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楼主 |
发表于 2005-5-24 16:20:11
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大家看一看这个！我想可以在这里找到答案！！不过我就现在还没有看出什么来！
Draw Demo
This example demonstrates several drawing functions and printer output. You can easily add you own drawing functions.
Implementation:
/****************************************************************************
** $Id: qt/drawdemo.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 <qwidget.h>
#include <qpainter.h>
#include <qprinter.h>
#include <qpushbutton.h>
#include <qradiobutton.h>
#include <qbuttongroup.h>
#include <qapplication.h>
#include <math.h>
//
// First we define the functionality our demo should present
// to the user. You might add different demo-modes if you wish so.
//
//
// This function draws a color wheel.
// The coordinate system x=(0..500), y=(0..500) spans the paint device.
//
void drawColorWheel( QPainter *p )
{
QFont f( "times", 18, QFont::Bold );
p->setFont( f );
p->setPen( Qt::black );
p->setWindow( 0, 0, 500, 500 ); // defines coordinate system
for ( int i=0; i<36; i++ ) { // draws 36 rotated rectangles
QWMatrix matrix;
matrix.translate( 250.0F, 250.0F ); // move to center
matrix.shear( 0.0F, 0.3F ); // twist it
matrix.rotate( (float)i*10 ); // rotate 0,10,20,.. degrees
p->setWorldMatrix( matrix ); // use this world matrix
QColor c;
c.setHsv( i*10, 255, 255 ); // rainbow effect
p->setBrush( c ); // solid fill with color c
p->drawRect( 70, -10, 80, 10 ); // draw the rectangle
QString n;
n.sprintf( "H=%d", i*10 );
p->drawText( 80+70+5, 0, n ); // draw the hue number
}
}
//
// This function draws a few lines of text using different fonts.
//
void drawFonts( QPainter *p )
{
static const char *fonts[] = { "Helvetica", "Courier", "Times", 0 };
static int sizes[] = { 10, 12, 18, 24, 36, 0 };
int f = 0;
int y = 0;
while ( fonts[f] ) {
int s = 0;
while ( sizes ) {
QFont font( fonts[f], sizes );
p->setFont( font );
QFontMetrics fm = p->fontMetrics();
y += fm.ascent();
p->drawText( 10, y, "Quartz Glyph Job Vex'd Cwm Finks" );
y += fm.descent();
s++;
}
f++;
}
}
//
// This function draws some shapes
//
void drawShapes( QPainter *p )
{
QBrush b1( Qt::blue );
QBrush b2( Qt::green, Qt::Dense6Pattern ); // green 12% fill
QBrush b3( Qt::NoBrush ); // void brush
QBrush b4( Qt::CrossPattern ); // black cross pattern
p->setPen( Qt::red );
p->setBrush( b1 );
p->drawRect( 10, 10, 200, 100 );
p->setBrush( b2 );
p->drawRoundRect( 10, 150, 200, 100, 20, 20 );
p->setBrush( b3 );
p->drawEllipse( 250, 10, 200, 100 );
p->setBrush( b4 );
p->drawPie( 250, 150, 200, 100, 45*16, 90*16 );
}
typedef void (*draw_func)(QPainter*);
struct DrawThing {
draw_func f;
const char *name;
};
//
// All previously implemented functions are collected
// in the following "table".
// If you implement different functionality, your new draw
// function must be assigned here with a function pointer and
// description.
// Leave the zeros at the end, they will be used
// as markers referring to the end of the array.
//
DrawThing ourDrawFunctions[] = {
// name of the function, title presented to the user
{ drawColorWheel, "Draw color wheel" },
{ drawFonts, "Draw fonts" },
{ drawShapes, "Draw shapes" },
{ 0, 0 } };
class DrawView : public QWidget
{
Q_OBJECT
public:
DrawView();
~DrawView();
public slots:
void updateIt( int );
void printIt();
protected:
void drawIt( QPainter * );
void paintEvent( QPaintEvent * );
void resizeEvent( QResizeEvent * );
private:
QPrinter *printer;
QButtonGroup *bgroup;
QPushButton *print;
int drawindex;
int maxindex;
};
//
// Construct the DrawView with buttons.
