Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Refresh policies for DRAW widgets in IDL
Hi "IDLers" ! When my application loads an image (tiff file) of larger than some certain limit (not known yet) the main viewing DRAW widget will not refresh itself when user scrolls around. It makes no difference which of the 2 RETAIN policies below I use. draw = WIDGET_DRAW(base, $ /BUTTON_EVENTS, $ /MOTION_EVENTS, $ /FRAME, $ RETAIN = 2, $ ;Make sure IDL provides backing store. ;RETAIN = 1, $ ;Ask X server to provide it. UVALUE = 'DRAW_WIN_EVENT', $ X_SCROLL_SIZE = view_x, $ Y_SCROLL_SIZE = view_y, $ XSIZE = size_x, $ YSIZE = size_y) I use an X term with 8MB RAM, running Solaris2.3 on a Sparc LX. Using X Backingstore is most successful, working for images of at least 1.5MB image data. But when I switch to a 7MB file, the image appears once correctly, but as soon as you scroll, nothing "scrolls" into view, and you have to refresh the window with TV or whatever. It doesn't surprise me that my X terminal maxes out at some limit of backingstore abilities, but when I the IDL refresh mechanism does not seem to work either. Has anyone had any experience with this phenomenon? Thanks a bunch, Russ Russ Welti /-\ (c-g) University of Washington \-/ Dept. of Molecular Biotechnology M/S FJ-20 / Seattle, WA 98195 /-\ (206) 685-3840 voice (a-t) (206) 685-7344 FAX \-/ rwelti@u.washington.edu \