src/kitemviews/kitemlistcontainer.cpp

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   Based on the Itemviews NG project from Trolltech Labs:                *
   5  *   http://qt.gitorious.org/qt-labs/itemviews-ng                          *
   6  *                                                                         *
   7  *   This program is free software; you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation; either version 2 of the License, or     *
  10  *   (at your option) any later version.                                   *
  11  *                                                                         *
  12  *   This program is distributed in the hope that it will be useful,       *
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  15  *   GNU General Public License for more details.                          *
  16  *                                                                         *
  17  *   You should have received a copy of the GNU General Public License     *
  18  *   along with this program; if not, write to the                         *
  19  *   Free Software Foundation, Inc.,                                       *
  20  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  21  ***************************************************************************/
  22
  23 #include "kitemlistcontainer.h"
  24
  25 #include "kitemlistcontroller.h"
  26 #include "kitemlistsmoothscroller_p.h"
  27 #include "kitemlistview.h"
  28 #include "kitemmodelbase.h"
  29
  30 #include <QApplication>
  31 #include <QGraphicsScene>
  32 #include <QGraphicsView>
  33 #include <QPropertyAnimation>
  34 #include <QScrollBar>
  35 #include <QStyle>
  36
  37 #include <KDebug>
  38
  39 /**
  40  * Replaces the default viewport of KItemListContainer by a
  41  * non-scrollable viewport. The scrolling is done in an optimized
  42  * way by KItemListView internally.
  43  */
  44 class KItemListContainerViewport : public QGraphicsView
  45 {
  46 public:
  47     KItemListContainerViewport(QGraphicsScene* scene, QWidget* parent);
  48 protected:
  49     virtual void wheelEvent(QWheelEvent* event);
  50 };
  51
  52 KItemListContainerViewport::KItemListContainerViewport(QGraphicsScene* scene, QWidget* parent) :
  53     QGraphicsView(scene, parent)
  54 {
  55     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
  56     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
  57     setViewportMargins(0, 0, 0, 0);
  58     setFrameShape(QFrame::NoFrame);
  59 }
  60
  61 void KItemListContainerViewport::wheelEvent(QWheelEvent* event)
  62 {
  63     // Assure that the wheel-event gets forwarded to the parent
  64     // and not handled at all by QGraphicsView.
  65     event->ignore();
  66 }
  67
  68
  69
  70 KItemListContainer::KItemListContainer(KItemListController* controller, QWidget* parent) :
  71     QAbstractScrollArea(parent),
  72     m_controller(controller),
  73     m_horizontalSmoothScroller(0),
  74     m_verticalSmoothScroller(0)
  75 {
  76     Q_ASSERT(controller);
  77     controller->setParent(this);
  78     initialize();
  79 }
  80
  81 KItemListContainer::KItemListContainer(QWidget* parent) :
  82     QAbstractScrollArea(parent),
  83     m_controller(0),
  84     m_horizontalSmoothScroller(0),
  85     m_verticalSmoothScroller(0)
  86 {
  87     initialize();
  88 }
  89
  90 KItemListContainer::~KItemListContainer()
  91 {
  92 }
  93
  94 KItemListController* KItemListContainer::controller() const
  95 {
  96     return m_controller;
  97 }
  98
  99 void KItemListContainer::keyPressEvent(QKeyEvent* event)
 100 {
 101     // TODO: We should find a better way to handle the key press events in the view.
 102     // The reasons why we need this hack are:
 103     // 1. Without reimplementing keyPressEvent() here, the event would not reach the QGraphicsView.
 104     // 2. By default, the KItemListView does not have the keyboard focus in the QGraphicsScene, so
 105     //    simply sending the event to the QGraphicsView which is the KItemListContainer's viewport
 106     //    does not work.
 107     KItemListView* view = m_controller->view();
 108     if (view) {
 109         QApplication::sendEvent(view, event);
 110     }
 111 }
 112
 113 void KItemListContainer::showEvent(QShowEvent* event)
 114 {
 115     QAbstractScrollArea::showEvent(event);
 116     updateGeometries();
 117 }
 118
 119 void KItemListContainer::resizeEvent(QResizeEvent* event)
 120 {
 121     QAbstractScrollArea::resizeEvent(event);
 122     updateGeometries();
 123 }
 124
 125 void KItemListContainer::scrollContentsBy(int dx, int dy)
 126 {
 127     m_horizontalSmoothScroller->scrollContentsBy(dx);
 128     m_verticalSmoothScroller->scrollContentsBy(dy);
 129 }
 130
 131 void KItemListContainer::wheelEvent(QWheelEvent* event)
 132 {
 133     if (event->modifiers().testFlag(Qt::ControlModifier)) {
 134         event->ignore();
 135         return;
 136     }
 137
 138     KItemListView* view = m_controller->view();
 139     if (!view) {
 140         event->ignore();
 141         return;
 142     }
 143
 144     const bool scrollHorizontally = (event->orientation() == Qt::Horizontal) ||
 145                                     (event->orientation() == Qt::Vertical && !verticalScrollBar()->isVisible());
