wallpapers/image: show light&&dark images side by side in previews

CCBUG: 207976

wallpapers/image/plugin/model/abstractimagelistmodel.cpp

@@ -6,6 +6,7 @@
 
 #include "abstractimagelistmodel.h"
 
+#include <QPainter>
 #include <QThreadPool>
 
 #include <KFileItem>
@@ -72,48 +73,95 @@ void AbstractImageListModel::slotHandleImageSizeFound(const QString &path, const
 
 void AbstractImageListModel::slotHandlePreview(const KFileItem &item, const QPixmap &preview)
 {
+    auto job = qobject_cast<KIO::PreviewJob *>(sender());
+    if (!job) {
+        return;
+    }
+
     const QString urlString = item.url().toLocalFile();
-    const QPersistentModelIndex pidx = m_previewJobsUrls.take(urlString);
-    QModelIndex idx;
+    const QPersistentModelIndex idx = job->property("index").toPersistentModelIndex();
 
-    if (!pidx.isValid()) {
-        if (int row = indexOf(urlString); row >= 0) {
-            idx = index(row, 0);
-        } else {
-            return;
-        }
+    auto it = m_previewJobsUrls.find(idx);
+    Q_ASSERT(it != m_previewJobsUrls.end());
+    it->removeOne(urlString);
+
+    const QStringList paths = job->property("paths").toStringList();
+    QPixmap *cachedPreview = m_imageCache.object(paths);
+
+    if (!cachedPreview) {
+        // Insert full preview
+        m_imageCache.insert(paths, new QPixmap(preview), 0);
     } else {
-        idx = pidx;
+        // Show multiple images side by side
+        QPainter p(cachedPreview);
+
+        const int i = paths.indexOf(urlString);
+        const double start = i / static_cast<double>(paths.size());
+        const double end = (i + 1) / static_cast<double>(paths.size());
+        // Cropped area
+        const QPoint topLeft(start * preview.width(), 0);
+        const QPoint bottomRight(end * preview.width(), preview.height());
+        // Inserted area
+        const QPoint topLeft2(start * cachedPreview->width(), 0);
+        const QPoint bottomRight2(end * cachedPreview->width(), cachedPreview->height());
+
+        p.drawPixmap(QRect(topLeft2, bottomRight2), preview.copy(QRect(topLeft, bottomRight)));
     }
 
-    const int cost = preview.width() * preview.height() * preview.depth() / 8;
+    if (it->empty()) {
+        // All images in the list have been loaded
+        m_previewJobsUrls.erase(it);
 
-    if (m_imageCache.insert(urlString, new QPixmap(preview), cost)) {
-        Q_EMIT dataChanged(idx, idx, {ScreenshotRole});
+        cachedPreview = m_imageCache.object(paths);
+        auto finalPreview = new QPixmap(*cachedPreview);
+
+        if (m_imageCache.insert(paths, finalPreview, 1)) {
+            Q_EMIT dataChanged(idx, idx, {ScreenshotRole});
+        } else {
+            delete finalPreview;
+        }
     }
 }
 
 void AbstractImageListModel::slotHandlePreviewFailed(const KFileItem &item)
 {
-    m_previewJobsUrls.remove(item.url().toLocalFile());
+    auto job = qobject_cast<KIO::PreviewJob *>(sender());
+    if (!job) {
+        return;
+    }
+
+    auto it = m_previewJobsUrls.find(job->property("index").toPersistentModelIndex());
+    Q_ASSERT(it != m_previewJobsUrls.end());
+
+    it->removeOne(item.url().toLocalFile());
+    if (it->empty()) {
+        m_previewJobsUrls.erase(it);
+    }
 }
 
-void AbstractImageListModel::asyncGetPreview(const QString &path, const QPersistentModelIndex &index) const
+void AbstractImageListModel::asyncGetPreview(const QStringList &paths, const QPersistentModelIndex &index) const
 {
-    if (m_previewJobsUrls.contains(path) || path.isEmpty()) {
+    if (m_previewJobsUrls.contains(index) || paths.isEmpty()) {
         return;
     }
 
