1 files changed, 120 insertions, 0 deletions
diff --git a/widget/gtk/nsImageToPixbuf.cpp b/widget/gtk/nsImageToPixbuf.cpp
new file mode 100644
index 000000000..e06605b2b
--- /dev/null
+++ b/widget/gtk/nsImageToPixbuf.cpp
@@ -0,0 +1,120 @@
+/* vim:set sw=4 sts=4 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+
+#include "nsImageToPixbuf.h"
+
+#include "imgIContainer.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/RefPtr.h"
+
+using mozilla::gfx::DataSourceSurface;
+using mozilla::gfx::SurfaceFormat;
+
+NS_IMPL_ISUPPORTS(nsImageToPixbuf, nsIImageToPixbuf)
+
+inline unsigned char
+unpremultiply (unsigned char color,
+               unsigned char alpha)
+{
+    if (alpha == 0)
+        return 0;
+    // plus alpha/2 to round instead of truncate
+    return (color * 255 + alpha / 2) / alpha;
+}
+
+NS_IMETHODIMP_(GdkPixbuf*)
+nsImageToPixbuf::ConvertImageToPixbuf(imgIContainer* aImage)
+{
+    return ImageToPixbuf(aImage);
+}
+
+GdkPixbuf*
+nsImageToPixbuf::ImageToPixbuf(imgIContainer* aImage)
+{
+    RefPtr<SourceSurface> surface =
+      aImage->GetFrame(imgIContainer::FRAME_CURRENT,
+                       imgIContainer::FLAG_SYNC_DECODE);
+
+    // If the last call failed, it was probably because our call stack originates
+    // in an imgINotificationObserver event, meaning that we're not allowed request
+    // a sync decode. Presumably the originating event is something sensible like
+    // OnStopFrame(), so we can just retry the call without a sync decode.
+    if (!surface)
+      surface = aImage->GetFrame(imgIContainer::FRAME_CURRENT,
+                                 imgIContainer::FLAG_NONE);
+
+    NS_ENSURE_TRUE(surface, nullptr);
+
+    return SourceSurfaceToPixbuf(surface,
+                                 surface->GetSize().width,
+                                 surface->GetSize().height);
+}
+
+GdkPixbuf*
+nsImageToPixbuf::SourceSurfaceToPixbuf(SourceSurface* aSurface,
+                                       int32_t aWidth,
+                                       int32_t aHeight)
+{
+    MOZ_ASSERT(aWidth <= aSurface->GetSize().width &&
+               aHeight <= aSurface->GetSize().height,
+               "Requested rect is bigger than the supplied surface");
+
+    GdkPixbuf* pixbuf = gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8,
+                                       aWidth, aHeight);
+    if (!pixbuf)
+        return nullptr;
+
+    uint32_t destStride = gdk_pixbuf_get_rowstride (pixbuf);
+    guchar* destPixels = gdk_pixbuf_get_pixels (pixbuf);
+
+    RefPtr<DataSourceSurface> dataSurface = aSurface->GetDataSurface();
+    DataSourceSurface::MappedSurface map;
+    if (!dataSurface->Map(DataSourceSurface::MapType::READ, &map))
+        return nullptr;
+
+    uint8_t* srcData = map.mData;
+    int32_t srcStride = map.mStride;
+
+    SurfaceFormat format = dataSurface->GetFormat();
+
+    for (int32_t row = 0; row < aHeight; ++row) {
+        for (int32_t col = 0; col < aWidth; ++col) {
+            guchar* destPixel = destPixels + row * destStride + 4 * col;
+
+            uint32_t* srcPixel =
+                reinterpret_cast<uint32_t*>((srcData + row * srcStride + 4 * col));
+
+            if (format == SurfaceFormat::B8G8R8A8) {
+                const uint8_t a = (*srcPixel >> 24) & 0xFF;
+                const uint8_t r = unpremultiply((*srcPixel >> 16) & 0xFF, a);
+                const uint8_t g = unpremultiply((*srcPixel >>  8) & 0xFF, a);
+                const uint8_t b = unpremultiply((*srcPixel >>  0) & 0xFF, a);
+
+                *destPixel++ = r;
+                *destPixel++ = g;
+                *destPixel++ = b;
+                *destPixel++ = a;
+            } else {
+                MOZ_ASSERT(format == SurfaceFormat::B8G8R8X8);
+
+                const uint8_t r = (*srcPixel >> 16) & 0xFF;
+                const uint8_t g = (*srcPixel >>  8) & 0xFF;
+                const uint8_t b = (*srcPixel >>  0) & 0xFF;
+
+                *destPixel++ = r;
+                *destPixel++ = g;
+                *destPixel++ = b;
+                *destPixel++ = 0xFF; // A
+            }
+        }
+    }
+
+    dataSurface->Unmap();
+
+    return pixbuf;
+}
+