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Jonah Williams
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share platform view slicing logic across iOS and Android. (#54010)
This removes support for "unobstructed platform views" on iOS - instead prefering to use the Android strategy of minimizing overlay layers, as this is generally more performant.
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‎ci/licenses_golden/excluded_files‎

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../../../flutter/flow/surface_frame_unittests.cc
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../../../flutter/flow/testing
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../../../flutter/flow/texture_unittests.cc
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../../../flutter/flow/view_slicer_unittests.cc
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../../../flutter/flutter_frontend_server
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../../../flutter/fml/ascii_trie_unittests.cc
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../../../flutter/fml/backtrace_unittests.cc

‎ci/licenses_golden/licenses_flutter‎

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@@ -41734,6 +41734,8 @@ ORIGIN: ../../../flutter/flow/surface.cc + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flow/surface.h + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flow/surface_frame.cc + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flow/surface_frame.h + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flow/view_slicer.cc + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flow/view_slicer.h + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flutter_vma/flutter_skia_vma.cc + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flutter_vma/flutter_skia_vma.h + ../../../flutter/LICENSE
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ORIGIN: ../../../flutter/flutter_vma/flutter_vma.cc + ../../../flutter/LICENSE
@@ -44616,6 +44618,8 @@ FILE: ../../../flutter/flow/surface.cc
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FILE: ../../../flutter/flow/surface.h
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FILE: ../../../flutter/flow/surface_frame.cc
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FILE: ../../../flutter/flow/surface_frame.h
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FILE: ../../../flutter/flow/view_slicer.cc
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FILE: ../../../flutter/flow/view_slicer.h
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FILE: ../../../flutter/flutter_vma/flutter_skia_vma.cc
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FILE: ../../../flutter/flutter_vma/flutter_skia_vma.h
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FILE: ../../../flutter/flutter_vma/flutter_vma.cc

‎flow/BUILD.gn‎

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@@ -88,6 +88,8 @@ source_set("flow") {
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"surface.h",
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"surface_frame.cc",
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"surface_frame.h",
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"view_slicer.cc",
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"view_slicer.h",
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]
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public_configs = [ "//flutter:config" ]
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"testing/mock_layer_unittests.cc",
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"testing/mock_texture_unittests.cc",
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"texture_unittests.cc",
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"view_slicer_unittests.cc",
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]
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deps = [

