wip: optimize

CMakeLists.txt

@@ -12,6 +12,10 @@ set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
+if(NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE Release)
+endif()
+
 find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Widgets)
 find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Widgets)
 
@@ -26,10 +30,12 @@ if(${QT_VERSION_MAJOR} GREATER_EQUAL 6)
     qt_add_executable(wallpaper-carousel
         MANUAL_FINALIZATION
         ${PROJECT_SOURCES}
+        src/utils.h
         src/images_carousel.h src/images_carousel.cpp src/designer/images_carousel.ui
         src/config.h src/config.cpp
         src/logger.h src/logger.cpp
         src/loading_indicator.h src/loading_indicator.cpp src/designer/loading_indicator.ui
+        src/image_item.h src/image_item.cpp
     )
 
 # Define target properties for Android with Qt 6 as:

src/image_item.cpp

@@ -0,0 +1,83 @@
+/*
+ * @Author: Uyanide pywang0608@foxmail.com
+ * @Date: 2025-11-30 20:32:27
+ * @LastEditTime: 2025-11-30 23:07:52
+ * @Description: Image item widget for displaying an image.
+ */
+#include "image_item.h"
+
+#include "logger.h"
+
+using namespace GeneralLogger;
+
+ImageData* ImageData::create(const QString& p, const int initWidth, const int initHeight) {
+    ImageData* data = new ImageData(p);
+
+    if (!data->image.load(p)) {
+        error(QString("Failed to load image from path: %1").arg(p));
+        delete data;
+        return nullptr;
+    }
+    const QSize targetSize(initWidth, initHeight);
+    data->image = data->image.scaled(targetSize, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation);
+
+    // Crop to center
+    int x       = (data->image.width() - targetSize.width()) / 2;
+    int y       = (data->image.height() - targetSize.height()) / 2;
+    data->image = data->image.copy(x, y, targetSize.width(), targetSize.height());
+    return data;
+}
+
+ImageItem::ImageItem(const ImageData* data,
+                     const int itemWidth,
+                     const int itemHeight,
+                     const int itemFocusWidth,
+                     const int itemFocusHeight,
+                     QWidget* parent)
+    : QLabel(parent),
+      m_data(data),
+      m_itemSize(itemWidth, itemHeight),
+      m_itemFocusSize(itemFocusWidth, itemFocusHeight) {
+    assert(data != nullptr);
+    setScaledContents(true);
+    if (data->image.isNull()) {
+        setText(":(");
+        setAlignment(Qt::AlignCenter);
+    } else {
+        setPixmap(QPixmap::fromImage(data->image));
+    }
+    setFixedSize(itemWidth, itemHeight);
+}
+
+ImageItem::~ImageItem() {
+    if (m_scaleAnimation) {
+        m_scaleAnimation->stop();
+        delete m_scaleAnimation;
+        m_scaleAnimation = nullptr;
+    }
+    delete m_data;
+}
+
+void ImageItem::setFocus(bool focus, bool animate) {
+    if (!animate) {
+        setFixedSize(focus ? m_itemFocusSize : m_itemSize);
+        return;
+    }
+    if (m_scaleAnimation) {
+        m_scaleAnimation->stop();
+        delete m_scaleAnimation;
+        m_scaleAnimation = nullptr;
+    }
+    m_scaleAnimation = new QPropertyAnimation(this, "size");
+    m_scaleAnimation->setDuration(ImageItem::s_animationDuration);
+    m_scaleAnimation->setStartValue(size());
+    m_scaleAnimation->setEndValue(focus ? m_itemFocusSize : m_itemSize);
+    m_scaleAnimation->setEasingCurve(QEasingCurve::OutCubic);
+    connect(m_scaleAnimation,
+            &QPropertyAnimation::valueChanged,
+            this,
+            [this](const QVariant& value) {
+                setFixedSize(value.toSize());
+            });
+    m_scaleAnimation->start();
+}

