renamed IconManager to KFilePreviewGenerator

svn path=/trunk/KDE/kdebase/apps/; revision=863324

1 files changed, 210 insertions, 0 deletions

diff --git a/src/kfilepreviewgenerator.h b/src/kfilepreviewgenerator.h
new file mode 100644
index 000000000..47aff66a7
--- /dev/null
+++ b/src/kfilepreviewgenerator.h
@@ -0,0 +1,210 @@
+/***************************************************************************
+ *   Copyright (C) 2008 by Peter Penz <[email protected]>                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
+ ***************************************************************************/
+
+#ifndef KFILEPREVIEWGENERATOR_H
+#define KFILEPREVIEWGENERATOR_H
+
+#include <kfileitem.h>
+#include <kurl.h>
+
+#include <QList>
+#include <QObject>
+#include <QPixmap>
+
+class KDirModel;
+class KDirSortFilterProxyModel;
+class KJob;
+class KMimeTypeResolver;
+class QAbstractItemView;
+
+/**
+ * @brief Manages the icon state of a directory model.
+ *
+ * Per default a preview is generated for each item.
+ * Additionally the clipboard is checked for cut items.
+ * The icon state for cut items gets dimmed automatically.
+ *
+ * The following strategy is used when creating previews:
+ * - The previews for currently visible items are created before
+ *   the previews for invisible items.
+ * - If the user changes the visible area by using the scrollbars,
+ *   all pending previews get paused. As soon as the user stays
+ *   on the same position for a short delay, the previews are
+ *   resumed. Also in this case the previews for the visible items
+ *   are generated first.
+ */
+class KFilePreviewGenerator : public QObject
+{
+    Q_OBJECT
+
+public:
+    KFilePreviewGenerator(QAbstractItemView* parent, KDirSortFilterProxyModel* model);
+    virtual ~KFilePreviewGenerator();
+    void setShowPreview(bool show);
+    bool showPreview() const;
+
+    /**
+     * Updates the previews for all already available items. It is only necessary
+     * to invoke this method when the icon size of the abstract item view has
+     * been changed.
+     */
+    void updatePreviews();
+
+    /**
+     * Cancels all pending previews. Should be invoked when the URL of the item
+     * view has been changed.
+     */
+    void cancelPreviews();
+
+private slots:
+    /**
+     * Generates previews for the items \a items asynchronously.
+     */
+    void generatePreviews(const KFileItemList& items);
+
+    /**
+     * Adds the preview \a pixmap for the item \a item to the preview
+     * queue and starts a timer which will dispatch the preview queue
+     * later.
+     */
+    void addToPreviewQueue(const KFileItem& item, const QPixmap& pixmap);
+
+    /**
+     * Is invoked when the preview job has been finished and
+     * removes the job from the m_previewJobs list.
+     */
+    void slotPreviewJobFinished(KJob* job);
+
+    /** Synchronizes the item icon with the clipboard of cut items. */
+    void updateCutItems();
+
+    /**
+     * Dispatches the preview queue  block by block within
+     * time slices.
+     */
+    void dispatchPreviewQueue();
+
+    /**
+     * Pauses all preview jobs and invokes KFilePreviewGenerator::resumePreviews()
+     * after a short delay. Is invoked as soon as the user has moved
+     * a scrollbar.
+     */
+    void pausePreviews();
+
+    /**
+     * Resumes the previews that have been paused after moving the
+     * scrollbar. The previews for the current visible area are
+     * generated first.
+     */
+    void resumePreviews();
+
+private:
+    /**
+     * Returns true, if the item \a item has been cut into
+     * the clipboard.
+     */
+    bool isCutItem(const KFileItem& item) const;
+
+    /** Applies an item effect to all cut items. */
+    void applyCutItemEffect();
+
+    /**
+     * Applies a frame around the icon. False is returned if
+     * no frame has been added because the icon is too small.
+     */
+    bool applyImageFrame(QPixmap& icon);
+
+    /**
+     * Resizes the icon to \a maxSize if the icon size does not
+     * fit into the maximum size. The aspect ratio of the icon
+     * is kept.
+     */
+    void limitToSize(QPixmap& icon, const QSize& maxSize);
+
+    /**
+     * Starts a new preview job for the items \a to m_previewJobs
+     * and triggers the preview timer.
+     */
+    void startPreviewJob(const KFileItemList& items);
+
+    /** Kills all ongoing preview jobs. */
+    void killPreviewJobs();
+
+    /**
+     * Orders the items \a items in a way that the visible items
+     * are moved to the front of the list. When passing this
+     * list to a preview job, the visible items will get generated
+     * first.
+     */
+    void orderItems(KFileItemList& items);
+
+private:
+    /** Remembers the pixmap for an item specified by an URL. */
+    struct ItemInfo
+    {
+        KUrl url;
+        QPixmap pixmap;
+    };
+
+    bool m_showPreview;
+
+    /**
+     * True, if m_pendingItems and m_dispatchedItems should be
+     * cleared when the preview jobs have been finished.
+     */
+    bool m_clearItemQueues;
+
+    /**
+     * True if a selection has been done which should cut items.
+     */
+    bool m_hasCutSelection;
+
+    int m_pendingVisiblePreviews;
+
+    QAbstractItemView* m_view;
+    QTimer* m_previewTimer;
+    QTimer* m_scrollAreaTimer;
+    QList<KJob*> m_previewJobs;
+    KDirModel* m_dirModel;
+    KDirSortFilterProxyModel* m_proxyModel;
+
+    KMimeTypeResolver* m_mimeTypeResolver;
+
+    QList<ItemInfo> m_cutItemsCache;
+    QList<ItemInfo> m_previews;
+
+    /**
+     * Contains all items where a preview must be generated, but
+     * where the preview job has not dispatched the items yet.
+     */
+    KFileItemList m_pendingItems;
+
+    /**
+     * Contains all items, where a preview has already been
+     * generated by the preview jobs.
+     */
+    KFileItemList m_dispatchedItems;
+};
+
+inline bool KFilePreviewGenerator::showPreview() const
+{
+    return m_showPreview;
+}
+
+#endif