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