[Qt-interest] QPixmap return null pixmap on VC

[Alessandro Portale]

Hi,

the supportedImageFormats() list proves that no image plugins are 
loaded. And as you say, you moved the Qt directory after building Qt.
Most probably, you did not change all places where the original build 
path is stored. For example QtCore[d].dll will also have those pathes 
inside, which is hard to patch.

Plugin loading is not a trivial topic, and Qt will attempt to load the 
plugins from several places:
  1) Where they where configured/built (absolute directory)
  2) Where QCoreApplication::libraryPaths() points to
  3) In the imageformats\ subdir next to your application.exe [*]
(I am not sure about the order right now, but apparently in your case 1, 
2 and 3 fail.)

The cleanest solution would be to reconfigure/rebuld Qt where it is 
right now and not moving it, afterwards. Solving (2) and (3) for your 
development environment would be a hack.

[*] For deployment to a client, you will put the plugin dlls into a 
subdirectory "imageformats\" next to your application.exe.

Hope that helps, best regards,
Alessandro

OS Prog schrieb:
> Hi,
> 
> The output of: "qDebug() << QImageReader::supportedImageFormats();" is:
> 
> /("bmp", "pbm", "pgm", "png", "ppm", "xbm", "xpm") /
> 
> 
> Best regards,
> Nikolay