Source/WebCore/rendering/RenderFrameSet.h

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Simon Hausmann <hausmann@kde.org>
 * Copyright (C) 2006-2026 Apple Inc. All rights reserved.
 * Copyright (C) 2025 Samuel Weinig <sam@webkit.org>
 *
 * 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.
 *
 */

#pragma once

#include "RenderBox.h"
#include <utility>

namespace WebCore {

class HTMLFrameSetElement;
class MouseEvent;
class RenderFrame;

struct HTMLDimensionsListValue;

enum class FrameEdge : uint8_t { Left, Right, Top, Bottom };

struct FrameEdgeInfo {
    explicit FrameEdgeInfo(bool preventResize = false, bool allowBorder = true)
        : m_preventResize(FillWith { }, 4, preventResize)
        , m_allowBorder(FillWith { }, 4, allowBorder)
    {
    }

    bool preventResize(FrameEdge edge) const { return m_preventResize[std::to_underlying(edge)]; }
    bool allowBorder(FrameEdge edge) const { return m_allowBorder[std::to_underlying(edge)]; }

    void setPreventResize(FrameEdge edge, bool preventResize) { m_preventResize[std::to_underlying(edge)] = preventResize; }
    void setAllowBorder(FrameEdge edge, bool allowBorder) { m_allowBorder[std::to_underlying(edge)] = allowBorder; }

private:
    Vector<bool> m_preventResize;
    Vector<bool> m_allowBorder;
};

class RenderFrameSet final : public RenderBox {
    WTF_MAKE_TZONE_ALLOCATED(RenderFrameSet);
    WTF_OVERRIDE_DELETE_FOR_CHECKED_PTR(RenderFrameSet);
public:
    RenderFrameSet(HTMLFrameSetElement&, Style::ComputedStyle&&);
    virtual ~RenderFrameSet();

    HTMLFrameSetElement& NODELETE frameSetElement() const;

    FrameEdgeInfo edgeInfo() const;

    bool userResize(MouseEvent&);

    bool NODELETE canResizeRow(const IntPoint&) const;
    bool NODELETE canResizeColumn(const IntPoint&) const;

    void notifyFrameEdgeInfoChanged();

private:
    void element() const = delete;
    std::pair<LayoutUnit, LayoutUnit> computeIntrinsicLogicalWidths() const override { return { }; }

    static const int noSplit = -1;

    class GridAxis {
        WTF_MAKE_NONCOPYABLE(GridAxis);
    public:
        GridAxis() = default;
        void resize(int);

        Vector<int> m_sizes;
        Vector<int> m_deltas;
        Vector<bool> m_preventResize;
        Vector<bool> m_allowBorder;
        int m_splitBeingResized { noSplit };
        int m_splitResizeOffset { 0 };
    };

    ASCIILiteral renderName() const override { return "RenderFrameSet"_s; }

    void layout() override;
    void paint(PaintInfo&, const LayoutPoint&) override;
    bool canHaveChildren() const override { return true; }
    bool isChildAllowed(const RenderObject&, const Style::ComputedStyle&) const override;
    CursorDirective getCursor(const LayoutPoint&, Cursor&) const override;

    void setIsResizing(bool);

    void layOutAxis(GridAxis&, std::span<const HTMLDimensionsListValue>, int availableSpace);
    void computeEdgeInfo();
    void NODELETE fillFromEdgeInfo(const FrameEdgeInfo&, int r, int c);
    void positionFrames();

    int NODELETE splitPosition(const GridAxis&, int split) const;
    int NODELETE hitTestSplit(const GridAxis&, int position) const;

    void NODELETE startResizing(GridAxis&, int position);
    void continueResizing(GridAxis&, int position);

    void paintRowBorder(const PaintInfo&, const IntRect&);
    void paintColumnBorder(const PaintInfo&, const IntRect&);

    GridAxis m_rows;
    GridAxis m_cols;

    bool m_isResizing { false };
};

} // namespace WebCore

SPECIALIZE_TYPE_TRAITS_RENDER_OBJECT(RenderFrameSet, isRenderFrameSet())