343 lines
10 KiB
C
343 lines
10 KiB
C
#include <u.h>
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#include <libc.h>
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#include <bio.h>
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#include <ctype.h>
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#include "../common/common.h"
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#include "tr2post.h"
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BOOLEAN drawflag = FALSE;
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BOOLEAN inpath = FALSE; /* TRUE if we're putting pieces together */
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void
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cover(double x, double y) {
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}
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void
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drawspline(Biobufhdr *Bp, int flag) { /* flag!=1 connect end points */
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int x[100], y[100];
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int i, N;
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/*
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*
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* Spline drawing routine for Postscript printers. The complicated stuff is
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* handled by procedure Ds, which should be defined in the library file. I've
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* seen wrong implementations of troff's spline drawing, so fo the record I'll
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* write down the parametric equations and the necessary conversions to Bezier
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* cubic splines (as used in Postscript).
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*
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*
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* Parametric equation (x coordinate only):
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*
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*
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* (x2 - 2 * x1 + x0) 2 (x0 + x1)
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* x = ------------------ * t + (x1 - x0) * t + ---------
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* 2 2
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*
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*
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* The coefficients in the Bezier cubic are,
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*
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*
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* A = 0
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* B = (x2 - 2 * x1 + x0) / 2
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* C = x1 - x0
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*
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*
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* while the current point is,
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*
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* current-point = (x0 + x1) / 2
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*
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* Using the relationships given in the Postscript manual (page 121) it's easy to
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* see that the control points are given by,
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*
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*
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* x0' = (x0 + 5 * x1) / 6
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* x1' = (x2 + 5 * x1) / 6
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* x2' = (x1 + x2) / 2
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*
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*
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* where the primed variables are the ones used by curveto. The calculations
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* shown above are done in procedure Ds using the coordinates set up in both
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* the x[] and y[] arrays.
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*
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* A simple test of whether your spline drawing is correct would be to use cip
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* to draw a spline and some tangent lines at appropriate points and then print
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* the file.
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*
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*/
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for (N=2; N<sizeof(x)/sizeof(x[0]); N++)
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if (Bgetfield(Bp, 'd', &x[N], 0)<=0 || Bgetfield(Bp, 'd', &y[N], 0)<=0)
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break;
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x[0] = x[1] = hpos;
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y[0] = y[1] = vpos;
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for (i = 1; i < N; i++) {
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x[i+1] += x[i];
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y[i+1] += y[i];
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}
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x[N] = x[N-1];
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y[N] = y[N-1];
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for (i = ((flag!=1)?0:1); i < ((flag!=1)?N-1:N-2); i++) {
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endstring();
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if (pageon())
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Bprint(Bstdout, "%d %d %d %d %d %d Ds\n", x[i], y[i], x[i+1], y[i+1], x[i+2], y[i+2]);
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/* if (dobbox == TRUE) { /* could be better */
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/* cover((double)(x[i] + x[i+1])/2,(double)-(y[i] + y[i+1])/2);
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/* cover((double)x[i+1], (double)-y[i+1]);
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/* cover((double)(x[i+1] + x[i+2])/2, (double)-(y[i+1] + y[i+2])/2);
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/* }
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*/
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}
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hpos = x[N]; /* where troff expects to be */
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vpos = y[N];
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}
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void
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draw(Biobufhdr *Bp) {
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int r, x1, y1, x2, y2, i;
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int d1, d2;
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drawflag = TRUE;
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r = Bgetrune(Bp);
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switch(r) {
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case 'l':
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if (Bgetfield(Bp, 'd', &x1, 0)<=0 || Bgetfield(Bp, 'd', &y1, 0)<=0 || Bgetfield(Bp, 'r', &i, 0)<=0)
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error(FATAL, "draw line function, destination coordinates not found.\n");
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endstring();
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if (pageon())
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Bprint(Bstdout, "%d %d %d %d Dl\n", hpos, vpos, hpos+x1, vpos+y1);
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hpos += x1;
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vpos += y1;
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break;
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case 'c':
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if (Bgetfield(Bp, 'd', &d1, 0)<=0)
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error(FATAL, "draw circle function, diameter coordinates not found.\n");
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endstring();
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if (pageon())
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Bprint(Bstdout, "%d %d %d %d De\n", hpos, vpos, d1, d1);
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hpos += d1;
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break;
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case 'e':
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if (Bgetfield(Bp, 'd', &d1, 0)<=0 || Bgetfield(Bp, 'd', &d2, 0)<=0)
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error(FATAL, "draw ellipse function, diameter coordinates not found.\n");
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endstring();
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if (pageon())
