Source/WebCore/layout/floats/FloatAvoider.h

/*
 * Copyright (C) 2018 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
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 */

#pragma once

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)

#include "DisplayBox.h"
#include "LayoutBox.h"
#include "LayoutPoint.h"
#include "LayoutUnits.h"
#include <wtf/IsoMalloc.h>
#include <wtf/WeakPtr.h>

namespace WebCore {

namespace Layout {

class FloatAvoider {
    WTF_MAKE_ISO_ALLOCATED(FloatAvoider);
public:
    FloatAvoider(const Box&, LayoutPoint absoluteTopLeft, LayoutUnit borderBoxWidth, const Edges& margin, HorizontalEdges containingBlockAbsoluteContentBox);
    virtual ~FloatAvoider() = default;

    void setHorizontalPosition(LayoutUnit);
    void setVerticalPosition(LayoutUnit);
    void resetHorizontalPosition() { m_absoluteTopLeft.setX(initialHorizontalPosition()); }

    bool overflowsContainingBlock() const;

    LayoutUnit top() const;
    LayoutUnit left() const;
    LayoutUnit right() const;

    bool isLeftAligned() const { return isFloatingBox() ? layoutBox().isLeftFloatingPositioned() : layoutBox().style().isLeftToRightDirection(); }

private:
    LayoutUnit borderBoxWidth() const { return m_borderBoxWidth; }
    LayoutUnit initialHorizontalPosition() const;

    LayoutUnit marginBefore() const { return m_margin.vertical.top; }
    LayoutUnit marginAfter() const { return m_margin.vertical.bottom; }
    LayoutUnit marginStart() const { return m_margin.horizontal.left; }
    LayoutUnit marginEnd() const { return m_margin.horizontal.right; }
    LayoutUnit marginBoxWidth() const { return marginStart() + borderBoxWidth() + marginEnd(); }

    bool isFloatingBox() const { return layoutBox().isFloatingPositioned(); }
    const Box& layoutBox() const { return *m_layoutBox; }

private:
    WeakPtr<const Box> m_layoutBox;
    // These coordinate values are relative to the formatting root's border box.
    LayoutPoint m_absoluteTopLeft;
    // Note that float avoider should work with no height value.
    LayoutUnit m_borderBoxWidth;
    Edges m_margin;
    HorizontalEdges m_containingBlockAbsoluteContentBox;
};

inline LayoutUnit FloatAvoider::top() const
{
    auto top = m_absoluteTopLeft.y();
    if (isFloatingBox())
        top -= marginBefore();
    return top;
}

inline LayoutUnit FloatAvoider::left() const
{
    auto left = m_absoluteTopLeft.x();
    if (isFloatingBox())
        left -= marginStart();
    return left;
}

inline LayoutUnit FloatAvoider::right() const
{
    auto right = left() + borderBoxWidth();
    if (isFloatingBox())
        right += marginAfter();
    return right;
}

}
}
#endif