third_party/blink/renderer/core/paint/rounded_inner_rect_clipper.cc

// Copyright 2015 The Chromium 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 "third_party/blink/renderer/core/paint/rounded_inner_rect_clipper.h"

#include "third_party/blink/renderer/platform/geometry/float_rounded_rect.h"
#include "third_party/blink/renderer/platform/geometry/layout_rect.h"
#include "third_party/blink/renderer/platform/graphics/graphics_context.h"

namespace blink {

RoundedInnerRectClipper::RoundedInnerRectClipper(
    GraphicsContext& context,
    const LayoutRect& rect,
    const FloatRoundedRect& clip_rect)
    : context_(context) {
  Vector<FloatRoundedRect> rounded_rect_clips;
  if (clip_rect.IsRenderable()) {
    rounded_rect_clips.push_back(clip_rect);
  } else {
    // We create a rounded rect for each of the corners and clip it, while
    // making sure we clip opposing corners together.
    if (!clip_rect.GetRadii().TopLeft().IsEmpty() ||
        !clip_rect.GetRadii().BottomRight().IsEmpty()) {
      FloatRect top_corner(clip_rect.Rect().X(), clip_rect.Rect().Y(),
                           rect.MaxX() - clip_rect.Rect().X(),
                           rect.MaxY() - clip_rect.Rect().Y());
      FloatRoundedRect::Radii top_corner_radii;
      top_corner_radii.SetTopLeft(clip_rect.GetRadii().TopLeft());
      rounded_rect_clips.push_back(
          FloatRoundedRect(top_corner, top_corner_radii));

      FloatRect bottom_corner(rect.X().ToFloat(), rect.Y().ToFloat(),
                              clip_rect.Rect().MaxX() - rect.X().ToFloat(),
                              clip_rect.Rect().MaxY() - rect.Y().ToFloat());
      FloatRoundedRect::Radii bottom_corner_radii;
      bottom_corner_radii.SetBottomRight(clip_rect.GetRadii().BottomRight());
      rounded_rect_clips.push_back(
          FloatRoundedRect(bottom_corner, bottom_corner_radii));
    }

    if (!clip_rect.GetRadii().TopRight().IsEmpty() ||
        !clip_rect.GetRadii().BottomLeft().IsEmpty()) {
      FloatRect top_corner(rect.X().ToFloat(), clip_rect.Rect().Y(),
                           clip_rect.Rect().MaxX() - rect.X().ToFloat(),
                           rect.MaxY() - clip_rect.Rect().Y());
      FloatRoundedRect::Radii top_corner_radii;
      top_corner_radii.SetTopRight(clip_rect.GetRadii().TopRight());
      rounded_rect_clips.push_back(
          FloatRoundedRect(top_corner, top_corner_radii));

      FloatRect bottom_corner(clip_rect.Rect().X(), rect.Y().ToFloat(),
                              rect.MaxX() - clip_rect.Rect().X(),
                              clip_rect.Rect().MaxY() - rect.Y().ToFloat());
      FloatRoundedRect::Radii bottom_corner_radii;
      bottom_corner_radii.SetBottomLeft(clip_rect.GetRadii().BottomLeft());
      rounded_rect_clips.push_back(
          FloatRoundedRect(bottom_corner, bottom_corner_radii));
    }
  }

  context.Save();
  for (const auto& rrect : rounded_rect_clips)
    context.ClipRoundedRect(rrect);
}

RoundedInnerRectClipper::~RoundedInnerRectClipper() {
  context_.Restore();
}

}  // namespace blink