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

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2009 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 LayoutReplaced_h
#define LayoutReplaced_h

#include "core/CoreExport.h"
#include "core/layout/LayoutBox.h"

namespace blink {

// LayoutReplaced is the base class for a replaced element as defined by CSS:
//
// "An element whose content is outside the scope of the CSS formatting model,
// such as an image, embedded document, or applet."
// http://www.w3.org/TR/CSS2/conform.html#defs
//
// Blink consider that replaced elements have an intrinsic sizes (e.g. the
// natural size of an image or a video). The intrinsic size is stored by
// m_intrinsicSize.
//
// The computation sometimes ask for the intrinsic ratio, defined as follow:
//
//                      intrinsicWidth
//   intrinsicRatio = -------------------
//                      intrinsicHeight
//
// The intrinsic ratio is used to keep the same proportion as the intrinsic
// size (thus avoiding visual distortions if width / height doesn't match
// the intrinsic value).
class CORE_EXPORT LayoutReplaced : public LayoutBox {
 public:
  LayoutReplaced(Element*);
  LayoutReplaced(Element*, const LayoutSize& intrinsicSize);
  ~LayoutReplaced() override;

  LayoutUnit computeReplacedLogicalWidth(
      ShouldComputePreferred = ComputeActual) const override;
  LayoutUnit computeReplacedLogicalHeight(
      LayoutUnit estimatedUsedWidth = LayoutUnit()) const override;

  bool hasReplacedLogicalHeight() const;
  // This function returns the local rect of the replaced content.
  virtual LayoutRect replacedContentRect() const;

  bool needsPreferredWidthsRecalculation() const override;

  // These values are specified to be 300 and 150 pixels in the CSS 2.1 spec.
  // http://www.w3.org/TR/CSS2/visudet.html#inline-replaced-width
  static const int defaultWidth;
  static const int defaultHeight;
  bool canHaveChildren() const override { return false; }
  virtual void paintReplaced(const PaintInfo&, const LayoutPoint&) const {}
  LayoutRect localSelectionRect() const final;

  bool hasObjectFit() const {
    return style()->getObjectFit() != ComputedStyle::initialObjectFit();
  }

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

  // Replaced objects often have contents to paint.
  bool paintedOutputOfObjectHasNoEffectRegardlessOfSize() const final {
    return false;
  }

  struct IntrinsicSizingInfo {
    STACK_ALLOCATED();
    IntrinsicSizingInfo() : hasWidth(true), hasHeight(true) {}

    FloatSize size;
    FloatSize aspectRatio;
    bool hasWidth;
    bool hasHeight;

    void transpose();
  };

 protected:
  void willBeDestroyed() override;

  void layout() override;

  LayoutSize intrinsicSize() const final { return m_intrinsicSize; }
  virtual void computeIntrinsicSizingInfo(IntrinsicSizingInfo&) const;

  void computePositionedLogicalWidth(
      LogicalExtentComputedValues&) const override;
  void computePositionedLogicalHeight(
      LogicalExtentComputedValues&) const override;

  void computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth,
                                     LayoutUnit& maxLogicalWidth) const final;

  // This function calculates the placement of the replaced contents. It takes
  // intrinsic size of the replaced contents, stretch to fit CSS content box
  // according to object-fit.
  LayoutRect computeObjectFit(
      const LayoutSize* overriddenIntrinsicSize = nullptr) const;

  virtual LayoutUnit intrinsicContentLogicalHeight() const {
    return intrinsicLogicalHeight();
  }

  virtual LayoutUnit minimumReplacedHeight() const { return LayoutUnit(); }

  void setSelectionState(SelectionState) final;

  void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;

  void setIntrinsicSize(const LayoutSize& intrinsicSize) {
    m_intrinsicSize = intrinsicSize;
  }

  // This callback is invoked whenever the intrinsic size changed.
  //
  // The intrinsic size can change due to the network (from the default
  // intrinsic size [see above] to the actual intrinsic size) or to some
  // CSS properties like 'zoom' or 'image-orientation'.
  virtual void intrinsicSizeChanged();

  virtual LayoutReplaced* embeddedReplacedContent() const { return nullptr; }

  PositionWithAffinity positionForPoint(const LayoutPoint&) override;

 private:
  void computePreferredLogicalWidths() final;

  bool canBeSelectionLeaf() const override { return true; }

  void computeIntrinsicSizingInfoForReplacedContent(LayoutReplaced*,
                                                    IntrinsicSizingInfo&) const;
  FloatSize constrainIntrinsicSizeToMinMax(const IntrinsicSizingInfo&) const;

  LayoutUnit computeConstrainedLogicalWidth(ShouldComputePreferred) const;

  mutable LayoutSize m_intrinsicSize;
};

}  // namespace blink

#endif