image bleeding

[vonCZ]

'morning,

I've got a QLabel with text that pops up when the user mouseOver a button. The problem is: part of an image elsewhere in the application is also showing up in the QLabel. Here's an image that will help explain:

http://www.beg.utexas.edu/coastal/wrl/del/both.jpg

In the primary window is a QStackedWidget with 2 widgets: the Introduction Widget (visible in the top half of the linked image) which is currently just a QLabel, and a widget containing a Coin3d scenegraph. The "Introduction" button sets the Stack index to the Introduction widget, and the other buttons on the bottom index the Coin3d widget.

When the Coin3d widget is active (bottom half of the image), mousing over buttons on the left cause QLabel information text boxes to pop up. The white text is part of the QLabel pop-up; unfortunately: part of the image from the Introduction widget is also present. How to make this stop? I've tried things like setting "hide()" on the information widget when it's not active, but that doesn't work.

as always, thank you.

[marcel]

Is the information widget transparent?

If you have overridden its paint event, than issue a fillRect before drawing the text and fill the background with a color.

Regards

[vonCZ]

no, no transparency.

& I don't *think* I overrode a paint event. This is how I'm drawing the panel:

panStack = new QStackedWidget(coinWidget);
 
  if(panNUM==0)
  {
 
//    QPainter *paint = new QPainter;
//    paint->fillRect((coinWidget->width() - 160), 10, 150, 300, QBrush(Qt::white));
//    panLabel[panNUM]->setAutoFillBackground(true);
 
    panLabel[panNUM]->setWordWrap(true);
    panStr0 = "Test text to see how much text I can put into a QString.";
    panLabel[panNUM]->setPalette(QPalette(QColor(1,1,1)));
    panLabel[panNUM]->setText(panStr0);
  }
 
  panStack->addWidget(panLabel[panNUM]);

panStack = new QStackedWidget(coinWidget);

  if(panNUM==0)
  {

//    QPainter *paint = new QPainter;
//    paint->fillRect((coinWidget->width() - 160), 10, 150, 300, QBrush(Qt::white));
//    panLabel[panNUM]->setAutoFillBackground(true);

    panLabel[panNUM]->setWordWrap(true);
    panStr0 = "Test text to see how much text I can put into a QString.";
    panLabel[panNUM]->setPalette(QPalette(QColor(1,1,1)));
    panLabel[panNUM]->setText(panStr0);
  }

  panStack->addWidget(panLabel[panNUM]);

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and here's the event filter for testing mouseOver:

bool Window::eventFilter(QObject *obj, QEvent *event)
{
  if(  (obj == myButton)  &&  (event->type() == QEvent::HoverEnter)  )
  {
    panStack->setGeometry((coinWidget->width() - 160), 10, 150, 300);
    panStack->setCurrentIndex(0);
    panStack->show();
    return QWidget::eventFilter(obj, event);
 
  }
  else if(  (event->type() == QEvent::HoverLeave)  )
  {
    panStack->hide();
    return QWidget::eventFilter(obj, event);
  }
  else
  {
    return QWidget::eventFilter(obj, event);
  }
}

bool Window::eventFilter(QObject *obj, QEvent *event)
{
  if(  (obj == myButton)  &&  (event->type() == QEvent::HoverEnter)  )
  {
    panStack->setGeometry((coinWidget->width() - 160), 10, 150, 300);
    panStack->setCurrentIndex(0);
    panStack->show();
    return QWidget::eventFilter(obj, event);

  }
  else if(  (event->type() == QEvent::HoverLeave)  )
  {
    panStack->hide();
    return QWidget::eventFilter(obj, event);
  }
  else
  {
    return QWidget::eventFilter(obj, event);
  }
}

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...ideas?

[marcel]

One observation regarding the commented code: you cannot paint a widget outside a paint event. Unless you set a flag to that widgets which explicitly states that it can be painted asynchronously( outside a paint event ).

As for the information widget, try adjusting its geometry also when you adjust it for the stacked widget. Or add it in a container widget with a horizontal/vertical layout and add this container to the stacked widget.

In the event filter, why do you always set the stack widget index to 0, no matter what button you hover? Shouldn't be an index based on the current button?

Regards

[vonCZ]

As for the information widget, try adjusting its geometry also when you adjust it for the stacked widget. Or add it in a container widget with a horizontal/vertical layout and add this container to the stacked widget.

i tried these: no success. I used a frame widget for the container; it didn't have an effect. I also adjusted the QLabel and QFrame geometry with the stacked widget- nothing.

I did, however, see a possible clue: if I barely resize the window, then the unwanted picture disappears from the Info Widget the next time I mouseOver. If I go back to the Introduction page, then go back to the coin3d widget/mouseOver: it reappears... but will then disappear again if I barely resize the window. Is there some way to flush out old image info?

In the event filter, why do you always set the stack widget index to 0, no matter what button you hover? Shouldn't be an index based on the current button?

oh yeah, i'm just trying to get it to work with the first button now.

[marcel]

I don't really know. You shouldn't get any garbage at all in your label. Unless you are doing something wrong...

I am curious if the label gets any update events...

The solution that has to work is: subclass QLabel or QWidget(better) and override the paintEvent. There, first fill the background with some color and next draw the text.

But again, normally, you shouldn't get rubbish. What is the parent of the label? From the code I see it is coinWidget. What is that? Could you switch to main window as parent?