src/image_item.h

@@ -0,0 +1,78 @@
+/*
+ * @Author: Uyanide pywang0608@foxmail.com
+ * @Date: 2025-11-30 20:31:15
+ * @LastEditTime: 2025-11-30 23:08:22
+ * @Description: Image item widget for displaying an image.
+ */
+#ifndef IMAGE_ITEM_H
+#define IMAGE_ITEM_H
+
+#include <QDateTime>
+#include <QFileInfo>
+#include <QImage>
+#include <QLabel>
+#include <QPropertyAnimation>
+
+/**
+ * @brief Data structure to hold image information
+ *        and can be safely created and passed between threads.
+ */
+struct ImageData {
+    QFileInfo file;
+    QImage image;
+
+  public:
+    static ImageData* create(const QString& p, const int initWidth, const int initHeight);
+
+  private:
+    ImageData(const QString& path) : file(path), image() {}
+};
+
+/**
+ * @brief Image label that displays an image,
+ *        which should always be created in the main thread.
+ */
+class ImageItem : public QLabel {
+    Q_OBJECT
+
+  public:
+    static constexpr int s_animationDuration = 300;
+
+    explicit ImageItem(const ImageData* data,
+                       const int itemWidth,
+                       const int itemHeight,
+                       const int itemFocusWidth,
+                       const int itemFocusHeight,
+                       QWidget* parent = nullptr);
+
+    ~ImageItem() override;
+
+    [[nodiscard]] QString getFileFullPath() const { return m_data->file.absoluteFilePath(); }
+
+    [[nodiscard]] QString getFileName() const { return m_data->file.fileName(); }
+
+    [[nodiscard]] QDateTime getFileDate() const { return m_data->file.lastModified(); }
+
+    [[nodiscard]] const QImage& getThumbnail() const { return m_data->image; }
+
+    [[nodiscard]] qint64 getFileSize() const { return m_data->file.size(); }
+
+    void setFocus(bool focus = true, bool animate = true);
+
+  protected:
+    void mousePressEvent(QMouseEvent* event) override {
+        emit clicked(getFileFullPath());
+        QLabel::mousePressEvent(event);
+    }
+
+  private:
+    const ImageData* m_data;
+    QSize m_itemSize;
+    QSize m_itemFocusSize;
+    QPropertyAnimation* m_scaleAnimation = nullptr;
+
+  signals:
+    void clicked(const QString& path);
+};
+
+#endif  // IMAGE_ITEM_H

src/images_carousel.cpp

@@ -1,13 +1,14 @@
 /*
  * @Author: Uyanide pywang0608@foxmail.com
  * @Date: 2025-08-05 01:22:53
- * @LastEditTime: 2025-08-11 19:44:06
+ * @LastEditTime: 2025-11-30 23:21:30
  * @Description: Animated carousel widget for displaying and selecting images.
  */
 #include "images_carousel.h"
 
 #include <assert.h>
 #include <pthread.h>
+// #include <stdlib.h>
 
 #include <QLabel>
 #include <QMetaObject>
@@ -18,6 +19,7 @@
 
 #include "logger.h"
 #include "ui_images_carousel.h"
+#include "utils.h"
 
 using namespace GeneralLogger;
 
@@ -31,7 +33,8 @@ ImagesCarousel::ImagesCarousel(const Config::StyleConfigItems& styleConfig,
       m_itemFocusWidth(styleConfig.imageFocusWidth),
       m_itemFocusHeight(static_cast<int>(styleConfig.imageFocusWidth / styleConfig.aspectRatio)),
       m_sortType(sortConfig.type),
-      m_sortReverse(sortConfig.reverse) {
+      m_sortReverse(sortConfig.reverse),
+      m_noLoadingScreen(styleConfig.noLoadingScreen) {
     ui->setupUi(this);
     m_scrollArea   = dynamic_cast<ImagesCarouselScrollArea*>(ui->scrollArea);
     m_imagesLayout = dynamic_cast<QHBoxLayout*>(ui->scrollAreaWidgetContents->layout());
@@ -45,6 +48,12 @@ ImagesCarousel::ImagesCarousel(const Config::StyleConfigItems& styleConfig,
             this,
             &ImagesCarousel::_onInitImagesLoaded);
 
