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