‎flow/view_slicer.cc‎

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// 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/view_slicer.h"
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#include <unordered_map>
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#include "flow/embedded_views.h"
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#include "fml/logging.h"
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namespace flutter {
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std::unordered_map<int64_t, SkRect> SliceViews(
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DlCanvas* background_canvas,
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const std::vector<int64_t>& composition_order,
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const std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>>&
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slices,
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const std::unordered_map<int64_t, SkRect>& view_rects) {
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std::unordered_map<int64_t, SkRect> overlay_layers;
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auto current_frame_view_count = composition_order.size();
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// Restore the clip context after exiting this method since it's changed
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// below.
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DlAutoCanvasRestore save(background_canvas, /*do_save=*/true);
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for (size_t i = 0; i < current_frame_view_count; i++) {
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int64_t view_id = composition_order[i];
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EmbedderViewSlice* slice = slices.at(view_id).get();
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if (slice->canvas() == nullptr) {
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continue;
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}
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slice->end_recording();
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SkRect full_joined_rect = SkRect::MakeEmpty();
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// Determinate if Flutter UI intersects with any of the previous
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// platform views stacked by z position.
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//
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// This is done by querying the r-tree that holds the records for the
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// picture recorder corresponding to the flow layers added after a platform
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// view layer.
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for (int j = i; j >= 0; j--) {
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int64_t current_view_id = composition_order[j];
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auto maybe_rect = view_rects.find(current_view_id);
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FML_DCHECK(maybe_rect != view_rects.end());
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if (maybe_rect == view_rects.end()) {
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continue;
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}
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SkRect current_view_rect = maybe_rect->second;
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const SkIRect rounded_in_platform_view_rect = current_view_rect.roundIn();
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// Each rect corresponds to a native view that renders Flutter UI.
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std::vector<SkIRect> intersection_rects =
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slice->region(current_view_rect).getRects();
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// Ignore intersections of single width/height on the edge of the platform
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// view.
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// This is to address the following performance issue when interleaving
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// adjacent platform views and layers: Since we `roundOut` both platform
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// view rects and the layer rects, as long as the coordinate is
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// fractional, there will be an intersection of a single pixel width (or
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// height) after rounding out, even if they do not intersect before
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// rounding out. We have to round out both platform view rect and the
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// layer rect. Rounding in platform view rect will result in missing pixel
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// on the intersection edge. Rounding in layer rect will result in missing
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// pixel on the edge of the layer on top of the platform view.
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for (auto it = intersection_rects.begin(); it != intersection_rects.end();
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/*no-op*/) {
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// If intersection_rect does not intersect with the *rounded in*
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// platform view rect, then the intersection must be a single pixel
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// width (or height) on edge.
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if (!SkIRect::Intersects(*it, rounded_in_platform_view_rect)) {
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it = intersection_rects.erase(it);
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} else {
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++it;
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}
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}
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// Limit the number of native views, so it doesn't grow forever.
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//
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// In this case, the rects are merged into a single one that is the union
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// of all the rects.
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SkRect partial_joined_rect = SkRect::MakeEmpty();
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for (const SkIRect& rect : intersection_rects) {
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partial_joined_rect.join(SkRect::Make(rect));
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}
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// Get the intersection rect with the `current_view_rect`,
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partial_joined_rect.intersect(SkRect::Make(current_view_rect.roundOut()));
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// Join the `partial_joined_rect` into `full_joined_rect` to get the rect
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// above the current `slice`
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full_joined_rect.join(partial_joined_rect);
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}
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if (!full_joined_rect.isEmpty()) {
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overlay_layers.insert({view_id, full_joined_rect});
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// Clip the background canvas, so it doesn't contain any of the pixels
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// drawn on the overlay layer.
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background_canvas->ClipRect(full_joined_rect,
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DlCanvas::ClipOp::kDifference);
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}
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slice->render_into(background_canvas);
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}
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// Manually trigger the DlAutoCanvasRestore before we submit the frame
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save.Restore();
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return overlay_layers;
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}
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} // namespace flutter

‎flow/view_slicer.h‎

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// 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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#ifndef FLUTTER_FLOW_VIEW_SLICER_H_
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#define FLUTTER_FLOW_VIEW_SLICER_H_
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#include <unordered_map>
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#include "display_list/dl_canvas.h"
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#include "flow/embedded_views.h"
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namespace flutter {
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/// @brief Compute the required overlay layers and clip the view slices
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/// according to the size and position of the platform views.
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std::unordered_map<int64_t, SkRect> SliceViews(
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DlCanvas* background_canvas,
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const std::vector<int64_t>& composition_order,
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const std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>>&
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slices,
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const std::unordered_map<int64_t, SkRect>& view_rects);
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} // namespace flutter
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#endif // FLUTTER_FLOW_VIEW_SLICER_H_

