ksaneviewer.h

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/* ============================================================
*
* This file is part of the KDE project
*
* Date        : 2008-11-15
* Description : Preview image viewer that can handle a selection.
*
* Copyright (C) 2008 by Kare Sars <kare dot sars at iki dot fi>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) version 3, or any
* later version accepted by the membership of KDE e.V. (or its
* successor approved by the membership of KDE e.V.), which shall
* act as a proxy defined in Section 6 of version 3 of the license.
*
* 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program.  If not, see <http://www.gnu.org/licenses/>.
*
* ============================================================ */

#ifndef KSANE_VIEWER_H
#define KSANE_VIEWER_H

#include <QGraphicsView>
#include <QWheelEvent>

namespace KSaneIface
{

class KSaneViewer : public QGraphicsView
{
    Q_OBJECT
public:
    explicit KSaneViewer(QImage *img, QWidget *parent = nullptr);
    ~KSaneViewer();

    void setQImage(QImage *img);
    void updateImage();
    void findSelections(float area = 10000.0);

    QSize sizeHint() const override;

public Q_SLOTS:

    void setTLX(float ratio);
    void setTLY(float ratio);
    void setBRX(float ratio);
    void setBRY(float ratio);

    void setSelection(float tl_x, float tl_y, float br_x, float br_y);
    void clearActiveSelection();
    void clearSavedSelections();
    void clearSelections();

    void setHighlightArea(float tl_x, float tl_y, float br_x, float br_y);

    void setHighlightShown(int percentage, QColor hideColor = Qt::white);

    void clearHighlight();

    void zoomIn();
    void zoomOut();
    void zoomSel();
    void zoom2Fit();

    int selListSize();
    /* This function returns the active visible selection in index 0 and after that the "saved" ones */
    bool selectionAt(int index, float &tl_x, float &tl_y, float &br_x, float &br_y);

Q_SIGNALS:
    void newSelection(float tl_x, float tl_y, float br_x, float br_y);

protected:
    void wheelEvent(QWheelEvent *e) override;
    void mousePressEvent(QMouseEvent *e) override;
    void mouseReleaseEvent(QMouseEvent *e) override;
    void mouseMoveEvent(QMouseEvent *e) override;
    void drawBackground(QPainter *painter, const QRectF &rect) override;

private:
    void updateSelVisibility();
    void updateHighlight();
    bool activeSelection(float &tl_x, float &tl_y, float &br_x, float &br_y);
    void refineSelections(int pixelMargin);

    // fromRow is the row to start the iterations from. fromRow can be grater than toRow.
    // rowStart is the x1 coordinate of the row
    // all parameters are corrected to be valid pixel indexes,
    // but start must be < end
    int  refineRow(int fromRow, int toRow, int rowStart, int rowEnd);
    int  refineColumn(int fromCol, int toCol, int colStart, int colEnd);

    QPointF scenePos(QMouseEvent *e) const;

    struct Private;
    Private *const d;

};

}  // NameSpace KSaneIface

#endif