+    // Also handle subsequent image loads
+    connect(this,
+            &ImagesCarousel::loadingCompleted,
+            this,
+            &ImagesCarousel::_onImagesLoaded);
+
     // Auto focus when scrolling
     m_scrollDebounceTimer = new QTimer(this);
     m_scrollDebounceTimer->setSingleShot(true);
@@ -69,12 +78,31 @@ ImagesCarousel::ImagesCarousel(const Config::StyleConfigItems& styleConfig,
 
 void ImagesCarousel::_onInitImagesLoaded() {
     disconnect(this, &ImagesCarousel::loadingCompleted, this, &ImagesCarousel::_onInitImagesLoaded);
+
+    // No images loaded
     if (m_loadedImages.isEmpty()) {
         return;
     }
+    // Focus the first image
+    if (m_currentIndex < 0) {
+        m_currentIndex = 0;
+    }
     focusCurrImage();
 }
 
+void ImagesCarousel::_onImagesLoaded() {
+    m_animationEnabled = true;
+    if (!m_noLoadingScreen) {
+        _enableUIUpdates(true);
+    } else if (m_imageInsertQueueTimer) {
+        m_imageInsertQueueTimer->stop();
+        m_imageInsertQueueTimer->deleteLater();
+        m_imageInsertQueueTimer = nullptr;
+    }
+
+    // exit(1);  // for debug
+}
+
 ImagesCarousel::~ImagesCarousel() {
     delete ui;
     // memory of items in m_loadedImages managed by Qt parent-child system
@@ -95,6 +123,18 @@ void ImagesCarousel::appendImages(const QStringList& paths) {
         QMutexLocker locker(&m_countMutex);
         m_addedImagesCount += paths.size();
     }
+    m_animationEnabled = false;
+    if (!m_noLoadingScreen) {
+        _enableUIUpdates(false);
+    } else if (m_imageInsertQueueTimer == nullptr) {
+        m_imageInsertQueueTimer = new QTimer(this);
+        m_imageInsertQueueTimer->setInterval(s_processBatchTimeout);
+        connect(m_imageInsertQueueTimer,
+                &QTimer::timeout,
+                this,
+                &ImagesCarousel::_processImageInsertQueue);
+        m_imageInsertQueueTimer->start();
+    }
     m_loadedImages.reserve(m_loadedImages.size() + paths.size());
     emit loadingStarted(paths.size());
     for (const QString& path : paths) {
@@ -111,7 +151,38 @@ ImageLoader::ImageLoader(const QString& path, ImagesCarousel* carousel)
     setAutoDelete(true);
 }
 
-void ImagesCarousel::_insertImage(const ImageData* data) {
+void ImagesCarousel::_insertImageQueue(const ImageData* data) {
+    if (!m_noLoadingScreen) {
+        _insertImage(data);
+        return;
+    }
+    {
+        QMutexLocker locker(&m_imageInsertQueueMutex);
+        m_imageInsertQueue.enqueue(const_cast<ImageData*>(data));
+    }
+}
+
+int ImagesCarousel::_insertImage(const ImageData* data) {
+    // Increase loaded count regardless of success or failure
+    Defer defer([this]() {
+        emit imageLoaded(m_loadedImages.size());
+        {
+            QMutexLocker countLocker(&m_countMutex);
+            if (++m_loadedImagesCount >= m_addedImagesCount) {
+                QMutexLocker stopSignLocker(&m_stopSignMutex);
+                if (m_stopSign) {
+                    // if all stopped
+                    emit stopped();
+                } else {
+                    emit loadingCompleted(m_loadedImagesCount);
+                }
+            }
+        }
+        return;
+    });
+
+    if (!data) return -1;
+
     auto item = new ImageItem(
         data,
         m_itemWidth,
@@ -136,71 +207,88 @@ void ImagesCarousel::_insertImage(const ImageData* data) {
     };
 
