improve image caching for better performance

Modules/Launcher/CarouselView.qml

@@ -233,7 +233,19 @@ Item {
 	}
 
 	implicitHeight: tileHeight + Tokens.spacing.small / 2 + Tokens.padding.large + Tokens.padding.normal
-	implicitWidth: screen ? Math.max(0, screen.width - Config.bar.rounding * 50 - panels.bar.implicitWidth * 2) : 0
+	implicitWidth: {
+		if (!screen)
+			return 0;
+
+		const barMargins = Config.bar.border * 2;
+		let margins = 0;
+		if (visibilities.utilities || visibilities.sidebar)
+			margins = panels.utilities.implicitWidth;
+		const maxWidth = screen.width - (barMargins + margins) * 2 - Config.bar.rounding * 4;
+
+		return maxWidth;
+	}
+	width: implicitWidth
 
 	Component.onCompleted: {
 		const idx = Wallpapers.list.findIndex(w => w.path === Wallpapers.actualCurrent);
@@ -248,7 +260,7 @@ Item {
 
 		anchors.fill: parent
 		boundsBehavior: Flickable.StopAtBounds
-		cacheBuffer: root.width * 10
+		cacheBuffer: root.width
 		clip: false
 		currentIndex: root.centerBlockStart
 		displayMarginBeginning: root.arrangement.effectiveExtraWidth

Modules/Launcher/Items/WallpaperTile.qml

@@ -55,6 +55,8 @@ Item {
 			height: root.tileHeight
 			path: root.modelData ? root.modelData.path : ""
 			smooth: root.isCurrent
+			sourceSize.height: root.tileHeight
+			sourceSize.width: root.tileHeight * (16 / 9)
 			width: root.tileHeight * (16 / 9)
 		}
 

Plugins/ZShell/Internal/cachingimagemanager.cpp

@@ -1,5 +1,7 @@
 #include "cachingimagemanager.hpp"
 
+#include <algorithm>
+
 #include <QtQuick/qquickwindow.h>
 #include <qcryptographichash.h>
 #include <qdir.h>
@@ -7,10 +9,27 @@
 #include <qfuturewatcher.h>
 #include <qimagereader.h>
 #include <qpainter.h>
+#include <qthread.h>
+#include <qthreadpool.h>
 #include <qtconcurrentrun.h>
 
 namespace ZShell::internal {
 
+namespace {
+
+QThreadPool* imageIoPool() {
+	static QThreadPool pool;
+	static const bool init = [] {
+		pool.setMaxThreadCount(std::max(2, QThread::idealThreadCount() / 2));
+		return true;
+	}();
+	(void)init;
+
+	return &pool;
+}
+
+} // namespace
+
 qreal CachingImageManager::effectiveScale() const {
 	if (m_item && m_item->window()) {
 		return m_item->window()->devicePixelRatio();
@@ -101,14 +120,13 @@ void CachingImageManager::updateSource() {
 
 void CachingImageManager::updateSource(const QString& path) {
 	if (path.isEmpty() || path == m_shaPath) {
-		// Path is empty or already calculating sha for path
 		return;
 	}
 
 	m_shaPath = path;
 
 	const auto future =
-		QtConcurrent::run(&CachingImageManager::sha256sum, path);
+		QtConcurrent::run(imageIoPool(), &CachingImageManager::sha256sum, path);
 
 	const auto watcher = new QFutureWatcher<QString>(this);
 
@@ -118,7 +136,16 @@ void CachingImageManager::updateSource(const QString& path) {
 		this,
 		[watcher, path, this]() {
 			if (m_path != path) {
-				// Object is destroyed or path has changed, ignore
+				watcher->deleteLater();
+				return;
+			}
+
+			const QString key = watcher->result();
+
+			if (key.isEmpty()) {
+				if (m_shaPath == path) {
+					m_shaPath = QString();
+				}
 				watcher->deleteLater();
 				return;
 			}
@@ -126,19 +153,29 @@ void CachingImageManager::updateSource(const QString& path) {
 			const QSize size = effectiveSize();
 
 			if (!m_item || !size.width() || !size.height()) {
+				if (m_shaPath == path) {
+					m_shaPath = QString();
+				}
 				watcher->deleteLater();
 				return;
 			}
 
 			const QString fillMode = m_item->property("fillMode").toString();
-			// clang-format off
-        const QString filename = QString("%1@%2x%3-%4.png")
-            .arg(watcher->result()).arg(size.width()).arg(size.height())
-            .arg(fillMode == "PreserveAspectCrop" ? "crop" : fillMode == "PreserveAspectFit" ? "fit" : "stretch");
-			// clang-format on
+			const QString filename =
+				QString("%1@%2x%3-%4.png")
+					.arg(key)
+					.arg(size.width())
+					.arg(size.height())
+					.arg(
+						fillMode == "PreserveAspectCrop"  ? "crop"
+						: fillMode == "PreserveAspectFit" ? "fit"
+														  : "stretch");
 
 			const QUrl cache = m_cacheDir.resolved(QUrl(filename));
 			if (m_cachePath == cache) {
+				if (m_shaPath == path) {
+					m_shaPath = QString();
+				}
 				watcher->deleteLater();
 				return;
 			}
@@ -149,6 +186,9 @@ void CachingImageManager::updateSource(const QString& path) {
 			if (!cache.isLocalFile()) {
 				qWarning() << "CachingImageManager::updateSource: cachePath"
 						   << cache << "is not a local file";
+				if (m_shaPath == path) {
+					m_shaPath = QString();
+				}
 				watcher->deleteLater();
 				return;
 			}
@@ -161,7 +201,6 @@ void CachingImageManager::updateSource(const QString& path) {
 				createCache(path, cache.toLocalFile(), fillMode, size);
 			}
 
