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 <QIcon>
  24 #include <KIO/JobUiDelegate>
  25 #include <KIO/PreviewJob>
  26 #include <KJobWidgets>
  27
  28 #include <QApplication>
  29 #include <QDesktopWidget>
  30 #include <QLayout>
  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, &QTimer::timeout, this, static_cast<void(ToolTipManager::*)()>(&ToolTipManager::showToolTip));
  54
  55     m_contentRetrievalTimer = new QTimer(this);
  56     m_contentRetrievalTimer->setSingleShot(true);
  57     m_contentRetrievalTimer->setInterval(200);
  58     connect(m_contentRetrievalTimer, &QTimer::timeout, this, &ToolTipManager::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, &FileMetaDataToolTip::metaDataRequestFinished,
  84             this, &ToolTipManager::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         // Do not delete the tool tip immediately to prevent crashes when
 107         // QCoreApplication tries to deliver an 'Enter' event to it, see bug 310579.
 108         m_fileMetaDataToolTip->deleteLater();
 109         m_fileMetaDataToolTip = 0;
 110     }
 111 }
 112
 113 void ToolTipManager::startContentRetrieval()
 114 {
 115     if (!m_toolTipRequested) {
 116         return;
 117     }
 118
 119     m_fileMetaDataToolTip->setName(m_item.text());
 120
 121     // Request the retrieval of meta-data. The slot
 122     // slotMetaDataRequestFinished() is invoked after the
 123     // meta-data have been received.
 124     m_metaDataRequested = true;
 125     m_fileMetaDataToolTip->setItems(KFileItemList() << m_item);
 126     m_fileMetaDataToolTip->adjustSize();
 127
 128     // Request a preview of the item
 129     m_fileMetaDataToolTip->setPreview(QPixmap());
 130
 131     KIO::PreviewJob* job = new KIO::PreviewJob(KFileItemList() << m_item, QSize(256, 256));
 132     job->setIgnoreMaximumSize(m_item.isLocalFile());
 133     if (job->ui()) {
 134         KJobWidgets::setWindow(job, qApp->activeWindow());
 135     }
 136
 137     connect(job, &KIO::PreviewJob::gotPreview,
 138             this, &ToolTipManager::setPreviewPix);
 139     connect(job, &KIO::PreviewJob::failed,
 140             this, &ToolTipManager::previewFailed);
 141 }
 142
 143
 144 void ToolTipManager::setPreviewPix(const KFileItem& item,
 145                                    const QPixmap& pixmap)
 146 {
 147     if (!m_toolTipRequested || (m_item.url() != item.url())) {
 148         // No tooltip is requested anymore or an old preview has been received
 149         return;
 150     }
 151
 152     if (pixmap.isNull()) {
 153         previewFailed();
 154     } else {
 155         m_fileMetaDataToolTip->setPreview(pixmap);
 156         if (!m_showToolTipTimer->isActive()) {
 157             showToolTip();
 158         }
 159     }
 160 }
 161
 162 void ToolTipManager::previewFailed()
 163 {
 164     if (!m_toolTipRequested) {
 165         return;
 166     }
 167
 168     const QPixmap pixmap = QIcon::fromTheme(m_item.iconName()).pixmap(128, 128);
 169     m_fileMetaDataToolTip->setPreview(pixmap);
 170     if (!m_showToolTipTimer->isActive()) {
 171         showToolTip();
 172     }
 173 }
 174
 175 void ToolTipManager::slotMetaDataRequestFinished()
 176 {
 177     if (!m_toolTipRequested) {
 178         return;
 179     }
 180
 181     m_metaDataRequested = false;
 182
 183     if (!m_showToolTipTimer->isActive()) {
 184         showToolTip();
 185     }
 186 }
 187
 188 void ToolTipManager::showToolTip()
 189 {
 190     Q_ASSERT(m_toolTipRequested);
 191     if (m_appliedWaitCursor) {
 192         QApplication::restoreOverrideCursor();
 193         m_appliedWaitCursor = false;
 194     }
 195
 196     if (m_fileMetaDataToolTip->preview().isNull() || m_metaDataRequested) {
 197         Q_ASSERT(!m_appliedWaitCursor);
 198         QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
 199         m_appliedWaitCursor = true;
 200         return;
 201     }
 202
 203     const QRect screen = QApplication::desktop()->screenGeometry(QCursor::pos());
 204
 205     // Restrict tooltip size to current screen size when needed.
 206     // Because layout controlling widget doesn't respect widget's maximumSize property
 207     // (correct me if I'm wrong), we need to let layout do its work, then manually change
 208     // geometry if resulting widget doesn't fit the screen.
 209
 210     // Step #1 - make sizeHint return calculated tooltip size
 211     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetFixedSize);
 212     m_fileMetaDataToolTip->adjustSize();
 213     QSize size = m_fileMetaDataToolTip->sizeHint();
 214
 215     // Step #2 - correct tooltip size when needed
 216     if (size.width() > screen.width()) {
 217         size.setWidth(screen.width());
 218     }
 219     if (size.height() > screen.height()) {
 220         size.setHeight(screen.height());
 221     }
 222
 223     // m_itemRect defines the area of the item, where the tooltip should be
 224     // shown. Per default the tooltip is shown centered at the bottom.
 225     // It must be assured that:
 226     // - the content is fully visible
 227     // - the content is not drawn inside m_itemRect
 228     const bool hasRoomToLeft  = (m_itemRect.left()   - size.width()  - m_margin >= screen.left());
 229     const bool hasRoomToRight = (m_itemRect.right()  + size.width()  + m_margin <= screen.right());
 230     const bool hasRoomAbove   = (m_itemRect.top()    - size.height() - m_margin >= screen.top());
 231     const bool hasRoomBelow   = (m_itemRect.bottom() + size.height() + m_margin <= screen.bottom());
 232     if (!hasRoomAbove && !hasRoomBelow && !hasRoomToLeft && !hasRoomToRight) {
 233         return;
 234     }
 235
 236     int x, y;
 237     if (hasRoomBelow || hasRoomAbove) {
 238         x = qMax(screen.left(), m_itemRect.center().x() - size.width() / 2);
 239         if (x + size.width() >= screen.right()) {
 240             x = screen.right() - size.width() + 1;
 241         }
 242         if (hasRoomBelow) {
 243             y = m_itemRect.bottom() + m_margin;
 244         } else {
 245             y = m_itemRect.top() - size.height() - m_margin;
 246         }
 247     } else {
 248         Q_ASSERT(hasRoomToLeft || hasRoomToRight);
 249         if (hasRoomToRight) {
 250             x = m_itemRect.right() + m_margin;
 251         } else {
 252             x = m_itemRect.left() - size.width() - m_margin;
 253         }
 254         // Put the tooltip at the bottom of the screen. The x-coordinate has already
 255         // been adjusted, so that no overlapping with m_itemRect occurs.
 256         y = screen.bottom() - size.height() + 1;
 257     }
 258
 259     // Step #3 - Alter tooltip geometry
 260     m_fileMetaDataToolTip->setFixedSize(size);
 261     m_fileMetaDataToolTip->layout()->setSizeConstraint(QLayout::SetNoConstraint);
 262     m_fileMetaDataToolTip->move(QPoint(x, y));
 263     m_fileMetaDataToolTip->show();
 264
 265     m_toolTipRequested = false;
 266 }
 267