/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc.
 * All rights reserved.
 * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2007 Alp Toker <alp@atoker.com>
 * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
 * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
 * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
 * Copyright (C) 2012, 2013 Adobe Systems Incorporated. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "third_party/blink/renderer/modules/canvas/canvas2d/canvas_path.h"

#include <array>
#include <cmath>
#include <ostream>  // IWYU pragma: keep (needed by String::Number(int), https://github.com/clangd/clangd/issues/2053)
#include <utility>

#include "base/check.h"
#include "base/check_op.h"
#include "base/compiler_specific.h"
#include "base/numerics/safe_conversions.h"
#include "third_party/blink/renderer/bindings/core/v8/v8_dom_point_init.h"
#include "third_party/blink/renderer/bindings/core/v8/v8_union_dompointinit_unrestricteddouble.h"
#include "third_party/blink/renderer/core/canvas_interventions/canvas_interventions_enums.h"
#include "third_party/blink/renderer/core/execution_context/execution_context.h"  // IWYU pragma: keep (https://github.com/clangd/clangd/issues/2044)
#include "third_party/blink/renderer/core/frame/web_feature.h"
#include "third_party/blink/renderer/modules/canvas/canvas2d/identifiability_study_helper.h"
#include "third_party/blink/renderer/platform/bindings/exception_code.h"
#include "third_party/blink/renderer/platform/bindings/exception_state.h"
#include "third_party/blink/renderer/platform/geometry/float_rounded_rect.h"
#include "third_party/blink/renderer/platform/geometry/path.h"
#include "third_party/blink/renderer/platform/geometry/path_builder.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_vector.h"
#include "third_party/blink/renderer/platform/heap/member.h"
#include "third_party/blink/renderer/platform/heap/visitor.h"
#include "third_party/blink/renderer/platform/instrumentation/use_counter.h"
#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
#include "third_party/blink/renderer/platform/transforms/affine_transform.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
#include "third_party/blink/renderer/platform/wtf/text/string_operators.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/size_f.h"

namespace blink {

void CanvasPath::closePath() {
  if (IsEmpty()) [[unlikely]] {
    return;
  }
  // If the current path is a zero lengthed path (ex: moveTo p1 and lineTo p1),
  // then closePath is no op.
  if (path_builder_.BoundingRect().height() == 0 &&
      path_builder_.BoundingRect().width() == 0 &&
      (IsLine() && line_builder_.BoundingRect().height() == 0 &&
       line_builder_.BoundingRect().width() == 0)) [[unlikely]] {
    const auto p = path_builder_.CurrentPoint();
    Clear();
    if (p) {
      moveTo(p->x(), p->y());
    }
    return;
  }

  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(CanvasOps::kClosePath);
  }
  if (IsArc()) {
    // Only the first close does something.
    if (!arc_builder_.IsClosed()) {
      path_builder_.Reset();
      arc_builder_.Close();
    }
  } else {
    UpdatePathFromLineOrArcIfNecessaryForMutation();
    path_builder_.Close();
  }
}

void CanvasPath::moveTo(double double_x, double double_y) {
  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);
  if (!std::isfinite(x) || !std::isfinite(y)) [[unlikely]] {
    return;
  }
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(CanvasOps::kMoveTo, double_x,
                                                double_y);
  }
  gfx::PointF point(x, y);
  if (!IsTransformInvertible()) [[unlikely]] {
    point = GetTransform().MapPoint(point);
  }
  if (IsEmpty()) {
    line_builder_.MoveTo(point);
  } else {
    UpdatePathFromLineOrArcIfNecessaryForMutation();
    path_builder_.MoveTo(point);
  }
}

void CanvasPath::lineTo(double double_x, double double_y) {
  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);
  if (!std::isfinite(x) || !std::isfinite(y)) [[unlikely]] {
    return;
  }
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(CanvasOps::kLineTo, double_x,
                                                double_y);
  }
  gfx::PointF p1(x, y);

  if (!IsTransformInvertible()) [[unlikely]] {
    p1 = GetTransform().MapPoint(p1);
  }

