📄 desktop-example.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- /home/reggie/tmp/qt-3.0-reggie-5401/qt-x11-commercial-3.0.5/examples/desktop/desktop.doc:5 --><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Painting on the Desktop</title><style type="text/css"><!--h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm; }a:link { color: #004faf; text-decoration: none }a:visited { color: #672967; text-decoration: none }body { background: #ffffff; color: black; }--></style></head><body><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr bgcolor="#E5E5E5"><td valign=center> <a href="index.html"><font color="#004faf">Home</font></a> | <a href="classes.html"><font color="#004faf">All Classes</font></a> | <a href="mainclasses.html"><font color="#004faf">Main Classes</font></a> | <a href="annotated.html"><font color="#004faf">Annotated</font></a> | <a href="groups.html"><font color="#004faf">Grouped Classes</font></a> | <a href="functions.html"><font color="#004faf">Functions</font></a></td><td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Painting on the Desktop</h1> <p> The desktop demo contains three routines, each of which drawssomething on the desktop. It does some nice stuff with <a href="qpainter.html">QPainter</a>,and also demonstrates how one can treat the desktop as a widget likeany other.<p> <hr><p> Implementation:<p> <pre>/****************************************************************************** $Id: qt/desktop.cpp 3.0.5 edited Oct 12 2001 $**** Copyright (C) 1992-2000 Trolltech AS. All rights reserved.**** This file is part of an example program for Qt. This example** program may be used, distributed and modified without limitation.*******************************************************************************/#include <<a href="qimage-h.html">qimage.h</a>>#include <<a href="qbitmap-h.html">qbitmap.h</a>>#include <<a href="qpainter-h.html">qpainter.h</a>>#include <<a href="qapplication-h.html">qapplication.h</a>>#include <<a href="qdropsite-h.html">qdropsite.h</a>>#include <<a href="qdragobject-h.html">qdragobject.h</a>>#include <stdio.h>static double seed = 0.353535353535;static const int KINDA_RAND_MAX = 32767;static int kindaRand(){ seed = seed*147; seed = seed - (double) ((int) seed); return (int) ( seed*(KINDA_RAND_MAX + 1) );}static int velocity( int i ) // change velocity{ const int velmax = 15; const int velmin = 4; if ( i == 1 || i == 2 ) i = (kindaRand()&0x7fff % velmax)/3 + velmin; else i = (kindaRand()&0x7fff % velmax) + velmin; return i;}//// Draw polygon on desktop.//void poly(){<a name="x1759"></a> <a href="qwidget.html">QWidget</a> *d = QApplication::<a href="qapplication.html#desktop">desktop</a>();<a name="x1799"></a> d-><a href="qwidget.html#setBackgroundColor">setBackgroundColor</a>( Qt::white ); // white desktop const int maxpoints = 5; const int maxcurves = 8; static int xvel[maxpoints]; static int yvel[maxpoints]; int head = 0; int tail = -maxcurves + 2; <a href="qpointarray.html">QPointArray</a> *a = new <a href="qpointarray.html">QPointArray</a>[ maxcurves ]; register QPointArray *p;<a name="x1798"></a> <a href="qrect.html">QRect</a> r = d-><a href="qwidget.html#rect">rect</a>(); // desktop rectangle int i; for ( i=0; i<maxcurves; i++ ) a[i].resize( maxpoints ); p = &a[0]; for ( i=0; i<maxpoints; i++ ) { // setup first polygon points<a name="x1794"></a> p->setPoint( i, (kindaRand()&0x7fff) % r.