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 #include <KJobWidgets>
  27
  28 #include <QApplication>
  29 #include <QDesktopWidget>
  30 #include <QLayout>
  31 #include <QScrollArea>
  32 #include <QScrollBar>
  33 #include <QStyle>
  34 #include <QTimer>
  35
  36 ToolTipManager::ToolTipManager(QWidget* parent) :
  37     QObject(parent),
  38     m_showToolTipTimer(0),
  39     m_contentRetrievalTimer(0),
  40     m_fileMetaDataToolTip(0),
  41     m_toolTipRequested(false),
  42     m_metaDataRequested(false),
  43     m_appliedWaitCursor(false),
  44     m_margin(4),
  45     m_item(),
  46     m_itemRect()
  47 {
  48     if (parent) {
  49         m_margin = qMax(m_margin, parent->style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth));
  50     }
  51
  52     m_showToolTipTimer = new QTimer(this);
  53     m_showToolTipTimer->setSingleShot(true);
  54     m_showToolTipTimer->setInterval(500);
  55     connect(m_showToolTipTimer, &QTimer::timeout, this, static_cast<void(ToolTipManager::*)()>(&ToolTipManager::showToolTip));
  56
  57     m_contentRetrievalTimer = new QTimer(this);
  58     m_contentRetrievalTimer->setSingleShot(true);
  59     m_contentRetrievalTimer->setInterval(200);
  60     connect(m_contentRetrievalTimer, &QTimer::timeout, this, &ToolTipManager::startContentRetrieval);
  61
  62     Q_ASSERT(m_contentRetrievalTimer->interval() < m_showToolTipTimer->interval());
  63 }
  64
  65 ToolTipManager::~ToolTipManager()
  66 {
  67     delete m_fileMetaDataToolTip;
  68     m_fileMetaDataToolTip = 0;
  69 }
  70
  71 void ToolTipManager::showToolTip(const KFileItem& item, const QRectF& itemRect)
  72 {
  73     hideToolTip();
  74
  75     m_itemRect = itemRect.toRect();
  76
  77     m_itemRect.adjust(-m_margin, -m_margin, m_margin, m_margin);
  78     m_item = item;
  79
  80     // Only start the retrieving of the content, when the mouse has been over this
  81     // item for 200 milliseconds. This prevents a lot of useless preview jobs and
  82     // meta data retrieval, when passing rapidly over a lot of items.
  83     Q_ASSERT(!m_fileMetaDataToolTip);
  84     m_fileMetaDataToolTip = new FileMetaDataToolTip();
  85     connect(m_fileMetaDataToolTip, &FileMetaDataToolTip::metaDataRequestFinished,
  86             this, &ToolTipManager::slotMetaDataRequestFinished);
  87
  88     m_contentRetrievalTimer->start();
  89     m_showToolTipTimer->start();
  90     m_toolTipRequested = true;
  91     Q_ASSERT(!m_metaDataRequested);
  92 }
  93
  94 void ToolTipManager::hideToolTip()
  95 {
  96     if (m_appliedWaitCursor) {
  97         QApplication::restoreOverrideCursor();
  98         m_appliedWaitCursor = false;
  99     }
 100
 101     m_toolTipRequested = false;
 102     m_metaDataRequested = false;
 103     m_showToolTipTimer->stop();
 104     m_contentRetrievalTimer->stop();
 105
 106     if (m_fileMetaDataToolTip) {
 107         m_fileMetaDataToolTip->hide();
 108         // Do not delete the tool tip immediately to prevent crashes when
 109         // QCoreApplication tries to deliver an 'Enter' event to it, see bug 310579.
 110         m_fileMetaDataToolTip->deleteLater();
 111         m_fileMetaDataToolTip = 0;
 112     }
 113 }
 114
 115 void ToolTipManager::startContentRetrieval()
 116 {
 117     if (!m_toolTipRequested) {
 118         return;
 119     }
 120
 121     m_fileMetaDataToolTip->setName(m_item.text());
 122
 123     // Request the retrieval of meta-data. The slot
 124     // slotMetaDataRequestFinished() is invoked after the
 125     // meta-data have been received.
