more files

1 files changed, 342 insertions, 0 deletions

diff --git a/src/cmd/postscript/tr2post/draw.c b/src/cmd/postscript/tr2post/draw.c
new file mode 100644
index 00000000..575ec884
--- /dev/null
+++ b/src/cmd/postscript/tr2post/draw.c
@@ -0,0 +1,342 @@
+#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(Biobuf *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(Biobuf *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");
+
+}