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/JobUiDelegate>
  25 #include <KIO/PreviewJob>
  26
  27 #include <QApplication>
  28 #include <QDesktopWidget>
  29 #include <QLayout>
  30 #include <QScrollArea>
  31 #include <QScrollBar>
  32 #include <QStyle>
  33 #include <QTimer>
  34
  35 ToolTipManager::ToolTipManager(QWidget* parent) :
  36     QObject(parent),
  37     m_showToolTipTimer(0),
  38     m_contentRetrievalTimer(0),
  39     m_fileMetaDataToolTip(0),
  40     m_toolTipRequested(false),
  41     m_metaDataRequested(false),
  42     m_appliedWaitCursor(false),
  43     m_margin(4),
  44     m_item(),
  45     m_itemRect()
  46 {
  47     if (parent) {
  48         m_margin = qMax(m_margin, parent->style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth));
  49     }
  50
  51     m_showToolTipTimer = new QTimer(this);
  52     m_showToolTipTimer->setSingleShot(true);
  53     m_showToolTipTimer->setInterval(500);
  54     connect(m_showToolTipTimer, SIGNAL(timeout()), this, SLOT(showToolTip()));
  55
  56     m_contentRetrievalTimer = new QTimer(this);
  57     m_contentRetrievalTimer->setSingleShot(true);
  58     m_contentRetrievalTimer->setInterval(200);
  59     connect(m_contentRetrievalTimer, SIGNAL(timeout()), this, SLOT(startContentRetrieval()));
  60
  61     Q_ASSERT(m_contentRetrievalTimer->interval() < m_showToolTipTimer->interval());
  62 }
  63
  64 ToolTipManager::~ToolTipManager()
  65 {
  66     delete m_fileMetaDataToolTip;
  67     m_fileMetaDataToolTip = 0;
  68 }
  69
  70 void ToolTipManager::showToolTip(const KFileItem& item, const QRectF& itemRect)
  71 {
  72     hideToolTip();
  73
  74     m_itemRect = itemRect.toRect();
  75
  76     m_itemRect.adjust(-m_margin, -m_margin, m_margin, m_margin);
  77     m_item = item;
  78
  79     // Only start the retrieving of the content, when the mouse has been over this
  80     // item for 200 milliseconds. This prevents a lot of useless preview jobs and
  81     // meta data retrieval, when passing rapidly over a lot of items.
  82     Q_ASSERT(!m_fileMetaDataToolTip);
  83     m_fileMetaDataToolTip = new FileMetaDataToolTip();
  84     connect(m_fileMetaDataToolTip, SIGNAL(metaDataRequestFinished(KFileItemList)),
  85             this, SLOT(slotMetaDataRequestFinished()));
  86
  87     m_contentRetrievalTimer->start();
  88     m_showToolTipTimer->start();
  89     m_toolTipRequested = true;
  90     Q_ASSERT(!m_metaDataRequested);
  91 }
  92
  93 void ToolTipManager::hideToolTip()
  94 {
  95     if (m_appliedWaitCursor) {
  96         QApplication::restoreOverrideCursor();
  97         m_appliedWaitCursor = false;
  98     }
  99
 100     m_toolTipRequested = false;
 101     m_metaDataRequested = false;
 102     m_showToolTipTimer->stop();
 103     m_contentRetrievalTimer->stop();
 104
 105     if (m_fileMetaDataToolTip) {
 106         m_fileMetaDataToolTip->hide();
 107         delete m_fileMetaDataToolTip;
 108         m_fileMetaDataToolTip = 0;
 109     }
 110 }
 111
 112 void ToolTipManager::startContentRetrieval()
 113 {
 114     if (!m_toolTipRequested) {
 115         return;
 116     }
 117
 118     m_fileMetaDataToolTip->setName(m_item.text());
 119
 120     // Request the retrieval of meta-data. The slot
 121     // slotMetaDataRequestFinished() is invoked after the
 122     // meta-data have been received.
