mica material: use separate thread to do time-consuming task

README.md

@@ -29,6 +29,7 @@ You can join our [Discord channel](https://discord.gg/grrM4Tmesy) to communicate
 - Linux: There have been many improvements to the Linux/X11 implementation! Most of them won't be directly visible to the user, but the code quality has been greatly improved.
 - macOS: The frameless windows will now use native window frame and buttons, only the title bar itself is hidden, which also means the window will have round corners as all other native windows on macOS.
 - Mica Material: It is now possible to load wallpaper images with very large file size or resolution, for example, 4K pictures. However, if the images have larger resolution than 1920x1080, they will be shrinked to reduce memory usage, and this process will also lower the image quality and break the aspect ratio of them.
+- Mica Material: FramelessHelper will now use a seperate thread to load and apply special effects to the wallpaper image, to speed up application startup performance and avoid such process block the main thread.
 - Window management: It is now possible to close the window (the dtor is executed) and show it again without breaking the frameless functionalities.
 - Theme: It is now possible to force a desired theme instead of always respecting the system theme.
 - Build system: The [**Ninja Multi-Config**](https://cmake.org/cmake/help/latest/generator/Ninja%20Multi-Config.html) generator is fully supported now, finally!

include/FramelessHelper/Core/private/micamaterial_p.h

@@ -31,6 +31,12 @@ FRAMELESSHELPER_BEGIN_NAMESPACE
 
 class MicaMaterial;
 
+using Transform = struct Transform
+{
+    qreal Horizontal = 0;
+    qreal Vertical = 0;
+};
+
 class FRAMELESSHELPER_CORE_API MicaMaterialPrivate : public QObject
 {
     Q_OBJECT
@@ -64,10 +70,7 @@ private:
     bool fallbackEnabled = true;
     QBrush micaBrush = {};
     bool initialized = false;
-    struct {
+    Transform transform = {};
-        qreal horizontal = 0;
-        qreal vertical = 0;
-    } transform = {};
 };
 
 FRAMELESSHELPER_END_NAMESPACE

src/core/micamaterial.cpp

@@ -30,6 +30,7 @@
 #include <QtCore/qsysinfo.h>
 #include <QtCore/qloggingcategory.h>
 #include <QtCore/qmutex.h>
+#include <QtCore/qthread.h>
 #include <QtGui/qpixmap.h>
 #include <QtGui/qimage.h>
 #include <QtGui/qimagereader.h>
@@ -78,7 +79,7 @@ struct MicaMaterialData
 {
     QPixmap blurredWallpaper = {};
     bool graphicsResourcesReady = false;
-    QMutex mutex;
+    QMutex mutex{};
 };
 
 Q_GLOBAL_STATIC(MicaMaterialData, g_micaMaterialData)
@@ -499,6 +500,130 @@ static inline void expblur(QImage &img, qreal radius, const bool improvedQuality
     return {x, y, w, h};
 }
 
