kdeui

kscrollview.cpp

00001 /* This file is part of the KDE libraries
00002    Copyright (C) 2005 Allan Sandfeld Jensen <kde@carewolf.com>
00003 
00004    This library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Library General Public
00006    License version 2 as published by the Free Software Foundation.
00007 
00008    This library is distributed in the hope that it will be useful,
00009    but WITHOUT ANY WARRANTY; without even the implied warranty of
00010    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00011    Library General Public License for more details.
00012 
00013    You should have received a copy of the GNU Library General Public License
00014    along with this library; see the file COPYING.LIB.  If not, write to
00015    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
00016    Boston, MA 02110-1301, USA.
00017 */
00018 
00019 #include "config.h"
00020 
00021 #include <qtimer.h>
00022 #include <qevent.h>
00023 #include <qapplication.h>
00024 
00025 #include "kscrollview.h"
00026 #include <kdebug.h>
00027 #include <kconfig.h>
00028 #include <kglobal.h>
00029 
00030 struct KScrollView::KScrollViewPrivate {
00031     KScrollViewPrivate() : dx(0), dy(0), ddx(0), ddy(0), rdx(0), rdy(0), scrolling(false) {}
00032     QTimer timer;
00033     int dx;
00034     int dy;
00035     // Step size * 16 and residual to avoid huge difference between 1px/step and 2px/step
00036     int ddx;
00037     int ddy;
00038     int rdx;
00039     int rdy;
00040     bool scrolling;
00041 };
00042 
00043 KScrollView::KScrollView( QWidget *parent, const char *name, Qt::WFlags f )
00044     : QScrollView( parent, name, f )
00045 {
00046     d = new KScrollViewPrivate;
00047     connect(&d->timer, SIGNAL(timeout()), this, SLOT(scrollTick()));
00048 }
00049 
00050 KScrollView::~KScrollView()
00051 {
00052     delete d;
00053 }
00054 
00055 void KScrollView::scrollBy(int dx, int dy)
00056 {
00057     KConfigGroup cfg( KGlobal::config(), "KDE" );
00058     if( !cfg.readBoolEntry( "SmoothScrolling", true )) {
00059         QScrollView::scrollBy( dx, dy );
00060         return;
00061     }
00062     // scrolling destination
00063     int full_dx = d->dx + dx;
00064     int full_dy = d->dy + dy;
00065 
00066     // scrolling speed
00067     int ddx = 0;
00068     int ddy = 0;
00069 
00070     int steps = SCROLL_TIME/SCROLL_TICK;
00071 
00072     ddx = (full_dx*16)/steps;
00073     ddy = (full_dy*16)/steps;
00074 
00075     // don't go under 1px/step
00076     if (ddx > 0 && ddx < 16) ddx = 16;
00077     if (ddy > 0 && ddy < 16) ddy = 16;
00078     if (ddx < 0 && ddx > -16) ddx = -16;
00079     if (ddy < 0 && ddy > -16) ddy = -16;
00080 
00081     d->dx = full_dx;
00082     d->dy = full_dy;
00083     d->ddx = ddx;
00084     d->ddy = ddy;
00085 
00086     if (!d->scrolling) {
00087         scrollTick();
00088         startScrolling();
00089     }
00090 }
00091 /*
00092 void KScrollView::scrollBy(int dx, int dy)
00093 {
00094     if (d->scrolling)
00095         setContentsPos( d->x+dx, d->y+dy );
00096     else
00097         setContentsPos( contentsX() + dx, contentsY() + dy);
00098 }
00099 
00100 void KScrollView::setContentsPos(int x, int y)
00101 {
00102     if (x < 0) x = 0;
00103     if (y < 0) y = 0;
00104 
00105     int dx = x - contentsX();
00106     int dy = y - contentsY();
00107 
00108     // to large to smooth out
00109 //     if (dx > 1000 || dy > 1000) return QScrollView::setContentsPos(x,y);
00110 
00111     // scrolling speed
00112     int ddx = 0;
00113     int ddy = 0;
00114 
00115     int steps = SCROLL_TIME/SCROLL_TICK;
00116 
00117     ddx = (dx*16)/steps;
00118     ddy = (dy*16)/steps;
00119 
00120     d->x = x;
00121     d->y = y;
00122     d->dx = dx;
00123     d->dy = dy;
00124     d->ddx = ddx;
00125     d->ddy = ddy;
00126 
00127     if (!d->scrolling) {
00128         scrollTick();
00129         startScrolling();
00130     }
00131 } */
00132 
00133 void KScrollView::scrollTick() {
00134     if (d->dx == 0 && d->dy == 0) {
00135         stopScrolling();
00136         return;
00137     }
00138 
00139     int tddx = d->ddx + d->rdx;
00140     int tddy = d->ddy + d->rdy;
00141 
00142     int ddx = tddx / 16;
00143     int ddy = tddy / 16;
00144     d->rdx = tddx % 16;
00145     d->rdy = tddy % 16;
00146 
00147     if (d->dx > 0 && ddx > d->dx) ddx = d->dx;
00148     else
00149     if (d->dx < 0 && ddx < d->dx) ddx = d->dx;
00150 
00151     if (d->dy > 0 && ddy > d->dy) ddy = d->dy;
00152     else
00153     if (d->dy < 0 && ddy < d->dy) ddy = d->dy;
00154 
00155     d->dx -= ddx;
00156     d->dy -= ddy;
00157 
00158 //    QScrollView::setContentsPos( contentsX() + ddx, contentsY() + ddy);
00159     QScrollView::scrollBy(ddx, ddy);
00160 }
00161 
00162 void KScrollView::startScrolling()
00163 {
00164     d->scrolling = true;
00165     d->timer.start(SCROLL_TICK, false);
00166 }
00167 
00168 void KScrollView::stopScrolling()
00169 {
00170     d->timer.stop();
00171     d->dx = d->dy = 0;
00172     d->scrolling = false;
00173 }
00174 
00175 // Overloaded from QScrollView and QScrollBar
00176 void KScrollView::wheelEvent( QWheelEvent *e )
00177 {
00178     int pageStep = verticalScrollBar()->pageStep();
00179     int lineStep = verticalScrollBar()->lineStep();
00180     int step = QMIN( QApplication::wheelScrollLines()*lineStep, pageStep );
00181     if ( ( e->state() & ControlButton ) || ( e->state() & ShiftButton ) )
00182         step = pageStep;
00183 
00184     int dy = (e->delta()*step)/120;
00185     scrollBy(0,-dy);
00186     e->accept();
00187 }
00188 
00189 #include "kscrollview.moc"
kdeui

kscrollview.cpp

kdeui

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