Another thing: I have seen that you keep the info widgets in an array and you also use a stacked widget.
My opinion is to lose the stacked widget and stick to the array.
When the mouse leaves a button then just hide its info widget. When it enters, you show it.
You could use a QMap<QWidget, QWidget>, where the first param is the button, the second is the info widget for the button.
Something like:

map[hoveredButton]->show().

map[hoveredButton]->show().

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A stacked widget could have unpredictable behavior when used like this( floating ). I'm just saying what seems easier to do. It still remains your decision.

Regards

[vonCZ]

I don't really know. You shouldn't get any garbage at all in your label. Unless you are doing something wrong...

that's what i'm worried about

you're right- lose the Stack. I was using it before I realized I would have to use hide()/show() anyway; it's redundant now. I'll clean this up and take another look. Thanks for your help: somebody is owed a case of beer.

[vonCZ]

There, first fill the background with some color and next draw the text.

good tip. Actually,

myLabel[0]->setAutoFillBackground(true);

myLabel[0]->setAutoFillBackground(true);

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pretty much did the trick. The ghost-image would still show up in the label's margin (if set to >0), but then I changed "setGeometry()" to "move()" in the event filter--and defined the size of the label when I created them--and this fixed it up.

there is one other thing i would ask you about, if I hadn't bugged you so much already. I'm setting the label sizes like so:

void Window::mkPan()
{
  int panNUM_TOT = dafo.get_panNUM_TOT();
  for(int panNUM=0; panNUM<panNUM_TOT; panNUM++)
  {
    panLabel[panNUM] = new QLabel(coinWidget);
    panLabel[panNUM]->setMargin(5);
    panLabel[panNUM]->setMinimumWidth(150);  //here
    panLabel[panNUM]->setMinimumHeight(  int(dafo.get_panStr(panNUM).length()*.8)  ); //here
    panLabel[panNUM]->setAlignment(Qt::AlignTop | Qt::AlignLeft);
    panLabel[panNUM]->setFrameStyle(QFrame::Panel | QFrame::Sunken);  // no effect
    panLabel[panNUM]->setPalette(QPalette(QColor(1,1,1)));
    panLabel[panNUM]->setWordWrap(true);
    panLabel[panNUM]->setAutoFillBackground(true);
    panLabel[panNUM]->setText(dafo.get_panStr(panNUM));
    panLabel[panNUM]->hide();
  }
}

void Window::mkPan()
{
  int panNUM_TOT = dafo.get_panNUM_TOT();
  for(int panNUM=0; panNUM<panNUM_TOT; panNUM++)
  {
    panLabel[panNUM] = new QLabel(coinWidget);
    panLabel[panNUM]->setMargin(5);
    panLabel[panNUM]->setMinimumWidth(150);  //here
    panLabel[panNUM]->setMinimumHeight(  int(dafo.get_panStr(panNUM).length()*.8)  ); //here
    panLabel[panNUM]->setAlignment(Qt::AlignTop | Qt::AlignLeft);
    panLabel[panNUM]->setFrameStyle(QFrame::Panel | QFrame::Sunken);  // no effect
    panLabel[panNUM]->setPalette(QPalette(QColor(1,1,1)));
    panLabel[panNUM]->setWordWrap(true);
    panLabel[panNUM]->setAutoFillBackground(true);
    panLabel[panNUM]->setText(dafo.get_panStr(panNUM));
    panLabel[panNUM]->hide();
  }
}

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As you can see, I want the width fixed at 150 for all, and the Height to fit the given text String, but this method isn't optimal: there's not a particular variable (.8, etc) that is optimal. Sometimes too long, other times too short. Better way?

[marcel]

This should do the trick:

#define LBL_FIXED_WIDTH 150 //you should do this if it is always fixed
...
int height = 0;
QFontMetrics metrics(panLabel[panNum]->font());
int txtWidth = metrics.width(panLabel[panNum]->text());
float factor = float(txtWidth)/LBL_FIXED_WIDTH;
height = int( factor*metrics.height() ) + 1;

#define LBL_FIXED_WIDTH 150 //you should do this if it is always fixed
...
int height = 0;
QFontMetrics metrics(panLabel[panNum]->font());
int txtWidth = metrics.width(panLabel[panNum]->text());
float factor = float(txtWidth)/LBL_FIXED_WIDTH;
height = int( factor*metrics.height() ) + 1;

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So this is the height you should use.
Factor is approximately how many text lines the label will have.
Probably you will have to add some vertical row space in there(probably 2-3 pixels)....

Regards

[vonCZ]

thanks again for your help, Marcel. The QFontMetrics example you provided certainly helped, but with one little problem: depending on how the text wrapped & how many lines of text, I would end up with extra space at the bottom of my QLabel. After (way too much) messing around with it, I finally found this to work perfect:

int height = 0;
QFontMetrics myMet(myFont);
QRect myRect;
myRect.setWidth(panWIDTH - (2*panMARGIN));  //  panWIDTH=150
height = myMet.boundingRect(myRect, Qt::AlignLeft | Qt::TextWordWrap, myString, 0, 0).height() + (2*panMARGIN);

int height = 0;
QFontMetrics myMet(myFont);
QRect myRect;
myRect.setWidth(panWIDTH - (2*panMARGIN));  //  panWIDTH=150
height = myMet.boundingRect(myRect, Qt::AlignLeft | Qt::TextWordWrap, myString, 0, 0).height() + (2*panMARGIN);

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figured I would post, in case it helps someone else.