canvas_unittests.cc

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#include <unordered_map>
#include "flutter/display_list/dl_tile_mode.h"
#include "flutter/display_list/effects/dl_image_filter.h"
#include "flutter/display_list/geometry/dl_geometry_types.h"
#include "flutter/testing/testing.h"
#include "gtest/gtest.h"
#include "impeller/core/formats.h"
#include "impeller/core/texture_descriptor.h"
#include "impeller/display_list/aiks_unittests.h"
#include "impeller/display_list/canvas.h"
#include "impeller/display_list/dl_image_impeller.h"
#include "impeller/display_list/dl_runtime_effect_impeller.h"
#include "impeller/display_list/dl_vertices_geometry.h"
#include "impeller/geometry/geometry_asserts.h"
#include "impeller/playground/playground.h"
#include "impeller/playground/widgets.h"
#include "impeller/renderer/render_target.h"
#include "third_party/abseil-cpp/absl/status/status_matchers.h"
 
namespace impeller {
namespace testing {
 
std::unique_ptr<Canvas> CreateTestCanvas(
    ContentContext& context,
    std::optional<Rect> cull_rect = std::nullopt,
    bool requires_readback = false) {
  TextureDescriptor onscreen_desc;
  onscreen_desc.size = {100, 100};
  onscreen_desc.format =
      context.GetDeviceCapabilities().GetDefaultColorFormat();
  onscreen_desc.usage = TextureUsage::kRenderTarget;
  onscreen_desc.storage_mode = StorageMode::kDevicePrivate;
  onscreen_desc.sample_count = SampleCount::kCount1;
  std::shared_ptr<Texture> onscreen =
      context.GetContext()->GetResourceAllocator()->CreateTexture(
          onscreen_desc);
 
  ColorAttachment color0;
  color0.load_action = LoadAction::kClear;
  if (context.GetContext()->GetCapabilities()->SupportsOffscreenMSAA()) {
    TextureDescriptor onscreen_msaa_desc = onscreen_desc;
    onscreen_msaa_desc.sample_count = SampleCount::kCount4;
    onscreen_msaa_desc.storage_mode = StorageMode::kDeviceTransient;
    onscreen_msaa_desc.type = TextureType::kTexture2DMultisample;
 
    std::shared_ptr<Texture> onscreen_msaa =
        context.GetContext()->GetResourceAllocator()->CreateTexture(
            onscreen_msaa_desc);
    color0.resolve_texture = onscreen;
    color0.texture = onscreen_msaa;
    color0.store_action = StoreAction::kMultisampleResolve;
  } else {
    color0.texture = onscreen;
  }
 
  RenderTarget render_target;
  render_target.SetColorAttachment(color0, 0);
 
  if (cull_rect.has_value()) {
    return std::make_unique<Canvas>(
        context, render_target, /*is_onscreen=*/false,
        /*requires_readback=*/requires_readback, cull_rect.value());
  }
  return std::make_unique<Canvas>(context, render_target, /*is_onscreen=*/false,
                                  /*requires_readback=*/requires_readback);
}
 
TEST_P(AiksTest, TransformMultipliesCorrectly) {
  ContentContext& context = GetContentContext();
  auto canvas = CreateTestCanvas(context);
 
  ASSERT_MATRIX_NEAR(canvas->GetCurrentTransform(), Matrix());
 
  // clang-format off
  canvas->Translate(Vector3(100, 200));
  ASSERT_MATRIX_NEAR(
    canvas->GetCurrentTransform(),
    Matrix(  1,   0,   0,   0,
             0,   1,   0,   0,
             0,   0,   1,   0,
           100, 200,   0,   1));
 
  canvas->Rotate(Radians(kPiOver2));
  ASSERT_MATRIX_NEAR(
    canvas->GetCurrentTransform(),
    Matrix(  0,   1,   0,   0,
            -1,   0,   0,   0,
             0,   0,   1,   0,
           100, 200,   0,   1));
 