//
DrawView::DrawView()
{
setCaption( "Qt Draw Demo Application" );
setBackgroundColor( white );
// Create a button group to contain all buttons
bgroup = new QButtonGroup( this );
bgroup->resize( 200, 200 );
connect( bgroup, SIGNAL(clicked(int)), SLOT(updateIt(int)) );
// Calculate the size for the radio buttons
int maxwidth = 80;
int maxheight = 10;
int i;
const char *n;
QFontMetrics fm = bgroup->fontMetrics();
// Find out the longest function description.
// Here we make use of the last "0,0"-entry in the
// ourDrawFunctions-array.
for ( i=0; (n=ourDrawFunctions.name) != 0; i++ ) {
int w = fm.width( n );
maxwidth = QMAX(w,maxwidth); // QMAX is a macro defined in qglobal.h
// and returns the biggest of to values.
// Due to its macro nature one should use it with care and with
// constant parameters only.
}
maxwidth = maxwidth + 30; // allow 30 pixels for radiobuttons
for ( i=0; (n=ourDrawFunctions.name) != 0; i++ ) {
QRadioButton *rb = new QRadioButton( n, bgroup );
rb->setGeometry( 10, i*30+10, maxwidth, 30 );
maxheight += 30;
if ( i == 0 )
rb->setChecked( TRUE );
}
maxheight += 10; // maxheight is now 10 pixels upper margin
// plus number_of_drawfunctions * 30
// plus 10 pixels lower margin
drawindex = 0; // draw first thing
maxindex = i;
maxwidth += 20; // add some margin, this results in the
// final width of bgroup
bgroup->resize( maxwidth, maxheight ); // resize bgroup to its final size
// when no printersupport is provided
// If -- at compile time -- printer support will be disabled,
// we won't set up printing functionality.
#ifndef QT_NO_PRINTER
printer = new QPrinter;
// Create and setup the print button
print = new QPushButton( "Print...", bgroup );
print->resize( 80, 30 );
print->move( maxwidth/2 - print->width()/2, maxindex*30+20 );
connect( print, SIGNAL(clicked()), SLOT(printIt()) );
// Resize bgroup to its final size when printersupport is given.
bgroup->resize( maxwidth, print->y()+print->height()+10 );
#endif
resize( 640,300 );
}
//
// Clean up.
//
DrawView::~DrawView()
{
#ifndef QT_NO_PRINTER
delete printer;
#endif
}
//
// Called when a radio button is clicked.
//
void DrawView::updateIt( int index )
{
if ( index < maxindex ) {
drawindex = index;
update();
}
}
//
// Calls the drawing function as specified by the radio buttons.
//
void DrawView::drawIt( QPainter *p )
{
(*ourDrawFunctions[drawindex].f)(p);
}
//
// Called when the print button is clicked.
//
void DrawView::printIt()
{
if ( printer->setup( this ) ) {
QPainter paint( printer );
drawIt( &paint );
}
}
//
// Called when the widget needs to be updated.
//
void DrawView::paintEvent( QPaintEvent * )
{
QPainter paint( this );
drawIt( &paint );
}
//
// Called when the widget has been resized.
// Moves the button group to the upper right corner
// of the widget.
void DrawView::resizeEvent( QResizeEvent * )
{
bgroup->move( width()-bgroup->width(), 0 );
}
//
// Create and display our widget.
//
#include "drawdemo.moc"
int main( int argc, char **argv )
{
QApplication app( argc, argv );
DrawView draw;
app.setMainWidget( &draw );
draw.setCaption("Qt Example - Drawdemo");
draw.show();
return app.exec();
} |
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