flowlayout.h

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/*
 
Pencil2D - Traditional Animation Software
Copyright (C) 2005-2007 Patrick Corrieri & Pascal Naidon
Copyright (C) 2012-2020 Matthew Chiawen Chang
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; version 2 of the License.
 
This program 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 General Public License for more details.
 
*/
 
#ifndef FLOWLAYOUT_H
#define FLOWLAYOUT_H
 
#include <QLayout>
#include <QRect>
#include <QStyle>
 
struct RowLayoutInfo {
    int startIndex;
    int startX;
    int spacing;
};
 
class FlowLayout : public QLayout
{
public:
    explicit FlowLayout(QWidget *parent, int margin = -1, int hSpacing = -1, int vSpacing = -1);
    explicit FlowLayout(int margin = -1, int hSpacing = -1, int vSpacing = -1);
    ~FlowLayout() override;
 
    void addItem(QLayoutItem *item) override;
    int horizontalSpacing() const;
    int verticalSpacing() const;
    Qt::Orientations expandingDirections() const override;
    bool hasHeightForWidth() const override;
    int heightForWidth(int) const override;
    int count() const override;
    QLayoutItem *itemAt(int index) const override;
    QSize minimumSize() const override;
    void setGeometry(const QRect &rect) override;
    QSize sizeHint() const override;
    QLayoutItem *takeAt(int index) override;
 
    int rows() const { return mNumberOfRows; }
 
protected:
    virtual void lastLineAlignment(int startIndex, int count, RowLayoutInfo rowInfo, const QRect& effectiveRect) const;
 
    QList<QLayoutItem *> itemList;
    int m_hSpace = 0;
    int m_vSpace = 0;
 
private:
    RowLayoutInfo alignHCenterRow(int startIndex, int count, const QRect &effectiveRect, int spaceX) const;
    RowLayoutInfo alignJustifiedRow(int startIndex, int count, const QRect& effectiveRect, int spaceX) const;
 
    int calculateHeightForWidth(int width) const;
    int calculateRowWidth(int start, int end, int spacing) const;
 
    int applyLayout(const QRect &rect) const;
    int smartSpacing(QStyle::PixelMetric pm) const;
 
    int mNumberOfRows = 0;
};
 
#endif // FLOWLAYOUT_H