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 KMimeTypeResolver;
  34 class QAbstractItemView;
  35
  36 /**
  37  * @brief Manages the icon state of a directory model.
  38  *
  39  * Per default a preview is generated for each item.
  40  * Additionally the clipboard is checked for cut items.
  41  * The icon state for cut items gets dimmed automatically.
  42  *
  43  * The following strategy is used when creating previews:
  44  * - The previews for currently visible items are created before
  45  *   the previews for invisible items.
  46  * - If the user changes the visible area by using the scrollbars,
  47  *   all pending previews get paused. As soon as the user stays
  48  *   on the same position for a short delay, the previews are
  49  *   resumed. Also in this case the previews for the visible items
  50  *   are generated first.
  51  */
  52 class IconManager : public QObject
  53 {
  54     Q_OBJECT
  55
  56 public:
  57     IconManager(QAbstractItemView* parent, DolphinSortFilterProxyModel* model);
  58     virtual ~IconManager();
  59     void setShowPreview(bool show);
  60     bool showPreview() const;
  61
  62     /**
  63      * Updates the previews for all already available items. It is only necessary
  64      * to invoke this method when the icon size of the abstract item view has
  65      * been changed.
  66      */
  67     void updatePreviews();
  68
  69     /**
  70      * Cancels all pending previews. Should be invoked when the URL of the item
  71      * view has been changed.
  72      */
  73     void cancelPreviews();
  74
  75 private slots:
  76     /**
  77      * Generates previews for the items \a items asynchronously.
  78      */
  79     void generatePreviews(const KFileItemList& items);
  80
  81     /**
  82      * Adds the preview \a pixmap for the item \a item to the preview
  83      * queue and starts a timer which will dispatch the preview queue
  84      * later.
  85      */
  86     void addToPreviewQueue(const KFileItem& item, const QPixmap& pixmap);
  87
  88     /**
  89      * Is invoked when the preview job has been finished and
  90      * removes the job from the m_previewJobs list.
  91      */
  92     void slotPreviewJobFinished(KJob* job);
  93
  94     /** Synchronizes the item icon with the clipboard of cut items. */
  95     void updateCutItems();
  96
  97     /**
  98      * Dispatches the preview queue  block by block within
  99      * time slices.
 100      */
 101     void dispatchPreviewQueue();
 102
 103     /**
 104      * Pauses all preview jobs and invokes IconManager::resumePreviews()
 105      * after a short delay. Is invoked as soon as the user has moved
 106      * a scrollbar.
 107      */
 108     void pausePreviews();
 109
 110     /**
 111      * Resumes the previews that have been paused after moving the
 112      * scrollbar. The previews for the current visible area are
 113      * generated first.
 114      */
 115     void resumePreviews();
 116
 117 private:
 118     /**
 119      * Replaces the icon of the item with the \a url by the preview pixmap
 120      * \a pixmap.
 121      */
 122     void replaceIcon(const KUrl& url, const QPixmap& pixmap);
 123
 124     /**
 125      * Returns true, if the item \a item has been cut into
 126      * the clipboard.
 127      */
 128     bool isCutItem(const KFileItem& item) const;
 129
 130     /** Applies an item effect to all cut items. */
 131     void applyCutItemEffect();
 132
 133     /**
 134      * Applies a frame around the icon. False is returned if
 135      * no frame has been added because the icon is too small.
 136      */
 137     bool applyImageFrame(QPixmap& icon);
 138
 139     /**
 140      * Resizes the icon to \a maxSize if the icon size does not
 141      * fit into the maximum size. The aspect ratio of the icon
 142      * is kept.
 143      */
 144     void limitToSize(QPixmap& icon, const QSize& maxSize);
 145
 146     /**
 147      * Starts a new preview job for the items \a to m_previewJobs
 148      * and triggers the preview timer.
 149      */
 150     void startPreviewJob(const KFileItemList& items);
 151
 152     /** Kills all ongoing preview jobs. */
 153     void killPreviewJobs();
 154
 155     /**
 156      * Returns true, if the item list \a items contains an item with the
 157      * URL \a url. This is a helper method for IconManager::generatePreviews().
 158      */
 159     bool itemListContains(const KFileItemList& items, const KUrl& url) const;
 160
 161 private:
 162     /** Remembers the pixmap for an item specified by an URL. */
 163     struct ItemInfo
 164     {
 165         KUrl url;
 166         QPixmap pixmap;
 167     };
 168
 169     bool m_showPreview;
 170
 171     /**
 172      * True, if m_pendingItems and m_dispatchedItems should be
 173      * cleared when the preview jobs have been finished.
 174      */
 175     bool m_clearItemQueues;
 176
 177     QAbstractItemView* m_view;
 178     QTimer* m_previewTimer;
 179     QTimer* m_scrollAreaTimer;
 180     QList<KJob*> m_previewJobs;
 181     DolphinModel* m_dolphinModel;
 182     DolphinSortFilterProxyModel* m_proxyModel;
 183
 184     KMimeTypeResolver* m_mimeTypeResolver;
 185
 186     QList<ItemInfo> m_cutItemsCache;
 187     QList<ItemInfo> m_previews;
 188
 189     /**
 190      * Contains the URLs of all items where a preview must be generated, but
 191      * where the preview job has not dispatched the items yet.
 192      */
 193     QList<KUrl> m_pendingItems;
 194
 195     /**
 196      * Contains the URLs of all items, where a preview has already been
 197      * generated by the preview jobs.
 198      */
 199     QList<KUrl> m_dispatchedItems;
 200 };
 201
 202 inline bool IconManager::showPreview() const
 203 {
 204     return m_showPreview;
 205 }
 206
 207 #endif