Clementine-audio-player-Mac-Linux-Windows/src/widgets/tracksliderpopup.cpp

#include "tracksliderpopup.h"

#include <QCoreApplication>
#include <QMouseEvent>
#include <QPainter>
#include <QTimer>
#include <QtDebug>

const int TrackSliderPopup::kTextMargin = 4;
const int TrackSliderPopup::kPointLength = 16;
const int TrackSliderPopup::kPointWidth = 4;
const int TrackSliderPopup::kBorderRadius = 4;
const qreal TrackSliderPopup::kBlurRadius = 10.0;

void qt_blurImage(QPainter *p, QImage &blurImage, qreal radius, bool quality, bool alphaOnly, int transposed = 0);

TrackSliderPopup::TrackSliderPopup(QWidget* parent)
  : QWidget(parent),
    text_("Test text"),
    font_metrics_(fontMetrics()),
    mouse_over_slider_(false),
    mouse_over_popup_(false),
    visibility_timer_(new QTimer(this))
{
  setWindowFlags(Qt::ToolTip | Qt::FramelessWindowHint |
                 Qt::WindowStaysOnTopHint);
  setAttribute(Qt::WA_NoSystemBackground);
  setAttribute(Qt::WA_TranslucentBackground);
#ifndef Q_OS_DARWIN
  // Paints the whole rect with a white background on Mac.
  setAttribute(Qt::WA_OpaquePaintEvent);
  // Creates flicker on Mac.
  setAttribute(Qt::WA_TransparentForMouseEvents);
#endif
  setMouseTracking(true);

  visibility_timer_->setSingleShot(true);
  visibility_timer_->setInterval(10);
  connect(visibility_timer_, SIGNAL(timeout()), SLOT(UpdateVisibility()));

  font_.setPointSizeF(7.5);
  font_metrics_ = QFontMetrics(font_);

  UpdatePixmap();
}

void TrackSliderPopup::SetText(const QString& text) {
  text_ = text;
  UpdatePixmap();
}

void TrackSliderPopup::SetPopupPosition(const QPoint& pos) {
  pos_ = pos;
  UpdatePosition();
}

void TrackSliderPopup::paintEvent(QPaintEvent*) {
  QPainter p(this);
  p.drawPixmap(0, 0, pixmap_);
}

void TrackSliderPopup::UpdatePixmap() {
  const QRect text_rect(kBlurRadius + kTextMargin, kBlurRadius + kTextMargin,
                        font_metrics_.width(text_) + 2, font_metrics_.height());
  const int bubble_bottom = text_rect.bottom() + kTextMargin;
  const QRect total_rect(0, 0, text_rect.right() + kBlurRadius + kTextMargin,
                         kBlurRadius + bubble_bottom + kPointLength);
  const QRect bubble_rect(kBlurRadius, kBlurRadius,
                          total_rect.width() - kBlurRadius * 2,
                          bubble_bottom - kBlurRadius);

  const QColor highlight(palette().color(QPalette::Active, QPalette::Highlight));
  const QColor bg_color_1(highlight.lighter(110));
  const QColor bg_color_2(highlight.darker(120));

  QPolygon pointy;
  pointy << QPoint(total_rect.width()/2 - kPointWidth, bubble_bottom)
         << QPoint(total_rect.width()/2, total_rect.bottom() - kBlurRadius)
         << QPoint(total_rect.width()/2 + kPointWidth, bubble_bottom);

  QPolygon inner_pointy;
  inner_pointy << QPoint(pointy[0].x() + 1, pointy[0].y() - 1)
               << QPoint(pointy[1].x(), pointy[1].y() - 1)
               << QPoint(pointy[2].x() - 1, pointy[2].y() - 1);

  pixmap_ = QPixmap(total_rect.size());
  pixmap_.fill(Qt::transparent);
  QPainter p(&pixmap_);
  p.setRenderHint(QPainter::Antialiasing);
  p.setRenderHint(QPainter::HighQualityAntialiasing);

  // Draw the shadow to a different image
  QImage blur_source(total_rect.size(), QImage::Format_ARGB32_Premultiplied);
  blur_source.fill(Qt::transparent);

  QPainter blur_painter(&blur_source);
  blur_painter.setRenderHint(QPainter::Antialiasing);
  blur_painter.setRenderHint(QPainter::HighQualityAntialiasing);
  blur_painter.setBrush(bg_color_2);
  blur_painter.setOpacity(0.5);
  blur_painter.drawRoundedRect(bubble_rect.adjusted(1, 1, -1, -1), kBorderRadius, kBorderRadius);
  blur_painter.drawPolygon(inner_pointy);
  blur_painter.end();

  p.save();
  qt_blurImage(&p, blur_source, kBlurRadius, true, false);
  p.restore();

  // Outer bubble
  p.setPen(Qt::NoPen);
  p.setBrush(bg_color_2);
  p.drawRoundedRect(bubble_rect, kBorderRadius, kBorderRadius);

  // Outer pointy
  p.drawPolygon(pointy);

  // Inner bubble
  p.setBrush(bg_color_1);
  p.drawRoundedRect(bubble_rect.adjusted(1, 1, -1, -1),
                    kBorderRadius, kBorderRadius);

  // Inner pointy
  p.drawPolygon(inner_pointy);

  // Text
  p.setPen(palette().color(QPalette::Text));
  p.setFont(font_);
  p.drawText(text_rect, Qt::AlignHCenter, text_);
  p.end();

  resize(pixmap_.size());
  UpdatePosition();
  update();
}

void TrackSliderPopup::UpdatePosition() {
  move(pos_.x() - pixmap_.width() / 2,
       pos_.y() - pixmap_.height() + kBlurRadius);
}

void TrackSliderPopup::enterEvent(QEvent* e) {
  mouse_over_popup_ = true;
  visibility_timer_->start();
}

void TrackSliderPopup::leaveEvent(QEvent* e) {
  mouse_over_popup_ = false;
  visibility_timer_->start();
}

void TrackSliderPopup::SetMouseOverSlider(bool mouse_over_slider) {
  mouse_over_slider_ = mouse_over_slider;
  visibility_timer_->start();
}

void TrackSliderPopup::UpdateVisibility() {
  setVisible(mouse_over_popup_ || mouse_over_slider_);
}

void TrackSliderPopup::SendMouseEventToParent(QMouseEvent* e) {
  QMouseEvent event(
      e->type(), parentWidget()->mapFromGlobal(e->globalPos()),
      e->button(), e->buttons(), e->modifiers());
  QCoreApplication::sendEvent(parentWidget(), &event);
}

void TrackSliderPopup::mousePressEvent(QMouseEvent* e) {
  SendMouseEventToParent(e);
}

void TrackSliderPopup::mouseReleaseEvent(QMouseEvent* e) {
  SendMouseEventToParent(e);
}

void TrackSliderPopup::mouseMoveEvent(QMouseEvent* e) {
  SendMouseEventToParent(e);
}