  canvas->Scale(Vector3(2, 3));
  ASSERT_MATRIX_NEAR(
    canvas->GetCurrentTransform(),
    Matrix(  0,   2,   0,   0,
            -3,   0,   0,   0,
             0,   0,   0,   0,
           100, 200,   0,   1));
 
  canvas->Translate(Vector3(100, 200));
  ASSERT_MATRIX_NEAR(
    canvas->GetCurrentTransform(),
    Matrix(   0,   2,   0,   0,
             -3,   0,   0,   0,
              0,   0,   0,   0,
           -500, 400,   0,   1));
  // clang-format on
}
 
TEST_P(AiksTest, CanvasCanPushPopCTM) {
  ContentContext& context = GetContentContext();
  auto canvas = CreateTestCanvas(context);
 
  ASSERT_EQ(canvas->GetSaveCount(), 1u);
  ASSERT_EQ(canvas->Restore(), false);
 
  canvas->Translate(Size{100, 100});
  canvas->Save(10);
  ASSERT_EQ(canvas->GetSaveCount(), 2u);
  ASSERT_MATRIX_NEAR(canvas->GetCurrentTransform(),
                     Matrix::MakeTranslation({100.0, 100.0, 0.0}));
  ASSERT_TRUE(canvas->Restore());
  ASSERT_EQ(canvas->GetSaveCount(), 1u);
  ASSERT_MATRIX_NEAR(canvas->GetCurrentTransform(),
                     Matrix::MakeTranslation({100.0, 100.0, 0.0}));
}
 
TEST_P(AiksTest, CanvasCTMCanBeUpdated) {
  ContentContext& context = GetContentContext();
  auto canvas = CreateTestCanvas(context);
 
  Matrix identity;
  ASSERT_MATRIX_NEAR(canvas->GetCurrentTransform(), identity);
  canvas->Translate(Size{100, 100});
  ASSERT_MATRIX_NEAR(canvas->GetCurrentTransform(),
                     Matrix::MakeTranslation({100.0, 100.0, 0.0}));
}
 
TEST_P(AiksTest, BackdropCountDownNormal) {
  ContentContext& context = GetContentContext();
  if (!context.GetDeviceCapabilities().SupportsFramebufferFetch()) {
    GTEST_SKIP() << "Test requires device with framebuffer fetch";
  }
  auto canvas = CreateTestCanvas(context, Rect::MakeLTRB(0, 0, 100, 100),
                                 /*requires_readback=*/true);
  // 3 backdrop filters
  canvas->SetBackdropData({}, 3);
 
  auto blur =
      flutter::DlImageFilter::MakeBlur(4, 4, flutter::DlTileMode::kClamp);
  flutter::DlRect rect = flutter::DlRect::MakeLTRB(0, 0, 50, 50);
 
  EXPECT_TRUE(canvas->RequiresReadback());
  canvas->DrawRect(rect, {.color = Color::Azure()});
  canvas->SaveLayer({}, rect, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/1);
  canvas->Restore();
  EXPECT_TRUE(canvas->RequiresReadback());
 
  canvas->SaveLayer({}, rect, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/1);
  canvas->Restore();
  EXPECT_TRUE(canvas->RequiresReadback());
 
  canvas->SaveLayer({}, rect, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/1);
  canvas->Restore();
  EXPECT_FALSE(canvas->RequiresReadback());
}
 
TEST_P(AiksTest, BackdropCountDownBackdropId) {
  ContentContext& context = GetContentContext();
  if (!context.GetDeviceCapabilities().SupportsFramebufferFetch()) {
    GTEST_SKIP() << "Test requires device with framebuffer fetch";
  }
  auto canvas = CreateTestCanvas(context, Rect::MakeLTRB(0, 0, 100, 100),
                                 /*requires_readback=*/true);
  // 3 backdrop filters all with same id.
  std::unordered_map<int64_t, BackdropData> data;
  data[1] = BackdropData{.backdrop_count = 3};
  canvas->SetBackdropData(data, 3);
 
  auto blur =
      flutter::DlImageFilter::MakeBlur(4, 4, flutter::DlTileMode::kClamp);
 