     // insert into correct position based on sort type and direction
-    qint64 inserPos = m_loadedImages.size();
+    qint64 insertPos = m_loadedImages.size();
     if (m_sortType != Config::SortType::None) {
-        for (auto it = m_loadedImages.rbegin();
-             it != m_loadedImages.rend() &&
-             cmpFuncs[static_cast<int>(m_sortType)](*it, item) == m_sortReverse;
-             (*it)->m_index++, ++it, --inserPos);
+        auto cmp     = cmpFuncs[static_cast<int>(m_sortType)];
+        auto reverse = m_sortReverse;
+
+        auto it = std::upper_bound(
+            m_loadedImages.begin(),
+            m_loadedImages.end(),
+            item,
+            [cmp, reverse](const ImageItem* a, const ImageItem* b) {
+                return reverse ? cmp(b, a) : cmp(a, b);
+            });
+
+        insertPos = std::distance(m_loadedImages.begin(), it);
     }
-    item->m_index = inserPos;
     connect(item,
             &ImageItem::clicked,
             this,
             &ImagesCarousel::_onItemClicked);
-    m_loadedImages.insert(inserPos, item);
-    m_imagesLayout->insertWidget(inserPos, item);
+    m_loadedImages.insert(insertPos, item);
+    m_imagesLayout->insertWidget(insertPos, item);
+    return insertPos;
+}
 
-    emit imageLoaded(m_loadedImages.size());
+void ImagesCarousel::_processImageInsertQueue() {
+    QVector<ImageData*> batch;
     {
-        QMutexLocker countLocker(&m_countMutex);
-        if (++m_loadedImagesCount >= m_addedImagesCount) {
-            QMutexLocker stopSignLocker(&m_stopSignMutex);
-            if (m_stopSign) {
-                // if all stopped
-                emit stopped();
-            } else {
-                emit loadingCompleted(m_loadedImagesCount);
-            }
+        QMutexLocker locker(&m_imageInsertQueueMutex);
+        while (!m_imageInsertQueue.isEmpty() && batch.size() < s_processBatchSize) {
+            batch.append(m_imageInsertQueue.dequeue());
         }
     }
+    if (m_noLoadingScreen) _enableUIUpdates(false);
+    int currPos = m_currentIndex;
+    for (ImageData* data : batch) {
+        int pos = _insertImage(data);
+        if (pos >= 0 && pos <= currPos) {
+            currPos++;
+        }
+    }
+    // Update focusing index if any
+    if (m_currentIndex >= 0) {
+        m_currentIndex = currPos;
+        if (m_currentIndex < 0 || m_currentIndex >= m_loadedImages.size()) {
+            m_currentIndex = 0;
+        }
+    }
+    if (m_noLoadingScreen) _enableUIUpdates(true);
+    focusCurrImage();
+}
+
+void ImagesCarousel::_enableUIUpdates(bool enable) {
+    m_imagesLayout->setEnabled(enable);
+    if (enable) {
+        m_imagesLayout->activate();
+    }
+    ui->scrollAreaWidgetContents->setUpdatesEnabled(enable);
 }
 
 void ImageLoader::run() {
+    ImageData* data = nullptr;
+    Defer defer([this, &data]() {
+        QMetaObject::invokeMethod(m_carousel,
+                                  "_insertImageQueue",
+                                  Qt::QueuedConnection,
+                                  Q_ARG(const ImageData*, data));
+    });
     {
-        QMutexLocker countLocker(&m_carousel->m_countMutex);
         QMutexLocker stopSignLocker(&m_carousel->m_stopSignMutex);
-        if (m_carousel->m_stopSign) {
-            // if all stopped
-            if (++m_carousel->m_loadedImagesCount == m_carousel->m_addedImagesCount) {
-                emit m_carousel->stopped();
-            }
-            return;
-        }
+        if (m_carousel->m_stopSign) return;
     }
-    auto data = new ImageData(m_path, m_initWidth, m_initHeight);
-    QMetaObject::invokeMethod(m_carousel,
-                              "_insertImage",
-                              Qt::QueuedConnection,
-                              Q_ARG(const ImageData*, data));
-}
-
-ImageData::ImageData(const QString& p, const int initWidth, const int initHeight) : file(p) {
-    if (!image.load(p)) {
-        warn(QString("Failed to load image from path: %1").arg(p));
-        return;
-    }
-    // resize in "cover" mode
-    const QSize targetSize(initWidth, initHeight);
-    image = image.scaled(targetSize, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation);
-
-    // Crop to center
-    int x = (image.width() - targetSize.width()) / 2;
-    int y = (image.height() - targetSize.height()) / 2;
-    image = image.copy(x, y, targetSize.width(), targetSize.height());
+    data = ImageData::create(m_path, m_initWidth, m_initHeight);
 }
 