 146     KItemListSmoothScroller* smoothScroller = scrollHorizontally ?
 147                                               m_horizontalSmoothScroller : m_verticalSmoothScroller;
 148
 149     const int numDegrees = event->delta() / 8;
 150     const int numSteps = numDegrees / 15;
 151
 152     const QScrollBar* scrollBar = smoothScroller->scrollBar();
 153     smoothScroller->scrollTo(scrollBar->value() - numSteps * scrollBar->pageStep() / 4);
 154
 155     event->accept();
 156 }
 157
 158 void KItemListContainer::slotScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous)
 159 {
 160     Q_UNUSED(previous);
 161     updateSmoothScrollers(current);
 162 }
 163
 164 void KItemListContainer::slotModelChanged(KItemModelBase* current, KItemModelBase* previous)
 165 {
 166     Q_UNUSED(current);
 167     Q_UNUSED(previous);
 168 }
 169
 170 void KItemListContainer::slotViewChanged(KItemListView* current, KItemListView* previous)
 171 {
 172     QGraphicsScene* scene = static_cast<QGraphicsView*>(viewport())->scene();
 173     if (previous) {
 174         scene->removeItem(previous);
 175         disconnect(current, SIGNAL(scrollOrientationChanged(Qt::Orientation,Qt::Orientation)), this, SLOT(slotScrollOrientationChanged(Qt::Orientation,Qt::Orientation)));
 176         disconnect(previous, SIGNAL(scrollOffsetChanged(qreal,qreal)),        this, SLOT(updateScrollOffsetScrollBar()));
 177         disconnect(previous, SIGNAL(maximumScrollOffsetChanged(qreal,qreal)), this, SLOT(updateScrollOffsetScrollBar()));
 178         disconnect(previous, SIGNAL(itemOffsetChanged(qreal,qreal)),          this, SLOT(updateItemOffsetScrollBar()));
 179         disconnect(previous, SIGNAL(maximumItemOffsetChanged(qreal,qreal)),   this, SLOT(updateItemOffsetScrollBar()));
 180         disconnect(previous, SIGNAL(scrollTo(qreal)),                         this, SLOT(scrollTo(qreal)));
 181         m_horizontalSmoothScroller->setTargetObject(0);
 182         m_verticalSmoothScroller->setTargetObject(0);
 183     }
 184     if (current) {
 185         scene->addItem(current);
 186         connect(current, SIGNAL(scrollOrientationChanged(Qt::Orientation,Qt::Orientation)), this, SLOT(slotScrollOrientationChanged(Qt::Orientation,Qt::Orientation)));
 187         connect(current, SIGNAL(scrollOffsetChanged(qreal,qreal)),        this, SLOT(updateScrollOffsetScrollBar()));
 188         connect(current, SIGNAL(maximumScrollOffsetChanged(qreal,qreal)), this, SLOT(updateScrollOffsetScrollBar()));
 189         connect(current, SIGNAL(itemOffsetChanged(qreal,qreal)),          this, SLOT(updateItemOffsetScrollBar()));
 190         connect(current, SIGNAL(maximumItemOffsetChanged(qreal,qreal)),   this, SLOT(updateItemOffsetScrollBar()));
 191         connect(current, SIGNAL(scrollTo(qreal)),                         this, SLOT(scrollTo(qreal)));
 192         m_horizontalSmoothScroller->setTargetObject(current);
 193         m_verticalSmoothScroller->setTargetObject(current);
 194         updateSmoothScrollers(current->scrollOrientation());
 195     }
 196 }
 197
 198 void KItemListContainer::scrollTo(qreal offset)
 199 {
 200     const KItemListView* view = m_controller->view();
 201     if (view) {
 202         if (view->scrollOrientation() == Qt::Vertical) {
 203             m_verticalSmoothScroller->scrollTo(offset);
 204         } else {
 205             m_horizontalSmoothScroller->scrollTo(offset);
 206         }
 207     }
 208 }
 209
 210 void KItemListContainer::updateScrollOffsetScrollBar()
 211 {
 212     const KItemListView* view = m_controller->view();
 213     if (!view) {
 214         return;
 215     }
 216
 217     KItemListSmoothScroller* smoothScroller = 0;
 218     QScrollBar* scrollOffsetScrollBar = 0;
 219     int singleStep = 0;
 220     int pageStep = 0;
 221     if (view->scrollOrientation() == Qt::Vertical) {
 222         smoothScroller = m_verticalSmoothScroller;
 223         scrollOffsetScrollBar = verticalScrollBar();
 224         singleStep = view->itemSize().height();
 225         pageStep = view->size().height();
 226     } else {
 227         smoothScroller = m_horizontalSmoothScroller;
 228         scrollOffsetScrollBar = horizontalScrollBar();
 229         singleStep = view->itemSize().width();
 230         pageStep = view->size().width();
 231     }
 232