  EXPECT_TRUE(canvas->RequiresReadback());
  canvas->DrawRect(flutter::DlRect::MakeLTRB(0, 0, 50, 50),
                   {.color = Color::Azure()});
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/1, /*can_distribute_opacity=*/false,
                    /*backdrop_id=*/1);
  canvas->Restore();
  EXPECT_FALSE(canvas->RequiresReadback());
 
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/1, /*can_distribute_opacity=*/false,
                    /*backdrop_id=*/1);
  canvas->Restore();
  EXPECT_FALSE(canvas->RequiresReadback());
 
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/1, /*can_distribute_opacity=*/false,
                    /*backdrop_id=*/1);
  canvas->Restore();
  EXPECT_FALSE(canvas->RequiresReadback());
}
 
TEST_P(AiksTest, BackdropCountDownBackdropIdMixed) {
  ContentContext& context = GetContentContext();
  if (!context.GetDeviceCapabilities().SupportsFramebufferFetch()) {
    GTEST_SKIP() << "Test requires device with framebuffer fetch";
  }
  auto canvas = CreateTestCanvas(context, Rect::MakeLTRB(0, 0, 100, 100),
                                 /*requires_readback=*/true);
  // 3 backdrop filters, 2 with same id.
  std::unordered_map<int64_t, BackdropData> data;
  data[1] = BackdropData{.backdrop_count = 2};
  canvas->SetBackdropData(data, 3);
 
  auto blur =
      flutter::DlImageFilter::MakeBlur(4, 4, flutter::DlTileMode::kClamp);
 
  EXPECT_TRUE(canvas->RequiresReadback());
  canvas->DrawRect(flutter::DlRect::MakeLTRB(0, 0, 50, 50),
                   {.color = Color::Azure()});
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents, 1, false);
  canvas->Restore();
  EXPECT_TRUE(canvas->RequiresReadback());
 
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents, 1, false, 1);
  canvas->Restore();
  EXPECT_FALSE(canvas->RequiresReadback());
 
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents, 1, false, 1);
  canvas->Restore();
  EXPECT_FALSE(canvas->RequiresReadback());
}
 
// We only know the total number of backdrop filters, not the number of backdrop
// filters in the root pass. If we reach a count of 0 while in a nested
// saveLayer, we should not restore to the onscreen.
TEST_P(AiksTest, BackdropCountDownWithNestedSaveLayers) {
  ContentContext& context = GetContentContext();
  if (!context.GetDeviceCapabilities().SupportsFramebufferFetch()) {
    GTEST_SKIP() << "Test requires device with framebuffer fetch";
  }
  auto canvas = CreateTestCanvas(context, Rect::MakeLTRB(0, 0, 100, 100),
                                 /*requires_readback=*/true);
 
  canvas->SetBackdropData({}, 2);
 
  auto blur =
      flutter::DlImageFilter::MakeBlur(4, 4, flutter::DlTileMode::kClamp);
 
  EXPECT_TRUE(canvas->RequiresReadback());
  canvas->DrawRect(flutter::DlRect::MakeLTRB(0, 0, 50, 50),
                   {.color = Color::Azure()});
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/3);
 
