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/opacity_layer.h"
6
7 #include "flutter/flow/layers/transform_layer.h"
8
9 namespace flutter {
10
OpacityLayer(int alpha,const SkPoint & offset)11 OpacityLayer::OpacityLayer(int alpha, const SkPoint& offset)
12 : alpha_(alpha), offset_(offset) {}
13
14 OpacityLayer::~OpacityLayer() = default;
15
EnsureSingleChild()16 void OpacityLayer::EnsureSingleChild() {
17 FML_DCHECK(layers().size() > 0); // OpacityLayer should never be a leaf
18
19 if (layers().size() == 1) {
20 return;
21 }
22
23 // Be careful: SkMatrix's default constructor doesn't initialize the matrix to
24 // identity. Hence we have to explicitly call SkMatrix::setIdentity.
25 SkMatrix identity;
26 identity.setIdentity();
27 auto new_child = std::make_shared<flutter::TransformLayer>(identity);
28
29 for (auto& child : layers()) {
30 new_child->Add(child);
31 }
32 ClearChildren();
33 Add(new_child);
34 }
35
Preroll(PrerollContext * context,const SkMatrix & matrix)36 void OpacityLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
37 EnsureSingleChild();
38 SkMatrix child_matrix = matrix;
39 child_matrix.postTranslate(offset_.fX, offset_.fY);
40 context->mutators_stack.PushTransform(
41 SkMatrix::MakeTrans(offset_.fX, offset_.fY));
42 context->mutators_stack.PushOpacity(alpha_);
43 ContainerLayer::Preroll(context, child_matrix);
44 context->mutators_stack.Pop();
45 context->mutators_stack.Pop();
46 set_paint_bounds(paint_bounds().makeOffset(offset_.fX, offset_.fY));
47 // See |EnsureSingleChild|.
48 FML_DCHECK(layers().size() == 1);
49
50 // Opacity Layer Cache will create SkSurface which can not be released.
51 #ifndef OHOS_PLATFORM
52 if (context->raster_cache &&
53 SkRect::Intersects(context->cull_rect, paint_bounds())) {
54 Layer* child = layers()[0].get();
55 SkMatrix ctm = child_matrix;
56 #ifndef SUPPORT_FRACTIONAL_TRANSLATION
57 ctm = RasterCache::GetIntegralTransCTM(ctm);
58 #endif
59 context->raster_cache->Prepare(context, child, ctm);
60 }
61 #endif
62 }
63
Paint(PaintContext & context) const64 void OpacityLayer::Paint(PaintContext& context) const {
65 TRACE_EVENT0("flutter", "OpacityLayer::Paint");
66 FML_DCHECK(needs_painting());
67
68 SkPaint paint;
69 paint.setAlpha(alpha_);
70
71 SkAutoCanvasRestore save(context.internal_nodes_canvas, true);
72 context.internal_nodes_canvas->translate(offset_.fX, offset_.fY);
73
74 #ifndef SUPPORT_FRACTIONAL_TRANSLATION
75 context.internal_nodes_canvas->setMatrix(RasterCache::GetIntegralTransCTM(
76 context.leaf_nodes_canvas->getTotalMatrix()));
77 #endif
78
79 // See |EnsureSingleChild|.
80 FML_DCHECK(layers().size() == 1);
81
82 // Embedded platform views are changing the canvas in the middle of the paint
83 // traversal. To make sure we paint on the right canvas, when the embedded
84 // platform views preview is enabled (context.view_embedded is not null) we
85 // don't use the cache.
86 if (context.view_embedder == nullptr && context.raster_cache) {
87 const SkMatrix& ctm = context.leaf_nodes_canvas->getTotalMatrix();
88 RasterCacheResult child_cache =
89 context.raster_cache->Get(layers()[0].get(), ctm);
90 if (child_cache.is_valid()) {
91 child_cache.draw(*context.leaf_nodes_canvas, &paint);
92 return;
93 }
94 }
95
96 // Skia may clip the content with saveLayerBounds (although it's not a
97 // guaranteed clip). So we have to provide a big enough saveLayerBounds. To do
98 // so, we first remove the offset from paint bounds since it's already in the
99 // matrix. Then we round out the bounds because of our
100 // RasterCache::GetIntegralTransCTM optimization.
101 //
102 // Note that the following lines are only accessible when the raster cache is
103 // not available (e.g., when we're using the software backend in golden
104 // tests).
105 SkRect saveLayerBounds;
106 paint_bounds()
107 .makeOffset(-offset_.fX, -offset_.fY)
108 .roundOut(&saveLayerBounds);
109
110 Layer::AutoSaveLayer save_layer =
111 Layer::AutoSaveLayer::Create(context, saveLayerBounds, &paint);
112 PaintChildren(context);
113 }
114
115 } // namespace flutter
116