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 "kitemlistselectionmanager.h"
  27 #include "kitemlistview.h"
  28 #include "kitemmodelbase.h"
  29
  30 #include "private/kitemlistsmoothscroller.h"
  31
  32 #include <QApplication>
  33 #include <QGraphicsScene>
  34 #include <QGraphicsView>
  35 #include <QPropertyAnimation>
  36 #include <QScrollBar>
  37 #include <QStyle>
  38 #include <QStyleOption>
  39
  40 #include <KDebug>
  41
  42 #include "kitemlistviewaccessible.h"
  43
  44 /**
  45  * Replaces the default viewport of KItemListContainer by a
  46  * non-scrollable viewport. The scrolling is done in an optimized
  47  * way by KItemListView internally.
  48  */
  49 class KItemListContainerViewport : public QGraphicsView
  50 {
  51 public:
  52     KItemListContainerViewport(QGraphicsScene* scene, QWidget* parent);
  53 protected:
  54     virtual void wheelEvent(QWheelEvent* event);
  55 };
  56
  57 KItemListContainerViewport::KItemListContainerViewport(QGraphicsScene* scene, QWidget* parent) :
  58     QGraphicsView(scene, parent)
  59 {
  60     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
  61     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
  62     setViewportMargins(0, 0, 0, 0);
  63     setFrameShape(QFrame::NoFrame);
  64 }
  65
  66 void KItemListContainerViewport::wheelEvent(QWheelEvent* event)
  67 {
  68     // Assure that the wheel-event gets forwarded to the parent
  69     // and not handled at all by QGraphicsView.
  70     event->ignore();
  71 }
  72
  73 QAccessibleInterface* accessibleContainerFactory(const QString &key, QObject *object)
  74 {
  75     Q_UNUSED(key)
  76     if (KItemListContainer*view = qobject_cast<KItemListContainer*>(object))
  77         return new KItemListContainerAccessible(view);
  78     if (KItemListView *view = qobject_cast<KItemListView*>(object))
  79         return new KItemListViewAccessible(view);
  80     return 0;
  81 }
  82
  83 KItemListContainer::KItemListContainer(KItemListController* controller, QWidget* parent) :
  84     QAbstractScrollArea(parent),
  85     m_controller(controller),
  86     m_horizontalSmoothScroller(0),
  87     m_verticalSmoothScroller(0)
  88 {
  89     Q_ASSERT(controller);
  90     controller->setParent(this);
  91
  92     QGraphicsView* graphicsView = new KItemListContainerViewport(new QGraphicsScene(this), this);
  93     setViewport(graphicsView);
  94
  95     m_horizontalSmoothScroller = new KItemListSmoothScroller(horizontalScrollBar(), this);
  96     m_verticalSmoothScroller = new KItemListSmoothScroller(verticalScrollBar(), this);
  97
  98     if (controller->model()) {
  99         slotModelChanged(controller->model(), 0);
 100     }
 101     if (controller->view()) {
 102         slotViewChanged(controller->view(), 0);
 103     }
 104
 105     connect(controller, SIGNAL(modelChanged(KItemModelBase*,KItemModelBase*)),
 106             this, SLOT(slotModelChanged(KItemModelBase*,KItemModelBase*)));
 107     connect(controller, SIGNAL(viewChanged(KItemListView*,KItemListView*)),
 108             this, SLOT(slotViewChanged(KItemListView*,KItemListView*)));
 109
 110 #ifndef QT_NO_ACCESSIBILITY
 111     QAccessible::installFactory(accessibleContainerFactory);
 112 #endif
 113 }
 114
 115 KItemListContainer::~KItemListContainer()
 116 {
 117     // Don't rely on the QObject-order to delete the controller, otherwise
 118     // the QGraphicsScene might get deleted before the view.