 void ImagesCarousel::focusNextImage() {
+    // If no focus, focus the first image
+    if (m_currentIndex < 0) {
+        if (m_loadedImages.isEmpty()) return;
+        m_currentIndex = 0;
+        focusCurrImage();
+        return;
+    }
     unfocusCurrImage();
     if (m_loadedImages.size() <= 1) return;
     m_currentIndex++;
@@ -211,6 +299,13 @@ void ImagesCarousel::focusNextImage() {
 }
 
 void ImagesCarousel::focusPrevImage() {
+    // If no focus, focus the last image
+    if (m_currentIndex < 0) {
+        if (m_loadedImages.isEmpty()) return;
+        m_currentIndex = m_loadedImages.size() - 1;
+        focusCurrImage();
+        return;
+    }
     if (m_loadedImages.size() <= 1) return;
     unfocusCurrImage();
     m_currentIndex--;
@@ -221,30 +316,42 @@ void ImagesCarousel::focusPrevImage() {
 }
 
 void ImagesCarousel::unfocusCurrImage() {
-    if (m_currentIndex < 0 || m_currentIndex >= m_loadedImages.size()) {
-        error(QString("Invalid index to unfocus: %1").arg(m_currentIndex));
+    if (m_currentIndex < 0) return;
+    if (m_currentIndex >= m_loadedImages.size()) {
+        warn(QString("Invalid index to unfocus: %1").arg(m_currentIndex));
         return;
     }
-    m_loadedImages[m_currentIndex]->setFocus(false);
+    m_loadedImages[m_currentIndex]->setFocus(false, m_animationEnabled);
+}
+
+int ImagesCarousel::_focusingLeftOffset(int index) {
+    int spacing      = ui->scrollAreaWidgetContents->layout()->spacing();
+    int centerOffset = (m_itemWidth + spacing) * index + m_itemFocusWidth / 2 - spacing;
+    return centerOffset - ui->scrollArea->width() / 2;
 }
 
 void ImagesCarousel::focusCurrImage() {
-    if (m_currentIndex < 0 || m_currentIndex >= m_loadedImages.size()) {
-        error(QString("Invalid index to focus: %1").arg(m_currentIndex));
+    // If no focus, do nothing
+    if (m_currentIndex < 0) return;
+    if (m_currentIndex >= m_loadedImages.size()) {
+        warn(QString("Invalid index to focus: %1").arg(m_currentIndex));
         return;
     }
-    m_loadedImages[m_currentIndex]->setFocus(true);
+    m_loadedImages[m_currentIndex]->setFocus(true, m_animationEnabled);
     emit imageFocused(m_loadedImages[m_currentIndex]->getFileFullPath(),
                       m_currentIndex,
                       m_loadedImages.size());
-    auto hScrollBar  = ui->scrollArea->horizontalScrollBar();
-    int spacing      = ui->scrollAreaWidgetContents->layout()->spacing();
-    int centerOffset = (m_itemWidth + spacing) * m_currentIndex + m_itemFocusWidth / 2 - spacing;
-    int leftOffset   = centerOffset - ui->scrollArea->width() / 2;
+    auto hScrollBar = ui->scrollArea->horizontalScrollBar();
+    int leftOffset  = _focusingLeftOffset(m_currentIndex);
     if (leftOffset < 0) {
         leftOffset = 0;
     }
 