+class WallpaperThread : public QThread
+{
+    Q_OBJECT
+    Q_DISABLE_COPY_MOVE(WallpaperThread)
+
+public:
+    explicit WallpaperThread(QObject *parent = nullptr) : QThread(parent) {}
+    ~WallpaperThread() override = default;
+
+Q_SIGNALS:
+    void imageUpdated(const Transform &);
+
+protected:
+    void run() override
+    {
+        Transform transform = {};
+        // ### FIXME: Ideally, we should not use virtual desktop size here.
+        QSize monitorSize = QGuiApplication::primaryScreen()->virtualSize();
+        if (monitorSize.isEmpty()) {
+            WARNING << "Failed to retrieve the monitor size. Using default size (1920x1080) instead ...";
+            monitorSize = kMaximumPictureSize;
+        }
+        const QSize imageSize = (monitorSize > kMaximumPictureSize ? kMaximumPictureSize : monitorSize);
+        if (imageSize != monitorSize) {
+            transform.Horizontal = (qreal(imageSize.width()) / qreal(monitorSize.width()));
+            transform.Vertical = (qreal(imageSize.height()) / qreal(monitorSize.height()));
+        }
+        const QString wallpaperFilePath = Utils::getWallpaperFilePath();
+        if (wallpaperFilePath.isEmpty()) {
+            WARNING << "Failed to retrieve the wallpaper file path.";
+            return;
+        }
+        QImageReader reader(wallpaperFilePath);
+        if (!reader.canRead()) {
+            WARNING << "Qt can't read the wallpaper file:" << reader.errorString();
+            return;
+        }
+        const QSize actualSize = reader.size();
+        if (actualSize.isEmpty()) {
+            WARNING << "The wallpaper picture size is invalid.";
+            return;
+        }
+        const QSize correctedSize = (actualSize > kMaximumPictureSize ? kMaximumPictureSize : actualSize);
+        if (correctedSize != actualSize) {
+            DEBUG << "The wallpaper picture size is greater than 1920x1080, it will be shrinked to reduce memory consumption.";
+            reader.setScaledSize(correctedSize);
+        }
+        QImage image(correctedSize, kDefaultImageFormat);
+        if (!reader.read(&image)) {
+            WARNING << "Failed to read the wallpaper image:" << reader.errorString();
+            return;
+        }
+        if (image.isNull()) {
+            WARNING << "The obtained image data is null.";
+            return;
+        }
+        WallpaperAspectStyle aspectStyle = Utils::getWallpaperAspectStyle();
+        QImage buffer(imageSize, kDefaultImageFormat);
+#ifdef Q_OS_WINDOWS
+        if (aspectStyle == WallpaperAspectStyle::Center) {
+            buffer.fill(kDefaultBlackColor);
+        }
+#endif
+        if ((aspectStyle == WallpaperAspectStyle::Stretch)
+            || (aspectStyle == WallpaperAspectStyle::Fit)
+            || (aspectStyle == WallpaperAspectStyle::Fill)) {
+            Qt::AspectRatioMode mode = Qt::KeepAspectRatioByExpanding;
+            if (aspectStyle == WallpaperAspectStyle::Stretch) {
+                mode = Qt::IgnoreAspectRatio;
+            } else if (aspectStyle == WallpaperAspectStyle::Fit) {
+                mode = Qt::KeepAspectRatio;
+            }
+            QSize newSize = image.size();
+            newSize.scale(imageSize, mode);
+            image = image.scaled(newSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+        }
+        static constexpr const QPoint desktopOriginPoint = {0, 0};
+        const QRect desktopRect = {desktopOriginPoint, imageSize};
+        if (aspectStyle == WallpaperAspectStyle::Tile) {
+            QPainter bufferPainter(&buffer);
+            bufferPainter.setRenderHints(QPainter::Antialiasing |
+                QPainter::TextAntialiasing | QPainter::SmoothPixmapTransform);
+            bufferPainter.fillRect(desktopRect, QBrush(image));
+        } else {
+            QPainter bufferPainter(&buffer);
+            bufferPainter.setRenderHints(QPainter::Antialiasing |
+                QPainter::TextAntialiasing | QPainter::SmoothPixmapTransform);
+            const QRect rect = alignedRect(Qt::LeftToRight, Qt::AlignCenter, image.size(), desktopRect);
+            bufferPainter.drawImage(rect.topLeft(), image);
+        }
+        g_micaMaterialData()->mutex.lock();
+        g_micaMaterialData()->blurredWallpaper = QPixmap(imageSize);
+        g_micaMaterialData()->blurredWallpaper.fill(kDefaultTransparentColor);
+        QPainter painter(&g_micaMaterialData()->blurredWallpaper);
+        painter.setRenderHints(QPainter::Antialiasing |
+            QPainter::TextAntialiasing | QPainter::SmoothPixmapTransform);
+#ifdef FRAMELESSHELPER_CORE_NO_PRIVATE
+        painter.drawImage(desktopOriginPoint, buffer);
+#else // !FRAMELESSHELPER_CORE_NO_PRIVATE
+        qt_blurImage(&painter, buffer, kDefaultBlurRadius, true, false);
+#endif // FRAMELESSHELPER_CORE_NO_PRIVATE
+        g_micaMaterialData()->mutex.unlock();
+        Q_EMIT imageUpdated(transform);
+    }
+};
+
+struct ThreadData
+{
+    std::unique_ptr<WallpaperThread> thread = nullptr;
+    QMutex mutex{};
+};
+
+Q_GLOBAL_STATIC(ThreadData, g_threadData)
+
+static inline void threadCleaner()
+{