 119     delete m_controller;
 120     m_controller = 0;
 121 #ifndef QT_NO_ACCESSIBIILTY
 122     QAccessible::removeFactory(accessibleContainerFactory);
 123 #endif
 124 }
 125
 126 KItemListController* KItemListContainer::controller() const
 127 {
 128     return m_controller;
 129 }
 130
 131 void KItemListContainer::setEnabledFrame(bool enable)
 132 {
 133     QGraphicsView* graphicsView = qobject_cast<QGraphicsView*>(viewport());
 134     if (enable) {
 135         setFrameShape(QFrame::StyledPanel);
 136         graphicsView->setPalette(palette());
 137         graphicsView->viewport()->setAutoFillBackground(true);
 138     } else {
 139         setFrameShape(QFrame::NoFrame);
 140         // Make the background of the container transparent and apply the window-text color
 141         // to the text color, so that enough contrast is given for all color
 142         // schemes
 143         QPalette p = graphicsView->palette();
 144         p.setColor(QPalette::Active,   QPalette::Text, p.color(QPalette::Active,   QPalette::WindowText));
 145         p.setColor(QPalette::Inactive, QPalette::Text, p.color(QPalette::Inactive, QPalette::WindowText));
 146         p.setColor(QPalette::Disabled, QPalette::Text, p.color(QPalette::Disabled, QPalette::WindowText));
 147         graphicsView->setPalette(p);
 148         graphicsView->viewport()->setAutoFillBackground(false);
 149     }
 150 }
 151
 152 bool KItemListContainer::enabledFrame() const
 153 {
 154     const QGraphicsView* graphicsView = qobject_cast<QGraphicsView*>(viewport());
 155     return graphicsView->autoFillBackground();
 156 }
 157
 158 void KItemListContainer::keyPressEvent(QKeyEvent* event)
 159 {
 160     // TODO: We should find a better way to handle the key press events in the view.
 161     // The reasons why we need this hack are:
 162     // 1. Without reimplementing keyPressEvent() here, the event would not reach the QGraphicsView.
 163     // 2. By default, the KItemListView does not have the keyboard focus in the QGraphicsScene, so
 164     //    simply sending the event to the QGraphicsView which is the KItemListContainer's viewport
 165     //    does not work.
 166     KItemListView* view = m_controller->view();
 167     if (view) {
 168         QApplication::sendEvent(view, event);
 169     }
 170     QAccessible::updateAccessibility(view, m_controller->selectionManager()->currentItem()+1, QAccessible::Focus);
 171     QAccessible::updateAccessibility(view, m_controller->selectionManager()->currentItem()+1, QAccessible::LocationChanged);
 172 }
 173
 174 void KItemListContainer::showEvent(QShowEvent* event)
 175 {
 176     QAbstractScrollArea::showEvent(event);
 177     updateGeometries();
 178 }
 179
 180 void KItemListContainer::resizeEvent(QResizeEvent* event)
 181 {
 182     QAbstractScrollArea::resizeEvent(event);
 183     updateGeometries();
 184 }
 185
 186 void KItemListContainer::scrollContentsBy(int dx, int dy)
 187 {
 188     m_horizontalSmoothScroller->scrollContentsBy(dx);
 189     m_verticalSmoothScroller->scrollContentsBy(dy);
 190     QAccessible::updateAccessibility(m_controller->view(), m_controller->selectionManager()->currentItem()+1, QAccessible::Focus);
 191     QAccessible::updateAccessibility(m_controller->view(), m_controller->selectionManager()->currentItem()+1, QAccessible::LocationChanged);
 192 }
 193
 194 void KItemListContainer::wheelEvent(QWheelEvent* event)
 195 {
 196     if (event->modifiers().testFlag(Qt::ControlModifier)) {
 197         event->ignore();
 198         return;
 199     }
 200
 201     KItemListView* view = m_controller->view();
 202     if (!view) {
 203         event->ignore();
 204         return;
 205     }
 206
 207     const bool scrollHorizontally = (event->orientation() == Qt::Horizontal) ||
 208                                     (event->orientation() == Qt::Vertical && !verticalScrollBar()->isVisible());