  if (IsEmpty()) [[unlikely]] {
    line_builder_.MoveTo(p1);
  }

  if (line_builder_.CanCreateLineTo()) {
    // `path_builder_` may contain the move to, reset it so that if
    // `path_builder_` is needed it will be updated.
    path_builder_.Reset();
    line_builder_.LineTo(p1);
    DCHECK(IsLine());
    return;
  }
  UpdatePathFromLineOrArcIfNecessaryForMutation();
  path_builder_.LineTo(p1);
}

void CanvasPath::quadraticCurveTo(double double_cpx,
                                  double double_cpy,
                                  double double_x,
                                  double double_y) {
  float cpx = base::saturated_cast<float>(double_cpx);
  float cpy = base::saturated_cast<float>(double_cpy);
  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);

  if (!std::isfinite(cpx) || !std::isfinite(cpy) || !std::isfinite(x) ||
      !std::isfinite(y)) [[unlikely]] {
    return;
  }
  UpdatePathFromLineOrArcIfNecessaryForMutation();
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(CanvasOps::kQuadradicCurveTo,
                                                double_cpx, double_cpy,
                                                double_x, double_y);
  }
  gfx::PointF p1(x, y);
  gfx::PointF cp(cpx, cpy);

  if (!IsTransformInvertible()) [[unlikely]] {
    p1 = GetTransform().MapPoint(p1);
    cp = GetTransform().MapPoint(cp);
  }

  if (!path_builder_.CurrentPoint()) [[unlikely]] {
    path_builder_.MoveTo(gfx::PointF(cpx, cpy));
  }

  path_builder_.QuadTo(cp, p1);
}

void CanvasPath::bezierCurveTo(double double_cp1x,
                               double double_cp1y,
                               double double_cp2x,
                               double double_cp2y,
                               double double_x,
                               double double_y) {
  float cp1x = base::saturated_cast<float>(double_cp1x);
  float cp1y = base::saturated_cast<float>(double_cp1y);
  float cp2x = base::saturated_cast<float>(double_cp2x);
  float cp2y = base::saturated_cast<float>(double_cp2y);
  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);
  if (!std::isfinite(cp1x) || !std::isfinite(cp1y) || !std::isfinite(cp2x) ||
      !std::isfinite(cp2y) || !std::isfinite(x) || !std::isfinite(y))
      [[unlikely]] {
    return;
  }
  UpdatePathFromLineOrArcIfNecessaryForMutation();
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(
        CanvasOps::kBezierCurveTo, double_cp1x, double_cp1y, double_cp2x,
        double_cp2y, double_x, double_y);
  }

  gfx::PointF p1(x, y);
  gfx::PointF cp1(cp1x, cp1y);
  gfx::PointF cp2(cp2x, cp2y);

  if (!IsTransformInvertible()) [[unlikely]] {
    p1 = GetTransform().MapPoint(p1);
    cp1 = GetTransform().MapPoint(cp1);
    cp2 = GetTransform().MapPoint(cp2);
  }
  if (!path_builder_.CurrentPoint()) [[unlikely]] {
    path_builder_.MoveTo(gfx::PointF(cp1x, cp1y));
  }

  path_builder_.CubicTo(cp1, cp2, p1);
}

void CanvasPath::arcTo(double double_x1,
                       double double_y1,
                       double double_x2,
                       double double_y2,
                       double double_r,
                       ExceptionState& exception_state) {
  float x1 = base::saturated_cast<float>(double_x1);
  float y1 = base::saturated_cast<float>(double_y1);
  float x2 = base::saturated_cast<float>(double_x2);
  float y2 = base::saturated_cast<float>(double_y2);
  float r = base::saturated_cast<float>(double_r);
  if (!std::isfinite(x1) || !std::isfinite(y1) || !std::isfinite(x2) ||
      !std::isfinite(y2) || !std::isfinite(r)) [[unlikely]] {
    return;
  }

  if (r < 0) [[unlikely]] {
    exception_state.ThrowDOMException(
        DOMExceptionCode::kIndexSizeError,
        "The radius provided (" + String::Number(r) + ") is negative.");
    return;
  }
  UpdatePathFromLineOrArcIfNecessaryForMutation();
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(CanvasOps::kArcTo, double_x1,
                                                double_y1, double_x2, double_y2,
                                                double_r);
  }

