xxjgh@dali.lerc.nasa.gov (Jay G. Horowitz) (10/04/90)
WARNING to those looking towards scrsave as an answer to their screen-saving problem: Do not be fooled by the apparent simplicity of scrsave.c. There is an undocumented subtlety in its usage. From our experiences it is crucial that the code within scrsave (or user-modifications of it) not be imbedded directly in a program that uses a graphics port. Note that scrsave runs with noport(); winopen();. Snapshot and others that require a graphics port to allow you do establish your capture window, eventually do a: system ("scrsave 0 1280 0"); /* or whatever xmin, xmax, ymin, ymax */ which spawns a new process. I assume that doing a succesfull screen capture (i.e., capture pixel rgb regardless whether that pixel was colormap, rgb, window border, background, or whatever) can only be done by a process that is not tied to a particular window. I can kind of guess why this would be so, but haven't invested the time to really understand it. I got my application to work and quit while I was ahead. If the above is incorrect I would appreciate being humbled on the network by an appropriate guru. -- .......................................................................... Jay G. Horowitz "For the finest in kosher pixels!" NASA Lewis Research Center (216) 433-5194 xxjgh@dali.lerc.nasa.gov (128.156.1.48) ..........................................................................