testing/mock_canvas.h

// 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.

#ifndef FLUTTER_TESTING_MOCK_CANVAS_H_
#define FLUTTER_TESTING_MOCK_CANVAS_H_

#include <ostream>
#include <variant>
#include <vector>

#include "flutter/display_list/dl_canvas.h"
#include "flutter/display_list/utils/dl_matrix_clip_tracker.h"
#include "gtest/gtest.h"
#include "third_party/skia/include/core/SkCanvas.h"
#include "third_party/skia/include/core/SkCanvasVirtualEnforcer.h"
#include "third_party/skia/include/core/SkClipOp.h"
#include "third_party/skia/include/core/SkData.h"
#include "third_party/skia/include/core/SkImage.h"
#include "third_party/skia/include/core/SkImageFilter.h"
#include "third_party/skia/include/core/SkM44.h"
#include "third_party/skia/include/core/SkPath.h"
#include "third_party/skia/include/core/SkRRect.h"
#include "third_party/skia/include/core/SkRect.h"
#include "third_party/skia/include/utils/SkNWayCanvas.h"

namespace flutter {
namespace testing {

static constexpr SkRect kEmptyRect = SkRect::MakeEmpty();

// Mock |SkCanvas|, useful for writing tests that use Skia but do not interact
// with the GPU.
//
// The |MockCanvas| stores a list of |DrawCall| that the test can later verify
// against the expected list of primitives to be drawn.
class MockCanvas final : public DlCanvas {
 public:
  enum ClipEdgeStyle {
    kHardClipEdgeStyle,
    kSoftClipEdgeStyle,
  };

  struct SaveData {
    int save_to_layer;
  };

  struct SaveLayerData {
    SkRect save_bounds;
    DlPaint restore_paint;
    std::shared_ptr<DlImageFilter> backdrop_filter;
    int save_to_layer;
  };

  struct RestoreData {
    int restore_to_layer;
  };

  struct ConcatMatrixData {
    SkM44 matrix;
  };

  struct SetMatrixData {
    SkM44 matrix;
  };

  struct DrawRectData {
    SkRect rect;
    DlPaint paint;
  };

  struct DrawPathData {
    SkPath path;
    DlPaint paint;
  };

  struct DrawTextData {
    sk_sp<SkData> serialized_text;
    DlPaint paint;
    SkPoint offset;
  };

  struct DrawImageDataNoPaint {
    sk_sp<DlImage> image;
    SkScalar x;
    SkScalar y;
    DlImageSampling options;
  };

  struct DrawImageData {
    sk_sp<DlImage> image;
    SkScalar x;
    SkScalar y;
    DlImageSampling options;
    DlPaint paint;
  };

  struct DrawDisplayListData {
    sk_sp<DisplayList> display_list;
    SkScalar opacity;
  };

  struct DrawShadowData {
    SkPath path;
    DlColor color;
    SkScalar elevation;
    bool transparent_occluder;
    SkScalar dpr;
  };

  struct ClipRectData {
    SkRect rect;
    ClipOp clip_op;
    ClipEdgeStyle style;
  };

  struct ClipRRectData {
    SkRRect rrect;
    ClipOp clip_op;
    ClipEdgeStyle style;
  };

  struct ClipPathData {
    SkPath path;
    ClipOp clip_op;
    ClipEdgeStyle style;
  };

  struct DrawPaintData {
    DlPaint paint;
  };

  // Discriminated union of all the different |DrawCall| types.  It is roughly
  // equivalent to the different methods in |SkCanvas|' public API.
  using DrawCallData = std::variant<SaveData,
                                    SaveLayerData,
                                    RestoreData,
                                    ConcatMatrixData,
                                    SetMatrixData,
                                    DrawRectData,
                                    DrawPathData,
                                    DrawTextData,
                                    DrawImageDataNoPaint,
                                    DrawImageData,
                                    DrawDisplayListData,
                                    DrawShadowData,
                                    ClipRectData,
                                    ClipRRectData,
                                    ClipPathData,
                                    DrawPaintData>;

  // A single call made against this canvas.
  struct DrawCall {
    int layer;
    DrawCallData data;
  };

