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List:       kde-devel
Subject:    [Fwd: QListView column resizing wrong]
From:       "Ming Poon" <mingp () corel ! com>
Date:       1999-07-27 14:12:32
[Download RAW message or body]

FYI ...

-------- Original Message --------
Subject: QListView column resizing wrong
Date: Tue, 20 Jul 1999 15:30:20 -0400
From: "Brian Rolfe" <brianr@corel.com>
To: qt-bugs@troll.no
CC: Ming Poon <mingp@corel.com>, Brian Jones <brianj@corel.com>

	In QListView (Qt 1.44), when using the automatic column resizing when
entering data, the columns are resized wrong if you move the headers.

	Step one:	Add some data to a multi column list
	Step two:	Move the columns around with the mouse
	Step three:	Add some more data that has smaller entries (text width)

Result:		The columns are resized improperly.

What's happening is the code checks the width of the new data entered,
and if larger, it resizes it to that size.  But if the call to
columnWidth() returns the width from the wrong column, say a small
column, then the new data entered will seem larger so it will go on to
resize it to that size.  Problem being, it's now resized it to the new
data which might be smaller than the data already in that column.

Cause:
	QListView is calling methods to get/set the column sizes in QHeader.
	This is the code:

int QHeader::cellSize( int i ) const
{
	int s = pSize( i );
return s;
}

int QHeader::pSize( int i ) const
{
	return data->sizes[mapToLogical(i)];
}

void QHeader::setCellSize( int i, int s )
{
	data->sizes[i] = s;
}

As you can see, the "cellSize()", which calls "pSize()" calls
"mapToLogical()" while the "setCellSize()" does not.
This is the root of the problem.....but it can be fixed in QListView


QListView code:

int QListView::columnWidth( int c ) const
{
	return d->h->cellSize(c);
}

void QListView::setColumnWidth( int column, int w )
{
	ASSERT( column < d->h->count() );
	if ( d->h->cellSize( column ) != w )
	{
		d->h->setCellSize( column, w );
		d->h->update(); // ##### paul, QHeader::setCellSize should do this.
	}
}

To fix, the columnWidth() method call mapToActual() to reverse the
mapToLogical() call in QHeader.  Then make setColumnWidth() call
columnWidth() to get the width.

P.S.:  I briefly looked at Qt 2.0 and it's looks pretty much the same
there.

--Brian R

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