third_party/blink/renderer/core/style/style_fetched_image_set.h

/*
 * Copyright (C) 2012 Apple Inc. 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 APPLE INC. AND ITS CONTRIBUTORS ``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 APPLE INC. OR ITS CONTRIBUTORS
 * 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.
 */

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_STYLE_STYLE_FETCHED_IMAGE_SET_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_STYLE_STYLE_FETCHED_IMAGE_SET_H_

#include "third_party/blink/renderer/core/loader/resource/image_resource_observer.h"
#include "third_party/blink/renderer/core/style/style_image.h"
#include "third_party/blink/renderer/platform/geometry/layout_size.h"
#include "third_party/blink/renderer/platform/weborigin/kurl.h"

namespace blink {

class CSSImageSetValue;
class ImageResourceObserver;

// This class represents an <image> that loads one image resource out of a set
// of alternatives (the -webkit-image-set(...) function.)
//
// This class keeps one cached image from the set, and has access to a set of
// alternatives via the referenced CSSImageSetValue.
class StyleFetchedImageSet final : public StyleImage,
                                   public ImageResourceObserver {
  USING_PRE_FINALIZER(StyleFetchedImageSet, Dispose);

 public:
  static StyleFetchedImageSet* Create(ImageResourceContent* image,
                                      float image_scale_factor,
                                      CSSImageSetValue* value,
                                      const KURL& url) {
    return MakeGarbageCollected<StyleFetchedImageSet>(image, image_scale_factor,
                                                      value, url);
  }

  StyleFetchedImageSet(ImageResourceContent*,
                       float image_scale_factor,
                       CSSImageSetValue*,
                       const KURL&);
  ~StyleFetchedImageSet() override;

  CSSValue* CssValue() const override;
  CSSValue* ComputedCSSValue() const override;

  // FIXME: This is used by StyleImage for equals comparison, but this
  // implementation only looks at the image from the set that we have loaded.
  // I'm not sure if that is meaningful enough or not.
  WrappedImagePtr Data() const override;

  bool CanRender() const override;
  bool IsLoaded() const override;
  bool ErrorOccurred() const override;
  FloatSize ImageSize(const Document&,
                      float multiplier,
                      const LayoutSize& default_object_size) const override;
  bool ImageHasRelativeSize() const override;
  bool UsesImageContainerSize() const override;
  void AddClient(ImageResourceObserver*) override;
  void RemoveClient(ImageResourceObserver*) override;
  scoped_refptr<Image> GetImage(const ImageResourceObserver&,
                                const Document&,
                                const ComputedStyle&,
                                const FloatSize& target_size) const override;
  float ImageScaleFactor() const override { return image_scale_factor_; }
  bool KnownToBeOpaque(const Document&, const ComputedStyle&) const override;
  ImageResourceContent* CachedImage() const override;

  void Trace(blink::Visitor*) override;

 private:
  bool IsEqual(const StyleImage& other) const override;
  void Dispose();

  String DebugName() const override { return "StyleFetchedImageSet"; }

  Member<ImageResourceContent> best_fit_image_;
  float image_scale_factor_;

  Member<CSSImageSetValue> image_set_value_;  // Not retained; it owns us.
  const KURL url_;
};

DEFINE_STYLE_IMAGE_TYPE_CASTS(StyleFetchedImageSet, IsImageResourceSet());

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_STYLE_STYLE_FETCHED_IMAGE_SET_H_