do not use QPixmap::handle(), as it may be 0
do not use QPixmap::handle(), as it may be 0

See comments in code for details. The usage of Xlib's Region type
internals is not nice, but seems to be ok in practice.

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core