[PyQt] Usage of QImageWriter.supportsOption()

[Vincent Vande Vyvre]

Le 29/11/12 11:41, Vincent Vande Vyvre a écrit :
> I'm trying to see what option is supported by QImageWriter().
>
> A test code:
> -----------------------------------------------------------------------------------------------------
> # -*- coding: utf-8 -*-
>
> from PyQt4.QtGui import QImageWriter, QImageIOHandler
>
> frmts = ['bmp', 'bw', 'eps', 'ico', 'jp2', 'jpg', 'pcx',
>                 'pgm', 'png', 'ppm', 'rgb', 'rgba', 'sgi', 'tga',
>                 'tiff', 'xbm', 'xpm', 'xv']
>
> opts = [QImageIOHandler.CompressionRatio, QImageIOHandler.Gamma,
>         QImageIOHandler.Quality]
>
> iw = QImageWriter()
> for fr in frmts:
>     print fr, "\t",
>     iw.setFormat(fr)
>     for opt in opts:
>         print iw.supportsOption(opt),
>     print
>
> ------------------------------------------------------------------------------------------------------
>
> But, for all formats the options are False:
>
> ...
> jpg     False False False
> pcx     False False False
> pgm     False False False
> png     False False False
> ppm     False False False
> tga     False False False
> tiff     False False False
> ...
>
> Python 2.7 > PyQt4 4.9.1
> Python 3.3 > PyQt4 4.9.5
>
> Thanks for all advices.
>
>
Found it, the QImageWriter needs a file name before request for the
support of option.

This works:
------------------------------------------------------------
for fr in frmts:
    print fr, "\t",
    iw.setFileName("imgfile." + fr)
    iw.setFormat(fr)
    for opt in opts:
        print iw.supportsOption(opt),
    print
------------------------------------------------------------
-- 
Vincent V.V.
Oqapy <https://launchpad.net/oqapy> . Qarte
<https://launchpad.net/qarte> . PaQager <https://launchpad.net/paqager>