  MockCanvas();
  MockCanvas(int width, int height);
  ~MockCanvas();

  const std::vector<DrawCall>& draw_calls() const { return draw_calls_; }
  void reset_draw_calls() { draw_calls_.clear(); }

  SkISize GetBaseLayerSize() const override;
  SkImageInfo GetImageInfo() const override;

  void Save() override;
  void SaveLayer(const SkRect* bounds,
                 const DlPaint* paint = nullptr,
                 const DlImageFilter* backdrop = nullptr) override;
  void Restore() override;
  int GetSaveCount() const { return current_layer_; }
  void RestoreToCount(int restore_count) {
    while (current_layer_ > restore_count) {
      Restore();
    }
  }

  // clang-format off

  // 2x3 2D affine subset of a 4x4 transform in row major order
  void Transform2DAffine(SkScalar mxx, SkScalar mxy, SkScalar mxt,
                         SkScalar myx, SkScalar myy, SkScalar myt) override;
  // full 4x4 transform in row major order
  void TransformFullPerspective(
      SkScalar mxx, SkScalar mxy, SkScalar mxz, SkScalar mxt,
      SkScalar myx, SkScalar myy, SkScalar myz, SkScalar myt,
      SkScalar mzx, SkScalar mzy, SkScalar mzz, SkScalar mzt,
      SkScalar mwx, SkScalar mwy, SkScalar mwz, SkScalar mwt) override;
  // clang-format on

  void Translate(SkScalar tx, SkScalar ty) override;
  void Scale(SkScalar sx, SkScalar sy) override;
  void Rotate(SkScalar degrees) override;
  void Skew(SkScalar sx, SkScalar sy) override;
  void TransformReset() override;
  void Transform(const SkMatrix* matrix) override;
  void Transform(const SkM44* matrix44) override;
  void SetTransform(const SkMatrix* matrix) override;
  void SetTransform(const SkM44* matrix44) override;
  using DlCanvas::SetTransform;
  using DlCanvas::Transform;

  SkM44 GetTransformFullPerspective() const override;
  SkMatrix GetTransform() const override;

  void ClipRect(const SkRect& rect, ClipOp clip_op, bool is_aa) override;
  void ClipRRect(const SkRRect& rrect, ClipOp clip_op, bool is_aa) override;
  void ClipPath(const SkPath& path, ClipOp clip_op, bool is_aa) override;

  SkRect GetDestinationClipBounds() const override;
  SkRect GetLocalClipBounds() const override;
  bool QuickReject(const SkRect& bounds) const override;

  void DrawPaint(const DlPaint& paint) override;
  void DrawColor(DlColor color, DlBlendMode mode) override;
  void DrawLine(const SkPoint& p0,
                const SkPoint& p1,
                const DlPaint& paint) override;
  void DrawDashedLine(const DlPoint& p0,
                      const DlPoint& p1,
                      DlScalar on_length,
                      DlScalar off_length,
                      const DlPaint& paint) override;
  void DrawRect(const SkRect& rect, const DlPaint& paint) override;
  void DrawOval(const SkRect& bounds, const DlPaint& paint) override;
  void DrawCircle(const SkPoint& center,
                  SkScalar radius,
                  const DlPaint& paint) override;
  void DrawRRect(const SkRRect& rrect, const DlPaint& paint) override;
  void DrawDRRect(const SkRRect& outer,
                  const SkRRect& inner,
                  const DlPaint& paint) override;
  void DrawPath(const SkPath& path, const DlPaint& paint) override;
  void DrawArc(const SkRect& bounds,
               SkScalar start,
               SkScalar sweep,
               bool useCenter,
               const DlPaint& paint) override;
  void DrawPoints(PointMode mode,
                  uint32_t count,
                  const SkPoint pts[],
                  const DlPaint& paint) override;
  void DrawVertices(const DlVertices* vertices,
                    DlBlendMode mode,
                    const DlPaint& paint) override;

