Move code that handles spinning album art to own class

src/components/spinningAlbumArt/spinningalbumart.cpp

@@ -0,0 +1,82 @@
+#include "spinningalbumart.h"
+#include <QPainter>
+#include <QPainterPath>
+
+SpinningAlbumArt::SpinningAlbumArt(const QString& imagePath, int size, QWidget* parent)
+    : QWidget(parent), size_(size)
+{
+    artLabel_ = new QLabel(this);
+    artLabel_->setAlignment(Qt::AlignCenter);
+
+    setFixedSize(size, size);
+
+    // Load and crop square
+    QPixmap pix(imagePath);
+    QPixmap scaled = pix.scaled(size, size,
+                                Qt::KeepAspectRatioByExpanding,
+                                Qt::SmoothTransformation);
+
+    int side = qMin(scaled.width(), scaled.height());
+    QPixmap square = scaled.copy(
+        (scaled.width() - side) / 2,
+        (scaled.height() - side) / 2,
+        side,
+        side
+        );
+
+    // Mask into circle
+    discArt_ = createCircularDisc(square, size);
+    artLabel_->setPixmap(discArt_);
+
+    // Setup spin timer
+    timer_ = new QTimer(this);
+    timer_->setInterval(16);
+    connect(timer_, &QTimer::timeout, this, &SpinningAlbumArt::updateRotation);
+}
+
+QPixmap SpinningAlbumArt::createCircularDisc(const QPixmap& src, int size)
+{
+    QPixmap disc(size, size);
+    disc.fill(Qt::transparent);
+
+    QPainter p(&disc);
+    p.setRenderHint(QPainter::Antialiasing);
+
+    QPainterPath path;
+    path.addEllipse(0, 0, size, size);
+    p.setClipPath(path);
+
+    p.drawPixmap(0, 0, src);
+
+    return disc;
+}
+
+void SpinningAlbumArt::start()
+{
+    timer_->start();
+}
+
+void SpinningAlbumArt::stop()
+{
+    timer_->stop();
+}
+
+void SpinningAlbumArt::updateRotation()
+{
+    rotationAngle_ += 0.6;
+
+    QPixmap frame(size_, size_);
+    frame.fill(Qt::transparent);
+
+    QPainter p(&frame);
+    p.setRenderHint(QPainter::Antialiasing);
+    p.setRenderHint(QPainter::SmoothPixmapTransform);
+
+    p.translate(size_ / 2, size_ / 2);
+    p.rotate(rotationAngle_);
+    p.translate(-size_ / 2, -size_ / 2);
+
+    p.drawPixmap(0, 0, discArt_);
+
+    artLabel_->setPixmap(frame);
+}

src/components/spinningAlbumArt/spinningalbumart.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <QWidget>
+#include <QLabel>
+#include <QPixmap>
+#include <QTimer>
+
+class SpinningAlbumArt : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit SpinningAlbumArt(const QString& imagePath, int size = 250, QWidget* parent = nullptr);
+
+public slots:
+    void start();
+    void stop();
+
+private slots:
+    void updateRotation();
+
+private:
+    QPixmap discArt_;        // circular-masked album image
+    QLabel* artLabel_;       // widget that displays the spinning frame
+    QTimer* timer_;          // animation timer
+    qreal rotationAngle_ = 0;
+    int size_;               // final diameter of the disc
+
+    QPixmap createCircularDisc(const QPixmap& src, int size);
+};