Qpainter function on a QFrame problem

[wysota]

What exactly is the widget supposed to display?

[impeteperry]

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]

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

[impeteperry]

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

[impeteperry]

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]

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

[impeteperry]

Well said.
I am still confused why a program compiled on one computer won't run on that computer, but will run on another one, I may try reinstalling Qt. but for now I will continue with the development of my program.
Thanks for your help and suggestions. Don't you ever sleep?
pete

[impeteperry]

I re-installed Qt-4 and all works now. Onward ever onword.
Thank you for your patience
pete

[impeteperry]

Hi, on the same subject.
My drawing is fine, but now I want to open a frame with a textEdit in it on top of the drawing with out the drawing showing through (help info) and when the frame is closed the drawinig is back. I thought Qt-4's "double buffering" took care of this.
Thanks

[jpn]

It's a matter of passing the QTextEdit widget a proper parent.

[impeteperry]

Thanks, it came to me last night what I was doing wrong.

[impeteperry]

I am still having problems which I have narrowed down to maybe a Qt problem.
I want to "show" a "help" box on a "QPainter" drawinq. I want to "toggle" this "box" by means of the keyboard "F1" key.
Line #4 in the following code activates a HelpFunction class to do this as has been suggested and line #5 does this in the painter function itself.
The first thumbnail just shows the drawing. The second shows the HelpFunction class "help box" after pressing the "F1" key.. The third shows the "help box" when generate by the painter itself.

///----------------------------------------------------------------------------Pb1
void BaseForm::slotPb1()
{
	emit activate();
	paintList.append("help");
	emit displayErectionDrawing(paintList, helpFlag);
}

///----------------------------------------------------------------------------Pb1
void BaseForm::slotPb1()
{
	emit activate();
	paintList.append("help");
	emit displayErectionDrawing(paintList, helpFlag);
}

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The code below is for the HelpFunction class. Below the horizontal line controls the toggle function.
Line 23 displays the status of the toggle so I can tell if the "F1" keystroke was received.

HelpFunction::HelpFunction(QWidget *parent)	: QWidget(parent)
{
	frameH = new QFrame();
	frameH->setAutoFillBackground ( true );
	frameH->setFrameShape ( QFrame::Box );
	frameH->setPalette ( QColor ( 200, 200, 200 ) );
	teHBox = new QTextEdit ( frameH );
	teHBox->setAutoFillBackground(true);
 	teHBox->setPalette(QColor ( 210, 255, 255 ));
	teHBox->setReadOnly ( true );
}
void HelpFunction::slotActivate()
{
	emit getDrawingFrameSize ( &W, &H );
	emit getTextListItem(2, &k);
	frameH->setGeometry ( W - 350, H - 420, 350, 430 );
	teHBox->setGeometry ( 10, 10,  330, 410 );
	teHBox->setPlainText ( k );
	emit showHelpFrame(frameH);
//--------------------------------------------------------------------------
	if(helpFlag == false) k = "false";
	else k = "true";
	emit setMessageBox("help 15 helpFlag = " + k);
	if(helpFlag == true) helpFlag = false;
	else if(helpFlag == false) helpFlag = true;
	else helpFlag = true;
}

HelpFunction::HelpFunction(QWidget *parent)	: QWidget(parent)
{
	frameH = new QFrame();
	frameH->setAutoFillBackground ( true );
	frameH->setFrameShape ( QFrame::Box );
	frameH->setPalette ( QColor ( 200, 200, 200 ) );
	teHBox = new QTextEdit ( frameH );
	teHBox->setAutoFillBackground(true);
 	teHBox->setPalette(QColor ( 210, 255, 255 ));
	teHBox->setReadOnly ( true );
}
void HelpFunction::slotActivate()
{
	emit getDrawingFrameSize ( &W, &H );
	emit getTextListItem(2, &k);
	frameH->setGeometry ( W - 350, H - 420, 350, 430 );
	teHBox->setGeometry ( 10, 10,  330, 410 );
	teHBox->setPlainText ( k );
	emit showHelpFrame(frameH);
//--------------------------------------------------------------------------
	if(helpFlag == false) k = "false";
	else k = "true";
	emit setMessageBox("help 15 helpFlag = " + k);
	if(helpFlag == true) helpFlag = false;
	else if(helpFlag == false) helpFlag = true;
	else helpFlag = true;
}

