Qpainter function on a QFrame problem

**impeteperry** · 27th January 2008, 20:14

I never have had as much trouble with anything I can remember.
As you suggested I setup a new class "MyDrawingFrame" and implemented it as best as I could. It compiles without any warnings

Qt Code:

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#ifndef MYDRAWINGFRAME_H
#define MYDRAWINGFRAME_H
 
#include "baseform.h"
#include <qframe.h>
#include <qpainter.h>
 
class MyDrawingFrame : public  QFrame
{
	Q_OBJECT
 
public:
 
public slots:
 
protected:
	void paintEvent(QPaintEvent * event);
 
protected slots:
 
private:
	QStringList tempList;
	QStringList paintSupportLines;
	QStringList paintColumns;
	QString clearWindow;
 
	QRect  viewportRect;
	QRect  windowRect;
	QRect clippingRect;
	double pi;
	int activeLevel;
	int functionNumber;
	int dwgScaleFactor;
	int count;
	int num;
	int n;
	int o1;
 
	bool ok;
 
private slots:
 
signals:
 
};
 
void MyDrawingFrame::paintEvent(QPaintEvent * event)
{
	QString k, h;
	double angle;
	int n, xs, xe, ys, ye, xc, yc;
	bool ok;
 
	QPainter p(this);
	QPen pen;
	QFont f;
 
	if ( paintSupportLines.count () > 0 )
	{
		f.setFamily ( "Courier" );
		f.setPointSize ( dwgScaleFactor );
		p.setFont ( f );
		pen.setBrush ( Qt::blue );
		p.setPen ( pen );
		p.setViewport ( viewportRect );
		p.setWindow ( windowRect );
 
		if ( clearWindow == "erase" ) { p.eraseRect ( windowRect ); clearWindow = "cancel erase"; }
		else
		{
			for ( n = 0; n < paintSupportLines.count(); ++n )
			{
				//teErrorMessages->setText("F5 key clicked");
				p.setClipRect ( clippingRect );
				k = paintSupportLines[n];
				tempList = k.split ( "," );
				xs = tempList[0].toInt ( &ok );
				ys = tempList[1].toInt ( &ok );
				xe = tempList[2].toInt ( &ok );
				ye = tempList[3].toInt ( &ok );
				p.drawLine ( 10, 10 * n, 200, 200 );
				p.drawLine ( xs, ys, xe, ye );
						/// start of labeling.
				if ( tempList[4] == "true" )
				{
					p.setClipRect ( windowRect );
					xc = ( xs + xe ) / 2;
					yc = ( ys + ye ) / 2;
					if ( xs == xe ) angle = pi/2.0;
					else if ( ys == ye ) angle = 0.0;
					else
					{
//					angle = atan((double)(ye-ys)/(xe-xs));			/// Why did Qt 4 drop trig functions????
						angle = ( double ) ( ye-ys ) / ( xe-xs );		/// hope this works!!!
						angle /= 2.0 * pi ;
					}
					angle = ( angle * 180.0 ) / pi;
					p.save();
					p.translate ( xc, yc );
					p.rotate ( angle );	//teErrorMessages->setText("F5 key clicked");
					p.scale ( 1, -1 );
					k = "S" + h.setNum ( n + 1 );
					p.drawText ( 0, 0, k );
					p.restore();
				}
			}
		}
		if ( paintColumns.count() > 0 )
		{
			p.setViewport ( viewportRect );
			p.setWindow ( windowRect );
			p.setClipRect ( windowRect );
			for ( n = 0; n < paintColumns.count(); ++n )
			{
				k = paintColumns[n];
				tempList = k.split ( "," );
				xs = tempList[0].toInt ( &ok );
				ys = tempList[1].toInt ( &ok );
				xe = tempList[2].toInt ( &ok );
				ye = tempList[3].toInt ( &ok );
				angle = tempList[4].toInt ( &ok );
				p.save();
				p.translate ( xs, ys );
				p.rotate ( angle );
				p.fillRect ( -xe/2, -ye/2, xe, ye, Qt::black );
				if ( tempList[5] == "true" )
				{
					f.setFamily ( "Courier" );
					f.setPointSize ( ( int ) ( .8 * dwgScaleFactor ) );
					p.setFont ( f );
					pen.setBrush ( Qt::black );
					p.setPen ( pen );
					p.rotate ( -angle + 25 );
					p.scale ( 1, -1 );
					k = "---C" + h.setNum ( n + 1 );
					p.drawText ( 0, 0, k );
				}
				p.restore();
			}
		}
	}
}
#endif	// MYDRAWINGFRAME_H