  gfx::PointF p1(x1, y1);
  gfx::PointF p2(x2, y2);

  if (!IsTransformInvertible()) [[unlikely]] {
    p1 = GetTransform().MapPoint(p1);
    p2 = GetTransform().MapPoint(p2);
  }

  const auto current_point = path_builder_.CurrentPoint();
  if (!current_point) [[unlikely]] {
    path_builder_.MoveTo(p1);
  } else if (p1 == *current_point || p1 == p2 || !r) [[unlikely]] {
    lineTo(x1, y1);
  } else {
    path_builder_.ArcTo(p1, p2, r);
  }
}

namespace {

float AdjustEndAngle(float start_angle, float end_angle, bool anticlockwise) {
  float new_end_angle = end_angle;
  /* http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-arc
   * If the anticlockwise argument is false and endAngle-startAngle is equal
   * to or greater than 2pi, or,
   * if the anticlockwise argument is true and startAngle-endAngle is equal to
   * or greater than 2pi,
   * then the arc is the whole circumference of this ellipse, and the point at
   * startAngle along this circle's circumference, measured in radians clockwise
   * from the ellipse's semi-major axis, acts as both the start point and the
   * end point.
   */
  if (!anticlockwise && end_angle - start_angle >= kTwoPiFloat) {
    new_end_angle = start_angle + kTwoPiFloat;
  } else if (anticlockwise && start_angle - end_angle >= kTwoPiFloat) {
    new_end_angle = start_angle - kTwoPiFloat;

    /*
     * Otherwise, the arc is the path along the circumference of this ellipse
     * from the start point to the end point, going anti-clockwise if the
     * anticlockwise argument is true, and clockwise otherwise.
     * Since the points are on the ellipse, as opposed to being simply angles
     * from zero, the arc can never cover an angle greater than 2pi radians.
     */
    /* NOTE: When startAngle = 0, endAngle = 2Pi and anticlockwise = true, the
     * spec does not indicate clearly.
     * We draw the entire circle, because some web sites use arc(x, y, r, 0,
     * 2*Math.PI, true) to draw circle.
     * We preserve backward-compatibility.
     */
  } else if (!anticlockwise && start_angle > end_angle) {
    new_end_angle = start_angle +
                    (kTwoPiFloat - fmodf(start_angle - end_angle, kTwoPiFloat));
  } else if (anticlockwise && start_angle < end_angle) {
    new_end_angle = start_angle -
                    (kTwoPiFloat - fmodf(end_angle - start_angle, kTwoPiFloat));
  }

  DCHECK(EllipseIsRenderable(start_angle, new_end_angle));
  DCHECK((anticlockwise && (start_angle >= new_end_angle)) ||
         (!anticlockwise && (new_end_angle >= start_angle)));
  return new_end_angle;
}

inline void LineTo(CanvasPath* path, const gfx::PointF& p) {
  path->lineTo(p.x(), p.y());
}

inline gfx::PointF GetPointOnEllipse(float radius_x,
                                     float radius_y,
                                     float theta) {
  return gfx::PointF(radius_x * cosf(theta), radius_y * sinf(theta));
}

void CanonicalizeAngle(float* start_angle, float* end_angle) {
  // Make 0 <= startAngle < 2*PI
  float new_start_angle = fmodf(*start_angle, kTwoPiFloat);

  if (new_start_angle < 0) {
    new_start_angle += kTwoPiFloat;
    // Check for possible catastrophic cancellation in cases where
    // newStartAngle was a tiny negative number (c.f. crbug.com/503422)
    if (new_start_angle >= kTwoPiFloat)
      new_start_angle -= kTwoPiFloat;
  }

  float delta = new_start_angle - *start_angle;
  *start_angle = new_start_angle;
  *end_angle = *end_angle + delta;