  void DrawImage(const sk_sp<DlImage>& image,
                 const SkPoint point,
                 DlImageSampling sampling,
                 const DlPaint* paint = nullptr) override;
  void DrawImageRect(
      const sk_sp<DlImage>& image,
      const SkRect& src,
      const SkRect& dst,
      DlImageSampling sampling,
      const DlPaint* paint = nullptr,
      SrcRectConstraint constraint = SrcRectConstraint::kFast) override;
  void DrawImageNine(const sk_sp<DlImage>& image,
                     const SkIRect& center,
                     const SkRect& dst,
                     DlFilterMode filter,
                     const DlPaint* paint = nullptr) override;
  void DrawAtlas(const sk_sp<DlImage>& atlas,
                 const SkRSXform xform[],
                 const SkRect tex[],
                 const DlColor colors[],
                 int count,
                 DlBlendMode mode,
                 DlImageSampling sampling,
                 const SkRect* cullRect,
                 const DlPaint* paint = nullptr) override;

  void DrawDisplayList(const sk_sp<DisplayList> display_list,
                       SkScalar opacity) override;
  void DrawTextBlob(const sk_sp<SkTextBlob>& blob,
                    SkScalar x,
                    SkScalar y,
                    const DlPaint& paint) override;
  void DrawTextFrame(const std::shared_ptr<impeller::TextFrame>& text_frame,
                     SkScalar x,
                     SkScalar y,
                     const DlPaint& paint) override;
  void DrawShadow(const SkPath& path,
                  const DlColor color,
                  const SkScalar elevation,
                  bool transparent_occluder,
                  SkScalar dpr) override;

  void Flush() override;

 private:
  SkISize base_layer_size_;
  std::vector<DisplayListMatrixClipState> state_stack_;
  std::vector<DrawCall> draw_calls_;
  int current_layer_;
};

extern bool operator==(const MockCanvas::SaveData& a,
                       const MockCanvas::SaveData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::SaveData& data);
extern bool operator==(const MockCanvas::SaveLayerData& a,
                       const MockCanvas::SaveLayerData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::SaveLayerData& data);
extern bool operator==(const MockCanvas::RestoreData& a,
                       const MockCanvas::RestoreData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::RestoreData& data);
extern bool operator==(const MockCanvas::ConcatMatrixData& a,
                       const MockCanvas::ConcatMatrixData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::ConcatMatrixData& data);
extern bool operator==(const MockCanvas::SetMatrixData& a,
                       const MockCanvas::SetMatrixData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::SetMatrixData& data);
extern bool operator==(const MockCanvas::DrawRectData& a,
                       const MockCanvas::DrawRectData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawRectData& data);
extern bool operator==(const MockCanvas::DrawPathData& a,
                       const MockCanvas::DrawPathData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawPathData& data);
extern bool operator==(const MockCanvas::DrawTextData& a,
                       const MockCanvas::DrawTextData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawTextData& data);
extern bool operator==(const MockCanvas::DrawImageData& a,
                       const MockCanvas::DrawImageData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawImageData& data);
extern bool operator==(const MockCanvas::DrawImageDataNoPaint& a,
                       const MockCanvas::DrawImageDataNoPaint& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawImageDataNoPaint& data);
extern bool operator==(const MockCanvas::DrawDisplayListData& a,
                       const MockCanvas::DrawDisplayListData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawDisplayListData& data);
extern bool operator==(const MockCanvas::DrawShadowData& a,
                       const MockCanvas::DrawShadowData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawShadowData& data);
extern bool operator==(const MockCanvas::ClipRectData& a,
                       const MockCanvas::ClipRectData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::ClipRectData& data);
extern bool operator==(const MockCanvas::ClipRRectData& a,
                       const MockCanvas::ClipRRectData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::ClipRRectData& data);
extern bool operator==(const MockCanvas::ClipPathData& a,
                       const MockCanvas::ClipPathData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::ClipPathData& data);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawCallData& data);
extern bool operator==(const MockCanvas::DrawCall& a,
                       const MockCanvas::DrawCall& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawCall& draw);
extern bool operator==(const MockCanvas::DrawPaintData& a,
                       const MockCanvas::DrawPaintData& b);
extern std::ostream& operator<<(std::ostream& os,
                                const MockCanvas::DrawPaintData& data);
}  // namespace testing
}  // namespace flutter

#endif  // FLUTTER_TESTING_MOCK_CANVAS_H_