Bug 1632249 - NON_PREMULT TextureClient iff NON_PREMULT CanvasClient. r=handyman

Differential Revision: https://phabricator.services.mozilla.com/D78800

dom/canvas/ClientWebGLContext.cpp

@@ -421,7 +421,6 @@ void ClientWebGLContext::Present(WebGLFramebufferJS* const fb,
                                  const layers::TextureType type) {
   if (!mIsCanvasDirty && !fb) return;
   mIsCanvasDirty = false;
-  mFrontBufferSnapshot = nullptr;
 
   Run<RPROC(Present)>(fb ? fb->mId : 0, type);
 }
@@ -882,7 +881,8 @@ already_AddRefed<gfx::SourceSurface> ClientWebGLContext::GetSurfaceSnapshot(
   return ret.forget();
 }
 
-RefPtr<gfx::SourceSurface> ClientWebGLContext::GetFrontBufferSnapshot() {
+RefPtr<gfx::SourceSurface> ClientWebGLContext::GetFrontBufferSnapshot(
+    const bool requireAlphaPremult) {
   const FuncScope funcScope(*this, "<GetSurfaceSnapshot>");
   if (IsContextLost()) return nullptr;
   const auto notLost =
@@ -890,20 +890,19 @@ RefPtr<gfx::SourceSurface> ClientWebGLContext::GetFrontBufferSnapshot() {
 
   const auto& options = mNotLost->info.options;
 
-  if (!mFrontBufferSnapshot) {
-    mFrontBufferSnapshot = Run<RPROC(GetFrontBufferSnapshot)>();
-    if (!mFrontBufferSnapshot) return nullptr;
+  auto snapshot = Run<RPROC(GetFrontBufferSnapshot)>();
+  if (!snapshot) return nullptr;
 
-    if (options.alpha && !options.premultipliedAlpha) {
-      const auto nonPremultSurf = mFrontBufferSnapshot;
-      const auto& size = nonPremultSurf->GetSize();
-      const auto format = nonPremultSurf->GetFormat();
-      mFrontBufferSnapshot =
-          gfx::Factory::CreateDataSourceSurface(size, format, /*zero=*/false);
-      gfxUtils::PremultiplyDataSurface(nonPremultSurf, mFrontBufferSnapshot);
-    }
+  if (requireAlphaPremult && options.alpha && !options.premultipliedAlpha) {
+    const auto nonPremultSurf = snapshot;
+    const auto& size = nonPremultSurf->GetSize();
+    const auto format = nonPremultSurf->GetFormat();
+    snapshot =
+        gfx::Factory::CreateDataSourceSurface(size, format, /*zero=*/false);
+    gfxUtils::PremultiplyDataSurface(nonPremultSurf, snapshot);
   }
-  return mFrontBufferSnapshot;
+
+  return snapshot;
 }
 
 RefPtr<gfx::DataSourceSurface> ClientWebGLContext::BackBufferSnapshot() {

dom/canvas/ClientWebGLContext.h

@@ -723,8 +723,6 @@ class ClientWebGLContext final : public nsICanvasRenderingContextInternal,
   bool mIsCanvasDirty = false;
   uvec2 mRequestedSize = {};
 
-  RefPtr<gfx::DataSourceSurface> mFrontBufferSnapshot;
-
  public:
   explicit ClientWebGLContext(bool webgl2);
 
@@ -997,7 +995,8 @@ class ClientWebGLContext final : public nsICanvasRenderingContextInternal,
   void Present(WebGLFramebufferJS*, layers::TextureType);
   Maybe<layers::SurfaceDescriptor> GetFrontBuffer(WebGLFramebufferJS*,
                                                   layers::TextureType);
-  RefPtr<gfx::SourceSurface> GetFrontBufferSnapshot() override;
+  RefPtr<gfx::SourceSurface> GetFrontBufferSnapshot(
+      bool requireAlphaPremult = true) override;
 
  private:
   RefPtr<gfx::DataSourceSurface> BackBufferSnapshot();

dom/canvas/nsICanvasRenderingContextInternal.h

@@ -137,7 +137,7 @@ class nsICanvasRenderingContextInternal : public nsISupports,
   virtual already_AddRefed<mozilla::gfx::SourceSurface> GetSurfaceSnapshot(
       gfxAlphaType* out_alphaType = nullptr) = 0;
 
-  virtual RefPtr<mozilla::gfx::SourceSurface> GetFrontBufferSnapshot() {
+  virtual RefPtr<mozilla::gfx::SourceSurface> GetFrontBufferSnapshot(bool) {
     return GetSurfaceSnapshot();
   }
 

gfx/layers/CanvasRenderer.cpp

@@ -46,7 +46,8 @@ bool CanvasRenderer::IsDataValid(const CanvasRendererData& aData) const {
   return mData.GetContext() == aData.GetContext();
 }
 
-std::shared_ptr<BorrowedSourceSurface> CanvasRenderer::BorrowSnapshot() const {
+std::shared_ptr<BorrowedSourceSurface> CanvasRenderer::BorrowSnapshot(
+    const bool requireAlphaPremult) const {
   const auto context = mData.GetContext();
   if (!context) return nullptr;
   const auto& provider = context->GetBufferProvider();
@@ -57,7 +58,7 @@ std::shared_ptr<BorrowedSourceSurface> CanvasRenderer::BorrowSnapshot() const {
     ss = provider->BorrowSnapshot();
   }
   if (!ss) {
-    ss = context->GetFrontBufferSnapshot();
+    ss = context->GetFrontBufferSnapshot(requireAlphaPremult);
   }
   if (!ss) return nullptr;
 

gfx/layers/CanvasRenderer.h

@@ -137,7 +137,8 @@ class CanvasRenderer : public RefCounted<CanvasRenderer> {
     return nullptr;
   }
 
-  std::shared_ptr<BorrowedSourceSurface> BorrowSnapshot() const;
+  std::shared_ptr<BorrowedSourceSurface> BorrowSnapshot(
+      bool requireAlphaPremult = true) const;
 
  protected:
   void FirePreTransactionCallback() const;

gfx/layers/ShareableCanvasRenderer.cpp

@@ -159,7 +159,8 @@ void ShareableCanvasRenderer::UpdateCompositableClient() {
 
       const RefPtr<DrawTarget> dt = tc->BorrowDrawTarget();
 
-      const auto borrowed = BorrowSnapshot();
+      const bool requireAlphaPremult = false;
+      const auto borrowed = BorrowSnapshot(requireAlphaPremult);
       if (!borrowed) return nullptr;
 
       dt->CopySurface(borrowed->mSurf, {{0, 0}, size}, {0, 0});

gfx/layers/client/CanvasClient.cpp

@@ -31,6 +31,12 @@ namespace layers {
 void CanvasClient::UseTexture(TextureClient* const aTexture) {
   MOZ_ASSERT(aTexture);
 
+  const auto isClientNonPremult =
+      bool(mTextureFlags & TextureFlags::NON_PREMULTIPLIED);
+  const auto isTextureNonPremult =
+      bool(aTexture->GetFlags() & TextureFlags::NON_PREMULTIPLIED);
+  MOZ_ALWAYS_TRUE(isTextureNonPremult == isClientNonPremult);
+
   bool changed = false;
 
   if (aTexture != mFrontBuffer) {