QDialog w/ transparent background

[LarryDobson]

Got it!
Here is the solution...

void resizeEvent(QResizeEvent *e)
{
	QDialog::resizeEvent(e);
 
	// grab the geometry
	QRect fg = frameGeometry();
	QRect rg = geometry();
 
	// get some reusable values
	int nCaptionHeight	= rg.top()	- fg.top();
	int nFrameWidth		= rg.left()	- fg.left();
 
	// map the global coords to local for the frame
	fg.moveTo(mapFromGlobal(fg.topLeft()));
 
	// create a rectangle for the frame
	QRect rectFrame(fg.left() - nFrameWidth,
				fg.top() - nCaptionHeight,
				fg.width() + ( nFrameWidth * 2 ),
				fg.height() + ( nCaptionHeight + nFrameWidth ) );
 
	// create a region from the frame rectangle
	QRegion regionFrame( rectFrame );
 
	// map the global coords to local for the client area
	rg.moveTo(mapFromGlobal(rg.topLeft()));
 
	// move the rect to 0,0
	rg.moveTo( QPoint(0,0) );
 
	// create a region from the client rect
	QRegion regionClient( rg );
 
	// set a mask to be the frame region minus the client region
	setMask( regionFrame - regionClient );
}

void resizeEvent(QResizeEvent *e)
{
	QDialog::resizeEvent(e);

	// grab the geometry
	QRect fg = frameGeometry();
	QRect rg = geometry();

	// get some reusable values
	int nCaptionHeight	= rg.top()	- fg.top();
	int nFrameWidth		= rg.left()	- fg.left();

	// map the global coords to local for the frame
	fg.moveTo(mapFromGlobal(fg.topLeft()));

	// create a rectangle for the frame
	QRect rectFrame(fg.left() - nFrameWidth,
				fg.top() - nCaptionHeight,
				fg.width() + ( nFrameWidth * 2 ),
				fg.height() + ( nCaptionHeight + nFrameWidth ) );

	// create a region from the frame rectangle
	QRegion regionFrame( rectFrame );
		
	// map the global coords to local for the client area
	rg.moveTo(mapFromGlobal(rg.topLeft()));

	// move the rect to 0,0
	rg.moveTo( QPoint(0,0) );

	// create a region from the client rect
	QRegion regionClient( rg );

	// set a mask to be the frame region minus the client region
	setMask( regionFrame - regionClient );
}

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You will probably recognize some of this code from this thread.
Many thanks to J-P Nurmi for laying the foundation...
It just took a bit to figure out that my problem was the math (e.g. negative numbers to allow the caption bar (since QPoint(0,0) is the upper left corner of the client area).
Thanks again JPN

This is what I was looking for...

[high_flyer]

does this works with semi transparency as well?
EDIT: after thinking about it a bit, I think it should - so:
(in this case) QDialog gets tsetWindowOpacity() to wanted degree of opacity
The rest as in the suggested above code.
This way we get a semi opaque non square resizeable dialog.
At least in theory.

[LarryDobson]

does this works with semi transparency as well?
EDIT: after thinking about it a bit, I think it should - so:
(in this case) QDialog gets tsetWindowOpacity() to wanted degree of opacity
The rest as in the suggested above code.
This way we get a semi opaque non square resizeable dialog.
At least in theory.

In Theory...

"non square" ??? making the dialog semi-tranparent will not effect the corners.

[wysota]

"non square" ??? making the dialog semi-tranparent will not effect the corners.

No, but setMask() will.