-    const QUrl url = QUrl::fromLocalFile(path);
     const QStringList availablePlugins = KIO::PreviewJob::availablePlugins();
+    KFileItemList list;
+
+    for (const QString &path : paths) {
+        list.append(KFileItem(QUrl::fromLocalFile(path), QString(), 0));
+    }
 
-    KIO::PreviewJob *const job = KIO::filePreview(KFileItemList{KFileItem(url, QString(), 0)}, m_screenshotSize, &availablePlugins);
+    KIO::PreviewJob *const job = KIO::filePreview(list, m_screenshotSize, &availablePlugins);
     job->setIgnoreMaximumSize(true);
 
+    job->setProperty("paths", paths);
+    job->setProperty("index", index);
+
     connect(job, &KIO::PreviewJob::gotPreview, this, &AbstractImageListModel::slotHandlePreview);
     connect(job, &KIO::PreviewJob::failed, this, &AbstractImageListModel::slotHandlePreviewFailed);
 
-    m_previewJobsUrls.insert(path, index);
+    m_previewJobsUrls.insert(index, paths);
 }
 
 void AbstractImageListModel::asyncGetImageSize(const QString &path, const QPersistentModelIndex &index) const

wallpapers/image/plugin/model/abstractimagelistmodel.h

@@ -53,7 +53,13 @@ Q_SIGNALS:
     void loaded(AbstractImageListModel *model);
 
 protected:
-    void asyncGetPreview(const QString &path, const QPersistentModelIndex &index) const;
+    /**
+     * Asynchronously generates a preview.
+     * Multiple images are displayed side by side following the order in @c paths
+     *
+     * @note @c paths should have no duplicate urls.
+     */
+    void asyncGetPreview(const QStringList &paths, const QPersistentModelIndex &index) const;
     void asyncGetImageSize(const QString &path, const QPersistentModelIndex &index) const;
 
     bool m_loading = false;
@@ -61,10 +67,10 @@ protected:
     QSize m_screenshotSize;
     QSize m_targetSize;
 
-    QCache<QString, QPixmap> m_imageCache;
+    QCache<QStringList, QPixmap> m_imageCache;
     QCache<QString, QSize> m_imageSizeCache;
 
-    mutable QHash<QString, QPersistentModelIndex> m_previewJobsUrls;
+    mutable QHash<QPersistentModelIndex, QStringList> m_previewJobsUrls;
     mutable QHash<QString, QPersistentModelIndex> m_sizeJobsUrls;
 
     QHash<QString, bool> m_pendingDeletion;

wallpapers/image/plugin/model/imagelistmodel.cpp

@@ -41,13 +41,13 @@ QVariant ImageListModel::data(const QModelIndex &index, int role) const
         return QFileInfo(m_data.at(row)).completeBaseName();
 
     case ScreenshotRole: {
-        QPixmap *cachedPreview = m_imageCache.object(m_data.at(row));
+        QPixmap *cachedPreview = m_imageCache.object({m_data.at(row)});
 
         if (cachedPreview) {
             return *cachedPreview;
         }
 
-        asyncGetPreview(m_data.at(row), QPersistentModelIndex(index));
+        asyncGetPreview({m_data.at(row)}, QPersistentModelIndex(index));
 
         return QVariant();
     }

wallpapers/image/plugin/model/packagelistmodel.cpp

@@ -46,15 +46,20 @@ QVariant PackageListModel::data(const QModelIndex &index, int role) const
         return PackageFinder::packageDisplayName(b);
 
     case ScreenshotRole: {
-        const QString path = b.filePath("preferred");
+        QStringList paths{b.filePath(QByteArrayLiteral("preferred"))};
+        const QString darkPath = b.filePath(QByteArrayLiteral("preferredDark"));
+
+        if (!darkPath.isEmpty()) {
+            paths.append(darkPath);
+        }
 
-        QPixmap *cachedPreview = m_imageCache.object(path);
+        QPixmap *cachedPreview = m_imageCache.object(paths);
 
         if (cachedPreview) {
             return *cachedPreview;
         }
 
-        asyncGetPreview(path, QPersistentModelIndex(index));
+        asyncGetPreview(paths, QPersistentModelIndex(index));
 
         return QVariant();
     }