tom@tubopal.UUCP (Thomas Sander) (06/07/89)
% Hello NeWS-Users,
% The following little program demonstrates a failure of the
% 'writescreen/readcanvas' operator, we cannot fix.
%-----cut here-----cut here-----cut here-----cut here-----cut here-----cut here
gsave
framebuffer setcanvas
gsave 80 280 100 200 rectpath 1 setgray fill grestore
100 300 translate 0 0 moveto
/yp showicon
0 0 64 64 rectpath
(test1.pic) writescreen
(test1.pic) readcanvas % 1st time that we use readcanvas
0 100 translate
64 64 scale
imagecanvas
grestore
gsave
framebuffer setcanvas
gsave 180 280 100 300 rectpath 1 setgray fill grestore
200 300 translate 0 0 moveto
/moose showicon
0 0 64 64 rectpath
(test3.pic) writescreen
(screendump -x 200 -y 536 -Y 64 -X 64 > test2.pic) forkunix
0.1 sleep
(test2.pic) readcanvas % 2nd time that we use readcanvas
gsave
0 100 translate
64 64 scale
imagecanvas
grestore
(test3.pic) readcanvas % 3rd time that we use readcanvas
0 200 translate
64 64 scale
imagecanvas
grestore
%-----cut here-----cut here-----cut here-----cut here-----cut here-----cut here
% The 3rd 'readcanvas' operator failes with an 'invalidaccess' error.
% This error occurs only with some Sun-Icons (e. g. /moose or /artist).
% With the icon /artist the 'writescreen' operator produces an empty file,
% with the /moose icon it produces a 'run-length byte encoded image', which
% cannot be interpreted by 'readcanvas'.
% The standard raster format files produced by the 'screendump' program
% never bother the 'readcanvas' operator. Why do the 'run-length byte encoded
% images', produced by the 'writescreen' operator.
% Who can help ?
% Thanks in advance, Tom
%-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
%Tom Sander TU Berlin FB-20 Sekr. FR 5-6
%UUCP: ...!unido!tubopal!tom Franklinstr. 28/29
%BITNET: tom%tubopal@db0tui11 D 1000 Berlin (West) 10
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%-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
%Tom Sander TU Berlin FB-20 Sekr. FR 5-6
%UUCP: ...!unido!tubopal!tom Franklinstr. 28/29
%BITNET: tom%tubopal@db0tui11 D 1000 Berlin (West) 10