1 files changed, 108 insertions, 0 deletions
diff --git a/widget/gtk/nsImageToPixbuf.cpp b/widget/gtk/nsImageToPixbuf.cpp
new file mode 100644
index 0000000000..c70e589576
--- /dev/null
+++ b/widget/gtk/nsImageToPixbuf.cpp
@@ -0,0 +1,108 @@
+/* vim:set sw=2 sts=2 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 | imgIContainer::FLAG_ASYNC_NOTIFY);
+
+  // 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;
+}