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b622d43c39
For https://github.com/flutter/flutter/issues/33807 We still need to make layers' children immutable for full immutability. That will require us to change the SceneBuilder API to build the layer bottom up instead of top down (post-order traversal instead of pre-order traversal).
69 lines
2.2 KiB
C++
69 lines
2.2 KiB
C++
// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "flutter/flow/layers/transform_layer.h"
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namespace flutter {
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TransformLayer::TransformLayer(const SkMatrix& transform)
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: transform_(transform) {
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// Checks (in some degree) that SkMatrix transform_ is valid and initialized.
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//
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// If transform_ is uninitialized, this assert may look flaky as it doesn't
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// fail all the time, and some rerun may make it pass. But don't ignore it and
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// just rerun the test if this is triggered, since even a flaky failure here
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// may signify a potentially big problem in the code.
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//
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// We have to write this flaky test because there is no reliable way to test
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// whether a variable is initialized or not in C++.
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FML_CHECK(transform_.isFinite());
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}
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TransformLayer::~TransformLayer() = default;
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void TransformLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
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SkMatrix child_matrix;
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child_matrix.setConcat(matrix, transform_);
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SkRect previous_cull_rect = context->cull_rect;
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SkMatrix inverse_transform_;
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// Perspective projections don't produce rectangles that are useful for
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// culling for some reason.
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if (!transform_.hasPerspective() && transform_.invert(&inverse_transform_)) {
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inverse_transform_.mapRect(&context->cull_rect);
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} else {
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context->cull_rect = kGiantRect;
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}
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SkRect child_paint_bounds = SkRect::MakeEmpty();
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PrerollChildren(context, child_matrix, &child_paint_bounds);
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transform_.mapRect(&child_paint_bounds);
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set_paint_bounds(child_paint_bounds);
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context->cull_rect = previous_cull_rect;
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}
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#if defined(OS_FUCHSIA)
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void TransformLayer::UpdateScene(SceneUpdateContext& context) {
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FML_DCHECK(needs_system_composite());
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SceneUpdateContext::Transform transform(context, transform_);
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UpdateSceneChildren(context);
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}
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#endif // defined(OS_FUCHSIA)
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void TransformLayer::Paint(PaintContext& context) const {
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FML_TRACE_EVENT0("flutter", "TransformLayer::Paint");
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FML_DCHECK(needs_painting());
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SkAutoCanvasRestore save(context.internal_nodes_canvas, true);
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context.internal_nodes_canvas->concat(transform_);
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PaintChildren(context);
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}
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} // namespace flutter
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