
     , m_ctx(0)
     , m_dirty(false)
+    , m_hasFillColor(false)
 {
     setSerialNumber(++qt_gl_pixmap_serial);
 }
@@ -196,6 +197,13 @@ void QGLPixmapData::fromImage(const QImage &image,
     resize(image.width(), image.height());
     m_source = image;
     m_dirty = true;
+    m_hasFillColor = false;
+
+    if (m_textureId) {
+        QGLShareContextScope ctx(qt_gl_share_widget()->context());
+        glDeleteTextures(1, &m_textureId);
+        m_textureId = 0;
+    }
 }
 
 bool QGLPixmapData::scroll(int dx, int dy, const QRect &rect)
@@ -222,7 +230,11 @@ void QGLPixmapData::fill(const QColor &color)
     if (!isValid())
         return;
 
-    if (!m_source.isNull()) {
+    if (useFramebufferObjects()) {
+        m_source = QImage();
+        m_hasFillColor = true;
+        m_fillColor = color;
+    } else if (!m_source.isNull()) {
         m_source.fill(PREMUL(color.rgba()));
     } else {
         // ## TODO: improve performance here
@@ -243,14 +255,18 @@ QImage QGLPixmapData::toImage() const
     if (!isValid())
         return QImage();
 
-    if (m_renderFbo)
+    if (m_renderFbo) {
         copyBackFromRenderFbo(true);
-    else if (!m_source.isNull())
+    } else if (!m_source.isNull()) {
         return m_source;
-    else if (m_dirty)
-        return QImage(m_width, m_height, QImage::Format_ARGB32_Premultiplied);
-    else
+    } else if (m_dirty || m_hasFillColor) {
+        QImage img(m_width, m_height, QImage::Format_ARGB32_Premultiplied);
+        if (m_hasFillColor)
+            img.fill(PREMUL(m_fillColor.rgba()));
+        return img;
+    } else {
         ensureCreated();
+    }
 
     QGLShareContextScope ctx(qt_gl_share_widget()->context());
     extern QImage qt_gl_read_texture(const QSize &size, bool alpha_format, bool include_alpha);
@@ -272,6 +288,8 @@ void QGLPixmapData::copyBackFromRenderFbo(bool keepCurrentFboBound) const
     if (!isValid())
         return;
 
+    m_hasFillColor = false;
+
     const QGLContext *share_ctx = qt_gl_share_widget()->context();
     QGLShareContextScope ctx(share_ctx);
 
@@ -356,9 +374,12 @@ QPaintEngine* QGLPixmapData::paintEngine() const
         return m_engine;
     else if (!useFramebufferObjects()) {
         m_dirty = true;
-
         if (m_source.size() != size())
             m_source = QImage(size(), QImage::Format_ARGB32_Premultiplied);
+        if (m_hasFillColor) {
+            m_source.fill(PREMUL(m_fillColor.rgba()));
+            m_hasFillColor = false;
+        }
         return m_source.paintEngine();
     }
 
@@ -394,10 +415,17 @@ QPaintEngine* QGLPixmapData::paintEngine() const
 
 GLuint QGLPixmapData::bind(bool copyBack) const
 {
-    if (m_renderFbo && copyBack)
+    if (m_renderFbo && copyBack) {
         copyBackFromRenderFbo(true);
-    else
+    } else {
+        if (m_hasFillColor) {
+            m_dirty = true;
+            m_source = QImage(m_width, m_height, QImage::Format_ARGB32_Premultiplied);
+            m_source.fill(PREMUL(m_fillColor.rgba()));
+            m_hasFillColor = false;
+        }
         ensureCreated();
+    }
 
     GLuint id = m_textureId;
     glBindTexture(GL_TEXTURE_2D, id);
diff --git a/src/opengl/qpixmapdata_gl_p.h b/src/opengl/qpixmapdata_gl_p.h
index 7e06db9..1b6b7ae 100644
--- a/src/opengl/qpixmapdata_gl_p.h
+++ b/src/opengl/qpixmapdata_gl_p.h
@@ -91,6 +91,9 @@ public:
 
     bool isUninitialized() const { return m_dirty && m_source.isNull(); }
 
+    bool needsFill() const { return m_hasFillColor; }
+    QColor fillColor() const { return m_fillColor; }
+
     QSize size() const { return QSize(m_width, m_height); }
     int width() const { return m_width; }
     int height() const { return m_height; }
@@ -119,8 +122,15 @@ private:
     mutable GLuint m_textureId;
     mutable QPaintEngine *m_engine;
     mutable QGLContext *m_ctx;
-    mutable bool m_dirty;
     mutable QImage m_source;
+
+    // the texture is not in sync with the source image
+    mutable bool m_dirty;
+
+    // fill has been called and no painting has been done, so the pixmap is
+    // represented by a single fill color
+    mutable QColor m_fillColor;
+    mutable bool m_hasFillColor;
 };
 
 QT_END_NAMESPACE