src/views/tooltips/tooltipmanager.cpp

   1 /*******************************************************************************
   2  *   Copyright (C) 2008 by Konstantin Heil <konst.heil@stud.uni-heidelberg.de> *
   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 #include "tooltipmanager.h"
  21
  22 #include "filemetadatatooltip.h"
  23 #include <KIcon>
  24 #include <KIO/PreviewJob>
  25
  26 #include <QApplication>
  27 #include <QDesktopWidget>
  28 #include <QLayout>
  29 #include <QScrollArea>
  30 #include <QScrollBar>
  31 #include <QStyle>
  32 #include <QTimer>
  33
  34 ToolTipManager::ToolTipManager(QWidget* parent) :
  35     QObject(parent),
  36     m_showToolTipTimer(0),
  37     m_contentRetrievalTimer(0),
  38     m_fileMetaDataToolTip(0),
  39     m_toolTipRequested(false),
  40     m_metaDataRequested(false),
  41     m_appliedWaitCursor(false),
  42     m_margin(4),
  43     m_item(),
  44     m_itemRect()
  45 {
  46     if (parent) {
  47         m_margin = qMax(m_margin, parent->style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth));
  48     }
  49
  50     m_showToolTipTimer = new QTimer(this);
  51     m_showToolTipTimer->setSingleShot(true);
  52     m_showToolTipTimer->setInterval(500);
  53     connect(m_showToolTipTimer, SIGNAL(timeout()), this, SLOT(showToolTip()));
  54
  55     m_contentRetrievalTimer = new QTimer(this);
  56     m_contentRetrievalTimer->setSingleShot(true);
  57     m_contentRetrievalTimer->setInterval(200);
  58     connect(m_contentRetrievalTimer, SIGNAL(timeout()), this, SLOT(startContentRetrieval()));
  59
  60     Q_ASSERT(m_contentRetrievalTimer->interval() < m_showToolTipTimer->interval());
  61 }
  62
  63 ToolTipManager::~ToolTipManager()
  64 {
  65     delete m_fileMetaDataToolTip;
  66     m_fileMetaDataToolTip = 0;
  67 }
  68
  69 void ToolTipManager::showToolTip(const KFileItem& item, const QRectF& itemRect)
  70 {
  71     hideToolTip();
  72
  73     m_itemRect = itemRect.toRect();
  74
  75     m_itemRect.adjust(-m_margin, -m_margin, m_margin, m_margin);
  76     m_item = item;
  77
  78     // Only start the retrieving of the content, when the mouse has been over this
  79     // item for 200 milliseconds. This prevents a lot of useless preview jobs and
  80     // meta data retrieval, when passing rapidly over a lot of items.
  81     Q_ASSERT(!m_fileMetaDataToolTip);
  82     m_fileMetaDataToolTip = new FileMetaDataToolTip();
  83     connect(m_fileMetaDataToolTip, SIGNAL(metaDataRequestFinished(KFileItemList)),
  84             this, SLOT(slotMetaDataRequestFinished()));
  85
  86     m_contentRetrievalTimer->start();
  87     m_showToolTipTimer->start();
  88     m_toolTipRequested = true;
  89     Q_ASSERT(!m_metaDataRequested);
  90 }
  91
  92 void ToolTipManager::hideToolTip()
  93 {
  94     if (m_appliedWaitCursor) {
  95         QApplication::restoreOverrideCursor();
  96         m_appliedWaitCursor = false;
  97     }
  98
  99     m_toolTipRequested = false;
 100     m_metaDataRequested = false;
 101     m_showToolTipTimer->stop();
 102     m_contentRetrievalTimer->stop();
 103
 104     if (m_fileMetaDataToolTip) {
 105         m_fileMetaDataToolTip->hide();
 106         delete m_fileMetaDataToolTip;
 107         m_fileMetaDataToolTip = 0;
 108     }
 109 }
 110
 111 void ToolTipManager::startContentRetrieval()
 112 {
 113     if (!m_toolTipRequested) {
 114         return;
 115     }
 116
 117     m_fileMetaDataToolTip->setName(m_item.text());
 118
 119     // Request the retrieval of meta-data. The slot
 120     // slotMetaDataRequestFinished() is invoked after the
 121     // meta-data have been received.