  // This filter is nested in the first saveLayer. We cannot restore to onscreen
  // here.
  canvas->SaveLayer({}, std::nullopt, blur.get(),
                    ContentBoundsPromise::kContainsContents,
                    /*total_content_depth=*/1);
  canvas->Restore();
  EXPECT_TRUE(canvas->RequiresReadback());
 
  canvas->Restore();
  EXPECT_TRUE(canvas->RequiresReadback());
}
 
TEST_P(AiksTest, DrawVerticesLinearGradientWithEmptySize) {
  RenderCallback callback = [&](RenderTarget& render_target) {
    ContentContext& context = GetContentContext();
    Canvas canvas(context, render_target, true, false);
 
    std::vector<flutter::DlPoint> vertex_coordinates = {
        flutter::DlPoint(0, 0),
        flutter::DlPoint(600, 0),
        flutter::DlPoint(0, 600),
    };
    std::vector<flutter::DlPoint> texture_coordinates = {
        flutter::DlPoint(0, 0),
        flutter::DlPoint(500, 0),
        flutter::DlPoint(0, 500),
    };
    std::vector<uint16_t> indices = {0, 1, 2};
    flutter::DlVertices::Builder vertices_builder(
        flutter::DlVertexMode::kTriangleStrip, vertex_coordinates.size(),
        flutter::DlVertices::Builder::kHasTextureCoordinates, indices.size());
    vertices_builder.store_vertices(vertex_coordinates.data());
    vertices_builder.store_indices(indices.data());
    vertices_builder.store_texture_coordinates(texture_coordinates.data());
    auto vertices = vertices_builder.build();
 
    // The start and end points of the gradient form an empty rectangle.
    std::vector<flutter::DlColor> colors = {flutter::DlColor::kBlue(),
                                            flutter::DlColor::kRed()};
    std::vector<Scalar> stops = {0.0, 1.0};
    auto gradient = flutter::DlColorSource::MakeLinear(
        {0, 0}, {0, 600}, 2, colors.data(), stops.data(),
        flutter::DlTileMode::kClamp);
 
    Paint paint;
    paint.color_source = gradient.get();
    canvas.DrawVertices(std::make_shared<DlVerticesGeometry>(vertices, context),
                        BlendMode::kSrcOver, paint);
 
    canvas.EndReplay();
    return true;
  };
 
  ASSERT_TRUE(Playground::OpenPlaygroundHere(callback));
}
 
TEST_P(AiksTest, DrawVerticesWithEmptyTextureCoordinates) {
  auto runtime_stages_result =
      OpenAssetAsRuntimeStage("runtime_stage_simple.frag.iplr");
  ABSL_ASSERT_OK(runtime_stages_result);
  std::shared_ptr<RuntimeStage> runtime_stage =
      runtime_stages_result.value()[GetRuntimeStageBackend()];
  ASSERT_TRUE(runtime_stage);
 
  auto runtime_effect = flutter::DlRuntimeEffectImpeller::Make(runtime_stage);
  auto uniform_data = std::make_shared<std::vector<uint8_t>>();
  auto color_source = flutter::DlColorSource::MakeRuntimeEffect(
      runtime_effect, {}, uniform_data);
 
  RenderCallback callback = [&](RenderTarget& render_target) {
    ContentContext& context = GetContentContext();
    Canvas canvas(context, render_target, true, false);
 
    std::vector<flutter::DlPoint> vertex_coordinates = {
        flutter::DlPoint(100, 100),
        flutter::DlPoint(300, 100),
        flutter::DlPoint(100, 300),
    };
    // The bounding box of the texture coordinates is empty.
    std::vector<flutter::DlPoint> texture_coordinates = {
        flutter::DlPoint(0, 0),
        flutter::DlPoint(0, 100),
        flutter::DlPoint(0, 0),
    };
    std::vector<uint16_t> indices = {0, 1, 2};
    flutter::DlVertices::Builder vertices_builder(
        flutter::DlVertexMode::kTriangleStrip, vertex_coordinates.size(),
        flutter::DlVertices::Builder::kHasTextureCoordinates, indices.size());
    vertices_builder.store_vertices(vertex_coordinates.data());
    vertices_builder.store_indices(indices.data());
    vertices_builder.store_texture_coordinates(texture_coordinates.data());
    auto vertices = vertices_builder.build();
 