 123     m_metaDataRequested = true;
 124     m_fileMetaDataToolTip->setItems(KFileItemList() << m_item);
 125     m_fileMetaDataToolTip->adjustSize();
 126
 127     // Request a preview of the item
 128     m_fileMetaDataToolTip->setPreview(QPixmap());
 129
 130     KIO::PreviewJob* job = new KIO::PreviewJob(KFileItemList() << m_item, QSize(256, 256));
 131     job->setIgnoreMaximumSize(m_item.isLocalFile());
 132     if (job->ui()) {
 133         job->ui()->setWindow(qApp->activeWindow());
 134     }
 135
 136     connect(job, SIGNAL(gotPreview(KFileItem,QPixmap)),
 137             this, SLOT(setPreviewPix(KFileItem,QPixmap)));
 138     connect(job, SIGNAL(failed(KFileItem)),
 139             this, SLOT(previewFailed()));
 140 }
 141
 142
 143 void ToolTipManager::setPreviewPix(const KFileItem& item,
 144                                    const QPixmap& pixmap)
 145 {
 146     if (!m_toolTipRequested || (m_item.url() != item.url())) {
 147         // No tooltip is requested anymore or an old preview has been received
 148         return;
 149     }
 150
 151     if (pixmap.isNull()) {
 152         previewFailed();
 153     } else {
 154         m_fileMetaDataToolTip->setPreview(pixmap);
 155         if (!m_showToolTipTimer->isActive()) {
 156             showToolTip();
 157         }
 158     }
 159 }
 160
 161 void ToolTipManager::previewFailed()
 162 {
 163     if (!m_toolTipRequested) {
 164         return;
 165     }
 166
 167     const QPixmap pixmap = KIcon(m_item.iconName()).pixmap(128, 128);
 168     m_fileMetaDataToolTip->setPreview(pixmap);
 169     if (!m_showToolTipTimer->isActive()) {
 170         showToolTip();
 171     }
 172 }
 173
 174 void ToolTipManager::slotMetaDataRequestFinished()
 175 {
 176     if (!m_toolTipRequested) {
 177         return;
 178     }
 179
 180     m_metaDataRequested = false;
 181
 182     if (!m_showToolTipTimer->isActive()) {
 183         showToolTip();
 184     }
 185 }
 186
 187 void ToolTipManager::showToolTip()
 188 {
 189     Q_ASSERT(m_toolTipRequested);
 190     if (m_appliedWaitCursor) {
 191         QApplication::restoreOverrideCursor();
 192         m_appliedWaitCursor = false;
 193     }
 194
 195     if (m_fileMetaDataToolTip->preview().isNull() || m_metaDataRequested) {
 196         Q_ASSERT(!m_appliedWaitCursor);
 197         QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 198         m_appliedWaitCursor = true;
 199         return;
 200     }
 201
 202     const QRect screen = QApplication::desktop()->screenGeometry(QCursor::pos());
 203
 204     // Restrict tooltip size to current screen size when needed.
 205     // Because layout controlling widget doesn't respect widget's maximumSize property
 206     // (correct me if I'm wrong), we need to let layout do its work, then manually change
 207     // geometry if resulting widget doesn't fit the screen.
 208
 209     // Step #1 - make sizeHint return calculated tooltip size
 210     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetFixedSize);
 211     m_fileMetaDataToolTip->adjustSize();
 212     QSize size = m_fileMetaDataToolTip->sizeHint();
 213
 214     // Step #2 - correct tooltip size when needed
 215     if (size.width() > screen.width()) {
 216         size.setWidth(screen.width());
 217     }
 218     if (size.height() > screen.height()) {
 219         size.setHeight(screen.height());
 220     }
 221
 222     // m_itemRect defines the area of the item, where the tooltip should be
 223     // shown. Per default the tooltip is shown centered at the bottom.
 224     // It must be assured that:
 225     // - the content is fully visible
 226     // - the content is not drawn inside m_itemRect
 227     const bool hasRoomToLeft  = (m_itemRect.left()   - size.width()  - m_margin >= screen.left());
 228     const bool hasRoomToRight = (m_itemRect.right()  + size.width()  + m_margin <= screen.right());
 229     const bool hasRoomAbove   = (m_itemRect.top()    - size.height() - m_margin >= screen.top());
 230     const bool hasRoomBelow   = (m_itemRect.bottom() + size.height() + m_margin <= screen.bottom());
 231     if (!hasRoomAbove && !hasRoomBelow && !hasRoomToLeft && !hasRoomToRight) {
 232         return;
 233     }
 234
 235     int x, y;
 236     if (hasRoomBelow || hasRoomAbove) {
 237         x = qMax(screen.left(), m_itemRect.center().x() - size.width() / 2);
 238         if (x + size.width() >= screen.right()) {
 239             x = screen.right() - size.width() + 1;
 240         }
 241         if (hasRoomBelow) {
 242             y = m_itemRect.bottom() + m_margin;
 243         } else {
 244             y = m_itemRect.top() - size.height() - m_margin;
 245         }
 246     } else {
 247         Q_ASSERT(hasRoomToLeft || hasRoomToRight);
 248         if (hasRoomToRight) {
 249             x = m_itemRect.right() + m_margin;
 250         } else {
 251             x = m_itemRect.left() - size.width() - m_margin;
 252         }
 253         // Put the tooltip at the bottom of the screen. The x-coordinate has already
 254         // been adjusted, so that no overlapping with m_itemRect occurs.
 255         y = screen.bottom() - size.height() + 1;
 256     }
 257
 258     // Step #3 - Alter tooltip geometry
 259     m_fileMetaDataToolTip->setFixedSize(size);
 260     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetNoConstraint);
 261     m_fileMetaDataToolTip->move(QPoint(x, y));
 262     m_fileMetaDataToolTip->show();
 263
 264     m_toolTipRequested = false;
 265 }
 266
 267 #include "tooltipmanager.moc"