+    if (!m_animationEnabled) {
+        hScrollBar->setValue(leftOffset);
+        return;
+    }
+
     if (m_scrollAnimation) {
         m_scrollAnimation->stop();
         m_scrollAnimation->deleteLater();
@@ -292,66 +399,25 @@ void ImagesCarousel::_onScrollBarValueChanged(int value) {
     focusCurrImage();
 }
 
-void ImagesCarousel::_onItemClicked(int index) {
+void ImagesCarousel::_onItemClicked(const QString& path) {
     // if (m_suppressAutoFocus) return;
     unfocusCurrImage();
-    m_currentIndex = index;
-    if (index < 0 || index >= m_loadedImages.size()) {
-        return;  // Out of bounds
+    // Most likely the clicked item is near the current index
+    for (int i = m_currentIndex, j = m_currentIndex + 1;
+         i >= 0 || j < m_loadedImages.size();
+         --i, ++j) {
+        if (i >= 0 && m_loadedImages[i]->getFileFullPath() == path) {
+            m_currentIndex = i;
+            break;
+        }
+        if (j < m_loadedImages.size() && m_loadedImages[j]->getFileFullPath() == path) {
+            m_currentIndex = j;
+            break;
+        }
     }
     focusCurrImage();
 }
 
-ImageItem::ImageItem(const ImageData* data,
-                     const int itemWidth,
-                     const int itemHeight,
-                     const int itemFocusWidth,
-                     const int itemFocusHeight,
-                     QWidget* parent)
-    : QLabel(parent),
-      m_data(data),
-      m_itemSize(itemWidth, itemHeight),
-      m_itemFocusSize(itemFocusWidth, itemFocusHeight) {
-    assert(data != nullptr);
-    setScaledContents(true);
-    if (data->image.isNull()) {
-        setText(":(");
-        setAlignment(Qt::AlignCenter);
-    } else {
-        setPixmap(QPixmap::fromImage(data->image));
-    }
-    setFixedSize(itemWidth, itemHeight);
-}
-
-ImageItem::~ImageItem() {
-    if (m_scaleAnimation) {
-        m_scaleAnimation->stop();
-        delete m_scaleAnimation;
-        m_scaleAnimation = nullptr;
-    }
-    delete m_data;
-}
-
-void ImageItem::setFocus(bool focus) {
-    if (m_scaleAnimation) {
-        m_scaleAnimation->stop();
-        delete m_scaleAnimation;
-        m_scaleAnimation = nullptr;
-    }
-    m_scaleAnimation = new QPropertyAnimation(this, "size");
-    m_scaleAnimation->setDuration(ImagesCarousel::s_animationDuration);
-    m_scaleAnimation->setStartValue(size());
-    m_scaleAnimation->setEndValue(focus ? m_itemFocusSize : m_itemSize);
-    m_scaleAnimation->setEasingCurve(QEasingCurve::OutCubic);
-    connect(m_scaleAnimation,
-            &QPropertyAnimation::valueChanged,
-            this,
-            [this](const QVariant& value) {
-                setFixedSize(value.toSize());
-            });
-    m_scaleAnimation->start();
-}
-
 void ImagesCarousel::onStop() {
     QMutexLocker locker(&m_stopSignMutex);
     m_stopSign = true;

src/images_carousel.h

@@ -1,15 +1,15 @@
 /*
  * @Author: Uyanide pywang0608@foxmail.com
  * @Date: 2025-08-05 01:22:53
- * @LastEditTime: 2025-08-08 04:17:53
+ * @LastEditTime: 2025-11-30 23:10:44
  * @Description: Animated carousel widget for displaying and selecting images.
  */
 #ifndef IMAGES_CAROUSEL_H
 #define IMAGES_CAROUSEL_H
 
+#include <qqueue.h>
 #include <qtmetamacros.h>
 
-#include <QFileInfo>
 #include <QHBoxLayout>
 #include <QKeyEvent>
 #include <QLabel>
@@ -25,6 +25,7 @@
 #include <QWidget>
 