  DCHECK_GE(new_start_angle, 0);
  DCHECK_LT(new_start_angle, kTwoPiFloat);
}

/*
 * degenerateEllipse() handles a degenerated ellipse using several lines.
 *
 * Let's see a following example: line to ellipse to line.
 *        _--^\
 *       (     )
 * -----(      )
 *            )
 *           /--------
 *
 * If radiusX becomes zero, the ellipse of the example is degenerated.
 *         _
 *        // P
 *       //
 * -----//
 *      /
 *     /--------
 *
 * To draw the above example, need to get P that is a local maximum point.
 * Angles for P are 0.5Pi and 1.5Pi in the ellipse coordinates.
 *
 * If radiusY becomes zero, the result is as follows.
 * -----__
 *        --_
 *          ----------
 *            ``P
 * Angles for P are 0 and Pi in the ellipse coordinates.
 *
 * To handle both cases, degenerateEllipse() lines to start angle, local maximum
 * points(every 0.5Pi), and end angle.
 * NOTE: Before ellipse() calls this function, adjustEndAngle() is called, so
 * endAngle - startAngle must be equal to or less than 2Pi.
 */
void DegenerateEllipse(CanvasPath* path,
                       float x,
                       float y,
                       float radius_x,
                       float radius_y,
                       float rotation,
                       float start_angle,
                       float end_angle,
                       bool anticlockwise) {
  DCHECK(EllipseIsRenderable(start_angle, end_angle));
  DCHECK_GE(start_angle, 0);
  DCHECK_LT(start_angle, kTwoPiFloat);
  DCHECK((anticlockwise && (start_angle - end_angle) >= 0) ||
         (!anticlockwise && (end_angle - start_angle) >= 0));

  gfx::PointF center(x, y);
  AffineTransform rotation_matrix;
  rotation_matrix.RotateRadians(rotation);
  // First, if the object's path has any subpaths, then the method must add a
  // straight line from the last point in the subpath to the start point of the
  // arc.
  LineTo(path, center + rotation_matrix
                            .MapPoint(GetPointOnEllipse(radius_x, radius_y,
                                                        start_angle))
                            .OffsetFromOrigin());
  if ((!radius_x && !radius_y) || start_angle == end_angle) [[unlikely]] {
    return;
  }

  if (!anticlockwise) {
    // start_angle - fmodf(start_angle, kPiOverTwoFloat) + kPiOverTwoFloat is
    // the one of (0, 0.5Pi, Pi, 1.5Pi, 2Pi) that is the closest to start_angle
    // on the clockwise direction.
    for (float angle = start_angle - fmodf(start_angle, kPiOverTwoFloat) +
                       kPiOverTwoFloat;
         angle < end_angle; angle += kPiOverTwoFloat) {
      LineTo(path, center + rotation_matrix
                                .MapPoint(GetPointOnEllipse(radius_x, radius_y,
                                                            angle))
                                .OffsetFromOrigin());
    }
  } else {
    for (float angle = start_angle - fmodf(start_angle, kPiOverTwoFloat);
         angle > end_angle; angle -= kPiOverTwoFloat) {
      LineTo(path, center + rotation_matrix
                                .MapPoint(GetPointOnEllipse(radius_x, radius_y,
                                                            angle))
                                .OffsetFromOrigin());
    }
  }

  LineTo(path, center + rotation_matrix
                            .MapPoint(GetPointOnEllipse(radius_x, radius_y,
                                                        end_angle))
                            .OffsetFromOrigin());
}

}  // namespace

void CanvasPath::arc(double double_x,
                     double double_y,
                     double double_radius,
                     double double_start_angle,
                     double double_end_angle,
                     bool anticlockwise,
                     ExceptionState& exception_state) {
  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);
  float radius = base::saturated_cast<float>(double_radius);
  float start_angle = base::saturated_cast<float>(double_start_angle);
  float end_angle = base::saturated_cast<float>(double_end_angle);
  if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(radius) ||
      !std::isfinite(start_angle) || !std::isfinite(end_angle)) [[unlikely]] {
    return;
  }

  if (radius < 0) [[unlikely]] {
    exception_state.ThrowDOMException(
        DOMExceptionCode::kIndexSizeError,
        "The radius provided (" + String::Number(radius) + ") is negative.");
    return;
  }

  if (!IsTransformInvertible()) [[unlikely]] {
    return;
  }

  UpdatePathFromLineOrArcIfNecessaryForMutation();
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(
        CanvasOps::kArc, double_x, double_y, double_radius, double_start_angle,
        double_end_angle, anticlockwise);
  }
  AddTriggersForCanvasIntervention(CanvasOperationType::kArc);

  if (!radius || start_angle == end_angle) [[unlikely]] {
    // The arc is empty but we still need to draw the connecting line.
    lineTo(x + radius * cosf(start_angle), y + radius * sinf(start_angle));
    return;
  }

