[cairo-qpainter] Create QPixmaps with an alpha channel if required

gfx/cairo/cairo/src/cairo-qpainter-surface.cpp

@@ -392,14 +392,13 @@ _cairo_qpainter_surface_create_similar (void *abstract_surface,
 
     if (!do_image && (!_qpixmaps_have_no_alpha || content == CAIRO_CONTENT_COLOR)) {
 	cairo_surface_t *result =
-	    cairo_qpainter_surface_create_with_qpixmap (width, height);
+	    cairo_qpainter_surface_create_with_qpixmap (content, width, height);
 
 	if (cairo_surface_get_content (result) == content) {
-	    D(fprintf(stderr, "qpixmap\n"));
+	    D(fprintf(stderr, "qpixmap content: %d\n", content));
 	    return result;
 	}
 
-	fprintf (stderr, " pixmaps have no alpha!\n");
 	_qpixmaps_have_no_alpha = TRUE;
 	cairo_surface_destroy (result);
     }
@@ -602,7 +601,7 @@ _cairo_qpainter_surface_clone_similar (void *abstract_surface,
     if (qs->image == NULL && (!_qpixmaps_have_no_alpha || src->content == CAIRO_CONTENT_COLOR))
     {
         new_surf = cairo_qpainter_surface_create_with_qpixmap
-                   (width, height);
+	    (src->content, width, height);
 	if (cairo_surface_get_content (new_surf) != src->content) {
 	    cairo_surface_destroy (new_surf);
 	    _qpixmaps_have_no_alpha = TRUE;
@@ -1571,11 +1570,16 @@ cairo_qpainter_surface_create_with_qimage (cairo_format_t format,
 }
 
 cairo_surface_t *
-cairo_qpainter_surface_create_with_qpixmap (int width,
+cairo_qpainter_surface_create_with_qpixmap (cairo_content_t content,
+					    int width,
                                             int height)
 {
     cairo_qpainter_surface_t *qs;
 
+    if (content != CAIRO_CONTENT_COLOR &&
+	content != CAIRO_CONTENT_COLOR_ALPHA)
+	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
+
     qs = (cairo_qpainter_surface_t *) malloc (sizeof(cairo_qpainter_surface_t));
     if (qs == NULL)
         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
@@ -1584,9 +1588,14 @@ cairo_qpainter_surface_create_with_qpixmap (int width,
 
     QPixmap *pixmap = new QPixmap (width, height);
 
-    _cairo_surface_init (&qs->base, &cairo_qpainter_surface_backend,
-                         pixmap->hasAlphaChannel() ? CAIRO_CONTENT_COLOR_ALPHA : CAIRO_CONTENT_COLOR);
+    // By default, a QPixmap is opaque; however, if it's filled
+    // with a color with a transparency component, it is converted
+    // to a format that preserves transparency.
+    if (content == CAIRO_CONTENT_COLOR_ALPHA)
+	pixmap->fill(Qt::transparent);
 
+    _cairo_surface_init (&qs->base, &cairo_qpainter_surface_backend,
+			 content);
 
     qs->pixmap = pixmap;
 

gfx/cairo/cairo/src/cairo-qpainter.h

@@ -55,7 +55,8 @@ cairo_qpainter_surface_create_with_qimage (cairo_format_t format,
                                            int height);
 
 cairo_public cairo_surface_t *
-cairo_qpainter_surface_create_with_qpixmap (int width,
+cairo_qpainter_surface_create_with_qpixmap (cairo_content_t content,
+					    int width,
                                             int height);
 
 cairo_public QPainter *

gfx/thebes/public/gfxASurface.h

@@ -140,6 +140,8 @@ public:
      */
     virtual PRInt32 GetDefaultContextFlags() const { return 0; }
 
