view widgets/Panner.h @ 349:369a197737c7

* Various fixes to object lifetime management, particularly in the spectrum
  layer and for notification of main model deletion.
  The main purpose of this is to improve the behaviour of the spectrum, but I
  think it may also help with #1840922 Various crashes in Layer Summary window.

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 QMUL.
    
    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; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef _PANNER_H_
#define _PANNER_H_

#include <QWidget>

class Panner : public QWidget
{
    Q_OBJECT

public:
    Panner(QWidget *parent = 0);
    virtual ~Panner();

    void setDefaultRectCentre(float, float);

    void setThumbColour(QColor colour);
    void setAlpha(int backgroundAlpha, int thumbAlpha);

    /**
     * Set the amount the scroll() function or mouse wheel movement
     * makes the panner rectangle move by.  The default value of 0
     * means to select a value automatically based on the dimensions
     * of the panner rectangle.
     */
    void setScrollUnit(float unit);

    void getRectExtents(float &x0, float &y0, float &width, float &height);

    virtual QSize sizeHint() const;

signals:
    /**
     * Emitted when the panned rectangle is dragged or otherwise
     * moved.  Arguments are x0, y0, width and height of the rectangle
     * in the range 0 -> 1 as proportions of the width and height of
     * the whole widget.
     */
    void rectExtentsChanged(float, float, float, float);

    /**
     * Emitted when the rectangle is dragged or otherwise moved (as
     * well as extentsChanged).  Arguments are the centre coordinates
     * of the rectangle in the range 0 -> 1 as proportions of the
     * width and height of the whole widget.
     */
    void rectCentreMoved(float, float);

    /**
     * Emitted when the panner is double-clicked (for the "customer"
     * code to pop up a value editing dialog, for example).
     */
    void doubleClicked();

    void mouseEntered();
    void mouseLeft();

public slots:
    /** 
     * Set the extents of the panned rectangle within the overall
     * panner widget.  Coordinates are in the range 0 -> 1 in both axes,
     * with 0 at the top in the y axis.
     */
    void setRectExtents(float x0, float y0, float width, float height);

    /**
     * Set the width of the panned rectangle as a fraction (0 -> 1) of
     * that of the whole panner widget.
     */
    void setRectWidth(float width);

    /**
     * Set the height of the panned rectangle as a fraction (0 -> 1)
     * of that of the whole panner widget.
     */
    void setRectHeight(float height);

    /**
     * Set the location of the centre of the panned rectangle on the x
     * axis, as a proportion (0 -> 1) of the width of the whole panner
     * widget.
     */
    void setRectCentreX(float x);
    
    /**
     * Set the location of the centre of the panned rectangle on the y
     * axis, as a proportion (0 -> 1) of the height of the whole panner
     * widget.
     */
    void setRectCentreY(float y);

    /**
     * Move up (if up is true) or down a bit.  This is basically the
     * same action as rolling the mouse wheel one notch.
     */
    void scroll(bool up);

    void resetToDefault();

protected:
    virtual void mousePressEvent(QMouseEvent *e);
    virtual void mouseDoubleClickEvent(QMouseEvent *e);
    virtual void mouseMoveEvent(QMouseEvent *e);
    virtual void mouseReleaseEvent(QMouseEvent *e);
    virtual void wheelEvent(QWheelEvent *e);
    virtual void paintEvent(QPaintEvent *e);
    virtual void enterEvent(QEvent *);
    virtual void leaveEvent(QEvent *);

    void normalise();
    void emitAndUpdate();

    float m_rectX;
    float m_rectY;
    float m_rectWidth;
    float m_rectHeight;
    float m_scrollUnit;

    float m_defaultCentreX;
    float m_defaultCentreY;
    bool m_defaultsSet;

    QColor m_thumbColour;
    int m_backgroundAlpha;
    int m_thumbAlpha;

    float centreX() const { return m_rectX + m_rectWidth/2; }
    float centreY() const { return m_rectY + m_rectHeight/2; }

    bool m_clicked;
    QPoint m_clickPos;
    float m_dragStartX;
    float m_dragStartY;
};

#endif