better wallpaper cropping on load, cache images to disk and fix image aspect ratio from creating black bars

Plugins/ZShell/Internal/CMakeLists.txt

@@ -8,6 +8,7 @@ qml_module(ZShell-internal
 		circularbuffer.hpp circularbuffer.cpp
 		sparklineitem.hpp sparklineitem.cpp
 		arcgauge.hpp arcgauge.cpp
+		wallpaperimage.hpp wallpaperimage.cpp
     LIBRARIES
         Qt::Gui
         Qt::Quick

Plugins/ZShell/Internal/arcgauge.cpp

@@ -4,7 +4,7 @@
 #include <qpainter.h>
 #include <qpen.h>
 
-namespace caelestia::internal {
+namespace ZShell::internal {
 
 ArcGauge::ArcGauge(QQuickItem* parent)
 	: QQuickPaintedItem(parent) {
@@ -116,4 +116,4 @@ void ArcGauge::setLineWidth(qreal width) {
 	update();
 }
 
-} // namespace caelestia::internal
+} // namespace ZShell::internal

Plugins/ZShell/Internal/arcgauge.hpp

@@ -5,7 +5,7 @@
 #include <qqmlintegration.h>
 #include <qquickpainteditem.h>
 
-namespace caelestia::internal {
+namespace ZShell::internal {
 
 class ArcGauge : public QQuickPaintedItem {
 Q_OBJECT
@@ -58,4 +58,4 @@ qreal m_sweepAngle = 1.5 * M_PI;
 qreal m_lineWidth = 10.0;
 };
 