#ifndef MYDRAWINGFRAME_H
#define MYDRAWINGFRAME_H

#include "baseform.h"
#include <qframe.h>
#include <qpainter.h>

class MyDrawingFrame : public  QFrame
{
	Q_OBJECT

public:

public slots:

protected:
	void paintEvent(QPaintEvent * event);

protected slots:

private:
	QStringList tempList;
	QStringList paintSupportLines;
	QStringList paintColumns;
	QString clearWindow;

	QRect  viewportRect;
	QRect  windowRect;
	QRect clippingRect;
	double pi;
	int activeLevel;
	int functionNumber;
	int dwgScaleFactor;
	int count;
	int num;
	int n;
	int o1;

	bool ok;

private slots:

signals:

};

void MyDrawingFrame::paintEvent(QPaintEvent * event)
{
	QString k, h;
	double angle;
	int n, xs, xe, ys, ye, xc, yc;
	bool ok;

	QPainter p(this);
	QPen pen;
	QFont f;

	if ( paintSupportLines.count () > 0 )
	{
		f.setFamily ( "Courier" );
		f.setPointSize ( dwgScaleFactor );
		p.setFont ( f );
		pen.setBrush ( Qt::blue );
		p.setPen ( pen );
		p.setViewport ( viewportRect );
		p.setWindow ( windowRect );

		if ( clearWindow == "erase" ) { p.eraseRect ( windowRect ); clearWindow = "cancel erase"; }
		else
		{
			for ( n = 0; n < paintSupportLines.count(); ++n )
			{
				//teErrorMessages->setText("F5 key clicked");
				p.setClipRect ( clippingRect );
				k = paintSupportLines[n];
				tempList = k.split ( "," );
				xs = tempList[0].toInt ( &ok );
				ys = tempList[1].toInt ( &ok );
				xe = tempList[2].toInt ( &ok );
				ye = tempList[3].toInt ( &ok );
				p.drawLine ( 10, 10 * n, 200, 200 );
				p.drawLine ( xs, ys, xe, ye );
						/// start of labeling.
				if ( tempList[4] == "true" )
				{
					p.setClipRect ( windowRect );
					xc = ( xs + xe ) / 2;
					yc = ( ys + ye ) / 2;
					if ( xs == xe ) angle = pi/2.0;
					else if ( ys == ye ) angle = 0.0;
					else
					{
//					angle = atan((double)(ye-ys)/(xe-xs));			/// Why did Qt 4 drop trig functions????
						angle = ( double ) ( ye-ys ) / ( xe-xs );		/// hope this works!!!
						angle /= 2.0 * pi ;
					}
					angle = ( angle * 180.0 ) / pi;
					p.save();
					p.translate ( xc, yc );
					p.rotate ( angle );	//teErrorMessages->setText("F5 key clicked");
					p.scale ( 1, -1 );
					k = "S" + h.setNum ( n + 1 );
					p.drawText ( 0, 0, k );
					p.restore();
				}
			}
		}
		if ( paintColumns.count() > 0 )
		{
			p.setViewport ( viewportRect );
			p.setWindow ( windowRect );
			p.setClipRect ( windowRect );
			for ( n = 0; n < paintColumns.count(); ++n )
			{
				k = paintColumns[n];
				tempList = k.split ( "," );
				xs = tempList[0].toInt ( &ok );
				ys = tempList[1].toInt ( &ok );
				xe = tempList[2].toInt ( &ok );
				ye = tempList[3].toInt ( &ok );
				angle = tempList[4].toInt ( &ok );
				p.save();
				p.translate ( xs, ys );
				p.rotate ( angle );
				p.fillRect ( -xe/2, -ye/2, xe, ye, Qt::black );
				if ( tempList[5] == "true" )
				{
					f.setFamily ( "Courier" );
					f.setPointSize ( ( int ) ( .8 * dwgScaleFactor ) );
					p.setFont ( f );
					pen.setBrush ( Qt::black );
					p.setPen ( pen );
					p.rotate ( -angle + 25 );
					p.scale ( 1, -1 );
					k = "---C" + h.setNum ( n + 1 );
					p.drawText ( 0, 0, k );
				}
				p.restore();
			}
		}
	}
}
#endif	// MYDRAWINGFRAME_H

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Great, but how do I access it to set the values of the variables and activate the paint event itself??. If I "#include "mydrawingframe.h" in my "baseframe.cpp" or anyplace else for that matter I get an

/home/pete/Desktop/pm-straight-C/pm/mydrawingframe.h:65: multiple definition of `MyDrawingFrame:

aintEvent(QPaintEvent*)'
baseform.o:/home/pete/Desktop/pm-straight-C/pm/mydrawingframe.h:65: first defined here
collect2: ld returned 1 exit status
make: *** [pm] Error 1

I have also tried setting up a "mydrawingframe.cpp" but I could not get a "MyDrawingFrame::MydrawingFrame( Q??? *parent ) : Q???
t(parent) that did not give an error when compiling.
Sorry to be so long winded, but I am desperate. What in H--- am I missing??? All I want to do is draw some lines of a QFrame widget!!!!!

