third_party/WebKit/Source/core/layout/svg/LayoutSVGResourcePaintServer.cpp

/*
 * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2007 Rob Buis <buis@kde.org>
 * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "core/layout/svg/LayoutSVGResourcePaintServer.h"

#include "core/layout/svg/SVGResources.h"
#include "core/layout/svg/SVGResourcesCache.h"
#include "core/style/ComputedStyle.h"
#include "platform/graphics/skia/SkiaUtils.h"
#include "third_party/skia/include/core/SkPaint.h"

namespace blink {

SVGPaintServer::SVGPaintServer(Color color) : m_color(color) {}

SVGPaintServer::SVGPaintServer(PassRefPtr<Gradient> gradient,
                               const AffineTransform& transform)
    : m_gradient(gradient), m_transform(transform), m_color(Color::black) {}

SVGPaintServer::SVGPaintServer(PassRefPtr<Pattern> pattern,
                               const AffineTransform& transform)
    : m_pattern(pattern), m_transform(transform), m_color(Color::black) {}

void SVGPaintServer::applyToSkPaint(SkPaint& paint, float paintAlpha) {
  SkColor baseColor = m_gradient || m_pattern ? SK_ColorBLACK : m_color.rgb();
  paint.setColor(scaleAlpha(baseColor, paintAlpha));
  if (m_pattern) {
    m_pattern->applyToPaint(paint, affineTransformToSkMatrix(m_transform));
  } else if (m_gradient) {
    m_gradient->applyToPaint(paint, affineTransformToSkMatrix(m_transform));
  } else {
    paint.setShader(nullptr);
  }
}

void SVGPaintServer::prependTransform(const AffineTransform& transform) {
  ASSERT(m_gradient || m_pattern);
  m_transform = transform * m_transform;
}

static SVGPaintDescription requestPaint(const LayoutObject& object,
                                        const ComputedStyle& style,
                                        LayoutSVGResourceMode mode) {
  // If we have no style at all, ignore it.
  const SVGComputedStyle& svgStyle = style.svgStyle();

  // If we have no fill/stroke, return 0.
  if (mode == ApplyToFillMode) {
    if (!svgStyle.hasFill())
      return SVGPaintDescription();
  } else {
    if (!svgStyle.hasStroke())
      return SVGPaintDescription();
  }

  bool applyToFill = mode == ApplyToFillMode;
  SVGPaintType paintType =
      applyToFill ? svgStyle.fillPaintType() : svgStyle.strokePaintType();
  ASSERT(paintType != SVG_PAINTTYPE_NONE);

  Color color;
  bool hasColor = false;
  switch (paintType) {
    case SVG_PAINTTYPE_CURRENTCOLOR:
    case SVG_PAINTTYPE_URI_CURRENTCOLOR:
      // The keyword `currentcolor` takes its value from the value of the
      // `color` property on the same element.
      color = style.visitedDependentColor(CSSPropertyColor);
      hasColor = true;
      break;
    case SVG_PAINTTYPE_RGBCOLOR:
    case SVG_PAINTTYPE_URI_RGBCOLOR:
      color =
          applyToFill ? svgStyle.fillPaintColor() : svgStyle.strokePaintColor();
      hasColor = true;
    default:
      break;
  }

  if (style.insideLink() == EInsideLink::kInsideVisitedLink) {
    // FIXME: This code doesn't support the uri component of the visited link
    // paint, https://bugs.webkit.org/show_bug.cgi?id=70006
    SVGPaintType visitedPaintType = applyToFill
                                        ? svgStyle.visitedLinkFillPaintType()
                                        : svgStyle.visitedLinkStrokePaintType();

    // For SVG_PAINTTYPE_CURRENTCOLOR, 'color' already contains the
    // 'visitedColor'.
    if (visitedPaintType < SVG_PAINTTYPE_URI_NONE &&
        visitedPaintType != SVG_PAINTTYPE_CURRENTCOLOR) {
      const Color& visitedColor = applyToFill
                                      ? svgStyle.visitedLinkFillPaintColor()
                                      : svgStyle.visitedLinkStrokePaintColor();
      color = Color(visitedColor.red(), visitedColor.green(),
                    visitedColor.blue(), color.alpha());
      hasColor = true;
    }
  }

  // If the primary resource is just a color, return immediately.
  if (paintType < SVG_PAINTTYPE_URI_NONE) {
    // |paintType| will be either <current-color> or <rgb-color> here - both of
    // which will have a color.
    ASSERT(hasColor);
    return SVGPaintDescription(color);
  }

  LayoutSVGResourcePaintServer* uriResource = nullptr;
  if (SVGResources* resources =
          SVGResourcesCache::cachedResourcesForLayoutObject(&object))
    uriResource = applyToFill ? resources->fill() : resources->stroke();

  // If the requested resource is not available, return the color resource or
  // 'none'.
  if (!uriResource) {
    // The fallback is 'none'. (SVG2 say 'none' is implied when no fallback is
    // specified.)
    if (paintType == SVG_PAINTTYPE_URI_NONE || !hasColor)
      return SVGPaintDescription();

    return SVGPaintDescription(color);
  }

  // The paint server resource exists, though it may be invalid (pattern with
  // width/height=0). Return the fallback color to our caller so it can use it,
  // if preparePaintServer() on the resource container failed.
  if (hasColor)
    return SVGPaintDescription(uriResource, color);

  return SVGPaintDescription(uriResource);
}

SVGPaintServer SVGPaintServer::requestForLayoutObject(
    const LayoutObject& layoutObject,
    const ComputedStyle& style,
    LayoutSVGResourceMode resourceMode) {
  ASSERT(resourceMode == ApplyToFillMode || resourceMode == ApplyToStrokeMode);

  SVGPaintDescription paintDescription =
      requestPaint(layoutObject, style, resourceMode);
  if (!paintDescription.isValid)
    return invalid();
  if (!paintDescription.resource)
    return SVGPaintServer(paintDescription.color);
  SVGPaintServer paintServer =
      paintDescription.resource->preparePaintServer(layoutObject);
  if (paintServer.isValid())
    return paintServer;
  if (paintDescription.hasFallback)
    return SVGPaintServer(paintDescription.color);
  return invalid();
}

bool SVGPaintServer::existsForLayoutObject(const LayoutObject& layoutObject,
                                           const ComputedStyle& style,
                                           LayoutSVGResourceMode resourceMode) {
  return requestPaint(layoutObject, style, resourceMode).isValid;
}

LayoutSVGResourcePaintServer::LayoutSVGResourcePaintServer(SVGElement* element)
    : LayoutSVGResourceContainer(element) {}

LayoutSVGResourcePaintServer::~LayoutSVGResourcePaintServer() {}

SVGPaintDescription LayoutSVGResourcePaintServer::requestPaintDescription(
    const LayoutObject& layoutObject,
    const ComputedStyle& style,
    LayoutSVGResourceMode resourceMode) {
  return requestPaint(layoutObject, style, resourceMode);
}

}  // namespace blink