source: trunk/doc/html/drawdemo-example.html

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[190]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
2<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/examples/drawdemo/drawdemo.doc:4 -->
3<html>
4<head>
5<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
6<title>Draw Demo</title>
7<style type="text/css"><!--
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14<body>
15
16<table border="0" cellpadding="0" cellspacing="0" width="100%">
17<tr bgcolor="#E5E5E5">
18<td valign=center>
19 <a href="index.html">
20<font color="#004faf">Home</font></a>
21 | <a href="classes.html">
22<font color="#004faf">All&nbsp;Classes</font></a>
23 | <a href="mainclasses.html">
24<font color="#004faf">Main&nbsp;Classes</font></a>
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26<font color="#004faf">Annotated</font></a>
27 | <a href="groups.html">
28<font color="#004faf">Grouped&nbsp;Classes</font></a>
29 | <a href="functions.html">
30<font color="#004faf">Functions</font></a>
31</td>
32<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Draw Demo</h1>
33
34
35<p>
36This example demonstrates several drawing functions and printer output.
37You can easily add you own drawing functions.
38<p> <hr>
39<p> Implementation:
40<p> <pre>/****************************************************************************
41** $Id: drawdemo-example.html 2051 2007-02-21 10:04:20Z chehrlic $
42**
43** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
44**
45** This file is part of an example program for Qt. This example
46** program may be used, distributed and modified without limitation.
47**
48*****************************************************************************/
49
50#include &lt;<a href="qwidget-h.html">qwidget.h</a>&gt;
51#include &lt;<a href="qpainter-h.html">qpainter.h</a>&gt;
52#include &lt;<a href="qprinter-h.html">qprinter.h</a>&gt;
53#include &lt;<a href="qpushbutton-h.html">qpushbutton.h</a>&gt;
54#include &lt;<a href="qradiobutton-h.html">qradiobutton.h</a>&gt;
55#include &lt;<a href="qbuttongroup-h.html">qbuttongroup.h</a>&gt;
56#include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;
57#include &lt;math.h&gt;
58
59//
60// First we define the functionality our demo should present
61// to the user. You might add different demo-modes if you wish so.
62//
63
64//
65// This function draws a color wheel.
66// The coordinate system x=(0..500), y=(0..500) spans the paint device.
67//
68
69void drawColorWheel( <a href="qpainter.html">QPainter</a> *p )
70{
71 <a href="qfont.html">QFont</a> f( "times", 18, QFont::Bold );
72<a name="x1075"></a> p-&gt;<a href="qpainter.html#setFont">setFont</a>( f );
73<a name="x1076"></a> p-&gt;<a href="qpainter.html#setPen">setPen</a>( Qt::black );
74<a name="x1077"></a> p-&gt;<a href="qpainter.html#setWindow">setWindow</a>( 0, 0, 500, 500 ); // defines coordinate system
75
76 for ( int i=0; i&lt;36; i++ ) { // draws 36 rotated rectangles
77
78 <a href="qwmatrix.html">QWMatrix</a> matrix;
79<a name="x1097"></a> matrix.<a href="qwmatrix.html#translate">translate</a>( 250.0F, 250.0F ); // move to center
80<a name="x1096"></a> matrix.<a href="qwmatrix.html#shear">shear</a>( 0.0F, 0.3F ); // twist it
81<a name="x1095"></a> matrix.<a href="qwmatrix.html#rotate">rotate</a>( (float)i*10 ); // rotate 0,10,20,.. degrees
82<a name="x1078"></a> p-&gt;<a href="qpainter.html#setWorldMatrix">setWorldMatrix</a>( matrix ); // use this world matrix
83
84 <a href="qcolor.html">QColor</a> c;
85<a name="x1063"></a> c.<a href="qcolor.html#setHsv">setHsv</a>( i*10, 255, 255 ); // rainbow effect
86<a name="x1074"></a> p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( c ); // solid fill with color c
87<a name="x1070"></a> p-&gt;<a href="qpainter.html#drawRect">drawRect</a>( 70, -10, 80, 10 ); // draw the rectangle
88
89 <a href="qstring.html">QString</a> n;
90 n.<a href="qstring.html#sprintf">sprintf</a>( "H=%d", i*10 );
91<a name="x1072"></a> p-&gt;<a href="qpainter.html#drawText">drawText</a>( 80+70+5, 0, n ); // draw the hue number
92 }
93}
94
95
96//
97// This function draws a few lines of text using different fonts.