 209     KItemListSmoothScroller* smoothScroller = scrollHorizontally ?
 210                                               m_horizontalSmoothScroller : m_verticalSmoothScroller;
 211
 212     const int numDegrees = event->delta() / 8;
 213     const int numSteps = numDegrees / 15;
 214
 215     const QScrollBar* scrollBar = smoothScroller->scrollBar();
 216     smoothScroller->scrollTo(scrollBar->value() - numSteps * scrollBar->pageStep() / 4);
 217
 218     event->accept();
 219 }
 220
 221 void KItemListContainer::slotScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous)
 222 {
 223     Q_UNUSED(previous);
 224     updateSmoothScrollers(current);
 225 }
 226
 227 void KItemListContainer::slotModelChanged(KItemModelBase* current, KItemModelBase* previous)
 228 {
 229     Q_UNUSED(current);
 230     Q_UNUSED(previous);
 231 }
 232
 233 void KItemListContainer::slotViewChanged(KItemListView* current, KItemListView* previous)
 234 {
 235     QGraphicsScene* scene = static_cast<QGraphicsView*>(viewport())->scene();
 236     if (previous) {
 237         scene->removeItem(previous);
 238         disconnect(previous, SIGNAL(scrollOrientationChanged(Qt::Orientation,Qt::Orientation)), this, SLOT(slotScrollOrientationChanged(Qt::Orientation,Qt::Orientation)));
 239         disconnect(previous, SIGNAL(scrollOffsetChanged(qreal,qreal)),        this, SLOT(updateScrollOffsetScrollBar()));
 240         disconnect(previous, SIGNAL(maximumScrollOffsetChanged(qreal,qreal)), this, SLOT(updateScrollOffsetScrollBar()));
 241         disconnect(previous, SIGNAL(itemOffsetChanged(qreal,qreal)),          this, SLOT(updateItemOffsetScrollBar()));
 242         disconnect(previous, SIGNAL(maximumItemOffsetChanged(qreal,qreal)),   this, SLOT(updateItemOffsetScrollBar()));
 243         disconnect(previous, SIGNAL(scrollTo(qreal)),                         this, SLOT(scrollTo(qreal)));
 244         m_horizontalSmoothScroller->setTargetObject(0);
 245         m_verticalSmoothScroller->setTargetObject(0);
 246     }
 247     if (current) {
 248         scene->addItem(current);
 249         connect(current, SIGNAL(scrollOrientationChanged(Qt::Orientation,Qt::Orientation)), this, SLOT(slotScrollOrientationChanged(Qt::Orientation,Qt::Orientation)));
 250         connect(current, SIGNAL(scrollOffsetChanged(qreal,qreal)),        this, SLOT(updateScrollOffsetScrollBar()));
 251         connect(current, SIGNAL(maximumScrollOffsetChanged(qreal,qreal)), this, SLOT(updateScrollOffsetScrollBar()));
 252         connect(current, SIGNAL(itemOffsetChanged(qreal,qreal)),          this, SLOT(updateItemOffsetScrollBar()));
 253         connect(current, SIGNAL(maximumItemOffsetChanged(qreal,qreal)),   this, SLOT(updateItemOffsetScrollBar()));
 254         connect(current, SIGNAL(scrollTo(qreal)),                         this, SLOT(scrollTo(qreal)));
 255         m_horizontalSmoothScroller->setTargetObject(current);
 256         m_verticalSmoothScroller->setTargetObject(current);
 257         updateSmoothScrollers(current->scrollOrientation());
 258     }
 259 }
 260
 261 void KItemListContainer::scrollTo(qreal offset)
 262 {
 263     const KItemListView* view = m_controller->view();
 264     if (view) {
 265         if (view->scrollOrientation() == Qt::Vertical) {
 266             m_verticalSmoothScroller->scrollTo(offset);
 267         } else {
 268             m_horizontalSmoothScroller->scrollTo(offset);
 269         }
 270     }
 271 }
 272
 273 void KItemListContainer::updateScrollOffsetScrollBar()
 274 {
 275     const KItemListView* view = m_controller->view();
 276     if (!view) {
 277         return;
 278     }
 279
 280     KItemListSmoothScroller* smoothScroller = 0;
 281     QScrollBar* scrollOffsetScrollBar = 0;
 282     int singleStep = 0;
 283     int pageStep = 0;
 284     if (view->scrollOrientation() == Qt::Vertical) {
 285         smoothScroller = m_verticalSmoothScroller;
 286         scrollOffsetScrollBar = verticalScrollBar();
 287         singleStep = view->itemSize().height();
 288         pageStep = view->size().height();
 289     } else {
 290         smoothScroller = m_horizontalSmoothScroller;
 291         scrollOffsetScrollBar = horizontalScrollBar();
 292         singleStep = view->itemSize().width();
 293         pageStep = view->size().width();
 294     }
 295
 296     const int value = view->scrollOffset();
 297     const int maximum = qMax(0, int(view->maximumScrollOffset() - pageStep));
 298     if (smoothScroller->requestScrollBarUpdate(maximum)) {
 299         const bool updatePolicy = (scrollOffsetScrollBar->maximum() > 0 && maximum == 0)
 300                                   || horizontalScrollBarPolicy() == Qt::ScrollBarAlwaysOn;
 301
 302         scrollOffsetScrollBar->setSingleStep(singleStep);
 303         scrollOffsetScrollBar->setPageStep(pageStep);
 304         scrollOffsetScrollBar->setMinimum(0);
 305         scrollOffsetScrollBar->setMaximum(maximum);
 306         scrollOffsetScrollBar->setValue(value);
 307
 308         if (updatePolicy) {
 309             // Prevent a potential endless layout loop (see bug #293318).
