| // Copyright 2013 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "flutter/flow/layers/opacity_layer.h" |
| |
| #include "flutter/fml/trace_event.h" |
| #include "third_party/skia/include/core/SkPaint.h" |
| |
| namespace flutter { |
| |
| OpacityLayer::OpacityLayer(SkAlpha alpha, const SkPoint& offset) |
| : alpha_(alpha), offset_(offset), children_can_accept_opacity_(false) { |
| // We can always inhert opacity even if we cannot pass it along to |
| // our children as we can accumulate the inherited opacity into our |
| // own opacity value before we recurse. |
| set_layer_can_inherit_opacity(true); |
| } |
| |
| void OpacityLayer::Diff(DiffContext* context, const Layer* old_layer) { |
| DiffContext::AutoSubtreeRestore subtree(context); |
| auto* prev = static_cast<const OpacityLayer*>(old_layer); |
| if (!context->IsSubtreeDirty()) { |
| FML_DCHECK(prev); |
| if (alpha_ != prev->alpha_ || offset_ != prev->offset_) { |
| context->MarkSubtreeDirty(context->GetOldLayerPaintRegion(old_layer)); |
| } |
| } |
| context->PushTransform(SkMatrix::Translate(offset_.fX, offset_.fY)); |
| #ifndef SUPPORT_FRACTIONAL_TRANSLATION |
| context->SetTransform( |
| RasterCache::GetIntegralTransCTM(context->GetTransform())); |
| #endif |
| DiffChildren(context, prev); |
| context->SetLayerPaintRegion(this, context->CurrentSubtreeRegion()); |
| } |
| |
| void OpacityLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) { |
| TRACE_EVENT0("flutter", "OpacityLayer::Preroll"); |
| FML_DCHECK(!GetChildContainer()->layers().empty()); // We can't be a leaf. |
| |
| SkMatrix child_matrix = matrix; |
| child_matrix.preTranslate(offset_.fX, offset_.fY); |
| |
| // Similar to what's done in TransformLayer::Preroll, we have to apply the |
| // reverse transformation to the cull rect to properly cull child layers. |
| context->cull_rect = context->cull_rect.makeOffset(-offset_.fX, -offset_.fY); |
| |
| context->mutators_stack.PushTransform( |
| SkMatrix::Translate(offset_.fX, offset_.fY)); |
| context->mutators_stack.PushOpacity(alpha_); |
| Layer::AutoPrerollSaveLayerState save = |
| Layer::AutoPrerollSaveLayerState::Create(context); |
| ContainerLayer::Preroll(context, child_matrix); |
| context->mutators_stack.Pop(); |
| context->mutators_stack.Pop(); |
| |
| set_children_can_accept_opacity(context->subtree_can_inherit_opacity); |
| |
| set_paint_bounds(paint_bounds().makeOffset(offset_.fX, offset_.fY)); |
| |
| if (!children_can_accept_opacity()) { |
| #ifndef SUPPORT_FRACTIONAL_TRANSLATION |
| child_matrix = RasterCache::GetIntegralTransCTM(child_matrix); |
| #endif |
| TryToPrepareRasterCache(context, GetCacheableChild(), child_matrix); |
| } |
| |
| // Restore cull_rect |
| context->cull_rect = context->cull_rect.makeOffset(offset_.fX, offset_.fY); |
| } |
| |
| void OpacityLayer::Paint(PaintContext& context) const { |
| TRACE_EVENT0("flutter", "OpacityLayer::Paint"); |
| FML_DCHECK(needs_painting(context)); |
| |
| SkAutoCanvasRestore save(context.internal_nodes_canvas, true); |
| context.internal_nodes_canvas->translate(offset_.fX, offset_.fY); |
| |
| #ifndef SUPPORT_FRACTIONAL_TRANSLATION |
| context.internal_nodes_canvas->setMatrix(RasterCache::GetIntegralTransCTM( |
| context.leaf_nodes_canvas->getTotalMatrix())); |
| #endif |
| |
| SkScalar inherited_opacity = context.inherited_opacity; |
| SkScalar subtree_opacity = opacity() * inherited_opacity; |
| |
| if (children_can_accept_opacity()) { |
| context.inherited_opacity = subtree_opacity; |
| PaintChildren(context); |
| context.inherited_opacity = inherited_opacity; |
| return; |
| } |
| |
| SkPaint paint; |
| paint.setAlphaf(subtree_opacity); |
| |
| if (context.raster_cache && |
| context.raster_cache->Draw(GetCacheableChild(), |
| *context.leaf_nodes_canvas, &paint)) { |
| return; |
| } |
| |
| // Skia may clip the content with saveLayerBounds (although it's not a |
| // guaranteed clip). So we have to provide a big enough saveLayerBounds. To do |
| // so, we first remove the offset from paint bounds since it's already in the |
| // matrix. Then we round out the bounds. |
| // |
| // Note that the following lines are only accessible when the raster cache is |
| // not available (e.g., when we're using the software backend in golden |
| // tests). |
| SkRect saveLayerBounds; |
| paint_bounds() |
| .makeOffset(-offset_.fX, -offset_.fY) |
| .roundOut(&saveLayerBounds); |
| |
| Layer::AutoSaveLayer save_layer = |
| Layer::AutoSaveLayer::Create(context, saveLayerBounds, &paint); |
| PaintChildren(context); |
| } |
| |
| } // namespace flutter |