archie/tk3.6/library/prolog.ps
2024-05-27 16:13:40 +02:00

204 lines
6.2 KiB
PostScript

% This file contains the standard Postscript prolog used when
% generating Postscript from canvas widgets.
%
% $Header: /user6/ouster/wish/library/RCS/prolog.ps,v 1.6 93/04/01 14:03:52 ouster Exp $ SPRITE (Berkeley);
%%BeginProlog
50 dict begin
% The definitions below just define all of the variables used in
% any of the procedures here. This is needed for obscure reasons
% explained on p. 716 of the Postscript manual (Section H.2.7,
% "Initializing Variables," in the section on Encapsulated Postscript).
/baseline 0 def
/stipimage 0 def
/height 0 def
/justify 0 def
/maxwidth 0 def
/spacing 0 def
/stipple 0 def
/strings 0 def
/xoffset 0 def
/yoffset 0 def
/tmpstip null def
/encoding {ISOLatin1Encoding} def
% Override setfont to automatically encode the font in the style defined by
% by 'encoding' (ISO Latin1 by default).
systemdict /encodefont known {
/realsetfont /setfont load def
/setfont {
encoding encodefont realsetfont
} def
} if
% desiredSize EvenPixels closestSize
%
% The procedure below is used for stippling. Given the optimal size
% of a dot in a stipple pattern in the current user coordinate system,
% compute the closest size that is an exact multiple of the device's
% pixel size. This allows stipple patterns to be displayed without
% aliasing effects.
/EvenPixels {
% Compute exact number of device pixels per stipple dot.
dup 0 matrix currentmatrix dtransform
dup mul exch dup mul add sqrt
% Round to an integer, make sure the number is at least 1, and compute
% user coord distance corresponding to this.
dup round dup 1 lt {pop 1} if
exch div mul
} bind def
% width height string filled StippleFill --
%
% Given a path and other graphics information already set up, this
% procedure will fill the current path in a stippled fashion. "String"
% contains a proper image description of the stipple pattern and
% "width" and "height" give its dimensions. If "filled" is true then
% it means that the area to be stippled is gotten by filling the
% current path (e.g. the interior of a polygon); if it's false, the
% area is gotten by stroking the current path (e.g. a wide line).
% Each stipple dot is assumed to be about one unit across in the
% current user coordinate system.
/StippleFill {
% Turn the path into a clip region that we can then cover with
% lots of images corresponding to the stipple pattern. Warning:
% some Postscript interpreters get errors during strokepath for
% dashed lines. If this happens, turn off dashes and try again.
1 index /tmpstip exch def %% Works around NeWSprint bug
gsave
{eoclip}
{{strokepath} stopped {grestore gsave [] 0 setdash strokepath} if clip}
ifelse
% Change the scaling so that one user unit in user coordinates
% corresponds to the size of one stipple dot.
1 EvenPixels dup scale
% Compute the bounding box occupied by the path (which is now
% the clipping region), and round the lower coordinates down
% to the nearest starting point for the stipple pattern.
pathbbox
4 2 roll
5 index div cvi 5 index mul 4 1 roll
6 index div cvi 6 index mul 3 2 roll
% Stack now: width height string y1 y2 x1 x2
% Below is a doubly-nested for loop to iterate across this area
% in units of the stipple pattern size, going up columns then
% across rows, blasting out a stipple-pattern-sized rectangle at
% each position
6 index exch {
2 index 5 index 3 index {
% Stack now: width height string y1 y2 x y
gsave
1 index exch translate
5 index 5 index true matrix tmpstip imagemask
grestore
} for
pop
} for
pop pop pop pop pop
grestore
newpath
} bind def
% -- AdjustColor --
% Given a color value already set for output by the caller, adjusts
% that value to a grayscale or mono value if requested by the CL
% variable.
/AdjustColor {
CL 2 lt {
currentgray
CL 0 eq {
.5 lt {0} {1} ifelse
} if
setgray
} if
} bind def
% x y strings spacing xoffset yoffset justify stipple stipimage DrawText --
% This procedure does all of the real work of drawing text. The
% color and font must already have been set by the caller, and the
% following arguments must be on the stack:
%
% x, y - Coordinates at which to draw text.
% strings - An array of strings, one for each line of the text item,
% in order from top to bottom.
% spacing - Spacing between lines.
% xoffset - Horizontal offset for text bbox relative to x and y: 0 for
% nw/w/sw anchor, -0.5 for n/center/s, and -1.0 for ne/e/se.
% yoffset - Vertical offset for text bbox relative to x and y: 0 for
% nw/n/ne anchor, +0.5 for w/center/e, and +1.0 for sw/s/se.
% justify - 0 for left justification, 0.5 for center, 1 for right justify.
% stipple - Boolean value indicating whether or not text is to be
% drawn in stippled fashion.
% stipimage - Image for stippling, if stipple is True.
%
% Also, when this procedure is invoked, the color and font must already
% have been set for the text.
/DrawText {
/stipimage exch def
/stipple exch def
/justify exch def
/yoffset exch def
/xoffset exch def
/spacing exch def
/strings exch def
% First scan through all of the text to find the widest line.
/maxwidth 0 def
strings {
stringwidth pop
dup maxwidth gt {/maxwidth exch def} {pop} ifelse
newpath
} forall
% Compute the baseline offset and the actual font height.
0 0 moveto (TXygqPZ) false charpath
pathbbox dup /baseline exch def
exch pop exch sub /height exch def pop
newpath
% Translate coordinates first so that the origin is at the upper-left
% corner of the text's bounding box. Remember that x and y for
% positioning are still on the stack.
translate
maxwidth xoffset mul
strings length 1 sub spacing mul height add yoffset mul translate
% Now use the baseline and justification information to translate so
% that the origin is at the baseline and positioning point for the
% first line of text.
justify maxwidth mul baseline neg translate
% Iterate over each of the lines to output it. For each line,
% compute its width again so it can be properly justified, then
% display it.
strings {
dup stringwidth pop
justify neg mul 0 moveto
show
0 spacing neg translate
} forall
} bind def
%%EndProlog