 310             updateScrollOffsetScrollBarPolicy();
 311         }
 312     }
 313 }
 314
 315 void KItemListContainer::updateItemOffsetScrollBar()
 316 {
 317     const KItemListView* view = m_controller->view();
 318     if (!view) {
 319         return;
 320     }
 321
 322     KItemListSmoothScroller* smoothScroller = 0;
 323     QScrollBar* itemOffsetScrollBar = 0;
 324     int singleStep = 0;
 325     int pageStep = 0;
 326     if (view->scrollOrientation() == Qt::Vertical) {
 327         smoothScroller = m_horizontalSmoothScroller;
 328         itemOffsetScrollBar = horizontalScrollBar();
 329         singleStep = view->size().width() / 10;
 330         pageStep = view->size().width();
 331     } else {
 332         smoothScroller = m_verticalSmoothScroller;
 333         itemOffsetScrollBar = verticalScrollBar();
 334         singleStep = view->size().height() / 10;
 335         pageStep = view->size().height();
 336     }
 337
 338     const int value = view->itemOffset();
 339     const int maximum = qMax(0, int(view->maximumItemOffset()) - pageStep);
 340     if (smoothScroller->requestScrollBarUpdate(maximum)) {
 341         itemOffsetScrollBar->setSingleStep(singleStep);
 342         itemOffsetScrollBar->setPageStep(pageStep);
 343         itemOffsetScrollBar->setMinimum(0);
 344         itemOffsetScrollBar->setMaximum(maximum);
 345         itemOffsetScrollBar->setValue(value);
 346     }
 347 }
 348
 349 void KItemListContainer::updateGeometries()
 350 {
 351     QRect rect = geometry();
 352
 353     int extra = frameWidth() * 2;
 354     QStyleOption option;
 355     option.initFrom(this);
 356     if (style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents, &option, this)) {
 357         extra += style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarSpacing, &option, this);
 358     }
 359
 360     const int widthDec = verticalScrollBar()->isVisible()
 361                          ? extra + style()->pixelMetric(QStyle::PM_ScrollBarExtent, &option, this)
 362                          : extra;
 363
 364     const int heightDec = horizontalScrollBar()->isVisible()
 365                           ? extra + style()->pixelMetric(QStyle::PM_ScrollBarExtent, &option, this)
 366                           : extra;
 367
 368     rect.adjust(0, 0, -widthDec, -heightDec);
 369
 370     const QRectF newGeometry(0, 0, rect.width(), rect.height());
 371     if (m_controller->view()->geometry() != newGeometry) {
 372         m_controller->view()->setGeometry(newGeometry);
 373
 374         static_cast<KItemListContainerViewport*>(viewport())->scene()->setSceneRect(0, 0, rect.width(), rect.height());
 375         static_cast<KItemListContainerViewport*>(viewport())->viewport()->setGeometry(QRect(0, 0, rect.width(), rect.height()));
 376
 377         updateScrollOffsetScrollBar();
 378         updateItemOffsetScrollBar();
 379         QAccessible::updateAccessibility(m_controller->view(), 0, QAccessible::LocationChanged);
 380         QAccessible::updateAccessibility(m_controller->view(), m_controller->selectionManager()->currentItem()+1, QAccessible::LocationChanged);
 381         QAccessible::updateAccessibility(m_controller->view(), m_controller->selectionManager()->currentItem()+1, QAccessible::Focus);
 382     }
 383 }
 384
 385 void KItemListContainer::updateSmoothScrollers(Qt::Orientation orientation)
 386 {
 387     if (orientation == Qt::Vertical) {
 388         m_verticalSmoothScroller->setPropertyName("scrollOffset");
 389         m_horizontalSmoothScroller->setPropertyName("itemOffset");
 390     } else {
 391         m_horizontalSmoothScroller->setPropertyName("scrollOffset");
 392         m_verticalSmoothScroller->setPropertyName("itemOffset");
 393     }
 394 }
 395
 396 void KItemListContainer::updateScrollOffsetScrollBarPolicy()
 397 {
 398     const KItemListView* view = m_controller->view();
 399     Q_ASSERT(view);
 400     const bool vertical = (view->scrollOrientation() == Qt::Vertical);
 401
 402     QStyleOption option;
 403     option.initFrom(this);
 404     const int scrollBarInc = style()->pixelMetric(QStyle::PM_ScrollBarExtent, &option, this);
 405
 406     QSizeF newViewSize = m_controller->view()->size();
 407     if (vertical) {
 408         newViewSize.rwidth() += scrollBarInc;
 409     } else {
 410         newViewSize.rheight() += scrollBarInc;
 411     }
 412
 413     const Qt::ScrollBarPolicy policy = view->scrollBarRequired(newViewSize)
 414                                        ? Qt::ScrollBarAlwaysOn : Qt::ScrollBarAsNeeded;
 415     if (vertical) {
 416         setVerticalScrollBarPolicy(policy);
 417     } else {
 418         setHorizontalScrollBarPolicy(policy);
 419     }
 420 }
 421
 422 #include "kitemlistcontainer.moc"