This is an issue specific to Qt-based view widget, and specific to Windows 7 (perhaps Vista as well).
- launch Qt sample from OCC package
- import a shape
- File/Export/Image, specify myfile.gif (.bmp or other)
- the image will be a plain gray rectangle
On Windows XP this should work fine.
On Windows 7 DRAW also works fine (pload ALL; box a 1 1 1; vinit; vdisplay a; vfit; vdump box.gif).
Based on limited investigation, I believe the root-cause is in the way Qt communicates with Windows through the handle (QWidget::winId()), window attributes ( setAttribute(Qt::WA_PaintOnScreen); setAttribute(Qt::WA_NoSystemBackground);) and alike. Seems like on Windows 7 the screen buffer does not update underlying widget buffer and when trying to export an image, the initial widget contents (that were created during QWidget creation) are just stored. The latter is true as in CAD Exchanger this bug is reproduced as storing not a gray rectangle but a fragment of a widget that was on the screen *right before* the OpenGL view was created.
Hope this helps.