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There are several problems
1. the first time the "F1" key was pressed, the HelpFunction "help box" was displayed as shown in the second thumbnail.
2. After that, pressing the "F1" key had no effect.
3. Clicking anywhere on the screen with the left mouse button closed the HelpFunction "help box" and left the "painter" help box displayed.
4. Now the "F1" key toggled the "painter" help box.
5, If I changed line #3 of the HelpFunction class to "frameH = new QFrame(this);", the toggle worked fine for the "painter" box thumbnail #2.
6. CONCLUSION: When the "Help Function" box was displayed, the "F1" key was DEACTIVATED.

If we get problem #6 corrected, I would much prefer the "Box" to look like the "painter" box, but with scroll bars and the functionality of the QTextEdit widget.
If I am doing somthing wrong, I am including the pb1 and fk1clicked items which have worked flawlessly up to now.

connect ( Pb1, SIGNAL ( clicked() ), this, SLOT ( slotPb1() ) );
///--------------------------------------------------------Function Keys
connect ( this, SIGNAL ( fk1clicked() ), this, SLOT ( slotPb1() ) );

connect ( Pb1, SIGNAL ( clicked() ), this, SLOT ( slotPb1() ) );
///--------------------------------------------------------Function Keys
connect ( this, SIGNAL ( fk1clicked() ), this, SLOT ( slotPb1() ) );

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[/CODE]

void BaseForm::keyPressEvent ( QKeyEvent *k )
{
	int n;
	QString h;
	n = k->key();
	h = h.setNum ( n );
	if ( k->key() == 16777264 && Pb1->text() != "-" ) emit fk1clicked();
	if ( k->key() == 16777265 && Pb2->text() != "-" ) emit fk2clicked();

void BaseForm::keyPressEvent ( QKeyEvent *k )
{
	int n;
	QString h;
	n = k->key();
	h = h.setNum ( n );
	if ( k->key() == 16777264 && Pb1->text() != "-" ) emit fk1clicked();
	if ( k->key() == 16777265 && Pb2->text() != "-" ) emit fk2clicked();

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Thank you very much

[impeteperry]

Ok, I don't blame you all if you are fed up with me, but please give me a answer

Can I do what I want to in Qt4?

Thanks

[wysota]

You see... the problem is we are not seeing your problem I suggest you forget about F keys and all that stuff and focus on implementing a widget with properties that allow you to modify the behaviour of the widget. When you have that done, start thinking about function keys.

[impeteperry]

I'm back with another very confusing problem.
I have 2 versions of the same program. Call them A & B. I use

void MyDrawingFrame::slotSetPaintItems ( QStringList list )
{
	int n;
	for(n = 0; n < list.count(); ++n )
	{
		tempList = list[n].split("|");						/// split the list into types of stringLists
		k = tempList[0];													/// get the type of element to draw
		if(k == "erase")	clearWindow = "erase";
		else
		{
			tempList.removeFirst();									/// remove the element with the code
			clearWindow = "false";
			if(k=="supports")
				paintSupportLines=tempList;
			else if(k=="columns")
				paintColumns=tempList;
			else if(k=="help")	
				paintDrawHelpWindow=tempList; 	
			else if(k=="erase")	
				clearWindow="true";
		}
	}
	emit getDrawingFrameSize (&W,&H);
	k = actionList.last();
	tempList = k.split(",");
	if(tempList[1] == "4")		setGeometry (10,10,W ,H);
	else	setGeometry (10,10,0,0);
	update();
}