  CanonicalizeAngle(&start_angle, &end_angle);
  end_angle = AdjustEndAngle(start_angle, end_angle, anticlockwise);

  // TODO(348683485): small arcs don't render as well with ganesh. Use
  // old code path in this case.
  if (IsEmpty() && RuntimeEnabledFeatures::CanvasUsesArcPaintOpEnabled() &&
      radius >= 1) {
    const float sweep_angle = end_angle - start_angle;
    arc_builder_.ArcTo(x, y, radius, start_angle, sweep_angle);
    DCHECK(IsArc());
    return;
  }

  path_builder_.AddEllipse(gfx::PointF(x, y), radius, radius, start_angle,
                           end_angle);
}

void CanvasPath::ellipse(double double_x,
                         double double_y,
                         double double_radius_x,
                         double double_radius_y,
                         double double_rotation,
                         double double_start_angle,
                         double double_end_angle,
                         bool anticlockwise,
                         ExceptionState& exception_state) {
  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);
  float radius_x = base::saturated_cast<float>(double_radius_x);
  float radius_y = base::saturated_cast<float>(double_radius_y);
  float rotation = base::saturated_cast<float>(double_rotation);
  float start_angle = base::saturated_cast<float>(double_start_angle);
  float end_angle = base::saturated_cast<float>(double_end_angle);
  if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(radius_x) ||
      !std::isfinite(radius_y) || !std::isfinite(rotation) ||
      !std::isfinite(start_angle) || !std::isfinite(end_angle)) [[unlikely]] {
    return;
  }

  if (radius_x < 0) [[unlikely]] {
    exception_state.ThrowDOMException(DOMExceptionCode::kIndexSizeError,
                                      "The major-axis radius provided (" +
                                          String::Number(radius_x) +
                                          ") is negative.");
    return;
  }
  if (radius_y < 0) [[unlikely]] {
    exception_state.ThrowDOMException(DOMExceptionCode::kIndexSizeError,
                                      "The minor-axis radius provided (" +
                                          String::Number(radius_y) +
                                          ") is negative.");
    return;
  }

  if (!IsTransformInvertible()) [[unlikely]] {
    return;
  }

  UpdatePathFromLineOrArcIfNecessaryForMutation();
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(
        CanvasOps::kEllipse, double_x, double_y, double_radius_x,
        double_radius_y, double_rotation, double_start_angle, double_end_angle,
        anticlockwise);
  }

  CanonicalizeAngle(&start_angle, &end_angle);
  float adjusted_end_angle =
      AdjustEndAngle(start_angle, end_angle, anticlockwise);
  if (!radius_x || !radius_y || start_angle == adjusted_end_angle)
      [[unlikely]] {
    // The ellipse is empty but we still need to draw the connecting line to
    // start point.
    DegenerateEllipse(this, x, y, radius_x, radius_y, rotation, start_angle,
                      adjusted_end_angle, anticlockwise);
    return;
  }

  AddTriggersForCanvasIntervention(CanvasOperationType::kEllipse);
  path_builder_.AddEllipse(gfx::PointF(x, y), radius_x, radius_y, rotation,
                           start_angle, adjusted_end_angle);
}

void CanvasPath::rect(double double_x,
                      double double_y,
                      double double_width,
                      double double_height) {
  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);
  float width = base::saturated_cast<float>(double_width);
  float height = base::saturated_cast<float>(double_height);
  if (!IsTransformInvertible()) [[unlikely]] {
    return;
  }

  if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(width) ||
      !std::isfinite(height)) [[unlikely]] {
    return;
  }