 122     m_metaDataRequested = true;
 123     m_fileMetaDataToolTip->setItems(KFileItemList() << m_item);
 124     m_fileMetaDataToolTip->adjustSize();
 125
 126     // Request a preview of the item
 127     m_fileMetaDataToolTip->setPreview(QPixmap());
 128
 129     KIO::PreviewJob* job = new KIO::PreviewJob(KFileItemList() << m_item, QSize(256, 256));
 130     job->setIgnoreMaximumSize(m_item.isLocalFile());
 131
 132     connect(job, SIGNAL(gotPreview(KFileItem,QPixmap)),
 133             this, SLOT(setPreviewPix(KFileItem,QPixmap)));
 134     connect(job, SIGNAL(failed(KFileItem)),
 135             this, SLOT(previewFailed()));
 136 }
 137
 138
 139 void ToolTipManager::setPreviewPix(const KFileItem& item,
 140                                    const QPixmap& pixmap)
 141 {
 142     if (!m_toolTipRequested || (m_item.url() != item.url())) {
 143         // No tooltip is requested anymore or an old preview has been received
 144         return;
 145     }
 146
 147     if (pixmap.isNull()) {
 148         previewFailed();
 149     } else {
 150         m_fileMetaDataToolTip->setPreview(pixmap);
 151         if (!m_showToolTipTimer->isActive()) {
 152             showToolTip();
 153         }
 154     }
 155 }
 156
 157 void ToolTipManager::previewFailed()
 158 {
 159     if (!m_toolTipRequested) {
 160         return;
 161     }
 162
 163     const QPixmap pixmap = KIcon(m_item.iconName()).pixmap(128, 128);
 164     m_fileMetaDataToolTip->setPreview(pixmap);
 165     if (!m_showToolTipTimer->isActive()) {
 166         showToolTip();
 167     }
 168 }
 169
 170 void ToolTipManager::slotMetaDataRequestFinished()
 171 {
 172     if (!m_toolTipRequested) {
 173         return;
 174     }
 175
 176     m_metaDataRequested = false;
 177
 178     if (!m_showToolTipTimer->isActive()) {
 179         showToolTip();
 180     }
 181 }
 182
 183 void ToolTipManager::showToolTip()
 184 {
 185     Q_ASSERT(m_toolTipRequested);
 186     if (m_appliedWaitCursor) {
 187         QApplication::restoreOverrideCursor();
 188         m_appliedWaitCursor = false;
 189     }
 190
 191     if (m_fileMetaDataToolTip->preview().isNull() || m_metaDataRequested) {
 192         Q_ASSERT(!m_appliedWaitCursor);
 193         QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 194         m_appliedWaitCursor = true;
 195         return;
 196     }
 197
 198     const QRect screen = QApplication::desktop()->screenGeometry(QCursor::pos());
 199
 200     // Restrict tooltip size to current screen size when needed.
 201     // Because layout controlling widget doesn't respect widget's maximumSize property
 202     // (correct me if I'm wrong), we need to let layout do its work, then manually change
 203     // geometry if resulting widget doesn't fit the screen.
 204
 205     // Step #1 - make sizeHint return calculated tooltip size
 206     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetFixedSize);
 207     m_fileMetaDataToolTip->adjustSize();
 208     QSize size = m_fileMetaDataToolTip->sizeHint();
 209
 210     // Step #2 - correct tooltip size when needed
 211     if (size.width() > screen.width()) {
 212         size.setWidth(screen.width());
 213     }
 214     if (size.height() > screen.height()) {
 215         size.setHeight(screen.height());
 216     }
 217
 218     // m_itemRect defines the area of the item, where the tooltip should be
 219     // shown. Per default the tooltip is shown centered at the bottom.
 220     // It must be assured that:
 221     // - the content is fully visible
 222     // - the content is not drawn inside m_itemRect
 223     const bool hasRoomToLeft  = (m_itemRect.left()   - size.width()  - m_margin >= screen.left());
 224     const bool hasRoomToRight = (m_itemRect.right()  + size.width()  + m_margin <= screen.right());
 225     const bool hasRoomAbove   = (m_itemRect.top()    - size.height() - m_margin >= screen.top());
 226     const bool hasRoomBelow   = (m_itemRect.bottom() + size.height() + m_margin <= screen.bottom());
 227     if (!hasRoomAbove && !hasRoomBelow && !hasRoomToLeft && !hasRoomToRight) {
 228         return;
 229     }
 230
 231     int x, y;
 232     if (hasRoomBelow || hasRoomAbove) {
 233         x = qMax(screen.left(), m_itemRect.center().x() - size.width() / 2);
 234         if (x + size.width() >= screen.right()) {
 235             x = screen.right() - size.width() + 1;
 236         }
 237         if (hasRoomBelow) {
 238             y = m_itemRect.bottom() + m_margin;
 239         } else {
 240             y = m_itemRect.top() - size.height() - m_margin;
 241         }
 242     } else {
 243         Q_ASSERT(hasRoomToLeft || hasRoomToRight);
 244         if (hasRoomToRight) {
 245             x = m_itemRect.right() + m_margin;
 246         } else {
 247             x = m_itemRect.left() - size.width() - m_margin;
 248         }
 249         // Put the tooltip at the bottom of the screen. The x-coordinate has already
 250         // been adjusted, so that no overlapping with m_itemRect occurs.
 251         y = screen.bottom() - size.height() + 1;
 252     }
 253
 254     // Step #3 - Alter tooltip geometry
 255     m_fileMetaDataToolTip->setFixedSize(size);
 256     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetNoConstraint);
 257     m_fileMetaDataToolTip->move(QPoint(x, y));
 258     m_fileMetaDataToolTip->show();
 259
 260     m_toolTipRequested = false;
 261 }
 262
 263 #include "tooltipmanager.moc"