third_party/WebKit/Source/core/paint/SVGImagePainter.cpp

// 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 "core/paint/SVGImagePainter.h"

#include "core/layout/ImageQualityController.h"
#include "core/layout/LayoutImageResource.h"
#include "core/layout/svg/LayoutSVGImage.h"
#include "core/paint/LayoutObjectDrawingRecorder.h"
#include "core/paint/ObjectPainter.h"
#include "core/paint/PaintInfo.h"
#include "core/paint/SVGPaintContext.h"
#include "core/svg/SVGImageElement.h"
#include "core/svg/graphics/SVGImage.h"
#include "platform/graphics/GraphicsContext.h"
#include "third_party/skia/include/core/SkPicture.h"

namespace blink {

void SVGImagePainter::paint(const PaintInfo& paintInfo) {
  if (paintInfo.phase != PaintPhaseForeground ||
      m_layoutSVGImage.style()->visibility() != EVisibility::Visible ||
      !m_layoutSVGImage.imageResource()->hasImage())
    return;

  FloatRect boundingBox =
      m_layoutSVGImage.paintInvalidationRectInLocalSVGCoordinates();
  if (!paintInfo.cullRect().intersectsCullRect(
          m_layoutSVGImage.localToSVGParentTransform(), boundingBox))
    return;

  PaintInfo paintInfoBeforeFiltering(paintInfo);
  // Images cannot have children so do not call updateCullRect.
  SVGTransformContext transformContext(
      paintInfoBeforeFiltering.context, m_layoutSVGImage,
      m_layoutSVGImage.localToSVGParentTransform());
  {
    SVGPaintContext paintContext(m_layoutSVGImage, paintInfoBeforeFiltering);
    if (paintContext.applyClipMaskAndFilterIfNecessary() &&
        !LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(
            paintContext.paintInfo().context, m_layoutSVGImage,
            paintContext.paintInfo().phase)) {
      LayoutObjectDrawingRecorder recorder(
          paintContext.paintInfo().context, m_layoutSVGImage,
          paintContext.paintInfo().phase, boundingBox);
      paintForeground(paintContext.paintInfo());
    }
  }

  if (m_layoutSVGImage.style()->outlineWidth()) {
    PaintInfo outlinePaintInfo(paintInfoBeforeFiltering);
    outlinePaintInfo.phase = PaintPhaseSelfOutlineOnly;
    ObjectPainter(m_layoutSVGImage)
        .paintOutline(outlinePaintInfo, LayoutPoint(boundingBox.location()));
  }
}

void SVGImagePainter::paintForeground(const PaintInfo& paintInfo) {
  const LayoutImageResource* imageResource = m_layoutSVGImage.imageResource();
  IntSize imageViewportSize = expandedIntSize(computeImageViewportSize());
  if (imageViewportSize.isEmpty())
    return;

  RefPtr<Image> image = imageResource->image(
      imageViewportSize, m_layoutSVGImage.style()->effectiveZoom());
  FloatRect destRect = m_layoutSVGImage.objectBoundingBox();
  FloatRect srcRect(0, 0, image->width(), image->height());

  SVGImageElement* imageElement = toSVGImageElement(m_layoutSVGImage.element());
  imageElement->preserveAspectRatio()->currentValue()->transformRect(destRect,
                                                                     srcRect);

  InterpolationQuality interpolationQuality = InterpolationDefault;
  interpolationQuality = ImageQualityController::imageQualityController()
                             ->chooseInterpolationQuality(
                                 m_layoutSVGImage, image.get(), image.get(),
                                 LayoutSize(destRect.size()));

  InterpolationQuality previousInterpolationQuality =
      paintInfo.context.imageInterpolationQuality();
  paintInfo.context.setImageInterpolationQuality(interpolationQuality);
  paintInfo.context.drawImage(image.get(), destRect, &srcRect);
  paintInfo.context.setImageInterpolationQuality(previousInterpolationQuality);
}

FloatSize SVGImagePainter::computeImageViewportSize() const {
  ASSERT(m_layoutSVGImage.imageResource()->hasImage());

  if (toSVGImageElement(m_layoutSVGImage.element())
          ->preserveAspectRatio()
          ->currentValue()
          ->align() != SVGPreserveAspectRatio::kSvgPreserveaspectratioNone)
    return m_layoutSVGImage.objectBoundingBox().size();

  ImageResource* cachedImage = m_layoutSVGImage.imageResource()->cachedImage();

  // Images with preserveAspectRatio=none should force non-uniform scaling. This
  // can be achieved by setting the image's container size to its viewport size
  // (i.e. concrete object size returned by the default sizing algorithm.)  See
  // https://www.w3.org/TR/SVG/single-page.html#coords-PreserveAspectRatioAttribute
  // and https://drafts.csswg.org/css-images-3/#default-sizing.

  // Avoid returning the size of the broken image.
  if (cachedImage->errorOccurred())
    return FloatSize();

  if (cachedImage->getImage()->isSVGImage())
    return toSVGImage(cachedImage->getImage())
        ->concreteObjectSize(m_layoutSVGImage.objectBoundingBox().size());

  return FloatSize(cachedImage->getImage()->size());
}

}  // namespace blink