-} // namespace caelestia::internal
+} // namespace ZShell::internal

Plugins/ZShell/Internal/wallpaperimage.cpp

@@ -0,0 +1,199 @@
+#include "wallpaperimage.hpp"
+
+#include <QStandardPaths>
+#include <QCryptographicHash>
+#include <QDir>
+#include <QFileInfo>
+#include <QtConcurrent>
+#include <QSGImageNode>
+#include <QQuickWindow>
+
+namespace ZShell::internal {
+
+WallpaperImage::WallpaperImage(QQuickItem *parent)
+	: QQuickItem(parent)
+{
+	setFlag(ItemHasContents, true);
+	connect(&m_imageWatcher, &QFutureWatcher<QImage>::finished, this, &WallpaperImage::handleImageLoaded);
+}
+
+WallpaperImage::~WallpaperImage() {
+	if (m_texture) delete m_texture;
+}
+
+void WallpaperImage::setSource(const QUrl &source) {
+	if (m_source == source) return;
+	m_source = source;
+	emit sourceChanged();
+	loadImage();
+}
+
+void WallpaperImage::setScreenResolution(const QSize &screenResolution) {
+	if (m_screenResolution == screenResolution) return;
+	m_screenResolution = screenResolution;
+	emit screenResolutionChanged();
+	loadImage();
+}
+
+void WallpaperImage::setZoom(qreal zoom) {
+	if (qFuzzyCompare(m_zoom, zoom)) return;
+	m_zoom = zoom;
+	emit zoomChanged();
+	update();
+}
+
+void WallpaperImage::setCropX(qreal x) {
+	if (qFuzzyCompare(m_cropX, x)) return;
+	m_cropX = x;
+	emit cropXChanged();
+	update();
+}
+
+void WallpaperImage::setCropY(qreal y) {
+	if (qFuzzyCompare(m_cropY, y)) return;
+	m_cropY = y;
+	emit cropYChanged();
+	update();
+}
+
+void WallpaperImage::setCropWidth(qreal w) {
+    if (w <= 0.0) w = 1.0;
+    if (qFuzzyCompare(m_cropWidth, w)) return;
+    m_cropWidth = w;
+    emit cropWidthChanged();
+    update();
+}
+
+void WallpaperImage::setCropHeight(qreal h) {
+    if (h <= 0.0) h = 1.0;
+    if (qFuzzyCompare(m_cropHeight, h)) return;
+    m_cropHeight = h;
+    emit cropHeightChanged();
+    update();
+}
+
+QString WallpaperImage::getCacheFilePath() const {
+	if (m_source.isEmpty() || m_screenResolution.isEmpty()) return QString();
+
+    QString cachePath = QStandardPaths::writableLocation(QStandardPaths::GenericCacheLocation) + "/zshell/imagecache";
+	QDir().mkpath(cachePath);
+
+	// Hash the source URL + resolution
+	QString id = m_source.toString() + "_" + QString::number(m_screenResolution.width()) + "x" + QString::number(m_screenResolution.height());
+	QByteArray hash = QCryptographicHash::hash(id.toUtf8(), QCryptographicHash::Md5).toHex();
+
+	return cachePath + "/" + hash + ".png";
+}
+
+void WallpaperImage::loadImage() {
+    if (m_source.isEmpty()) return;
+
+    QString cacheFile = getCacheFilePath();
+    QString sourceFile = m_source.isLocalFile() ? m_source.toLocalFile() : m_source.toString();
+    
+    // Qt resource path correction if passed as a standard URL string
+    if (sourceFile.startsWith("qrc:/")) {
+        sourceFile = sourceFile.mid(3); // Converts "qrc:/" to ":/"
+    }
+    
+    QSize targetRes = m_screenResolution;
+
+    // Run off the main thread to avoid blocking the UI
+    QFuture<QImage> future = QtConcurrent::run([sourceFile, cacheFile, targetRes]() -> QImage {
+        if (!targetRes.isEmpty() && !cacheFile.isEmpty() && QFileInfo::exists(cacheFile)) {
+            QImage cached(cacheFile);
+            if (!cached.isNull()) return cached;
+        }
+
+        QImage original(sourceFile);
+        if (original.isNull()) return QImage();
+
+        if (targetRes.isEmpty()) {
+            // Screen resolution not set yet by QML, return the unscaled original for now to prevent a black screen
+            return original;
+        }
+
+        // Check if original is strictly larger than screen resolution
+        if (original.width() > targetRes.width() || original.height() > targetRes.height()) {
+            QImage scaled = original.scaled(targetRes, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation);
+            if (!cacheFile.isEmpty()) scaled.save(cacheFile, "PNG");
+            return scaled;
+        }
+
+        // Otherwise just cache and return the original
+        if (!cacheFile.isEmpty()) original.save(cacheFile, "PNG");
+        return original;
+    });
+
+    m_imageWatcher.setFuture(future);
+}
+
+void WallpaperImage::handleImageLoaded() {
+	m_image = m_imageWatcher.result();
+	m_textureDirty = true;
+	update(); // Request redraw
+}
+
+QSGNode *WallpaperImage::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *) {
+	auto *node = static_cast<QSGImageNode *>(oldNode);
+
+	if (m_image.isNull()) {
+		delete node;
+		return nullptr;
+	}
+
+	if (!node) {
+		node = window()->createImageNode();
+	}
+
+	if (m_textureDirty) {
+		if (m_texture) delete m_texture;
+        m_texture = window()->createTextureFromImage(m_image, QQuickWindow::TextureHasAlphaChannel);
+		m_textureDirty = false;
+	}
+
+	if (m_texture) {
+		node->setTexture(m_texture);
+		node->setRect(boundingRect());
+		node->setFiltering(QSGTexture::Linear);
+
+        qreal cW = m_cropWidth / m_zoom;
+        qreal cH = m_cropHeight / m_zoom;
+
+        QRectF reqRect(
+            m_cropX * m_texture->textureSize().width(),
+            m_cropY * m_texture->textureSize().height(),
+            cW * m_texture->textureSize().width(),
+            cH * m_texture->textureSize().height()
+        );
+
+        QRectF bounds = boundingRect();
+        if (bounds.isEmpty() || reqRect.isEmpty()) return node;
+
+        qreal targetRatio = bounds.width() / bounds.height();
+        qreal reqRatio = reqRect.width() / reqRect.height();
+
+        QRectF sourceRect = reqRect;
+
+        // Force 'PreserveAspectCrop' behavior on the requested region
+        if (reqRatio > targetRatio) {
+            // Requested region is too wide, center-crop the sides
+            qreal newWidth = reqRect.height() * targetRatio;
+            qreal xOffset = (reqRect.width() - newWidth) / 2.0;
+            sourceRect.setX(reqRect.x() + xOffset);
+            sourceRect.setWidth(newWidth);
+        } else if (reqRatio < targetRatio) {
+            // Requested region is too tall, center-crop the top/bottom
+            qreal newHeight = reqRect.width() / targetRatio;
+            qreal yOffset = (reqRect.height() - newHeight) / 2.0;
+            sourceRect.setY(reqRect.y() + yOffset);
+            sourceRect.setHeight(newHeight);
+        }
+
+        node->setSourceRect(sourceRect);
+	}
+
+	return node;
+}
+
+} // namespace ZShell::internal