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Bprint(Bstdout, "%d %d %d %d De\n", hpos, vpos, d1, d2);
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hpos += d1;
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break;
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case 'a':
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if (Bgetfield(Bp, 'd', &x1, 0)<=0 || Bgetfield(Bp, 'd', &y1, 0)<=0 || Bgetfield(Bp, 'd', &x2, 0)<=0 || Bgetfield(Bp, 'd', &y2, 0)<=0)
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error(FATAL, "draw arc function, coordinates not found.\n");
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endstring();
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if (pageon())
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Bprint(Bstdout, "%d %d %d %d %d %d Da\n", hpos, vpos, x1, y1, x2, y2);
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hpos += x1 + x2;
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vpos += y1 + y2;
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break;
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case 'q':
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drawspline(Bp, 1);
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break;
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case '~':
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drawspline(Bp, 2);
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break;
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default:
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error(FATAL, "unknown draw function <%c>\n", r);
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break;
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}
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}
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void
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beginpath(char *buf, int copy) {
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/*
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* Called from devcntrl() whenever an "x X BeginPath" command is read. It's used
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* to mark the start of a sequence of drawing commands that should be grouped
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* together and treated as a single path. By default the drawing procedures in
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* *drawfile treat each drawing command as a separate object, and usually start
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* with a newpath (just as a precaution) and end with a stroke. The newpath and
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* stroke isolate individual drawing commands and make it impossible to deal with
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* composite objects. "x X BeginPath" can be used to mark the start of drawing
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* commands that should be grouped together and treated as a single object, and
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* part of what's done here ensures that the PostScript drawing commands defined
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* in *drawfile skip the newpath and stroke, until after the next "x X DrawPath"
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* command. At that point the path that's been built up can be manipulated in
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* various ways (eg. filled and/or stroked with a different line width).
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*
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* Color selection is one of the options that's available in parsebuf(),
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* so if we get here we add *colorfile to the output file before doing
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* anything important.
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*
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*/
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if (inpath == FALSE) {
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endstring();
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/* getdraw(); */
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/* getcolor(); */
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Bprint(Bstdout, "gsave\n");
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Bprint(Bstdout, "newpath\n");
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Bprint(Bstdout, "%d %d m\n", hpos, vpos);
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Bprint(Bstdout, "/inpath true def\n");
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if ( copy == TRUE )
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Bprint(Bstdout, "%s\n", buf);
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inpath = TRUE;
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}
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}
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static void parsebuf(char*);
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void
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drawpath(char *buf, int copy) {
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/*
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*
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* Called from devcntrl() whenever an "x X DrawPath" command is read. It marks the
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* end of the path started by the last "x X BeginPath" command and uses whatever
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* has been passed along in *buf to manipulate the path (eg. fill and/or stroke
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* the path). Once that's been done the drawing procedures are restored to their
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* default behavior in which each drawing command is treated as an isolated path.
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* The new version (called after "x X DrawPath") has copy set to FALSE, and calls
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* parsebuf() to figure out what goes in the output file. It's a feeble attempt
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* to free users and preprocessors (like pic) from having to know PostScript. The
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* comments in parsebuf() describe what's handled.
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*
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* In the early version a path was started with "x X BeginObject" and ended with
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* "x X EndObject". In both cases *buf was just copied to the output file, and
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* was expected to be legitimate PostScript that manipulated the current path.
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* The old escape sequence will be supported for a while (for Ravi), and always
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* call this routine with copy set to TRUE.
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*
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*
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*/
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if ( inpath == TRUE ) {
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if ( copy == TRUE )
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Bprint(Bstdout, "%s\n", buf);
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else
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parsebuf(buf);
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Bprint(Bstdout, "grestore\n");
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Bprint(Bstdout, "/inpath false def\n");
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/* reset(); */
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inpath = FALSE;
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}
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}
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/*****************************************************************************/
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static void
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parsebuf(char *buf)
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{
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char *p; /* usually the next token */
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char *q;
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int gsavelevel = 0; /* non-zero if we've done a gsave */
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/*
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*
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* Simple minded attempt at parsing the string that followed an "x X DrawPath"
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* command. Everything not recognized here is simply ignored - there's absolutely
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* no error checking and what was originally in buf is clobbered by strtok().