 126     m_metaDataRequested = true;
 127     m_fileMetaDataToolTip->setItems(KFileItemList() << m_item);
 128     m_fileMetaDataToolTip->adjustSize();
 129
 130     // Request a preview of the item
 131     m_fileMetaDataToolTip->setPreview(QPixmap());
 132
 133     KIO::PreviewJob* job = new KIO::PreviewJob(KFileItemList() << m_item, QSize(256, 256));
 134     job->setIgnoreMaximumSize(m_item.isLocalFile());
 135     if (job->ui()) {
 136         KJobWidgets::setWindow(job, qApp->activeWindow());
 137     }
 138
 139     connect(job, &KIO::PreviewJob::gotPreview,
 140             this, &ToolTipManager::setPreviewPix);
 141     connect(job, &KIO::PreviewJob::failed,
 142             this, &ToolTipManager::previewFailed);
 143 }
 144
 145
 146 void ToolTipManager::setPreviewPix(const KFileItem& item,
 147                                    const QPixmap& pixmap)
 148 {
 149     if (!m_toolTipRequested || (m_item.url() != item.url())) {
 150         // No tooltip is requested anymore or an old preview has been received
 151         return;
 152     }
 153
 154     if (pixmap.isNull()) {
 155         previewFailed();
 156     } else {
 157         m_fileMetaDataToolTip->setPreview(pixmap);
 158         if (!m_showToolTipTimer->isActive()) {
 159             showToolTip();
 160         }
 161     }
 162 }
 163
 164 void ToolTipManager::previewFailed()
 165 {
 166     if (!m_toolTipRequested) {
 167         return;
 168     }
 169
 170     const QPixmap pixmap = KIcon(m_item.iconName()).pixmap(128, 128);
 171     m_fileMetaDataToolTip->setPreview(pixmap);
 172     if (!m_showToolTipTimer->isActive()) {
 173         showToolTip();
 174     }
 175 }
 176
 177 void ToolTipManager::slotMetaDataRequestFinished()
 178 {
 179     if (!m_toolTipRequested) {
 180         return;
 181     }
 182
 183     m_metaDataRequested = false;
 184
 185     if (!m_showToolTipTimer->isActive()) {
 186         showToolTip();
 187     }
 188 }
 189
 190 void ToolTipManager::showToolTip()
 191 {
 192     Q_ASSERT(m_toolTipRequested);
 193     if (m_appliedWaitCursor) {
 194         QApplication::restoreOverrideCursor();
 195         m_appliedWaitCursor = false;
 196     }
 197
 198     if (m_fileMetaDataToolTip->preview().isNull() || m_metaDataRequested) {
 199         Q_ASSERT(!m_appliedWaitCursor);
 200         QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 201         m_appliedWaitCursor = true;
 202         return;
 203     }
 204
 205     const QRect screen = QApplication::desktop()->screenGeometry(QCursor::pos());
 206
 207     // Restrict tooltip size to current screen size when needed.
 208     // Because layout controlling widget doesn't respect widget's maximumSize property
 209     // (correct me if I'm wrong), we need to let layout do its work, then manually change
 210     // geometry if resulting widget doesn't fit the screen.
 211
 212     // Step #1 - make sizeHint return calculated tooltip size
 213     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetFixedSize);
 214     m_fileMetaDataToolTip->adjustSize();
 215     QSize size = m_fileMetaDataToolTip->sizeHint();
 216
 217     // Step #2 - correct tooltip size when needed
 218     if (size.width() > screen.width()) {
 219         size.setWidth(screen.width());
 220     }
 221     if (size.height() > screen.height()) {
 222         size.setHeight(screen.height());
 223     }
 224
 225     // m_itemRect defines the area of the item, where the tooltip should be
 226     // shown. Per default the tooltip is shown centered at the bottom.
 227     // It must be assured that:
 228     // - the content is fully visible
 229     // - the content is not drawn inside m_itemRect
 230     const bool hasRoomToLeft  = (m_itemRect.left()   - size.width()  - m_margin >= screen.left());
 231     const bool hasRoomToRight = (m_itemRect.right()  + size.width()  + m_margin <= screen.right());
 232     const bool hasRoomAbove   = (m_itemRect.top()    - size.height() - m_margin >= screen.top());
 233     const bool hasRoomBelow   = (m_itemRect.bottom() + size.height() + m_margin <= screen.bottom());
 234     if (!hasRoomAbove && !hasRoomBelow && !hasRoomToLeft && !hasRoomToRight) {
 235         return;
 236     }
 237
 238     int x, y;
 239     if (hasRoomBelow || hasRoomAbove) {
 240         x = qMax(screen.left(), m_itemRect.center().x() - size.width() / 2);
 241         if (x + size.width() >= screen.right()) {
 242             x = screen.right() - size.width() + 1;
 243         }
 244         if (hasRoomBelow) {
 245             y = m_itemRect.bottom() + m_margin;
 246         } else {
 247             y = m_itemRect.top() - size.height() - m_margin;
 248         }
 249     } else {
 250         Q_ASSERT(hasRoomToLeft || hasRoomToRight);
 251         if (hasRoomToRight) {
 252             x = m_itemRect.right() + m_margin;
 253         } else {
 254             x = m_itemRect.left() - size.width() - m_margin;
 255         }
 256         // Put the tooltip at the bottom of the screen. The x-coordinate has already
 257         // been adjusted, so that no overlapping with m_itemRect occurs.
 258         y = screen.bottom() - size.height() + 1;
 259     }
 260
 261     // Step #3 - Alter tooltip geometry
 262     m_fileMetaDataToolTip->setFixedSize(size);
 263     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetNoConstraint);
 264     m_fileMetaDataToolTip->move(QPoint(x, y));
 265     m_fileMetaDataToolTip->show();
 266
 267     m_toolTipRequested = false;
 268 }
 269