gwenview/lib/scrolltool.cpp

   1 // vim: set tabstop=4 shiftwidth=4 noexpandtab:
   2 /*
   3 Gwenview: an image viewer
   4 Copyright 2007 Aurélien Gâteau <aurelien.gateau@free.fr>
   5
   6 This program is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public License
   8 as published by the Free Software Foundation; either version 2
   9 of the License, or (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19
  20 */
  21 // Self
  22 #include "scrolltool.moc"
  23
  24 // Qt
  25 #include <QApplication>
  26 #include <QMouseEvent>
  27 #include <QScrollBar>
  28
  29 // KDE
  30 #include <kdebug.h>
  31 #include <kstandarddirs.h>
  32
  33 // Local
  34 #include "imageview.h"
  35
  36 namespace Gwenview {
  37
  38 enum State { StateNone, StateZooming, StateDragging };
  39
  40 struct ScrollToolPrivate {
  41         ScrollTool::MouseWheelBehavior mMouseWheelBehavior;
  42         int mScrollStartX;
  43         int mScrollStartY;
  44         State mState;
  45         QCursor mZoomCursor;
  46 };
  47
  48
  49 ScrollTool::ScrollTool(ImageView* view)
  50 : AbstractImageViewTool(view)
  51 , d(new ScrollToolPrivate) {
  52         d->mState = StateNone;
  53         d->mMouseWheelBehavior = MouseWheelScroll;
  54
  55         QString path = KStandardDirs::locate("appdata", "cursors/zoom.png");
  56         QPixmap cursorPixmap = QPixmap(path);
  57         d->mZoomCursor = QCursor(cursorPixmap);
  58 }
  59
  60
  61 ScrollTool::~ScrollTool() {
  62         delete d;
  63 }
  64
  65
  66 void ScrollTool::setMouseWheelBehavior(ScrollTool::MouseWheelBehavior behavior) {
  67         d->mMouseWheelBehavior = behavior;
  68 }
  69
  70
  71 ScrollTool::MouseWheelBehavior ScrollTool::mouseWheelBehavior() const {
  72         return d->mMouseWheelBehavior;
  73 }
  74
  75
  76 void ScrollTool::mousePressEvent(QMouseEvent* event) {
  77         if (event->modifiers() == Qt::ControlModifier) {
  78                 // Ctrl + Left or right button => zoom in or out
  79                 if (event->button() == Qt::LeftButton) {
  80                         emit zoomInRequested(event->pos());
  81                 } else if (event->button() == Qt::RightButton) {
  82                         emit zoomOutRequested(event->pos());
  83                 }
  84                 return;
  85         }
  86
  87         if (imageView()->zoomToFit()) {
  88                 return;
  89         }
  90
  91         if (event->button() != Qt::LeftButton) {
  92                 return;
  93         }
  94
  95         d->mScrollStartY = event->y();
  96         d->mScrollStartX = event->x();
  97         d->mState = StateDragging;
  98         imageView()->viewport()->setCursor(Qt::ClosedHandCursor);
  99 }
 100
 101
 102 void ScrollTool::mouseMoveEvent(QMouseEvent* event) {
 103         if (d->mState != StateDragging) {
 104                 return;
 105         }
 106
 107         int deltaX,deltaY;
 108
 109         deltaX = d->mScrollStartX - event->x();
 110         deltaY = d->mScrollStartY - event->y();
 111
 112         d->mScrollStartX = event->x();
 113         d->mScrollStartY = event->y();
 114         imageView()->horizontalScrollBar()->setValue(
 115                 imageView()->horizontalScrollBar()->value() + deltaX);
 116         imageView()->verticalScrollBar()->setValue(
 117                 imageView()->verticalScrollBar()->value() + deltaY);
 118 }
 119
 120
 121 void ScrollTool::mouseReleaseEvent(QMouseEvent* /*event*/) {
 122         if (d->mState != StateDragging) {
 123                 return;
 124         }
 125
 126         d->mState = StateNone;
 127         imageView()->viewport()->setCursor(Qt::OpenHandCursor);
 128 }
 129
 130
 131 void ScrollTool::wheelEvent(QWheelEvent* event) {
 132         if (event->modifiers() & Qt::ControlModifier) {
 133                 // Ctrl + wheel => zoom in or out
 134                 if (event->delta() > 0) {
 135                         emit zoomInRequested(event->pos());
 136                 } else {
 137                         emit zoomOutRequested(event->pos());
 138                 }
 139                 return;
 140         }
 141
 142         if (d->mMouseWheelBehavior == MouseWheelScroll) {
 143                 // Forward events to the scrollbars, like
 144                 // QAbstractScrollArea::wheelEvent() do.
 145                 if (event->orientation() == Qt::Horizontal) {
 146                         QApplication::sendEvent(imageView()->horizontalScrollBar(), event);
 147                 } else {
 148                         QApplication::sendEvent(imageView()->verticalScrollBar(), event);
 149                 }
 150         } else {
 151                 // Browse
 152                 if (event->delta() > 0) {
 153                         emit previousImageRequested();
 154                 } else {
 155                         emit nextImageRequested();
 156                 }
 157         }
 158 }
 159
 160
 161 void ScrollTool::keyPressEvent(QKeyEvent* event) {
 162         if (event->modifiers() == Qt::ControlModifier && d->mState == StateNone) {
 163                 d->mState = StateZooming;
 164                 imageView()->viewport()->setCursor(d->mZoomCursor);
 165         }
 166 }
 167
 168
 169 void ScrollTool::keyReleaseEvent(QKeyEvent* event) {
 170         if (!(event->modifiers() & Qt::ControlModifier) && d->mState == StateZooming) {
 171                 d->mState = StateNone;
 172                 imageView()->viewport()->setCursor(Qt::ArrowCursor);
 173         }
 174 }
 175
 176
 177 void ScrollTool::toolActivated() {
 178         imageView()->viewport()->setCursor(Qt::OpenHandCursor);
 179         imageView()->viewport()->installEventFilter(this);
 180 }
 181
 182
 183 void ScrollTool::toolDeactivated() {
 184         imageView()->viewport()->removeEventFilter(this);
 185         imageView()->viewport()->setCursor(Qt::ArrowCursor);
 186 }
 187
 188
 189 bool ScrollTool::eventFilter(QObject*, QEvent* event) {
 190         if (event->type() == QEvent::ContextMenu) {
 191                 // Filter out context menu if Ctrl is down to avoid showing it when
 192                 // zooming out with Ctrl + Right button
 193                 QContextMenuEvent* contextMenuEvent = static_cast<QContextMenuEvent*>(event);
 194                 if (contextMenuEvent->modifiers() == Qt::ControlModifier) {
 195                         return true;
 196                 }
 197         }
 198
 199         return false;
 200 }
 201
 202
 203 } // namespace