yacreader/custom_widgets/yacreader_busy_widget.cpp

#include "yacreader_busy_widget.h"

#include <QDebug>
#include <QPainter>
#include <QPixmapCache>
#include <QGradient>

YACReaderBusyWidget::YACReaderBusyWidget(QWidget *parent)
    : QWidget(parent)
{
    setFixedSize(70, 70);
    BusyIndicator *busy = new BusyIndicator(this);
    busy->setIndicatorStyle(BusyIndicator::StyleArc);
    busy->setColor(Qt::white);
    busy->move(20, 20);
}

BusyIndicator::BusyIndicator(QWidget *parent, int size)
    : QWidget(parent),
      startAngle(0),
      m_style(StyleArc),
      size(size)
{
    QSizePolicy policy(QSizePolicy::Preferred, QSizePolicy::Fixed);
    policy.setHeightForWidth(true);
    setSizePolicy(policy);

    fillColor = palette().color(QPalette::WindowText);

    timer.setInterval(16);
    connect(&timer, &QTimer::timeout, this, &BusyIndicator::rotate);
    timer.start();
}

void BusyIndicator::rotate()
{
    startAngle += 9;
    startAngle %= 360;
    update();
}

void BusyIndicator::setIndicatorStyle(IndicatorStyle style)
{
    m_style = style;
    update();
}

void BusyIndicator::setColor(QColor color)
{
    fillColor = color;
}

BusyIndicator::IndicatorStyle BusyIndicator::indicatorStyle() const
{
    return m_style;
}

void BusyIndicator::mouseReleaseEvent(QMouseEvent *event)
{
    Q_UNUSED(event);
    emit clicked();
}

QPixmap BusyIndicator::generatePixmap(int side)
{
    QPixmap pixmap(QSize(side, side));
    pixmap.fill(QColor(255, 255, 255, 0));

    QPainter painter(&pixmap);
    painter.setRenderHint(QPainter::Antialiasing);

    painter.translate(side / 2, side / 2);
    painter.scale(side / 200.0, side / 200.0);

    switch (m_style) {
    case StyleRect:
        drawRectStyle(&painter);
        break;
    case StyleEllipse:
        drawEllipseStyle(&painter);
        break;
    case StyleArc:
        drawArcStyle(&painter);
        break;
    }
    return pixmap;
}

void BusyIndicator::drawRectStyle(QPainter *painter)
{
    //    QColor color = palette().color(QPalette::WindowText);
    QColor color = fillColor;
    QBrush brush(color);
    painter->setPen(Qt::NoPen);

    painter->rotate(startAngle);

    float angle = 0;
    while (angle < 360) {
        painter->setBrush(brush);
        painter->drawRect(-8, -100, 16, 35);

        painter->rotate(30);
        angle += 30;

        color.setAlphaF(angle / 360);
        brush.setColor(color);
    }
}

void BusyIndicator::drawEllipseStyle(QPainter *painter)
{
    //    QColor color = palette().color(QPalette::WindowText);
    QColor color = fillColor;
    QBrush brush(color);
    painter->setPen(Qt::NoPen);

    painter->rotate(startAngle);

    float angle = 0;
    while (angle < 360) {
        painter->setBrush(brush);
        painter->drawEllipse(-10, -100, 30, 30);

        painter->rotate(30);
        angle += 30;

        color.setAlphaF(angle / 360);
        brush.setColor(color);
    }
}

void BusyIndicator::drawArcStyle(QPainter *painter)
{
    //    QColor color = palette().color(QPalette::WindowText);
    QColor color = fillColor;
    QConicalGradient gradient(0, 0, -startAngle);
    gradient.setColorAt(0, color);
    color.setAlpha(0);
    gradient.setColorAt(0.8, color);
    color.setAlpha(255);
    gradient.setColorAt(1, color);

    QPen pen;
    pen.setWidth(30);
    pen.setBrush(QBrush(gradient));
    painter->setPen(pen);

    painter->drawArc(-85, -85, 170, 170, 0 * 16, 360 * 16);
}

void BusyIndicator::paintEvent(QPaintEvent *)
{
    QString key = QString("%1:%2:%3:%4:%5")
                          .arg(metaObject()->className())
                          .arg(width())
                          .arg(height())
                          .arg(startAngle)
                          .arg(m_style);

    QPixmap pixmap;
    pixmap.setDevicePixelRatio(devicePixelRatioF());
    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing);

    int side = qMin(width(), height());

    if (!QPixmapCache::find(key, &pixmap)) {
        pixmap = generatePixmap(side * devicePixelRatioF());
        QPixmapCache::insert(key, pixmap);
    }

    painter.translate(width() / 2 - side / 2, height() / 2 - side / 2);

    painter.drawPixmap(0, 0, side, side, pixmap);
}

QSize BusyIndicator::minimumSizeHint() const
{
    return QSize(size, size);
}

QSize BusyIndicator::sizeHint() const
{
    return QSize(size, size);
}