-			// Clear current running sha if same
 			if (m_shaPath == path) {
 				m_shaPath = QString();
 			}
@@ -170,7 +209,6 @@ void CachingImageManager::updateSource(const QString& path) {
 		});
 
 	watcher->setFuture(future);
-	// NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks)
 }
 
 QUrl CachingImageManager::cachePath() const {
@@ -182,61 +220,105 @@ void CachingImageManager::createCache(
 	const QString& cache,
 	const QString& fillMode,
 	const QSize& size) const {
-	QThreadPool::globalInstance()->start([path, cache, fillMode, size] {
-		QImage image(path);
+	auto* watcher =
+		new QFutureWatcher<bool>(const_cast<CachingImageManager*>(this));
 
-		if (image.isNull()) {
-			qWarning() << "CachingImageManager::createCache: failed to read"
-					   << path;
-			return;
-		}
+	connect(
+		watcher,
+		&QFutureWatcher<bool>::finished,
+		this,
+		[this, watcher, cache, path]() {
+			if (watcher->result() && m_item && m_path == path &&
+				m_cachePath.toLocalFile() == cache) {
+				m_item->setProperty("source", QUrl::fromLocalFile(cache));
+			}
 
-		image.convertTo(QImage::Format_ARGB32);
+			watcher->deleteLater();
+		});
 
-		if (fillMode == "PreserveAspectCrop") {
-			image = image.scaled(
-				size, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation);
-		} else if (fillMode == "PreserveAspectFit") {
-			image = image.scaled(
-				size, Qt::KeepAspectRatio, Qt::SmoothTransformation);
-		} else {
-			image = image.scaled(
-				size, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
-		}
+	const auto future =
+		QtConcurrent::run(
+			imageIoPool(), [path, cache, fillMode, size]() -> bool {
+				QImageReader reader(path);
 
-		if (fillMode == "PreserveAspectCrop" ||
-			fillMode == "PreserveAspectFit") {
-			QImage canvas(size, QImage::Format_ARGB32);
-			canvas.fill(Qt::transparent);
+				if (reader.supportsOption(QImageIOHandler::ScaledSize)) {
+					const QSize full = reader.size();
+					if (full.isValid() && !full.isEmpty()) {
+						const QSize hint = size * 2;
+						QSize scaled = full;
+						scaled.scale(hint, Qt::KeepAspectRatioByExpanding);
+						scaled = QSize(
+							std::min(scaled.width(), full.width()),
+							std::min(scaled.height(), full.height()));
+						reader.setScaledSize(scaled);
+					}
+				}
 
-			QPainter painter(&canvas);
-			painter.drawImage(
-				(size.width() - image.width()) / 2,
-				(size.height() - image.height()) / 2,
-				image);
-			painter.end();
+				QImage image = reader.read();
 
-			image = canvas;
-		}
+				if (image.isNull()) {
+					qWarning()
+						<< "CachingImageManager::createCache: failed to read"
+						<< path << reader.errorString();
+					return false;
+				}
 
-		const QString parent = QFileInfo(cache).absolutePath();
-		if (!QDir().mkpath(parent) || !image.save(cache)) {
-			qWarning() << "CachingImageManager::createCache: failed to save to"
-					   << cache;
-		}
-	});
+				image.convertTo(QImage::Format_ARGB32);
+
+				if (fillMode == "PreserveAspectCrop") {
+					image = image.scaled(
+						size,
+						Qt::KeepAspectRatioByExpanding,
+						Qt::SmoothTransformation);
+				} else if (fillMode == "PreserveAspectFit") {
+					image = image.scaled(
+						size, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+				} else {
+					image = image.scaled(
+						size, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+				}
+
+				if (fillMode == "PreserveAspectCrop" ||
+					fillMode == "PreserveAspectFit") {
+					QImage canvas(size, QImage::Format_ARGB32);
+					canvas.fill(Qt::transparent);
+
+					QPainter painter(&canvas);
+					painter.drawImage(
+						(size.width() - image.width()) / 2,
+						(size.height() - image.height()) / 2,
+						image);
+					painter.end();
+
+					image = canvas;
+				}
+
+				const QString parent = QFileInfo(cache).absolutePath();
+				if (!QDir().mkpath(parent) || !image.save(cache)) {
+					qWarning()
+						<< "CachingImageManager::createCache: failed to save to"
+						<< cache;
+					return false;
+				}
+
+				return true;
+			});
+
+	watcher->setFuture(future);
 }
 
 QString CachingImageManager::sha256sum(const QString& path) {
-	QFile file(path);
-	if (!file.open(QIODevice::ReadOnly)) {
-		qWarning() << "CachingImageManager::sha256sum: failed to open" << path;
-		return "";
+	const QFileInfo info(path);
+
+	if (!info.exists() || !info.isFile()) {
+		qWarning() << "CachingImageManager::sha256sum: failed to stat" << path;
+		return QString();
 	}
 
 	QCryptographicHash hash(QCryptographicHash::Sha256);
-	hash.addData(&file);
-	file.close();
+	hash.addData(path.toUtf8());
+	hash.addData(QByteArray::number(info.size()));
+	hash.addData(QByteArray::number(info.lastModified().toMSecsSinceEpoch()));
 
 	return hash.result().toHex();
 }