Flutter Engine
layer.cc
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #include "flutter/flow/layers/layer.h"
6 
7 #include "flutter/flow/paint_utils.h"
8 #include "third_party/skia/include/core/SkColorFilter.h"
9 
10 namespace flutter {
11 
13  : paint_bounds_(SkRect::MakeEmpty()),
14  unique_id_(NextUniqueID()),
15  needs_system_composite_(false) {}
16 
17 Layer::~Layer() = default;
18 
19 uint64_t Layer::NextUniqueID() {
20  static std::atomic<uint64_t> nextID(1);
21  uint64_t id;
22  do {
23  id = nextID.fetch_add(1);
24  } while (id == 0); // 0 is reserved for an invalid id.
25  return id;
26 }
27 
28 void Layer::Preroll(PrerollContext* context, const SkMatrix& matrix) {}
29 
30 Layer::AutoPrerollSaveLayerState::AutoPrerollSaveLayerState(
31  PrerollContext* preroll_context,
32  bool save_layer_is_active,
33  bool layer_itself_performs_readback)
34  : preroll_context_(preroll_context),
35  save_layer_is_active_(save_layer_is_active),
36  layer_itself_performs_readback_(layer_itself_performs_readback) {
37  if (save_layer_is_active_) {
38  prev_surface_needs_readback_ = preroll_context_->surface_needs_readback;
39  preroll_context_->surface_needs_readback = false;
40  }
41 }
42 
44  PrerollContext* preroll_context,
45  bool save_layer_is_active,
46  bool layer_itself_performs_readback) {
47  return Layer::AutoPrerollSaveLayerState(preroll_context, save_layer_is_active,
48  layer_itself_performs_readback);
49 }
50 
52  if (save_layer_is_active_) {
53  preroll_context_->surface_needs_readback =
54  (prev_surface_needs_readback_ || layer_itself_performs_readback_);
55  }
56 }
57 
58 #if defined(LEGACY_FUCHSIA_EMBEDDER)
59 
60 void Layer::CheckForChildLayerBelow(PrerollContext* context) {
61  // If there is embedded Fuchsia content in the scene (a ChildSceneLayer),
62  // PhysicalShapeLayers that appear above the embedded content will be turned
63  // into their own Scenic layers.
64  child_layer_exists_below_ = context->child_scene_layer_exists_below;
65  if (child_layer_exists_below_) {
67  }
68 }
69 
70 void Layer::UpdateScene(std::shared_ptr<SceneUpdateContext> context) {
72  FML_DCHECK(child_layer_exists_below_);
73 
75  context, SkRRect::MakeRect(paint_bounds()), SK_ColorTRANSPARENT,
76  SkScalarRoundToInt(context->alphaf() * 255), "flutter::Layer");
77 
78  frame.AddPaintLayer(this);
79 }
80 
81 #endif
82 
83 Layer::AutoSaveLayer::AutoSaveLayer(const PaintContext& paint_context,
84  const SkRect& bounds,
85  const SkPaint* paint)
86  : paint_context_(paint_context), bounds_(bounds) {
87  paint_context_.internal_nodes_canvas->saveLayer(bounds_, paint);
88 }
89 
90 Layer::AutoSaveLayer::AutoSaveLayer(const PaintContext& paint_context,
91  const SkCanvas::SaveLayerRec& layer_rec)
92  : paint_context_(paint_context), bounds_(*layer_rec.fBounds) {
93  paint_context_.internal_nodes_canvas->saveLayer(layer_rec);
94 }
95 
97  const PaintContext& paint_context,
98  const SkRect& bounds,
99  const SkPaint* paint) {
100  return Layer::AutoSaveLayer(paint_context, bounds, paint);
101 }
102 
104  const PaintContext& paint_context,
105  const SkCanvas::SaveLayerRec& layer_rec) {
106  return Layer::AutoSaveLayer(paint_context, layer_rec);
107 }
108 
110  if (paint_context_.checkerboard_offscreen_layers) {
111  DrawCheckerboard(paint_context_.internal_nodes_canvas, bounds_);
112  }
113  paint_context_.internal_nodes_canvas->restore();
114 }
115 
116 } // namespace flutter
#define FML_DCHECK(condition)
Definition: logging.h:86
static AutoSaveLayer Create(const PaintContext &paint_context, const SkRect &bounds, const SkPaint *paint)
Definition: layer.cc:96
bool needs_system_composite() const
Definition: layer.h:161
static AutoPrerollSaveLayerState Create(PrerollContext *preroll_context, bool save_layer_is_active=true, bool layer_itself_performs_readback=false)
Definition: layer.cc:43
const SkRect & paint_bounds() const
Definition: layer.h:166
virtual void Preroll(PrerollContext *context, const SkMatrix &matrix)
Definition: layer.cc:28
int32_t id
void set_needs_system_composite(bool value)
Definition: layer.h:162
virtual ~Layer()
void DrawCheckerboard(SkCanvas *canvas, SkColor c1, SkColor c2, int size)
Definition: paint_utils.cc:28