QT 4.2 widget setmask problem

[PiXeL16]

Hi all,
Hope someone can help.
I develop my application main widget so it have transparent edges, by following the TUX example.
This work perfectly in QT 4.1.
But now i move to QT 4.2 and does not work anymore, all the borders come black, and its look like the widget mask is not been applied.
Any info on this?
What can i do???
Any help will be much appreciated
Thanks
CJC.

[Glitch]

Can you post some code you are using?

[PiXeL16]

Sure, this is basically my code.

QPixmap pixmap("transparentImage.png");
	    QImage image("transparentImage.png");
	    QBitmap bt();
 
 
 
		//Create the mask
		 image = image.createAlphaMask(Qt::AutoColor);
 
 
	     bt= QBitmap::fromImage(image,Qt::AutoColor);
	     pixmap.setMask(bt);
 
 
 
		//Aply the mask to the widget
		_mainWidget->setMask(pixmap.mask());

QPixmap pixmap("transparentImage.png");
	    QImage image("transparentImage.png");
	    QBitmap bt();
		


		//Create the mask
		 image = image.createAlphaMask(Qt::AutoColor);
		 
		 
	     bt= QBitmap::fromImage(image,Qt::AutoColor);
	     pixmap.setMask(bt);

		 

		//Aply the mask to the widget
		_mainWidget->setMask(pixmap.mask());

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The result in qt 4.1 is that the mask is applied to the mainwidget and the transparent pixel in the image come clipped.
The result in qt 4.2 is that the transparent pixels in the image are black, and looks like the mask is not been applied

Any help plz
THanks
CJC

[PiXeL16]

Any help on this plz

[jpn]

I thought it was something as simple as this when the image had transparent edges:

QPixmap pixmap("transparentImage.png");
_mainWidget->setMask(pixmap.mask());

QPixmap pixmap("transparentImage.png");
_mainWidget->setMask(pixmap.mask());

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[PiXeL16]

Me too, but it didnt work.
So I try to do it like the tux example and it work very good in qt 4.1 but in qt 4.2 now dont work.
Any more help on this?
Maybe someone has a workarround or and example that work in qt 4.2?
Thanks
CJC!

[fullmetalcoder]

Me too, but it didnt work.
So I try to do it like the tux example and it work very good in qt 4.1 but in qt 4.2 now dont work.
Any more help on this?
Maybe someone has a workarround or and example that work in qt 4.2?

Have you checked the Tux example in Qt 4.2???

[PiXeL16]

The problem is that the TUX example is not included.
Even in qt 4.1 it was not included. I need to work with the old example i think from qt 3 and change all the not working and old functions.
Any way, someone has and example of this or maybe some workaround to make this work?
Please, any help will be much appreciated.
Thanks
CJC

[jpn]

I'm using Qt 4.2.2 on X11 and it works for me the simple way I described.. Doesn't the attached example work for you?

[PiXeL16]

Thanks,
Yeah thats the effect that i want to give.
Maybe is because im using a dialog? and you are using a label?
Or also, im using a qpainter to create the image. maybe something change from qt 4.1 to qt 4.2 and the qpainter draw images does not create transparent parts?

Thanks
CJC

[jpn]

Maybe is because im using a dialog? and you are using a label?

That should not have effect of any kind. Both are QWidgets.

Or also, im using a qpainter to create the image. maybe something change from qt 4.1 to qt 4.2 and the qpainter draw images does not create transparent parts?

Try filling the image with a transparent color before painting the shape.

[Glitch]

Sure, this is basically my code.

QPixmap pixmap("transparentImage.png");
	    QImage image("transparentImage.png");
	    QBitmap bt();
 
 
 
		//Create the mask
		 image = image.createAlphaMask(Qt::AutoColor);
 
 
	     bt= QBitmap::fromImage(image,Qt::AutoColor);
	     pixmap.setMask(bt);
 
 
 
		//Aply the mask to the widget
		_mainWidget->setMask(pixmap.mask());

QPixmap pixmap("transparentImage.png");
	    QImage image("transparentImage.png");
	    QBitmap bt();
		


		//Create the mask
		 image = image.createAlphaMask(Qt::AutoColor);
		 
		 
	     bt= QBitmap::fromImage(image,Qt::AutoColor);
	     pixmap.setMask(bt);

		 

		//Aply the mask to the widget
		_mainWidget->setMask(pixmap.mask());

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The result in qt 4.1 is that the mask is applied to the mainwidget and the transparent pixel in the image come clipped.
The result in qt 4.2 is that the transparent pixels in the image are black, and looks like the mask is not been applied

This looks reasonable. Have you thought that maybe your app isn't finding transparentImage.png. I notice a relative path here. Try using the qt resource system to embed your images into the executable.

--Justin

[PiXeL16]

Hi thanks for the reply.
No, that was an example. Im using a qrc resource file, and the app is finding the image correctly.
Also, im using a qpainter to create a big image from small image. The qpainter default color is transparent, so i dont have to do that according to QT.
Anyway, i try setting a transparent color with no luck.
Anything that i could be missing here?

[jpn]

Also, im using a qpainter to create a big image from small image.

How about scaling?

The qpainter default color is transparent, so i dont have to do that according to QT.

Yes, but QPixmap might not be. As you said, a new QPixmap is constructed. What I actually meant was filling that pixmap with transparent color.

[wysota]

You could be using some window flags that cause the problem. Could we see the _mainWidget constructor and the way you call it?

[PiXeL16]

Hi, thanks for the reply
What i mean by creating an image with small images is that i'm creating and pixmap using small various pixmap. So i cant use scaling.
I'm going to try your idea of filling the pixmap first with transparent color. Maybe that work.
Also, about the flags, i'm just basically using a frameless flag. like this.

Qt::WindowFlags flags = 0;
flags = Qt::FramelessWindowHint;
 _mainWidget->setWindowFlags(flags);

Qt::WindowFlags flags = 0;
flags = Qt::FramelessWindowHint;
 _mainWidget->setWindowFlags(flags);

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Could something change in the way qt manage transparent colors from qt 4.1 to 4.2?
Thanks
Any help will be much appreciated
CJC

[PiXeL16]

I forget, im calling it with the show function
like this

_mainWidget->show();

_mainWidget->show();

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Thanks
CJC