1 files changed, 51 insertions, 0 deletions
diff --git a/gfx/layers/LayersHelpers.h b/gfx/layers/LayersHelpers.h
new file mode 100644
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+++ b/gfx/layers/LayersHelpers.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef mozilla_gfx_layers_LayersHelpers_h
+#define mozilla_gfx_layers_LayersHelpers_h
+
+#include "mozilla/Maybe.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/gfx/Matrix.h"
+#include "mozilla/gfx/Polygon.h"
+#include "nsRegion.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+namespace layers {
+
+class Layer;
+
+// Compute compositor information for copying the backdrop for a mix-blend
+// operation.
+gfx::IntRect ComputeBackdropCopyRect(const gfx::Rect& aRect,
+                                     const gfx::IntRect& aClipRect,
+                                     const gfx::Matrix4x4& aTransform,
+                                     const gfx::IntRect& aRenderTargetRect,
+                                     gfx::Matrix4x4* aOutTransform,
+                                     gfx::Rect* aOutLayerQuad = nullptr);
+
+// Compute uv-coordinates for a rect inside a texture.
+template <typename T>
+static inline gfx::Rect TextureRectToCoords(const T& aRect,
+                                            const gfx::IntSize& aSize) {
+  return gfx::Rect(
+      float(aRect.X()) / aSize.width, float(aRect.Y()) / aSize.height,
+      float(aRect.Width()) / aSize.width, float(aRect.Height()) / aSize.height);
+}
+
+// This is defined in Compositor.cpp.
+nsTArray<gfx::TexturedTriangle> GenerateTexturedTriangles(
+    const gfx::Polygon& aPolygon, const gfx::Rect& aRect,
+    const gfx::Rect& aTexRect);
+
+// This is defined in ContainerLayerComposite.cpp.
+void TransformLayerGeometry(Layer* aLayer, Maybe<gfx::Polygon>& aGeometry);
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_gfx_layers_LayersHelpers_h