    Paint paint;
    paint.color_source = color_source.get();
    canvas.DrawVertices(std::make_shared<DlVerticesGeometry>(vertices, context),
                        BlendMode::kSrcOver, paint);
 
    canvas.EndReplay();
    return true;
  };
 
  ASSERT_TRUE(Playground::OpenPlaygroundHere(callback));
}
 
TEST_P(AiksTest, SupportsBlitToOnscreen) {
  ContentContext& context = GetContentContext();
  auto canvas = CreateTestCanvas(context, Rect::MakeLTRB(0, 0, 100, 100),
                                 /*requires_readback=*/true);
 
  if (GetBackend() != PlaygroundBackend::kMetal &&
      GetBackend() != PlaygroundBackend::kMetalSDF) {
    EXPECT_FALSE(canvas->SupportsBlitToOnscreen());
  } else {
    EXPECT_TRUE(canvas->SupportsBlitToOnscreen());
  }
}
 
TEST_P(AiksTest, RoundSuperellipseShadowComparison) {
  // Config
  Size default_size(600, 400);
  Point left_center(400, 700);
  Point right_center(1300, 700);
  Color color = Color::Red();
 
  // Convert `color` to a `color_source`. This forces
  // `canvas.DrawRoundSuperellipse` to use the regular shadow algorithm
  // (blurring) instead of the fast shadow algorithm.
  std::shared_ptr<flutter::DlColorSource> color_source;
  {
    flutter::DlColor dl_color = flutter::DlColor(color.ToARGB());
    std::vector<flutter::DlColor> colors = {dl_color, dl_color};
    std::vector<Scalar> stops = {0.0, 1.0};
    color_source = flutter::DlColorSource::MakeLinear(
        {0, 0}, {1000, 1000}, 2, colors.data(), stops.data(),
        flutter::DlTileMode::kClamp);
  }
 
  RenderCallback callback = [&](RenderTarget& render_target) {
    ContentContext& context = GetContentContext();
    Canvas canvas(context, render_target, true, false);
    // Somehow there's a scaling factor between PlaygroundPoint and Canvas.
    Matrix ctm = Matrix::MakeScale(Vector2(1, 1) * 0.5);
    Matrix i_ctm = ctm.Invert();
 
    static Scalar sigma = 0.05;
    static Scalar radius = 200;
 
    // Define the ImGui
    ImGui::Begin("Shadow", nullptr, ImGuiWindowFlags_AlwaysAutoResize);
    {
      ImGui::SliderFloat("Sigma", &sigma, 0, 100);
      ImGui::SliderFloat("Radius", &radius, 0, 1000);
    }
    ImGui::End();
 
    static PlaygroundPoint right_reference_var(
        ctm * (right_center + default_size / 2), 30, Color::White());
    Point right_reference = i_ctm * DrawPlaygroundPoint(right_reference_var);
    Point half_size = (right_reference - right_center).Abs();
    Rect left_bounds = Rect::MakeEllipseBounds(left_center, half_size);
    Rect right_bounds = Rect::MakeEllipseBounds(right_center, half_size);
 
    Paint paint{
        .color = color,
        .mask_blur_descriptor =
            Paint::MaskBlurDescriptor{
                .sigma = Sigma(sigma),
            },
    };
 
    // Left: Draw with canvas
    canvas.DrawRoundSuperellipse(
        RoundSuperellipse::MakeRectRadius(left_bounds, radius), paint);
 
    // Right: Direct draw
    paint.color_source = color_source.get();
    canvas.DrawRoundSuperellipse(
        RoundSuperellipse::MakeRectRadius(right_bounds, radius), paint);
 
    canvas.EndReplay();
    return true;
  };
 
  ASSERT_TRUE(Playground::OpenPlaygroundHere(callback));
}
 
TEST_P(AiksTest, ImageTextureCacheBehavesCorrectly) {
  ContentContext& context = GetContentContext();
 