98//
99
100void drawFonts( <a href="qpainter.html">QPainter</a> *p )
101{
102 static const char *fonts[] = { "Helvetica", "Courier", "Times", 0 };
103 static int sizes[] = { 10, 12, 18, 24, 36, 0 };
104 int f = 0;
105 int y = 0;
106 while ( fonts[f] ) {
107 int s = 0;
108 while ( sizes[s] ) {
109 <a href="qfont.html">QFont</a> font( fonts[f], sizes[s] );
110 p-&gt;<a href="qpainter.html#setFont">setFont</a>( font );
111<a name="x1073"></a> <a href="qfontmetrics.html">QFontMetrics</a> fm = p-&gt;<a href="qpainter.html#fontMetrics">fontMetrics</a>();
112<a name="x1064"></a> y += fm.<a href="qfontmetrics.html#ascent">ascent</a>();
113 p-&gt;<a href="qpainter.html#drawText">drawText</a>( 10, y, "Quartz Glyph Job Vex'd Cwm Finks" );
114<a name="x1065"></a> y += fm.<a href="qfontmetrics.html#descent">descent</a>();
115 s++;
116 }
117 f++;
118 }
119}
120
121
122//
123// This function draws some shapes
124//
125
126void drawShapes( <a href="qpainter.html">QPainter</a> *p )
127{
128 <a href="qbrush.html">QBrush</a> b1( Qt::blue );
129 <a href="qbrush.html">QBrush</a> b2( Qt::green, Qt::Dense6Pattern ); // green 12% fill
130 <a href="qbrush.html">QBrush</a> b3( Qt::NoBrush ); // void brush
131 <a href="qbrush.html">QBrush</a> b4( Qt::CrossPattern ); // black cross pattern
132
133 p-&gt;<a href="qpainter.html#setPen">setPen</a>( Qt::red );
134 p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( b1 );
135 p-&gt;<a href="qpainter.html#drawRect">drawRect</a>( 10, 10, 200, 100 );
136 p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( b2 );
137<a name="x1071"></a> p-&gt;<a href="qpainter.html#drawRoundRect">drawRoundRect</a>( 10, 150, 200, 100, 20, 20 );
138 p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( b3 );
139<a name="x1068"></a> p-&gt;<a href="qpainter.html#drawEllipse">drawEllipse</a>( 250, 10, 200, 100 );
140 p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( b4 );
141<a name="x1069"></a> p-&gt;<a href="qpainter.html#drawPie">drawPie</a>( 250, 150, 200, 100, 45*16, 90*16 );
142}
143
144
145typedef void (*draw_func)(QPainter*);
146
147struct DrawThing {
148 draw_func f;
149 const char *name;
150};
151
152//
153// All previously implemented functions are collected
154// in the following "table".
155// If you implement different functionality, your new draw
156// function must be assigned here with a function pointer and
157// description.
158// Leave the zeros at the end, they will be used
159// as markers referring to the end of the array.
