third_party/WebKit/Source/core/layout/LayoutImage.h

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2006 Allan Sandfeld Jensen (kde@carewolf.com)
 *           (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
 * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc.
 *               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.
 *
 */

#ifndef LayoutImage_h
#define LayoutImage_h

#include "core/CoreExport.h"
#include "core/layout/LayoutImageResource.h"
#include "core/layout/LayoutReplaced.h"
#include "platform/loader/fetch/ResourceClient.h"

namespace blink {

class HTMLAreaElement;
class HTMLMapElement;

// LayoutImage is used to display any image type.
//
// There is 2 types of images:
// * normal images, e.g. <image>, <picture>.
// * content images with "content: url(path/to/image.png)".
// We store the type inside  m_isGeneratedContent.
//
// The class is image type agnostic as it only manipulates decoded images.
// See LayoutImageResource that holds this image.
class CORE_EXPORT LayoutImage : public LayoutReplaced {
 public:
  // These are the paddings to use when displaying either alt text or an image.
  static const unsigned short kPaddingWidth = 4;
  static const unsigned short kPaddingHeight = 4;

  LayoutImage(Element*);
  ~LayoutImage() override;

  static LayoutImage* CreateAnonymous(PseudoElement&);

  void SetImageResource(LayoutImageResource*);

  LayoutImageResource* ImageResource() { return image_resource_.Get(); }
  const LayoutImageResource* ImageResource() const {
    return image_resource_.Get();
  }
  ImageResourceContent* CachedImage() const {
    return image_resource_ ? image_resource_->CachedImage() : 0;
  }

  HTMLMapElement* ImageMap() const;
  void AreaElementFocusChanged(HTMLAreaElement*);

  void SetIsGeneratedContent(bool generated = true) {
    is_generated_content_ = generated;
  }

  bool IsGeneratedContent() const { return is_generated_content_; }

  inline void SetImageDevicePixelRatio(float factor) {
    image_device_pixel_ratio_ = factor;
  }
  float ImageDevicePixelRatio() const { return image_device_pixel_ratio_; }

  void IntrinsicSizeChanged() override {
    if (image_resource_)
      ImageChanged(image_resource_->ImagePtr());
  }

  const char* GetName() const override { return "LayoutImage"; }

 protected:
  bool NeedsPreferredWidthsRecalculation() const final;
  LayoutReplaced* EmbeddedReplacedContent() const final;
  void ComputeIntrinsicSizingInfo(IntrinsicSizingInfo&) const final;

  void ImageChanged(WrappedImagePtr, const IntRect* = nullptr) override;

  void Paint(const PaintInfo&, const LayoutPoint&) const final;

  bool IsOfType(LayoutObjectType type) const override {
    return type == kLayoutObjectLayoutImage || LayoutReplaced::IsOfType(type);
  }

  void WillBeDestroyed() override;

  void StyleDidChange(StyleDifference, const ComputedStyle* old_style) override;

 private:
  bool IsImage() const override { return true; }

  void PaintReplaced(const PaintInfo&, const LayoutPoint&) const override;

  bool ForegroundIsKnownToBeOpaqueInRect(
      const LayoutRect& local_rect,
      unsigned max_depth_to_test) const final;
  bool ComputeBackgroundIsKnownToBeObscured() const final;

  bool BackgroundShouldAlwaysBeClipped() const override { return true; }

  LayoutUnit MinimumReplacedHeight() const override;

  void ImageNotifyFinished(ImageResourceContent*) final;
  bool NodeAtPoint(HitTestResult&,
                   const HitTestLocation& location_in_container,
                   const LayoutPoint& accumulated_offset,
                   HitTestAction) final;

  void InvalidatePaintAndMarkForLayoutIfNeeded();
  void UpdateIntrinsicSizeIfNeeded(const LayoutSize&);

  // This member wraps the associated decoded image.
  //
  // This field is set using setImageResource above which can be called in
  // several ways:
  // * For normal images, from the network stack (ImageLoader) once we have
  // some image data.
  // * For generated content, the resource is loaded during style resolution
  // and thus is stored in ComputedStyle (see ContentData::image) that gets
  // propagated to the anonymous LayoutImage in LayoutObject::createObject.
  Persistent<LayoutImageResource> image_resource_;
  bool did_increment_visually_non_empty_pixel_count_;

  // This field stores whether this image is generated with 'content'.
  bool is_generated_content_;
  float image_device_pixel_ratio_;
};

DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutImage, IsLayoutImage());

}  // namespace blink

#endif  // LayoutImage_h