  if (width == 0 && height == 0) {
    moveTo(x, y);
    return;
  }
  UpdatePathFromLineOrArcIfNecessaryForMutation();
  if (identifiability_study_helper_.ShouldUpdateBuilder()) [[unlikely]] {
    identifiability_study_helper_.UpdateBuilder(
        CanvasOps::kRect, double_x, double_y, double_width, double_height);
  }

  path_builder_.AddRect(gfx::PointF(x, y), gfx::PointF(x + width, y + height));
}

void CanvasPath::roundRect(
    double double_x,
    double double_y,
    double double_width,
    double double_height,
    const HeapVector<Member<V8UnionDOMPointInitOrUnrestrictedDouble>>& radii,
    ExceptionState& exception_state) {
  UseCounter::Count(GetTopExecutionContext(),
                    WebFeature::kCanvasRenderingContext2DRoundRect);
  constexpr int kMaxRadii = 4;
  const int num_radii = radii.size();
  if (num_radii < 1 || num_radii > kMaxRadii) [[unlikely]] {
    exception_state.ThrowRangeError(
        String::Number(num_radii) +
        " radii provided. Between one and four radii are necessary.");
    return;
  }

  float x = base::saturated_cast<float>(double_x);
  float y = base::saturated_cast<float>(double_y);
  float width = base::saturated_cast<float>(double_width);
  float height = base::saturated_cast<float>(double_height);
  if (!IsTransformInvertible()) [[unlikely]] {
    return;
  }

  if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(width) ||
      !std::isfinite(height)) [[unlikely]] {
    return;
  }
  UpdatePathFromLineOrArcIfNecessaryForMutation();
  // TODO(crbug.com/1234113): Instrument new canvas APIs.
  identifiability_study_helper_.set_encountered_skipped_ops();

  std::array<gfx::SizeF, kMaxRadii> r;
  for (int i = 0; i < num_radii; ++i) {
    switch (radii[i]->GetContentType()) {
      case V8UnionDOMPointInitOrUnrestrictedDouble::ContentType::
          kDOMPointInit: {
        DOMPointInit* p = radii[i]->GetAsDOMPointInit();
        float r_x = base::saturated_cast<float>(p->x());
        float r_y = base::saturated_cast<float>(p->y());
        if (!std::isfinite(r_x) || !std::isfinite(r_y)) [[unlikely]] {
          return;
        }
        if (r_x < 0.0f) [[unlikely]] {
          exception_state.ThrowRangeError(
              "X-radius value " + String::Number(r_x) + " is negative.");
          return;
        }
        if (r_y < 0.0f) [[unlikely]] {
          exception_state.ThrowRangeError(
              "Y-radius value " + String::Number(r_y) + " is negative.");
          return;
        }
        r[i] = gfx::SizeF(base::saturated_cast<float>(p->x()),
                          base::saturated_cast<float>(p->y()));
        break;
      }
      case V8UnionDOMPointInitOrUnrestrictedDouble::ContentType::
          kUnrestrictedDouble: {
        float a =
            base::saturated_cast<float>(radii[i]->GetAsUnrestrictedDouble());
        if (!std::isfinite(a)) [[unlikely]] {
          return;
        }
        if (a < 0.0f) [[unlikely]] {
          exception_state.ThrowRangeError("Radius value " + String::Number(a) +
                                          " is negative.");
          return;
        }
        r[i] = gfx::SizeF(a, a);
        break;
      }
    }
  }

  if (width == 0 || height == 0) [[unlikely]] {
    // AddRoundRect does not handle flat rects, correctly.  But since there are
    // no rounded corners on a flat rect, we can just use AddRect.