+    static gfxContentType ContentFromFormat(gfxImageFormat format);
+
 protected:
     gfxASurface() : mSurface(nsnull), mFloatingRefs(0), mSurfaceValid(PR_FALSE) { }
 

gfx/thebes/public/gfxQPainterSurface.h

@@ -48,7 +48,7 @@ class THEBES_API gfxQPainterSurface : public gfxASurface {
 public:
     gfxQPainterSurface(QPainter *painter);
     gfxQPainterSurface(const gfxIntSize& size, gfxImageFormat format);
-    gfxQPainterSurface(const gfxIntSize& size);
+    gfxQPainterSurface(const gfxIntSize& size, gfxContentType content);
 
     gfxQPainterSurface(cairo_surface_t *csurf);
 

gfx/thebes/src/gfxASurface.cpp

@@ -354,3 +354,21 @@ gfxASurface::EndPage()
 {
     return NS_OK;
 }
+
+gfxASurface::gfxContentType
+gfxASurface::ContentFromFormat(gfxImageFormat format)
+{
+    switch (format) {
+        case ImageFormatARGB32:
+            return CONTENT_COLOR_ALPHA;
+        case ImageFormatRGB24:
+            return CONTENT_COLOR;
+        case ImageFormatA8:
+        case ImageFormatA1:
+            return CONTENT_ALPHA;
+
+        case ImageFormatUnknown:
+        default:
+            return CONTENT_COLOR;
+    }
+}

gfx/thebes/src/gfxQPainterSurface.cpp

@@ -59,9 +59,10 @@ gfxQPainterSurface::gfxQPainterSurface(const gfxIntSize& size, gfxImageFormat fo
     Init (csurf);
 }
 
-gfxQPainterSurface::gfxQPainterSurface(const gfxIntSize& size)
+gfxQPainterSurface::gfxQPainterSurface(const gfxIntSize& size, gfxContentType content)
 {
-    cairo_surface_t *csurf = cairo_qpainter_surface_create_with_qpixmap (size.width,
+    cairo_surface_t *csurf = cairo_qpainter_surface_create_with_qpixmap ((cairo_content_t) content,
+                                                                         size.width,
                                                                          size.height);
     mPainter = cairo_qpainter_surface_get_qpainter (csurf);
 

gfx/thebes/src/gfxQtPlatform.cpp

@@ -63,6 +63,10 @@
 #include <ft2build.h>
 #include FT_FREETYPE_H
 
+#ifndef Q_WS_X11
+#define OPTIMIZE_TO_QPIXMAP
+#endif
+
 PRInt32 gfxQtPlatform::sDPI = -1;
 gfxFontconfigUtils *gfxQtPlatform::sFontconfigUtils = nsnull;
 static cairo_user_data_key_t cairo_qt_pixmap_key;
@@ -124,9 +128,8 @@ already_AddRefed<gfxASurface>
 gfxQtPlatform::CreateOffscreenSurface(const gfxIntSize& size,
                                       gfxASurface::gfxImageFormat imageFormat)
 {
-    // XXX we may be able to create a QPixmap here, instead of a QImage always
     nsRefPtr<gfxASurface> newSurface =
-        new gfxQPainterSurface (size, imageFormat);
+        new gfxQPainterSurface (size, gfxASurface::ContentFromFormat(imageFormat));
 
     return newSurface.forget();
 }
@@ -135,10 +138,7 @@ already_AddRefed<gfxASurface>
 gfxQtPlatform::OptimizeImage(gfxImageSurface *aSurface,
                              gfxASurface::gfxImageFormat format)
 {
-    NS_ADDREF(aSurface);
-    return aSurface;
-
-#if 0
+#ifdef OPTIMIZE_TO_QPIXMAP
     const gfxIntSize& surfaceSize = aSurface->GetSize();
 
     nsRefPtr<gfxASurface> optSurface = CreateOffscreenSurface(surfaceSize, format);
@@ -150,9 +150,9 @@ gfxQtPlatform::OptimizeImage(gfxImageSurface *aSurface,
     tmpCtx.SetSource(aSurface);
     tmpCtx.Paint();
 
-    gfxASurface *ret = optSurface;
-    NS_ADDREF(ret);
-    return ret;
+    return optSurface.forget();
+#else
+    return nsnull;
 #endif
 }
 

widget/src/qt/nsWindow.cpp

@@ -2389,7 +2389,7 @@ nsWindow::GetThebesSurface()
             mThebesSurface->SetDeviceOffset(gfxPoint(-x_offset, -y_offset));
         }
 #else
-        mThebesSurface = new gfxQPainterSurface(gfxIntSize(5,5));
+        mThebesSurface = new gfxQPainterSurface(gfxIntSize(5,5), gfxASurface::CONTENT_COLOR_ALPHA);
 #endif
     }