QProgressIndicator.h

/*
 
    This file is part of QProgressIndicator,
    an open-source recent files menu widget
 
    SPDX-FileCopyrightText: 2009-2010 Morgan Leborgne
    SPDX-License-Identifier: LGPL-3.0-or-later
*/
 
#pragma once
 
#include <QWidget>
#include <QColor>
 
/**
 * @class QProgressIndicator
 * @brief The QProgressIndicator class lets an application display a progress indicator to show that a long task is
 * under way.
 * Progress indicators are indeterminate and do nothing more than spin to show that the application is busy.
 *
 * @sa QProgressBar
 */
class QProgressIndicator : public QWidget
{
    Q_OBJECT
    Q_PROPERTY(int delay READ animationDelay WRITE setAnimationDelay)
    Q_PROPERTY(bool displayedWhenStopped READ isDisplayedWhenStopped WRITE setDisplayedWhenStopped)
    Q_PROPERTY(QColor color READ color WRITE setColor)
  public:
    explicit QProgressIndicator(QWidget *parent = nullptr);
 
    /**
     * Returns the delay between animation steps.
     * @return The number of milliseconds between animation steps. By default, the animation delay is set to
     * 40 milliseconds.
     *
     * @sa setAnimationDelay
     */
    int animationDelay() const { return m_delay; }
 
    /**
     * Returns a Boolean value indicating whether the component is currently animated.
     * @return Animation state.
     * @sa startAnimation stopAnimation
     */
    bool isAnimated() const;
 
    /**
     * Returns a Boolean value indicating whether the receiver shows itself even when it is not animating.
     * @return Return true if the progress indicator shows itself even when it is not animating. By default,
     * it returns false.
     * @sa setDisplayedWhenStopped
     */
    bool isDisplayedWhenStopped() const;
 
    /**
     * Returns the color of the component.
     * @sa setColor
     */
    const QColor &color() const { return m_color; }
 
    QSize sizeHint() const override;
    int heightForWidth(int w) const override;
  public slots:
    /**
     * Starts the spin animation.
     * @sa stopAnimation isAnimated
     */
    void startAnimation();
 
    /**
     * Stops the spin animation.
     * @sa startAnimation isAnimated
     */
    void stopAnimation();
 
    /**
     * Sets the delay between animation steps.
     * Setting the \a delay to a value larger than 40 slows the animation, while setting the @a delay to a
     * smaller value speeds it up.
     * @param delay The delay, in milliseconds.
     * @sa animationDelay
     */
    void setAnimationDelay(int delay);
 
    /**
     * Sets whether the component hides itself when it is not animating.
     * @param state The animation state. Set false to hide the progress indicator when it is not animating; otherwise true.
     * @sa isDisplayedWhenStopped
     */
    void setDisplayedWhenStopped(bool state);
 
    /**
     * Sets the color of the components to the given color.
     * @sa color
     */
    void setColor(const QColor &color);
 
  protected:
    void timerEvent(QTimerEvent *event) override;
    void paintEvent(QPaintEvent *event) override;
 
  private:
    int m_angle { 0 };
    int m_timerId { -1 };
    int m_delay { 40 };
    bool m_displayedWhenStopped { false };
    QColor m_color { Qt::black };
};