 #include "config.h"
+#include "image_item.h"
 
 class ImageData;
 class ImageItem;
@@ -32,64 +33,6 @@ class ImageLoader;
 class ImagesCarousel;
 class ImagesCarouselScrollArea;
 
-/**
- * @brief Data structure to hold image information
- *        and can be safely created and passed between threads.
- */
-struct ImageData {
-    QFileInfo file;
-    QImage image;
-
-    explicit ImageData(const QString& p, const int initWidth, const int initHeight);
-};
-
-/**
- * @brief Image label that displays an image,
- *        which should always be created in the main thread.
- */
-class ImageItem : public QLabel {
-    Q_OBJECT
-
-  public:
-    explicit ImageItem(const ImageData* data,
-                       const int itemWidth,
-                       const int itemHeight,
-                       const int itemFocusWidth,
-                       const int itemFocusHeight,
-                       QWidget* parent = nullptr);
-
-    ~ImageItem() override;
-
-    [[nodiscard]] QString getFileFullPath() const { return m_data->file.absoluteFilePath(); }
-
-    [[nodiscard]] QString getFileName() const { return m_data->file.fileName(); }
-
-    [[nodiscard]] QDateTime getFileDate() const { return m_data->file.lastModified(); }
-
-    [[nodiscard]] const QImage& getThumbnail() const { return m_data->image; }
-
-    [[nodiscard]] qint64 getFileSize() const { return m_data->file.size(); }
-
-    void setFocus(bool focus = true);
-
-    int m_index = 0;
-
-  protected:
-    void mousePressEvent(QMouseEvent* event) override {
-        emit clicked(m_index);
-        QLabel::mousePressEvent(event);
-    }
-
-  private:
-    const ImageData* m_data;
-    QSize m_itemSize;
-    QSize m_itemFocusSize;
-    QPropertyAnimation* m_scaleAnimation = nullptr;
-
-  signals:
-    void clicked(int index);
-};
-
 /**
  * @brief Worker class for loading images in a separate thread.
  */
@@ -120,8 +63,10 @@ class ImagesCarousel : public QWidget {
                             QWidget* parent = nullptr);
     ~ImagesCarousel();
 
-    static constexpr int s_debounceInterval  = 200;
-    static constexpr int s_animationDuration = 300;
+    static constexpr int s_debounceInterval    = 200;
+    static constexpr int s_animationDuration   = 300;
+    static constexpr int s_processBatchTimeout = 50;  // ms
+    static constexpr int s_processBatchSize    = 10;  // items
 
     [[nodiscard]] QString getCurrentImagePath() const {
         if (m_currentIndex < 0 || m_currentIndex >= m_loadedImages.size()) {
@@ -147,6 +92,7 @@ class ImagesCarousel : public QWidget {
     const int m_itemFocusHeight;
     const Config::SortType m_sortType;
     const bool m_sortReverse;
+    const bool m_noLoadingScreen;
 
   public slots:
     void focusNextImage();
@@ -157,14 +103,21 @@ class ImagesCarousel : public QWidget {
 
   private slots:
     void _onScrollBarValueChanged(int value);
-    void _onItemClicked(int index);
+    void _onItemClicked(const QString& path);
     void _onInitImagesLoaded();
+    void _onImagesLoaded();
+
+    void _processImageInsertQueue();
 
   public:
     void appendImages(const QStringList& paths);
 
   private:
-    Q_INVOKABLE void _insertImage(const ImageData* item);
+    int _insertImage(const ImageData* item);
+    Q_INVOKABLE void _insertImageQueue(const ImageData* item);
+
+    void _enableUIUpdates(bool enable);
+    int _focusingLeftOffset(int index);
 
   private:
     // UI elements
@@ -177,10 +130,16 @@ class ImagesCarousel : public QWidget {
     int m_loadedImagesCount = 0;         // increase when _insertImage is called OR ImageLoader::run() is called with m_stopSign as true
     int m_addedImagesCount  = 0;         // increase when appendImages called
     QMutex m_countMutex;                 // for m_loadedImagesCount and m_addedImagesCount
-    int m_currentIndex = 0;
+    int m_currentIndex = -1;             // initially no focus
+
+    // Threading
+    QQueue<ImageData*> m_imageInsertQueue;
+    QMutex m_imageInsertQueueMutex;
+    QTimer* m_imageInsertQueueTimer = nullptr;
 