Plugins/ZShell/Internal/wallpaperimage.hpp

@@ -0,0 +1,95 @@
+#pragma once
+
+#include <QQuickItem>
+#include <QImage>
+#include <QUrl>
+#include <QSGTexture>
+#include <QFutureWatcher>
+#include <QtQml/qqml.h>
+
+namespace ZShell::internal {
+
+class WallpaperImage : public QQuickItem {
+Q_OBJECT
+QML_NAMED_ELEMENT(WallpaperImage)
+Q_PROPERTY(QUrl source READ source WRITE setSource NOTIFY sourceChanged)
+Q_PROPERTY(QSize screenResolution READ screenResolution WRITE setScreenResolution NOTIFY screenResolutionChanged)
+Q_PROPERTY(qreal zoom READ zoom WRITE setZoom NOTIFY zoomChanged)
+
+Q_PROPERTY(qreal cropX READ cropX WRITE setCropX NOTIFY cropXChanged)
+Q_PROPERTY(qreal cropY READ cropY WRITE setCropY NOTIFY cropYChanged)
+Q_PROPERTY(qreal cropWidth READ cropWidth WRITE setCropWidth NOTIFY cropWidthChanged)
+Q_PROPERTY(qreal cropHeight READ cropHeight WRITE setCropHeight NOTIFY cropHeightChanged)
+
+public:
+explicit WallpaperImage(QQuickItem *parent = nullptr);
+~WallpaperImage() override;
+
+QUrl source() const {
+	return m_source;
+}
+void setSource(const QUrl &source);
+
+QSize screenResolution() const {
+	return m_screenResolution;
+}
+void setScreenResolution(const QSize &screenResolution);
+
+qreal zoom() const {
+	return m_zoom;
+}
+void setZoom(qreal zoom);
+
+qreal cropX() const {
+	return m_cropX;
+}
+void setCropX(qreal x);
+
+qreal cropY() const {
+	return m_cropY;
+}
+void setCropY(qreal y);
+
+qreal cropWidth() const {
+	return m_cropWidth;
+}
+void setCropWidth(qreal w);
+
+qreal cropHeight() const {
+	return m_cropHeight;
+}
+void setCropHeight(qreal h);
+
+protected:
+QSGNode *updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *updatePaintNodeData) override;
+
+signals:
+void sourceChanged();
+void screenResolutionChanged();
+void zoomChanged();
+void cropXChanged();
+void cropYChanged();
+void cropWidthChanged();
+void cropHeightChanged();
+
+private:
+void loadImage();
+void handleImageLoaded();
+QString getCacheFilePath() const;
+
+QUrl m_source;
+QSize m_screenResolution;
+qreal m_zoom = 1.0;
+
+qreal m_cropX = 0.0;
+qreal m_cropY = 0.0;
+qreal m_cropWidth = 1.0;
+qreal m_cropHeight = 1.0;
+
+QImage m_image;
+QSGTexture *m_texture = nullptr;
+bool m_textureDirty = false;
+QFutureWatcher<QImage> m_imageWatcher;
+};
+
+} // namespace ZShell::internal