src/iconmanager.h

   1 /***************************************************************************
   2  *   Copyright (C) 2008 by Peter Penz <peter.penz@gmx.at>                  *
   3  *                                                                         *
   4  *   This program is free software; you can redistribute it and/or modify  *
   5  *   it under the terms of the GNU General Public License as published by  *
   6  *   the Free Software Foundation; either version 2 of the License, or     *
   7  *   (at your option) any later version.                                   *
   8  *                                                                         *
   9  *   This program is distributed in the hope that it will be useful,       *
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  12  *   GNU General Public License for more details.                          *
  13  *                                                                         *
  14  *   You should have received a copy of the GNU General Public License     *
  15  *   along with this program; if not, write to the                         *
  16  *   Free Software Foundation, Inc.,                                       *
  17  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  18  ***************************************************************************/
  19
  20 #ifndef ICONMANAGER_H
  21 #define ICONMANAGER_H
  22
  23 #include <kfileitem.h>
  24 #include <kurl.h>
  25
  26 #include <QList>
  27 #include <QObject>
  28 #include <QPixmap>
  29
  30 class DolphinModel;
  31 class DolphinSortFilterProxyModel;
  32 class KJob;
  33 class QAbstractItemView;
  34
  35 /**
  36  * @brief Manages the icon state of a directory model.
  37  *
  38  * Per default a preview is generated for each item.
  39  * Additionally the clipboard is checked for cut items.
  40  * The icon state for cut items gets dimmed automatically.
  41  *
  42  * The following strategy is used when creating previews:
  43  * - The previews for currently visible items are created before
  44  *   the previews for invisible items.
  45  * - If the user changes the visible area by using the scrollbars,
  46  *   all pending previews get paused. As soon as the user stays
  47  *   on the same position for a short delay, the previews are
  48  *   resumed. Also in this case the previews for the visible items
  49  *   are generated first.
  50  */
  51 class IconManager : public QObject
  52 {
  53     Q_OBJECT
  54
  55 public:
  56     IconManager(QAbstractItemView* parent, DolphinSortFilterProxyModel* model);
  57     virtual ~IconManager();
  58     void setShowPreview(bool show);
  59     bool showPreview() const;
  60     void updatePreviews();
  61
  62 private slots:
  63     /**
  64      * Generates previews for the items \a items asynchronously.
  65      */
  66     void generatePreviews(const KFileItemList &items);
  67
  68     /**
  69      * Adds the preview \a pixmap for the item \a item to the preview
  70      * queue and starts a timer which will dispatch the preview queue
  71      * later.
  72      */
  73     void addToPreviewQueue(const KFileItem& item, const QPixmap& pixmap);
  74
  75     /**
  76      * Is invoked when the preview job has been finished and
  77      * set m_previewJob to 0.
  78      */
  79     void slotPreviewJobFinished(KJob* job);
  80
  81     /** Synchronizes the item icon with the clipboard of cut items. */
  82     void updateCutItems();
  83
  84     /**
  85      * Dispatches the preview queue  block by block within
  86      * time slices.
  87      */
  88     void dispatchPreviewQueue();
  89
  90     /**
  91      * Pauses all preview jobs and invokes IconManager::resumePreviews()
  92      * after a short delay. Is invoked as soon as the user has moved
  93      * a scrollbar.
  94      */
  95     void pausePreviews();
  96
  97     /**
  98      * Resumes the previews that have been paused after moving the
  99      * scrollbar. The previews for the current visible area are
 100      * generated first.
 101      */
 102     void resumePreviews();
 103
 104 private:
 105     /**
 106      * Replaces the icon of the item with the \a url by the preview pixmap
 107      * \a pixmap.
 108      */
 109     void replaceIcon(const KUrl& url, const QPixmap& pixmap);
 110
 111     /**
 112      * Returns true, if the item \a item has been cut into
 113      * the clipboard.
 114      */
 115     bool isCutItem(const KFileItem& item) const;
 116
 117     /** Applies an item effect to all cut items. */
 118     void applyCutItemEffect();
 119
 120     /**
 121      * Applies a frame around the icon. False is returned if
 122      * no frame has been added because the icon is too small.
 123      */
 124     bool applyImageFrame(QPixmap& icon);
 125
 126     /**
 127      * Resizes the icon to \a maxSize if the icon size does not
 128      * fit into the maximum size. The aspect ratio of the icon
 129      * is kept.
 130      */
 131     void limitToSize(QPixmap& icon, const QSize& maxSize);
 132
 133     /**
 134      * Starts a new preview job for the items \a to m_previewJobs
 135      * and triggers the preview timer.
 136      */
 137     void startPreviewJob(const KFileItemList& items);
 138
 139     /** Kills all ongoing preview jobs. */
 140     void killPreviewJobs();
 141
 142 private:
 143     /** Remembers the pixmap for an item specified by an URL. */
 144     struct ItemInfo
 145     {
 146         KUrl url;
 147         QPixmap pixmap;
 148     };
 149
 150     bool m_showPreview;
 151
 152     /**
 153      * True, if m_pendingItems and m_dispatchedItems should be
 154      * cleared when the preview jobs have been finished.
 155      */
 156     bool m_clearItemQueues;
 157
 158     QAbstractItemView* m_view;
 159     QTimer* m_previewTimer;
 160     QTimer* m_scrollAreaTimer;
 161     QList<KJob*> m_previewJobs;
 162     DolphinModel* m_dolphinModel;
 163     DolphinSortFilterProxyModel* m_proxyModel;
 164
 165     QList<ItemInfo> m_cutItemsCache;
 166     QList<ItemInfo> m_previews;
 167
 168     /**
 169      * Contains the URLs of all items where a preview must be generated, but
 170      * where the preview job has not dispatched the items yet.
 171      */
 172     QList<KUrl> m_pendingItems;
 173
 174     /**
 175      * Containts the URLs of all items, where a preview has already been
 176      * generated by the preview jobs.
 177      */
 178     QList<KUrl> m_dispatchedItems;
 179 };
 180
 181 inline bool IconManager::showPreview() const
 182 {
 183     return m_showPreview;
 184 }
 185
 186 #endif