  TextureDescriptor desc;
  desc.size = {100, 100};
  desc.format = context.GetDeviceCapabilities().GetDefaultColorFormat();
  auto texture =
      context.GetContext()->GetResourceAllocator()->CreateTexture(desc);
 
  auto dl_image = impeller::DlImageImpeller::Make(texture);
 
  context.SetTextureCachingEnabled(true);
  auto cached_tex1 = dl_image->GetCachedTexture(context);
  ASSERT_EQ(cached_tex1, texture);
 
  auto cached_tex2 = context.GetCachedTexture(dl_image.get());
  ASSERT_EQ(cached_tex2, texture);
 
  context.RemoveCachedTexture(dl_image.get());
  auto cached_tex3 = context.GetCachedTexture(dl_image.get());
  ASSERT_EQ(cached_tex3, nullptr);
 
  auto cached_tex4 = dl_image->GetCachedTexture(context);
  ASSERT_EQ(cached_tex4, texture);
 
  context.ClearCachedTextures();
  auto cached_tex5 = context.GetCachedTexture(dl_image.get());
  ASSERT_EQ(cached_tex5, nullptr);
 
  context.SetTextureCachingEnabled(false);
}
 
/// Verifies blend mode compatibility with SDF rendering.
///
/// The compatibility condition is:
/// `mix(blend(src, dst), dst, 1 - sdf_alpha) == blend(src * sdf_alpha, dst)`
TEST_P(AiksTest, BlendModeCompatibilityWithSDFRendering) {
  std::vector<Color> colors = {
      Color::BlackTransparent(),
      Color::Black(),
      Color::White(),
      Color::LimeGreen(),
      Color::CornflowerBlue(),
      Color::LimeGreen().WithAlpha(0.8),
      Color::CornflowerBlue().WithAlpha(0.7),
  };
 
  for (int i = 0; i <= static_cast<int>(BlendMode::kLastMode); i++) {
    BlendMode blend_mode = static_cast<BlendMode>(i);
    bool blend_mode_is_compatible = true;
 
    for (const auto& src : colors) {
      for (const auto& dst : colors) {
        for (Scalar sdf_alpha = 0.0; sdf_alpha < 1.01; sdf_alpha += 0.2) {
          // `mix(blend(src, dst), dst, 1 - sdf_alpha)`:
          // 1. Blend src onto dst.
          Color blended = dst.Blend(src, blend_mode);
          // 2. Mix with dst using sdf_alpha. Mix by lerping using
          // pre-multiplied colors.
          Color blended_then_sdf_alpha_applied =
              Color::Lerp(blended.Premultiply(), dst.Premultiply(),
                          1.0 - sdf_alpha)
                  .Unpremultiply();
 
          // `blend(src * sdf_alpha, dst)`:
          // 1. Apply sdf_alpha to src's alpha.
          Color sdf_alpha_applied = src.WithAlpha(src.alpha * sdf_alpha);
          // 2. Blend onto dst.
          Color sdf_alpha_applied_then_blended =
              dst.Blend(sdf_alpha_applied, blend_mode);
 
          // Compare results.
          if (blended_then_sdf_alpha_applied !=
              sdf_alpha_applied_then_blended) {
            blend_mode_is_compatible = false;
          }
        }
      }
    }
 
    Paint paint = {.blend_mode = blend_mode};
    EXPECT_EQ(blend_mode_is_compatible,
              Canvas::IsCompatibleWithSDFRendering(paint))
        << "Failure for BlendMode: " << BlendModeToString(blend_mode);
  }
}
 
TEST(CanvasTest, NonAntialiasedPaintIncompatibleWithSDFRendering) {
  Paint paint;
  paint.anti_alias = false;
  EXPECT_FALSE(Canvas::IsCompatibleWithSDFRendering(paint));
}
 
TEST(CanvasTest, AntialiasedPaintCompatibleWithSDFRendering) {
  Paint paint;
  EXPECT_TRUE(Canvas::IsCompatibleWithSDFRendering(paint));
}
 
}  // namespace testing
}  // namespace impeller