+    const QMutexLocker locker(&g_threadData()->mutex);
+    if (g_threadData()->thread && g_threadData()->thread->isRunning()) {
+        g_threadData()->thread->requestInterruption();
+        g_threadData()->thread->quit();
+        g_threadData()->thread->wait();
+    }
+}
+
 MicaMaterialPrivate::MicaMaterialPrivate(MicaMaterial *q) : QObject(q)
 {
     Q_ASSERT(q);
@@ -537,98 +662,13 @@ void MicaMaterialPrivate::maybeGenerateBlurredWallpaper(const bool force)
         return;
     }
     g_micaMaterialData()->mutex.unlock();
-    // ### FIXME: Ideally, we should not use virtual desktop size here.
+    const QMutexLocker locker(&g_threadData()->mutex);
-    QSize monitorSize = QGuiApplication::primaryScreen()->virtualSize();
+    if (g_threadData()->thread->isRunning()) {
-    if (monitorSize.isEmpty()) {
+        g_threadData()->thread->requestInterruption();
-        WARNING << "Failed to retrieve the monitor size. Using default size (1920x1080) instead ...";
+        g_threadData()->thread->quit();
-        monitorSize = kMaximumPictureSize;
+        g_threadData()->thread->wait();
-    }
-    const QSize imageSize = (monitorSize > kMaximumPictureSize ? kMaximumPictureSize : monitorSize);
-    if (imageSize == monitorSize) {
-        transform = {};
-    } else {
-        transform.horizontal = (qreal(imageSize.width()) / qreal(monitorSize.width()));
-        transform.vertical = (qreal(imageSize.height()) / qreal(monitorSize.height()));
-    }
-    const QString wallpaperFilePath = Utils::getWallpaperFilePath();
-    if (wallpaperFilePath.isEmpty()) {
-        WARNING << "Failed to retrieve the wallpaper file path.";
-        return;
-    }
-    QImageReader reader(wallpaperFilePath);
-    if (!reader.canRead()) {
-        WARNING << "Qt can't read the wallpaper file:" << reader.errorString();
-        return;
-    }
-    const QSize actualSize = reader.size();
-    if (actualSize.isEmpty()) {
-        WARNING << "The wallpaper picture size is invalid.";
-        return;
-    }
-    const QSize correctedSize = (actualSize > kMaximumPictureSize ? kMaximumPictureSize : actualSize);
-    if (correctedSize != actualSize) {
-        DEBUG << "The wallpaper picture size is greater than 1920x1080, it will be shrinked to reduce memory consumption.";
-        reader.setScaledSize(correctedSize);
-    }
-    QImage image(correctedSize, kDefaultImageFormat);
-    if (!reader.read(&image)) {
-        WARNING << "Failed to read the wallpaper image:" << reader.errorString();
-        return;
-    }
-    if (image.isNull()) {
-        WARNING << "The obtained image data is null.";
-        return;
-    }
-    WallpaperAspectStyle aspectStyle = Utils::getWallpaperAspectStyle();
-    QImage buffer(imageSize, kDefaultImageFormat);
-#ifdef Q_OS_WINDOWS
-    if (aspectStyle == WallpaperAspectStyle::Center) {
-        buffer.fill(kDefaultBlackColor);
-    }
-#endif
-    if ((aspectStyle == WallpaperAspectStyle::Stretch)
-        || (aspectStyle == WallpaperAspectStyle::Fit)
-        || (aspectStyle == WallpaperAspectStyle::Fill)) {
-        Qt::AspectRatioMode mode = Qt::KeepAspectRatioByExpanding;
-        if (aspectStyle == WallpaperAspectStyle::Stretch) {
-            mode = Qt::IgnoreAspectRatio;
-        } else if (aspectStyle == WallpaperAspectStyle::Fit) {
-            mode = Qt::KeepAspectRatio;
-        }
-        QSize newSize = image.size();
-        newSize.scale(imageSize, mode);
-        image = image.scaled(newSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
-    }
-    static constexpr const QPoint desktopOriginPoint = {0, 0};
-    const QRect desktopRect = {desktopOriginPoint, imageSize};
-    if (aspectStyle == WallpaperAspectStyle::Tile) {
-        QPainter bufferPainter(&buffer);
-        bufferPainter.setRenderHints(QPainter::Antialiasing |
-            QPainter::TextAntialiasing | QPainter::SmoothPixmapTransform);
-        bufferPainter.fillRect(desktopRect, QBrush(image));
-    } else {
-        QPainter bufferPainter(&buffer);
-        bufferPainter.setRenderHints(QPainter::Antialiasing |
-            QPainter::TextAntialiasing | QPainter::SmoothPixmapTransform);
-        const QRect rect = alignedRect(Qt::LeftToRight, Qt::AlignCenter, image.size(), desktopRect);
-        bufferPainter.drawImage(rect.topLeft(), image);
-    }
-    g_micaMaterialData()->mutex.lock();
-    g_micaMaterialData()->blurredWallpaper = QPixmap(imageSize);
-    g_micaMaterialData()->blurredWallpaper.fill(kDefaultTransparentColor);
-    QPainter painter(&g_micaMaterialData()->blurredWallpaper);
-    painter.setRenderHints(QPainter::Antialiasing |
-        QPainter::TextAntialiasing | QPainter::SmoothPixmapTransform);
-#ifdef FRAMELESSHELPER_CORE_NO_PRIVATE
-    painter.drawImage(desktopOriginPoint, buffer);
-#else // !FRAMELESSHELPER_CORE_NO_PRIVATE
-    qt_blurImage(&painter, buffer, kDefaultBlurRadius, true, false);
-#endif // FRAMELESSHELPER_CORE_NO_PRIVATE
-    g_micaMaterialData()->mutex.unlock();
-    if (initialized) {
-        Q_Q(MicaMaterial);
-        Q_EMIT q->shouldRedraw();
     }
+    g_threadData()->thread->start(QThread::LowPriority);
 }
 
