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