move carouselview to standalone c++ component, fix crash due to memory leak in wallpaper object creation

Plugins/ZShell/Internal/wallpaperimage.hpp

@@ -4,9 +4,15 @@
 #include <QImage>
 #include <QUrl>
 #include <QSGTexture>
+#include <QSGOpacityNode>
+#include <QSGImageNode>
 #include <QFutureWatcher>
+#include <QElapsedTimer>
+#include <QThreadPool>
+#include <QTimer>
 #include <QtQml/qqml.h>
 #include <qtmetamacros.h>
+#include <atomic>
 
 namespace ZShell::internal {
 
@@ -19,6 +25,9 @@ class WallpaperImage : public QQuickItem {
 			NOTIFY screenResolutionChanged)
 	Q_PROPERTY(qreal zoom READ zoom WRITE setZoom NOTIFY zoomChanged)
 	Q_PROPERTY(Status status READ status NOTIFY statusChanged)
+	Q_PROPERTY(
+		int fadeDuration READ fadeDuration WRITE setFadeDuration NOTIFY
+			fadeDurationChanged)
 
 	Q_PROPERTY(qreal actualCropX READ actualCropX NOTIFY actualCropChanged)
 	Q_PROPERTY(qreal actualCropY READ actualCropY NOTIFY actualCropChanged)
@@ -54,12 +63,12 @@ class WallpaperImage : public QQuickItem {
 	qreal zoom() const { return m_zoom; }
 	void setZoom(qreal zoom);
 
+	int fadeDuration() const { return m_fadeDuration; }
+	void setFadeDuration(int ms);
+
 	qreal actualCropX() const { return m_actualCropX; }
-
 	qreal actualCropY() const { return m_actualCropY; }
-
 	qreal actualCropWidth() const { return m_actualCropWidth; }
-
 	qreal actualCropHeight() const { return m_actualCropHeight; }
 
 	qreal cropX() const { return m_cropX; }
@@ -82,6 +91,7 @@ class WallpaperImage : public QQuickItem {
 	void sourceChanged();
 	void screenResolutionChanged();
 	void zoomChanged();
+	void fadeDurationChanged();
 	void actualCropChanged();
 	void cropXChanged();
 	void cropYChanged();
@@ -90,15 +100,18 @@ class WallpaperImage : public QQuickItem {
 	void statusChanged();
 
 	private:
-	void loadImage();
+	void beginLoad();
 	void handleImageLoaded();
 	QString getCacheFilePath() const;
 	void setStatus(const Status s);
+	QRectF computeSourceRect(QSGTexture* texture) const;
+	void configureImageNode(QSGImageNode* node, QSGTexture* texture);
 
 	Status m_status = Null;
 	QUrl m_source;
 	QSize m_screenResolution;
 	qreal m_zoom = 1.0;
+	int m_fadeDuration = 400;
 
 	qreal m_actualCropX = 0.0;
 	qreal m_actualCropY = 0.0;
@@ -110,10 +123,25 @@ class WallpaperImage : public QQuickItem {
 	qreal m_cropWidth = 1.0;
 	qreal m_cropHeight = 1.0;
 
-	QImage m_image;
-	QSGTexture* m_texture = nullptr;
-	bool m_textureDirty = false;
+	QTimer m_loadDebounceTimer;
 	QFutureWatcher<QImage> m_imageWatcher;
+	std::shared_ptr<std::atomic<quint64>> m_requestGeneration =
+		std::make_shared<std::atomic<quint64>>(0);
+	static QThreadPool* loadPool();
+	QImage m_pendingImage;
+	bool m_hasPending = false;
+
+	QSGTexture* m_texture = nullptr;
+	QSGTexture* m_previousTexture = nullptr;
+
+	bool m_fading = false;
+	QElapsedTimer m_fadeTimer;
+
+	QSGNode* m_rootNode = nullptr;
+	QSGOpacityNode* m_newOpacityNode = nullptr;
+	QSGOpacityNode* m_oldOpacityNode = nullptr;
+	QSGImageNode* m_newImageNode = nullptr;
+	QSGImageNode* m_oldImageNode = nullptr;
 };
 
 } // namespace ZShell::internal