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