160//
161
162DrawThing ourDrawFunctions[] = {
163// name of the function, title presented to the user
164 { drawColorWheel, "Draw color wheel" },
165 { drawFonts, "Draw fonts" },
166 { drawShapes, "Draw shapes" },
167 { 0, 0 } };
168
169
170
171class DrawView : public <a href="qwidget.html">QWidget</a>
172{
173 <a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a>
174public:
175 DrawView();
176 ~DrawView();
177public slots:
178 void updateIt( int );
179 void printIt();
180protected:
181 void drawIt( <a href="qpainter.html">QPainter</a> * );
182 void paintEvent( <a href="qpaintevent.html">QPaintEvent</a> * );
183 void resizeEvent( <a href="qresizeevent.html">QResizeEvent</a> * );
184private:
185 <a href="qprinter.html">QPrinter</a> *printer;
186 <a href="qbuttongroup.html">QButtonGroup</a> *bgroup;
187 <a href="qpushbutton.html">QPushButton</a> *print;
188 int drawindex;
189 int maxindex;
190};
191
192
193//
194// Construct the DrawView with buttons.
195//
196
197<a name="f367"></a>DrawView::DrawView()
198{
199 <a href="qwidget.html#setCaption">setCaption</a>( "Qt Draw Demo Application" );
200 <a href="qwidget.html#setBackgroundMode">setBackgroundMode</a>(PaletteBase);
201
202 // Create a button group to contain all buttons
203 bgroup = new <a href="qbuttongroup.html">QButtonGroup</a>( this );
204<a name="x1088"></a> bgroup-&gt;<a href="qwidget.html#resize">resize</a>( 200, 200 );
205<a name="x1062"></a> <a href="qobject.html#connect">connect</a>( bgroup, SIGNAL(<a href="qbuttongroup.html#clicked">clicked</a>(int)), SLOT(updateIt(int)) );
206
207 // Calculate the size for the radio buttons
208 int maxwidth = 80;
209 int maxheight = 10;
210 int i;
211 const char *n;
212<a name="x1084"></a> <a href="qfontmetrics.html">QFontMetrics</a> fm = bgroup-&gt;<a href="qwidget.html#fontMetrics">fontMetrics</a>();
213
214 // Find out the longest function description.
215 // Here we make use of the last "0,0"-entry in the
216 // ourDrawFunctions-array.
217 for ( i=0; (n=ourDrawFunctions[i].name) != 0; i++ ) {
218<a name="x1066"></a> int w = fm.<a href="qfontmetrics.html#width">width</a>( n );
219 maxwidth = QMAX(w,maxwidth); // QMAX is a macro defined in qglobal.h
220 // and returns the biggest of to values.
221 // Due to its macro nature one should use it with care and with
222 // constant parameters only.
223 }
224
225 maxwidth = maxwidth + 30; // allow 30 pixels for radiobuttons
226
227 for ( i=0; (n=ourDrawFunctions[i].name) != 0; i++ ) {
228 <a href="qradiobutton.html">QRadioButton</a> *rb = new <a href="qradiobutton.html">QRadioButton</a>( n, bgroup );
229<a name="x1091"></a> rb-&gt;<a href="qwidget.html#setGeometry">setGeometry</a>( 10, i*30+10, maxwidth, 30 );
230
231 maxheight += 30;
232
233 if ( i == 0 )
234<a name="x1082"></a> rb-&gt;<a href="qradiobutton.html#setChecked">setChecked</a>( TRUE );
235 }
236
237 maxheight += 10; // maxheight is now 10 pixels upper margin
238 // plus number_of_drawfunctions * 30
239 // plus 10 pixels lower margin
240
241 drawindex = 0; // draw first thing
242 maxindex = i;
243
244 maxwidth += 20; // add some margin, this results in the
245 // final width of bgroup
246
247 bgroup-&gt;<a href="qwidget.html#resize">resize</a>( maxwidth, maxheight ); // resize bgroup to its final size
248 // when no printersupport is provided
249
250
251// If -- at compile time -- printer support will be disabled,
252// we won't set up printing functionality.