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* A typical *buf might look like,
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*
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* gray .9 fill stroke
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*
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* to fill the current path with a gray level of .9 and follow that by stroking the
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* outline of the path. Since unrecognized tokens are ignored the last example
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* could also be written as,
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*
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* with gray .9 fill then stroke
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*
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* The "with" and "then" strings aren't recognized tokens and are simply discarded.
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* The "stroke", "fill", and "wfill" force out appropriate PostScript code and are
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* followed by a grestore. In otherwords changes to the grahics state (eg. a gray
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* level or color) are reset to default values immediately after the stroke, fill,
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* or wfill tokens. For now "fill" gets invokes PostScript's eofill operator and
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* "wfill" calls fill (ie. the operator that uses the non-zero winding rule).
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*
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* The tokens that cause temporary changes to the graphics state are "gray" (for
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* setting the gray level), "color" (for selecting a known color from the colordict
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* dictionary defined in *colorfile), and "line" (for setting the line width). All
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* three tokens can be extended since strncmp() makes the comparison. For example
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* the strings "line" and "linewidth" accomplish the same thing. Colors are named
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* (eg. "red"), but must be appropriately defined in *colorfile. For now all three
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* tokens must be followed immediately by their single argument. The gray level
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* (ie. the argument that follows "gray") should be a number between 0 and 1, with
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* 0 for black and 1 for white.
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*
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* To pass straight PostScript through enclose the appropriate commands in double
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* quotes. Straight PostScript is only bracketed by the outermost gsave/grestore
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* pair (ie. the one from the initial "x X BeginPath") although that's probably
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* a mistake. Suspect I may have to change the double quote delimiters.
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*
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*/
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for( ; p != nil ; p = q ) {
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if( q = strchr(p, ' ') ) {
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*q++ = '\0';
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}
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if ( gsavelevel == 0 ) {
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Bprint(Bstdout, "gsave\n");
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gsavelevel++;
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}
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if ( strcmp(p, "stroke") == 0 ) {
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Bprint(Bstdout, "closepath stroke\ngrestore\n");
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gsavelevel--;
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} else if ( strcmp(p, "openstroke") == 0 ) {
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Bprint(Bstdout, "stroke\ngrestore\n");
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gsavelevel--;
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} else if ( strcmp(p, "fill") == 0 ) {
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Bprint(Bstdout, "eofill\ngrestore\n");
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gsavelevel--;
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} else if ( strcmp(p, "wfill") == 0 ) {
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Bprint(Bstdout, "fill\ngrestore\n");
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gsavelevel--;
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} else if ( strcmp(p, "sfill") == 0 ) {
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Bprint(Bstdout, "eofill\ngrestore\ngsave\nstroke\ngrestore\n");
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gsavelevel--;
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} else if ( strncmp(p, "gray", strlen("gray")) == 0 ) {
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if( q ) {
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p = q;
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if ( q = strchr(p, ' ') )
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*q++ = '\0';
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Bprint(Bstdout, "%s setgray\n", p);
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}
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} else if ( strncmp(p, "color", strlen("color")) == 0 ) {
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if( q ) {
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p = q;
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if ( q = strchr(p, ' ') )
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*q++ = '\0';
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Bprint(Bstdout, "/%s setcolor\n", p);
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}
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} else if ( strncmp(p, "line", strlen("line")) == 0 ) {
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if( q ) {
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p = q;
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if ( q = strchr(p, ' ') )
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*q++ = '\0';
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Bprint(Bstdout, "%s resolution mul 2 div setlinewidth\n", p);
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}
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} else if ( strncmp(p, "reverse", strlen("reverse")) == 0 )
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Bprint(Bstdout, "reversepath\n");
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else if ( *p == '"' ) {
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for ( ; gsavelevel > 0; gsavelevel-- )
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Bprint(Bstdout, "grestore\n");
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if ( q != nil )
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*--q = ' ';
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if ( (q = strchr(p, '"')) != nil ) {
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*q++ = '\0';
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Bprint(Bstdout, "%s\n", p);
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}
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}
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}
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for ( ; gsavelevel > 0; gsavelevel-- )
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Bprint(Bstdout, "grestore\n");
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}
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