qprogressindicator.cpp

#include "qprogressindicator.h"
#include <QPainter>

QProgressIndicator::QProgressIndicator(QWidget *parent)
    : QWidget(parent), m_angle(0), m_timerId(-1), m_delay(40),
      m_displayedWhenStopped(false), m_color(Qt::black) {
  setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
  setFocusPolicy(Qt::NoFocus);
}

bool QProgressIndicator::isAnimated() const { return m_timerId != -1; }

void QProgressIndicator::setDisplayedWhenStopped(bool state) {
  m_displayedWhenStopped = state;

  update();
}

bool QProgressIndicator::isDisplayedWhenStopped() const {
  return m_displayedWhenStopped;
}

void QProgressIndicator::startAnimation() {
  m_angle = 0;

  if (m_timerId == -1)
    m_timerId = startTimer(m_delay);
}

void QProgressIndicator::stopAnimation() {
  if (m_timerId != -1)
    killTimer(m_timerId);

  m_timerId = -1;

  update();
}

void QProgressIndicator::setAnimationDelay(int delay) {
  if (m_timerId != -1)
    killTimer(m_timerId);

  m_delay = delay;

  if (m_timerId != -1)
    m_timerId = startTimer(m_delay);
}

void QProgressIndicator::setColor(const QColor &color) {
  m_color = color;

  update();
}

QSize QProgressIndicator::sizeHint() const { return QSize(20, 20); }

int QProgressIndicator::heightForWidth(int w) const { return w; }

void QProgressIndicator::timerEvent(QTimerEvent * /*event*/) {
  m_angle = (m_angle + 30) % 360;

  update();
}

void QProgressIndicator::paintEvent(QPaintEvent * /*event*/) {
  if (!m_displayedWhenStopped && !isAnimated())
    return;

  int width = qMin(this->width(), this->height());

  QPainter p(this);
  p.setRenderHint(QPainter::Antialiasing);

  int outerRadius = (width - 1) * 0.5;
  int innerRadius = (width - 1) * 0.5 * 0.38;

  int capsuleHeight = outerRadius - innerRadius;
  int capsuleWidth = (width > 32) ? capsuleHeight * .23 : capsuleHeight * .35;
  int capsuleRadius = capsuleWidth / 2;

  for (int i = 0; i < 12; ++i) {
    QColor color = m_color;
    color.setAlphaF(1.0f - (i / 12.0f));
    p.setPen(Qt::NoPen);
    p.setBrush(color);
    p.save();
    p.translate(rect().center());
    p.rotate(m_angle - i * 30.0f);
    p.drawRoundedRect(-capsuleWidth * 0.5, -(innerRadius + capsuleHeight),
                      capsuleWidth, capsuleHeight, capsuleRadius,
                      capsuleRadius);
    p.restore();
  }
}