     // Animations
     QPropertyAnimation* m_scrollAnimation = nullptr;
+    bool m_animationEnabled               = true;
 
     // Auto focusing
     bool m_suppressAutoFocus      = false;

src/main_window.cpp

@@ -1,7 +1,7 @@
 /*
  * @Author: Uyanide pywang0608@foxmail.com
  * @Date: 2025-08-05 00:37:58
- * @LastEditTime: 2025-10-25 12:04:38
+ * @LastEditTime: 2025-11-30 22:37:48
  * @Description: MainWindow implementation.
  */
 #include "main_window.h"
@@ -210,6 +210,15 @@ void MainWindow::wheelEvent(QWheelEvent* event) {
     }
 }
 
+void MainWindow::closeEvent(QCloseEvent* event) {
+    if (m_state == Loading) {
+        event->ignore();
+        _onCancelPressed();
+    } else {
+        event->accept();
+    }
+}
+
 void MainWindow::onConfirm() {
     close();
     const auto path = m_carousel->getCurrentImagePath();

src/main_window.h

@@ -1,7 +1,7 @@
 /*
  * @Author: Uyanide pywang0608@foxmail.com
  * @Date: 2025-08-05 00:37:58
- * @LastEditTime: 2025-08-08 03:37:24
+ * @LastEditTime: 2025-11-30 22:37:27
  * @Description: MainWindow implementation.
  */
 #ifndef MAINWINDOW_H
@@ -25,7 +25,7 @@ class MainWindow : public QMainWindow {
     Q_OBJECT
 
   public:
-    MainWindow(const Config &config, QWidget *parent = nullptr);
+    MainWindow(const Config& config, QWidget* parent = nullptr);
     ~MainWindow();
 
   public slots:
@@ -33,14 +33,15 @@ class MainWindow : public QMainWindow {
     void onCancel();
 
   protected:
-    void keyPressEvent(QKeyEvent *event) override;
-    void wheelEvent(QWheelEvent *event) override;
+    void keyPressEvent(QKeyEvent* event) override;
+    void wheelEvent(QWheelEvent* event) override;
+    void closeEvent(QCloseEvent* event) override;
 
   private:
     void _setupUI();
 
   private slots:
-    void _onImageFocused(const QString &path, const int index, const int count);
+    void _onImageFocused(const QString& path, const int index, const int count);
     void _onLoadingStarted(const qsizetype amount);
     void _onLoadingCompleted(const qsizetype amount);
 
@@ -55,11 +56,11 @@ class MainWindow : public QMainWindow {
         Ready,
     } m_state = Init;
 
-    Ui::MainWindow *ui;
-    ImagesCarousel *m_carousel           = nullptr;
-    LoadingIndicator *m_loadingIndicator = nullptr;
+    Ui::MainWindow* ui;
+    ImagesCarousel* m_carousel           = nullptr;
+    LoadingIndicator* m_loadingIndicator = nullptr;
     int m_carouselIndex, m_loadingIndicatorIndex;
-    const Config &m_config;
+    const Config& m_config;
 
   signals:
     void stop();

src/utils.h

@@ -0,0 +1,22 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+#include <utility>
+
+template <typename Callable>
+class Defer {
+    Callable m_func;
+
+  public:
+    explicit Defer(Callable&& func)
+        : m_func(std::forward<Callable>(func)) {}
+
+    Defer()             = delete;
+    Defer(const Defer&) = delete;
+
+    ~Defer() {
+        m_func();
+    }
+};
+
+#endif  // UTILS_H