void MyDrawingFrame::slotSetPaintItems ( QStringList list )
{
	int n;
	for(n = 0; n < list.count(); ++n )
	{
		tempList = list[n].split("|");						/// split the list into types of stringLists
		k = tempList[0];													/// get the type of element to draw
		if(k == "erase")	clearWindow = "erase";
		else
		{
			tempList.removeFirst();									/// remove the element with the code
			clearWindow = "false";
			if(k=="supports")
				paintSupportLines=tempList;
			else if(k=="columns")
				paintColumns=tempList;
			else if(k=="help")	
				paintDrawHelpWindow=tempList; 	
			else if(k=="erase")	
				clearWindow="true";
		}
	}
	emit getDrawingFrameSize (&W,&H);
	k = actionList.last();
	tempList = k.split(",");
	if(tempList[1] == "4")		setGeometry (10,10,W ,H);
	else	setGeometry (10,10,0,0);
	update();
}

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for both versions and as near as I can tell the same data. There are two stages. The first just displays the "support lines" and the second displays both the "support lines" and the "colums".(see attachments from version B) Version A is fine for just the support lines, but when trying to display both the program crashes with the following statement which I don't understand at all.

{ Q_ASSERT_X(i >= 0 && i < p.size(), "QList<T>:perator[]", "index out of range");
detach(); return reinterpret_cast<Node *>(p.at(i))->t(); }

I have replaced the "update" with "redraw" but same problem. I don't think the problem is in the "paint event" itself,

As usual I would appreciate any help you can give me.
thanks.

[wysota]

I'd say tempList has no items and so tempList[0] fails. Or it can have one value and tempList[1] fails.

Could you explain what is preventing you from using Qt4 and QGraphicsView?

[impeteperry]

I am going back and check my data as I am sure that is where it must be as you suggest, but I would like to know about the "{ Q_ASSERT_X(i >= 0 && i < p.size(),...." message. can it help me find where and what is the problem is?.

I looked at QGraphicsView, as you suggested earlier, but for some reason decided not to go there. I will however do so now and try to make a parallel program to the one I have now.

What I am trying to do as a structural engineer is write a parametric driven program to replace the current CAD programs used in the industry and one that someone can learn to use in a day or two by going back to a modified command line operation similar to one I had written in pre-dos days. I do not have any time restraints, but a need to get it right.

I took a quick look at "graphicsview" and noted it was a 2D program and the program i am trying to re-write was a 3D rendered structure
Thanks for you indulgence

[wysota]

I am going back and check my data as I am sure that is where it must be as you suggest, but I would like to know about the "{ Q_ASSERT_X(i >= 0 && i < p.size(),...." message. can it help me find where and what is the problem is?.

Not really. But a backtrace from a debugger will and I suggest you use one here. There is no point in guessing if the application itself can tell you what is wrong.

I looked at QGraphicsView, as you suggested earlier, but for some reason decided not to go there. I will however do so now and try to make a parallel program to the one I have now.

I really suggest you reconsider using GV. It's perfect for your usecase.

I took a quick look at "graphicsview" and noted it was a 2D program and the program i am trying to re-write was a 3D rendered structure

But you are rendering it on a 2D canvas, so everything is ok. If you want to have real 3D, consider using OpenGL with one of the viewer frameworks available for Qt.

[impeteperry]

Thanks
I am using opengl.

There are 2 parts to the program.
1. developing a library of concrete elements (columns, beams, plank, connection hardware etc.) using opengl.

2. defining where they go.

This in a replacement for conventional CAD! which is prone for errors resulting from a multiplicity of input points for a given item. (floor plan, excavations, wall sections and details);

I layout a set of grids( support lines)
select a level (1st, 2nd, 3rd etc floor, )
place columns from the column library and locate them on grid intersections
place beams from the beam library and locate them by their supporting columns
place plank from the plank library and locate them by their supporting beams

now, if a grid line is moved, the associated columns move, the beam location and spans change, the plank location and spans change.
Now is a change levels, the column length changes etc.

this is all done automatically. Sort of like a "solid modeler" which I had tried.

Sorry to be so verbose, and I thank you for you patients.

[wysota]

Hmm... honestly I don't see anything 3D in the second image you attached to the last post.