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81 lines
2.8 KiB
C++
81 lines
2.8 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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#include <optional>
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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_DCHECK(transform_.isFinite());
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if (!transform_.isFinite()) {
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FML_LOG(ERROR) << "TransformLayer is constructed with an invalid matrix.";
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transform_.setIdentity();
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}
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set_layer_can_inherit_opacity(true);
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}
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void TransformLayer::Diff(DiffContext* context, const Layer* old_layer) {
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DiffContext::AutoSubtreeRestore subtree(context);
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auto* prev = static_cast<const TransformLayer*>(old_layer);
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if (!context->IsSubtreeDirty()) {
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FML_DCHECK(prev);
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if (transform_ != prev->transform_) {
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context->MarkSubtreeDirty(context->GetOldLayerPaintRegion(old_layer));
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}
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}
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context->PushTransform(transform_);
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DiffChildren(context, prev);
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context->SetLayerPaintRegion(this, context->CurrentSubtreeRegion());
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}
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void TransformLayer::Preroll(PrerollContext* context, const SkMatrix& matrix) {
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TRACE_EVENT0("flutter", "TransformLayer::Preroll");
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SkMatrix child_matrix;
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child_matrix.setConcat(matrix, transform_);
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context->mutators_stack.PushTransform(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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context->mutators_stack.Pop();
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}
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void TransformLayer::Paint(PaintContext& context) const {
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TRACE_EVENT0("flutter", "TransformLayer::Paint");
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FML_DCHECK(needs_painting(context));
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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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