    path_builder_.AddRect(gfx::PointF(x, y),
                          gfx::PointF(x + width, y + height));
    return;
  }

  gfx::SizeF corner_radii[4];  // row-wise ordering
  switch (num_radii) {
    case 1:
      corner_radii[0] = corner_radii[1] = corner_radii[2] = corner_radii[3] =
          r[0];
      break;
    case 2:
      corner_radii[0] = corner_radii[3] = r[0];
      corner_radii[1] = corner_radii[2] = r[1];
      break;
    case 3:
      corner_radii[0] = r[0];
      corner_radii[1] = corner_radii[2] = r[1];
      corner_radii[3] = r[2];
      break;
    case 4:
      corner_radii[0] = r[0];
      corner_radii[1] = r[1];
      corner_radii[2] = r[3];
      corner_radii[3] = r[2];
  }

  bool clockwise = true;
  if (width < 0) [[unlikely]] {
    // Horizontal flip
    clockwise = false;
    x += width;
    width = -width;
    using std::swap;
    swap(corner_radii[0], corner_radii[1]);
    swap(corner_radii[2], corner_radii[3]);
  }

  if (height < 0) [[unlikely]] {
    // Vertical flip
    clockwise = !clockwise;
    y += height;
    height = -height;
    using std::swap;
    swap(corner_radii[0], corner_radii[2]);
    swap(corner_radii[1], corner_radii[3]);
  }

  gfx::RectF rect(x, y, width, height);

  path_builder_
      .AddRoundedRect(FloatRoundedRect(rect, corner_radii[0], corner_radii[1],
                                       corner_radii[2], corner_radii[3]),
                      clockwise)
      .MoveTo(gfx::PointF(x, y));
}

void CanvasPath::roundRect(
    double double_x,
    double double_y,
    double double_width,
    double double_height,
    const Member<V8UnionDOMPointInitOrUnrestrictedDouble>& radius,
    ExceptionState& exception_state) {
  const auto radii =
      HeapVector<Member<V8UnionDOMPointInitOrUnrestrictedDouble>>(1, radius);
  roundRect(double_x, double_y, double_width, double_height, radii,
            exception_state);
}

gfx::RectF CanvasPath::BoundingRect() const {
  if (!line_builder_.IsEmpty()) {
    return line_builder_.BoundingRect();
  } else if (IsArc()) {
    return arc_builder_.BoundingRect();
  }
  return path_builder_.BoundingRect();
}

void CanvasPath::Trace(Visitor* visitor) const {
  visitor->Trace(identifiability_study_helper_);
}

ALWAYS_INLINE gfx::RectF CanvasPath::LineBuilder::BoundingRect() const {
  DCHECK_NE(state_, State::kEmpty);
  if (state_ == State::kStartingPoint) {
    return gfx::BoundingRect(line_.start, line_.start);
  }
  return gfx::BoundingRect(line_.start, line_.end);
}

ALWAYS_INLINE gfx::RectF CanvasPath::ArcBuilder::BoundingRect() const {
  DCHECK_NE(state_, State::kEmpty);
  return gfx::BoundingRect(
      gfx::PointF(arc_.x - arc_.radius, arc_.y - arc_.radius),
      gfx::PointF(arc_.x + arc_.radius, arc_.y + arc_.radius));
}

ALWAYS_INLINE void CanvasPath::ArcBuilder::UpdatePath(
    PathBuilder& path_builder) const {
  DCHECK_NE(state_, State::kEmpty);
  path_builder.AddEllipse(gfx::PointF(arc_.x, arc_.y), arc_.radius, arc_.radius,
                          arc_.start_angle_radians,
                          arc_.start_angle_radians + arc_.sweep_angle_radians);
  if (state_ == State::kClosed) {
    path_builder.Close();
  }
}

void CanvasPath::UpdatePathFromLineOrArcIfNecessary() const {
  if (!DoesPathNeedUpdatingFromLineOrArc()) {
    return;
  }
  DCHECK(path_builder_.IsEmpty());
  if (!line_builder_.IsEmpty()) {
    // There is a starting point, but possibly no ending point.
    path_builder_.MoveTo(line_builder_.starting_point());
    if (IsLine()) {
      path_builder_.LineTo(line_builder_.ending_point());
    }
  } else {
    DCHECK(!arc_builder_.IsEmpty());
    arc_builder_.UpdatePath(path_builder_);
  }
}

void CanvasPath::UpdatePathFromLineOrArcIfNecessaryForMutation() {
  UpdatePathFromLineOrArcIfNecessary();
  line_builder_.Clear();
  arc_builder_.Clear();
}

}  // namespace blink