void ReadbackProcessor::BuildUpdatesForLayer(ReadbackLayer* aLayer) { if (!aLayer->mSink) return; nsIntPoint offset; Layer* newBackground = FindBackgroundLayer(aLayer, &offset); if (!newBackground) { aLayer->SetUnknown(); return; } if (newBackground->GetType() == Layer::TYPE_COLOR) { ColorLayer* colorLayer = static_cast<ColorLayer*>(newBackground); if (aLayer->mBackgroundColor != colorLayer->GetColor()) { aLayer->mBackgroundLayer = nullptr; aLayer->mBackgroundColor = colorLayer->GetColor(); NS_ASSERTION(aLayer->mBackgroundColor.a == 1.0, "Color layer said it was opaque!"); nsRefPtr<gfxContext> ctx = aLayer->mSink->BeginUpdate(aLayer->GetRect(), aLayer->AllocateSequenceNumber()); if (ctx) { ctx->SetColor(aLayer->mBackgroundColor); nsIntSize size = aLayer->GetSize(); ctx->Rectangle(gfxRect(0, 0, size.width, size.height)); ctx->Fill(); aLayer->mSink->EndUpdate(ctx, aLayer->GetRect()); } } } else { NS_ASSERTION(newBackground->AsThebesLayer(), "Must be ThebesLayer"); ThebesLayer* thebesLayer = static_cast<ThebesLayer*>(newBackground); // updateRect is relative to the ThebesLayer nsIntRect updateRect = aLayer->GetRect() - offset; if (thebesLayer != aLayer->mBackgroundLayer || offset != aLayer->mBackgroundLayerOffset) { aLayer->mBackgroundLayer = thebesLayer; aLayer->mBackgroundLayerOffset = offset; aLayer->mBackgroundColor = gfxRGBA(0,0,0,0); thebesLayer->SetUsedForReadback(true); } else { nsIntRegion invalid; invalid.Sub(updateRect, thebesLayer->GetValidRegion()); updateRect = invalid.GetBounds(); } Update update = { aLayer, updateRect, aLayer->AllocateSequenceNumber() }; mAllUpdates.AppendElement(update); } }