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

// Copyright 2014 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/html_canvas_painter.h"

#include "third_party/blink/renderer/core/html/canvas/canvas_rendering_context.h"
#include "third_party/blink/renderer/core/html/canvas/html_canvas_element.h"
#include "third_party/blink/renderer/core/layout/layout_html_canvas.h"
#include "third_party/blink/renderer/core/paint/paint_info.h"
#include "third_party/blink/renderer/platform/geometry/layout_point.h"
#include "third_party/blink/renderer/platform/graphics/paint/drawing_recorder.h"
#include "third_party/blink/renderer/platform/graphics/paint/foreign_layer_display_item.h"
#include "third_party/blink/renderer/platform/graphics/scoped_interpolation_quality.h"

namespace blink {

namespace {

InterpolationQuality InterpolationQualityForCanvas(const ComputedStyle& style) {
  if (style.ImageRendering() == EImageRendering::kWebkitOptimizeContrast)
    return kInterpolationLow;

  if (style.ImageRendering() == EImageRendering::kPixelated)
    return kInterpolationNone;

  return CanvasDefaultInterpolationQuality;
}

}  // namespace

void HTMLCanvasPainter::PaintReplaced(const PaintInfo& paint_info,
                                      const LayoutPoint& paint_offset) {
  GraphicsContext& context = paint_info.context;

  LayoutRect paint_rect = layout_html_canvas_.ReplacedContentRect();
  paint_rect.MoveBy(paint_offset);

  HTMLCanvasElement* canvas =
      ToHTMLCanvasElement(layout_html_canvas_.GetNode());

  if (RuntimeEnabledFeatures::CompositeAfterPaintEnabled()) {
    if (auto* layer = canvas->ContentsCcLayer()) {
      IntRect pixel_snapped_rect = PixelSnappedIntRect(paint_rect);
      layer->SetOffsetToTransformParent(
          gfx::Vector2dF(pixel_snapped_rect.X(), pixel_snapped_rect.Y()));
      layer->SetBounds(gfx::Size(pixel_snapped_rect.Size()));
      layer->SetIsDrawable(true);
      RecordForeignLayer(context, DisplayItem::kForeignLayerCanvas, layer);
      return;
    }
  }

  if (DrawingRecorder::UseCachedDrawingIfPossible(context, layout_html_canvas_,
                                                  paint_info.phase))
    return;

  DrawingRecorder recorder(context, layout_html_canvas_, paint_info.phase);
  ScopedInterpolationQuality interpolation_quality_scope(
      context, InterpolationQualityForCanvas(layout_html_canvas_.StyleRef()));
  canvas->Paint(context, paint_rect);
}

}  // namespace blink