[PyQt] Problem with boundingRect in PyQt snapshot

[Mark Summerfield]

On 2009-09-16, Phil Thompson wrote:
> On Wed, 16 Sep 2009 20:04:48 +0100, Jeremy Sanders
> 
> <jeremy at jeremysanders.net> wrote:
> > Hi - for some reason the following code does not produce the
> > correct answer after updating PyQt.
> >
> > On Ubuntu with the PyQt 4.4.4 package the following returns
> > 18.0
> >
> > from PyQt4.QtGui import *
> > from PyQt4.QtCore import *
> > import sys
> >
> > app = QApplication(sys.argv)
> >
> > pix = QPixmap(128, 128)
> > p = QPainter(pix)
> > font = QFont("Times New Roman", 20)
> >
> > fm = QFontMetricsF(font, p.device())
> > print fm.boundingRect(QChar('0')).height()
> >
> > On the same system with the same Qt (4.5.0), PyQt-x11-
> > gpl-4.6-snapshot-20090906 and returns 32.0!
> >
> > The text is misaligned when using height to align it using
> > the snapshot.
> >
> > My guess is that the QChar is being promoted to QString. This
> > function returns a different result for QString, so it breaks
> > my code. The QString version returns the font height, not the
> > height of the character given.
> 
> Your guess is correct.
> 
> You could use tightBoundingRect() instead.
> 
> I can back out the automatic conversion from QChar to QString, but that
> leaves the question of what should happen with v2 of the QString API, ie.
> should QChar not be dropped?

I think it would be a pity to keep it. Most of its methods are available
in Python anyway, and for those few that aren't couldn't you provide
some static methods that either take a one character string or that only
consider the first character?

-- 
Mark Summerfield, Qtrac Ltd, www.qtrac.eu
    C++, Python, Qt, PyQt - training and consultancy
        "C++ GUI Programming with Qt 4" - ISBN 0132354160