253
254#ifndef QT_NO_PRINTER
255
256 printer = new <a href="qprinter.html">QPrinter</a>;
257
258 // Create and setup the print button
259 print = new <a href="qpushbutton.html">QPushButton</a>( "Print...", bgroup );
260<a name="x1081"></a> print-&gt;<a href="qwidget.html#resize">resize</a>( 80, 30 );
261<a name="x1093"></a><a name="x1080"></a> print-&gt;<a href="qwidget.html#move">move</a>( maxwidth/2 - print-&gt;<a href="qwidget.html#width">width</a>()/2, maxindex*30+20 );
262 <a href="qobject.html#connect">connect</a>( print, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), SLOT(printIt()) );
263
264 // Resize bgroup to its final size when printersupport is given.
265<a name="x1094"></a><a name="x1085"></a> bgroup-&gt;<a href="qwidget.html#resize">resize</a>( maxwidth, print-&gt;<a href="qwidget.html#y">y</a>()+print-&gt;<a href="qwidget.html#height">height</a>()+10 );
266
267#endif
268
269 <a href="qwidget.html#resize">resize</a>( 640,300 );
270}
271
272//
273// Clean up.
274//
275DrawView::~DrawView()
276{
277#ifndef QT_NO_PRINTER
278 delete printer;
279#endif
280}
281
282//
283// Called when a radio button is clicked.
284//
285
286void <a name="f368"></a>DrawView::updateIt( int index )
287{
288 if ( index &lt; maxindex ) {
289 drawindex = index;
290 <a href="qwidget.html#update">update</a>();
291 }
292}
293
294//
295// Calls the drawing function as specified by the radio buttons.
296//
297
298void <a name="f369"></a>DrawView::drawIt( <a href="qpainter.html">QPainter</a> *p )
299{
300 (*ourDrawFunctions[drawindex].f)(p);
301}
302
303//
304// Called when the print button is clicked.
305//
306
307void <a name="f370"></a>DrawView::printIt()
308{
309<a name="x1079"></a> if ( printer-&gt;<a href="qprinter.html#setup">setup</a>( this ) ) {
310 <a href="qpainter.html">QPainter</a> paint;
311<a name="x1067"></a> if( !paint.<a href="qpainter.html#begin">begin</a>( printer ) )
312 return;
313 drawIt( &amp;paint );
314 }
315}
316
317//
318// Called when the widget needs to be updated.
319//
320
321void DrawView::<a href="qwidget.html#paintEvent">paintEvent</a>( <a href="qpaintevent.html">QPaintEvent</a> * )
322{
323 <a href="qpainter.html">QPainter</a> paint( this );
324 drawIt( &amp;paint );
325}
326
327//
328// Called when the widget has been resized.
329// Moves the button group to the upper right corner
330// of the widget.
331
332<a name="x1089"></a>void DrawView::<a href="qwidget.html#resizeEvent">resizeEvent</a>( <a href="qresizeevent.html">QResizeEvent</a> * )
333{
334<a name="x1086"></a> bgroup-&gt;<a href="qwidget.html#move">move</a>( <a href="qwidget.html#width">width</a>()-bgroup-&gt;<a href="qwidget.html#width">width</a>(), 0 );
335}
336
337
338//
339// Create and display our widget.
340//
341
342#include "drawdemo.moc"
343
344int main( int argc, char **argv )
345{
346 <a href="qapplication.html">QApplication</a> app( argc, argv );
347 DrawView draw;
348 app.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &amp;draw );
349 draw.<a href="qwidget.html#setCaption">setCaption</a>("Qt Example - Drawdemo");
350 draw.<a href="qwidget.html#show">show</a>();
351 return app.<a href="qapplication.html#exec">exec</a>();
352}
353</pre>
354
355<p>See also <a href="examples.html">Examples</a>.
356
357<!-- eof -->
358<p><address><hr><div align=center>
359<table width=100% cellspacing=0 border=0><tr>
360<td>Copyright &copy; 2007
361<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
362<td align=right><div align=right>Qt 3.3.8</div>
363</table></div></address></body>
364</html>
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