**wysota** · 27th January 2008, 20:57

Have you seen this thread?

http://www.qtcentre.org/forum/f-qt-d...bel-11504.html

Especially take a look at how the line is drawn depending on the size of the widget.

**impeteperry** · 28th January 2008, 06:43

Thanks Mysota It was a great help.My big problem I forgot the line under the "public;" when defining the class. What ever you do, don't get old (I'm 81).

Now all I have to do is figure out how to set the size of the frame, but I"m going to bed it's 12:30.

Thanks again.

**ashukla** · 28th January 2008, 06:54

Thanks Mysota It was a great help.My big problem

Please mention the name correctly as Wysota, Qt Guru.

**impeteperry** · 29th January 2008, 20:48

Wysots, Qi Guru, I'm sorry about the name. It was late and I don't see to well.
I have made some progress. I can draw some lines, so I am back at setting up my scaling functions.
I do have a question. In the distant past I wrote to a "pixmap". is there any advantage to that now with the paintEvent functionallity?
Thanks

**impeteperry** · 30th January 2008, 20:02

Hi
I now have my painter working on my laptop whereI compiled the program.
It also runs on my desk computer as long as I don't re-compile it there. If I re-compile the same source code there it locks up the computer on the first "p.drawText" command. I have single stepped the program on both computers. Everything is the same. There is no problem with the "p.drawLine" command. If I option out the single p.drawText(x, y, "text"); line 16, the program runs fine.

Qt Code:

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p.drawLine ( xs, ys, xe, ye );
						/// start of labeling.
				if ( tempList[4] == "true" )
				{
					xc = ( xs + xe ) / 2;
					yc = ( ys + ye ) / 2;
					if ( xs == xe ) angle = pi/2.0;
					else if ( ys == ye ) angle = 0.0;
					else	angle = atan((double)(ye - ys) / (double)(xe - xs));
					angle = ( angle * 180.0 ) / pi;
					p.save();
					p.translate ( xc, yc );
					p.rotate ( angle );
					p.scale ( 1, -1 );
					k = "S" + h.setNum ( n + 1 );
					p.drawText ( 0, 0, k );
					p.restore();
				}

p.drawLine ( xs, ys, xe, ye );
						/// start of labeling.
				if ( tempList[4] == "true" )
				{
					xc = ( xs + xe ) / 2;
					yc = ( ys + ye ) / 2;
					if ( xs == xe ) angle = pi/2.0;
					else if ( ys == ye ) angle = 0.0;
					else	angle = atan((double)(ye - ys) / (double)(xe - xs));
					angle = ( angle * 180.0 ) / pi;
					p.save();
					p.translate ( xc, yc );
					p.rotate ( angle );
					p.scale ( 1, -1 );
					k = "S" + h.setNum ( n + 1 );
					p.drawText ( 0, 0, k );
					p.restore();
				}

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I am using the same Kubuntu 7.10 on each computer.
I am sorry to be such a pest.
Thanks for help.

**wysota** · 30th January 2008, 21:51

What exactly is the widget supposed to display?

**impeteperry** · 30th January 2008, 23:25

I have a bunch of lines and i label them with their number. the text I want to display is "S1" See attachment. These are "Grid" lines are used for locating building columns and other elements.
Except for the screen size the data is identical on the two computers. The lines draw correctly so the "viewWindow" and "viewPort" are set correctly. If I take the compiled program from the second machine, it runes fine on the firsrt machine.

In essense, the program compiled on the first computer runs fine on both computers
The program compiled on the second computer locks it up when run, but runs fine on the first computer.

**wysota** · 30th January 2008, 23:44

Why don't you use QGraphicsView to make the visualization?

**impeteperry** · 31st January 2008, 05:12

QGraphicsView was add in Qt4.2. I was unaware of its existance
Thanks, I will take a look at it.

**impeteperry** · 31st January 2008, 06:18

I took a quick look at your QGraphicView and found

By default, the items are drawn onto the viewport by using a regular QPainter, and using default render hints.

What would be the advantage using this when I already have the geometry and am already using the "painter" to draw items onto the "viewPort"?

**wysota** · 31st January 2008, 10:19

Ease of handling. I don't say you should take that approach, but that if you have problems with one mechanism, try using another.

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