‎flow/view_slicer_unittests.cc‎

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// 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 <unordered_map>
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#include "display_list/dl_builder.h"
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#include "flow/embedded_views.h"
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#include "flutter/flow/view_slicer.h"
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#include "gtest/gtest.h"
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namespace flutter {
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namespace testing {
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namespace {
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void AddSliceOfSize(
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std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>>& slices,
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int64_t id,
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SkRect rect) {
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slices[id] = std::make_unique<DisplayListEmbedderViewSlice>(rect);
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DlPaint paint;
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paint.setColor(DlColor::kBlack());
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slices[id]->canvas()->DrawRect(rect, paint);
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}
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} // namespace
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TEST(ViewSlicerTest, CanSlicerNonOverlappingViews) {
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DisplayListBuilder builder(SkRect::MakeLTRB(0, 0, 100, 100));
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std::vector<int64_t> composition_order = {1};
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std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>> slices;
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AddSliceOfSize(slices, 1, SkRect::MakeLTRB(99, 99, 100, 100));
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std::unordered_map<int64_t, SkRect> view_rects = {
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{1, SkRect::MakeLTRB(50, 50, 60, 60)}};
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auto computed_overlays =
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SliceViews(&builder, composition_order, slices, view_rects);
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EXPECT_TRUE(computed_overlays.empty());
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}
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TEST(ViewSlicerTest, IgnoresFractionalOverlaps) {
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DisplayListBuilder builder(SkRect::MakeLTRB(0, 0, 100, 100));
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std::vector<int64_t> composition_order = {1};
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std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>> slices;
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AddSliceOfSize(slices, 1, SkRect::MakeLTRB(0, 0, 50.49, 50.49));
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std::unordered_map<int64_t, SkRect> view_rects = {
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{1, SkRect::MakeLTRB(50.5, 50.5, 100, 100)}};
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auto computed_overlays =
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SliceViews(&builder, composition_order, slices, view_rects);
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EXPECT_TRUE(computed_overlays.empty());
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}
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TEST(ViewSlicerTest, ComputesOverlapWith1PV) {
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DisplayListBuilder builder(SkRect::MakeLTRB(0, 0, 100, 100));
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std::vector<int64_t> composition_order = {1};
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std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>> slices;
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AddSliceOfSize(slices, 1, SkRect::MakeLTRB(0, 0, 50, 50));
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std::unordered_map<int64_t, SkRect> view_rects = {
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{1, SkRect::MakeLTRB(0, 0, 100, 100)}};
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auto computed_overlays =
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SliceViews(&builder, composition_order, slices, view_rects);
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EXPECT_EQ(computed_overlays.size(), 1u);
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auto overlay = computed_overlays.find(1);
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ASSERT_NE(overlay, computed_overlays.end());
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EXPECT_EQ(overlay->second, SkRect::MakeLTRB(0, 0, 50, 50));
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}
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TEST(ViewSlicerTest, ComputesOverlapWith2PV) {
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DisplayListBuilder builder(SkRect::MakeLTRB(0, 0, 100, 100));
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std::vector<int64_t> composition_order = {1, 2};
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std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>> slices;
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AddSliceOfSize(slices, 1, SkRect::MakeLTRB(0, 0, 50, 50));
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AddSliceOfSize(slices, 2, SkRect::MakeLTRB(50, 50, 100, 100));
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std::unordered_map<int64_t, SkRect> view_rects = {
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{1, SkRect::MakeLTRB(0, 0, 50, 50)}, //
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{2, SkRect::MakeLTRB(50, 50, 100, 100)}, //
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};
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auto computed_overlays =
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SliceViews(&builder, composition_order, slices, view_rects);
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EXPECT_EQ(computed_overlays.size(), 2u);
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auto overlay = computed_overlays.find(1);
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ASSERT_NE(overlay, computed_overlays.end());
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EXPECT_EQ(overlay->second, SkRect::MakeLTRB(0, 0, 50, 50));
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overlay = computed_overlays.find(2);
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ASSERT_NE(overlay, computed_overlays.end());
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EXPECT_EQ(overlay->second, SkRect::MakeLTRB(50, 50, 100, 100));
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}
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TEST(ViewSlicerTest, OverlappingTwoPVs) {
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DisplayListBuilder builder(SkRect::MakeLTRB(0, 0, 100, 100));
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std::vector<int64_t> composition_order = {1, 2};
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std::unordered_map<int64_t, std::unique_ptr<EmbedderViewSlice>> slices;
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// This embeded view overlaps both platform views:
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//
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// [ A [ ]]
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// [_____[ C ]]
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// [ B [ ]]
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// [ ]
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AddSliceOfSize(slices, 1, SkRect::MakeLTRB(0, 0, 0, 0));
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AddSliceOfSize(slices, 2, SkRect::MakeLTRB(0, 0, 100, 100));
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std::unordered_map<int64_t, SkRect> view_rects = {
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{1, SkRect::MakeLTRB(0, 0, 50, 50)}, //
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{2, SkRect::MakeLTRB(50, 50, 100, 100)}, //
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};
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auto computed_overlays =
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SliceViews(&builder, composition_order, slices, view_rects);
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EXPECT_EQ(computed_overlays.size(), 1u);
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auto overlay = computed_overlays.find(2);
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ASSERT_NE(overlay, computed_overlays.end());
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// We create a single overlay for both overlapping sections.
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EXPECT_EQ(overlay->second, SkRect::MakeLTRB(0, 0, 100, 100));
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}
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} // namespace testing
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} // namespace flutter

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