 void MicaMaterialPrivate::updateMaterialBrush()
@@ -669,13 +709,15 @@ void MicaMaterialPrivate::paint(QPainter *painter, const QSize &size, const QPoi
     static constexpr const QPointF originPoint = {0, 0};
     QPointF correctedPos = pos;
     QSizeF correctedSize = size;
-    if (!qFuzzyIsNull(transform.horizontal) && (transform.horizontal > qreal(0)) && !qFuzzyCompare(transform.horizontal, qreal(1))) {
+    if (!qFuzzyIsNull(transform.Horizontal) && (transform.Horizontal > qreal(0))
-        correctedPos.setX(correctedPos.x() * transform.horizontal);
+            && !qFuzzyCompare(transform.Horizontal, qreal(1))) {
-        correctedSize.setWidth(correctedSize.width() * transform.horizontal);
+        correctedPos.setX(correctedPos.x() * transform.Horizontal);
+        correctedSize.setWidth(correctedSize.width() * transform.Horizontal);
     }
-    if (!qFuzzyIsNull(transform.vertical) && (transform.vertical > qreal(0)) && !qFuzzyCompare(transform.vertical, qreal(1))) {
+    if (!qFuzzyIsNull(transform.Vertical) && (transform.Vertical > qreal(0))
-        correctedPos.setY(correctedPos.y() * transform.vertical);
+            && !qFuzzyCompare(transform.Vertical, qreal(1))) {
-        correctedSize.setHeight(correctedSize.height() * transform.vertical);
+        correctedPos.setY(correctedPos.y() * transform.Vertical);
+        correctedSize.setHeight(correctedSize.height() * transform.Vertical);
     }
     painter->save();
     painter->setRenderHints(QPainter::Antialiasing |
@@ -700,6 +742,20 @@ void MicaMaterialPrivate::paint(QPainter *painter, const QSize &size, const QPoi
 
 void MicaMaterialPrivate::initialize()
 {
+    g_threadData()->mutex.lock();
+    if (!g_threadData()->thread) {
+        g_threadData()->thread = std::make_unique<WallpaperThread>();
+        qAddPostRoutine(threadCleaner);
+    }
+    connect(g_threadData()->thread.get(), &WallpaperThread::imageUpdated, this, [this](const Transform &t){
+        transform = t;
+        if (initialized) {
+            Q_Q(MicaMaterial);
+            Q_EMIT q->shouldRedraw();
+        }
+    });
+    g_threadData()->mutex.unlock();
+
     tintColor = kDefaultTransparentColor;
     tintOpacity = kDefaultTintOpacity;
     // Leave fallbackColor invalid, we need to use this state to judge
@@ -851,3 +907,5 @@ void MicaMaterial::paint(QPainter *painter, const QSize &size, const QPoint &pos
 }
 
 FRAMELESSHELPER_END_NAMESPACE
+
+#include "micamaterial.moc"