<a href="qrect.html#width">width</a>(),<a name="x1787"></a> (kindaRand()&0x7fff) % r.<a href="qrect.html#height">height</a>() ); xvel[i] = velocity(i); yvel[i] = velocity(i); } <a href="qpainter.html">QPainter</a> paint;<a name="x1771"></a> paint.<a href="qpainter.html#begin">begin</a>( d ); // start painting desktop for ( int ntimes=0; ntimes<2000; ntimes++ ) { paint.<a href="qpainter.html#setBrush">setBrush</a>( QColor(kindaRand()%360, 180, 255, QColor::Hsv) );<a name="x1773"></a> paint.<a href="qpainter.html#drawPolygon">drawPolygon</a>( a[head] ); if ( ++tail >= maxcurves ) tail = 0;<a name="x1789"></a><a name="x1788"></a> int minx=r.<a href="qrect.html#left">left</a>(), maxx=r.<a href="qrect.html#right">right</a>();<a name="x1793"></a><a name="x1786"></a> int miny=r.<a href="qrect.html#top">top</a>(), maxy=r.<a href="qrect.html#bottom">bottom</a>(); int x, y; p = &a[head]; if ( ++head >= maxcurves ) head = 0; for ( i=0; i<maxpoints; i++ ) { // calc new curve p->point( i, &x, &y ); x += xvel[i]; y += yvel[i]; if ( x >= maxx ) { x = maxx - (x - maxx + 1); xvel[i] = -velocity(i); } if ( x <= minx ) { x = minx + (minx - x + 1); xvel[i] = velocity(i); } if ( y >= maxy ) { y = maxy - (y - maxy + 1); yvel[i] = -velocity(i); } if ( y <= miny ) { y = miny + (miny - y + 1); yvel[i] = velocity(i); } a[head].setPoint( i, x, y ); } }<a name="x1775"></a> paint.<a href="qpainter.html#end">end</a>(); // painting done delete[] a;}//// Rotate pattern on desktop.//void rotate(){ int i; const int w = 64; const int h = 64; <a href="qimage.html">QImage</a> image( w, h, 8, 128 ); // create image for ( i=0; i<128; i++ ) // build color table<a name="x1768"></a> image.<a href="qimage.html#setColor">setColor</a>( i, qRgb(i,0,0) ); for ( int y=0; y<h; y++ ) { // set image pixels<a name="x1767"></a> uchar *p = image.<a href="qimage.html#scanLine">scanLine</a>(y); for ( int x=0; x<w; x++ ) *p++ = (x+y)%128; } <a href="qpixmap.html">QPixmap</a> pm; pm = image; // convert image to pixmap<a name="x1783"></a> pm.<a href="qpixmap.html#setOptimization">setOptimization</a>( QPixmap::BestOptim ); // rotation will be faster <a href="qwidget.html">QWidget</a> *d = QApplication::<a href="qapplication.html#desktop">desktop</a>(); // w = desktop widget for ( i=0; i<=360; i += 2 ) { <a href="qwmatrix.html">QWMatrix</a> m;<a name="x1802"></a> m.<a href="qwmatrix.html#rotate">rotate</a>( i ); // rotate coordinate system<a name="x1785"></a> <a href="qpixmap.html">QPixmap</a> rpm = pm.<a href="qpixmap.html#xForm">xForm</a>( m ); // rpm = rotated pixmap<a name="x1800"></a> d-><a href="qwidget.html#setBackgroundPixmap">setBackgroundPixmap</a>( rpm ); // set desktop pixmap<a name="x1801"></a> d-><a href="qwidget.html#update">update</a>(); // repaint desktop }}//// Generates a marble-like pattern in pm.//void generateStone( <a href="qpixmap.html">QPixmap</a> *pm, const <a href="qcolor.html">QColor</a> &c1, const <a href="qcolor.html">QColor</a> &c2, const <a href="qcolor.html">QColor</a> &c3 ){ <a href="qpainter.html">QPainter</a> p; <a href="qpen.html">QPen</a> p1 ( c1, 0 ); <a href="qpen.html">QPen</a> p2 ( c2, 0 ); <a href="qpen.html">QPen</a> p3 ( c3, 0 ); p.<a href="qpainter.html#begin">begin</a>( pm );<a name="x1784"></a> for( int i = 0 ; i < pm-><a href="qpixmap.html#width">width</a>() ; i++ )⌨️ 快捷键说明
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