Allow dynamic change of image clipping rectangle #136
Description
Allow changing of image clipping rectangle dynamically, without restarting Plus. See this discussion: https://www.assembla.com/spaces/plus/messages/5076633
Implementation notes: Changing the frame buffer size would be problematic for many reasons, including possible out-of-memory errors when allocating memory for larger images, not being able to save frames of different size into metafiles (image size is constant throughout), accessing frames while switching between frame sizes. Therefore, probably we would need to allocate the maximum frame size and provide additional information about the current extent.
Migrated from https://app.assembla.com/spaces/plus/tickets/1008/details