 233     const int value = view->scrollOffset();
 234     const int maximum = qMax(0, int(view->maximumScrollOffset() - pageStep));
 235     if (smoothScroller->requestScrollBarUpdate(maximum)) {
 236         scrollOffsetScrollBar->setSingleStep(singleStep);
 237         scrollOffsetScrollBar->setPageStep(pageStep);
 238         scrollOffsetScrollBar->setMinimum(0);
 239         scrollOffsetScrollBar->setMaximum(maximum);
 240         scrollOffsetScrollBar->setValue(value);
 241     }
 242 }
 243
 244 void KItemListContainer::updateItemOffsetScrollBar()
 245 {
 246     const KItemListView* view = m_controller->view();
 247     if (!view) {
 248         return;
 249     }
 250
 251     KItemListSmoothScroller* smoothScroller = 0;
 252     QScrollBar* itemOffsetScrollBar = 0;
 253     int singleStep = 0;
 254     int pageStep = 0;
 255     if (view->scrollOrientation() == Qt::Vertical) {
 256         smoothScroller = m_horizontalSmoothScroller;
 257         itemOffsetScrollBar = horizontalScrollBar();
 258         singleStep = view->size().width() / 10;
 259         pageStep = view->size().width();
 260     } else {
 261         smoothScroller = m_verticalSmoothScroller;
 262         itemOffsetScrollBar = verticalScrollBar();
 263         singleStep = view->size().height() / 10;
 264         pageStep = view->size().height();
 265     }
 266
 267     const int value = view->itemOffset();
 268     const int maximum = qMax(0, int(view->maximumItemOffset()) - pageStep);
 269     if (smoothScroller->requestScrollBarUpdate(maximum)) {
 270         itemOffsetScrollBar->setSingleStep(singleStep);
 271         itemOffsetScrollBar->setPageStep(pageStep);
 272         itemOffsetScrollBar->setMinimum(0);
 273         itemOffsetScrollBar->setMaximum(maximum);
 274         itemOffsetScrollBar->setValue(value);
 275     }
 276 }
 277
 278 void KItemListContainer::updateGeometries()
 279 {
 280     QRect rect = geometry();
 281
 282     const int widthDec = verticalScrollBar()->isVisible()
 283                          ? frameWidth() + style()->pixelMetric(QStyle::PM_ScrollBarExtent)
 284                          : frameWidth() * 2;
 285
 286     const int heightDec = horizontalScrollBar()->isVisible()
 287                           ? frameWidth() + style()->pixelMetric(QStyle::PM_ScrollBarExtent)
 288                           : frameWidth() * 2;
 289
 290     rect.adjust(0, 0, -widthDec, -heightDec);
 291
 292     const QRectF newGeometry(0, 0, rect.width(), rect.height());
 293     if (m_controller->view()->geometry() != newGeometry) {
 294         m_controller->view()->setGeometry(newGeometry);
 295
 296         static_cast<KItemListContainerViewport*>(viewport())->scene()->setSceneRect(0, 0, rect.width(), rect.height());
 297         static_cast<KItemListContainerViewport*>(viewport())->viewport()->setGeometry(QRect(0, 0, rect.width(), rect.height()));
 298
 299         updateScrollOffsetScrollBar();
 300         updateItemOffsetScrollBar();
 301     }
 302 }
 303
 304 void KItemListContainer::updateSmoothScrollers(Qt::Orientation orientation)
 305 {
 306     if (orientation == Qt::Vertical) {
 307         m_verticalSmoothScroller->setPropertyName("scrollOffset");
 308         m_horizontalSmoothScroller->setPropertyName("itemOffset");
 309     } else {
 310         m_horizontalSmoothScroller->setPropertyName("scrollOffset");
 311         m_verticalSmoothScroller->setPropertyName("itemOffset");
 312     }
 313 }
 314
 315 void KItemListContainer::initialize()
 316 {
 317     if (!m_controller) {
 318         m_controller = new KItemListController(this);
 319     }
 320
 321     connect(m_controller, SIGNAL(modelChanged(KItemModelBase*,KItemModelBase*)),
 322             this, SLOT(slotModelChanged(KItemModelBase*,KItemModelBase*)));
 323     connect(m_controller, SIGNAL(viewChanged(KItemListView*,KItemListView*)),
 324             this, SLOT(slotViewChanged(KItemListView*,KItemListView*)));
 325
 326     QGraphicsView* graphicsView = new KItemListContainerViewport(new QGraphicsScene(this), this);
 327     setViewport(graphicsView);
 328
 329     m_horizontalSmoothScroller = new KItemListSmoothScroller(horizontalScrollBar(), this);
 330     m_verticalSmoothScroller = new KItemListSmoothScroller(verticalScrollBar(), this);
 331 }
 332
 333 #include "kitemlistcontainer.moc"