1 #include <u.h> 2 #include <libc.h> 3 #include <bio.h> 4 #include <ctype.h> 5 #include "../common/common.h" 6 #include "tr2post.h" 7 8 BOOLEAN drawflag = FALSE; 9 BOOLEAN inpath = FALSE; /* TRUE if we're putting pieces together */ 10 11 void 12 cover(double x, double y) { 13 USED(x, y); 14 } 15 16 void 17 drawspline(Biobufhdr *Bp, int flag) { /* flag!=1 connect end points */ 18 int x[100], y[100]; 19 int i, N; 20 /* 21 * Spline drawing routine for Postscript printers. The complicated stuff is 22 * handled by procedure Ds, which should be defined in the library file. I've 23 * seen wrong implementations of troff's spline drawing, so fo the record I'll 24 * write down the parametric equations and the necessary conversions to Bezier 25 * cubic splines (as used in Postscript). 26 * 27 * Parametric equation (x coordinate only): 28 * 29 * (x2 - 2 * x1 + x0) 2 (x0 + x1) 30 * x = ------------------ * t + (x1 - x0) * t + --------- 31 * 2 2 32 * 33 * The coefficients in the Bezier cubic are, 34 * 35 * A = 0 36 * B = (x2 - 2 * x1 + x0) / 2 37 * C = x1 - x0 38 * 39 * while the current point is, 40 * 41 * current-point = (x0 + x1) / 2 42 * 43 * Using the relationships given in the Postscript manual (page 121) it's easy to 44 * see that the control points are given by, 45 * 46 * x0' = (x0 + 5 * x1) / 6 47 * x1' = (x2 + 5 * x1) / 6 48 * x2' = (x1 + x2) / 2 49 * 50 * where the primed variables are the ones used by curveto. The calculations 51 * shown above are done in procedure Ds using the coordinates set up in both 52 * the x[] and y[] arrays. 53 * 54 * A simple test of whether your spline drawing is correct would be to use cip 55 * to draw a spline and some tangent lines at appropriate points and then print 56 * the file. 57 */ 58 for (N=2; N<sizeof(x)/sizeof(x[0]); N++) 59 if (Bgetfield(Bp, 'd', &x[N], 0)<=0 || Bgetfield(Bp, 'd', &y[N], 0)<=0) 60 break; 61 62 x[0] = x[1] = hpos; 63 y[0] = y[1] = vpos; 64 65 for (i = 1; i < N; i++) { 66 x[i+1] += x[i]; 67 y[i+1] += y[i]; 68 } 69 70 x[N] = x[N-1]; 71 y[N] = y[N-1]; 72 73 for (i = ((flag!=1)?0:1); i < ((flag!=1)?N-1:N-2); i++) { 74 endstring(); 75 if (pageon()) 76 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]); 77 /* if (dobbox == TRUE) { /* could be better */ 78 /* cover((double)(x[i] + x[i+1])/2,(double)-(y[i] + y[i+1])/2); 79 /* cover((double)x[i+1], (double)-y[i+1]); 80 /* cover((double)(x[i+1] + x[i+2])/2, (double)-(y[i+1] + y[i+2])/2); 81 /* } 82 */ 83 } 84 85 hpos = x[N]; /* where troff expects to be */ 86 vpos = y[N]; 87 } 88 89 void 90 draw(Biobufhdr *Bp) { 91 92 int r, x1, y1, x2, y2, i; 93 int d1, d2; 94 95 drawflag = TRUE; 96 r = Bgetrune(Bp); 97 switch(r) { 98 case 'l': 99 if (Bgetfield(Bp, 'd', &x1, 0)<=0 || Bgetfield(Bp, 'd', &y1, 0)<=0 || Bgetfield(Bp, 'r', &i, 0)<=0) 100 error(FATAL, "draw line function, destination coordinates not found.\n"); 101 102 endstring(); 103 if (pageon()) 104 Bprint(Bstdout, "%d %d %d %d Dl\n", hpos, vpos, hpos+x1, vpos+y1); 105 hpos += x1; 106 vpos += y1; 107 break; 108 case 'c': 109 if (Bgetfield(Bp, 'd', &d1, 0)<=0) 110 error(FATAL, "draw circle function, diameter coordinates not found.\n"); 111 112 endstring(); 113 if (pageon()) 114 Bprint(Bstdout, "%d %d %d %d De\n", hpos, vpos, d1, d1); 115 hpos += d1; 116 break; 117 case 'e': 118 if (Bgetfield(Bp, 'd', &d1, 0)<=0 || Bgetfield(Bp, 'd', &d2, 0)<=0) 119 error(FATAL, "draw ellipse function, diameter coordinates not found.\n"); 120 121 endstring(); 122 if (pageon()) 123 Bprint(Bstdout, "%d %d %d %d De\n", hpos, vpos, d1, d2); 124 hpos += d1; 125 break; 126 case 'a': 127 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) 128 error(FATAL, "draw arc function, coordinates not found.\n"); 129 130 endstring(); 131 if (pageon()) 132 Bprint(Bstdout, "%d %d %d %d %d %d Da\n", hpos, vpos, x1, y1, x2, y2); 133 hpos += x1 + x2; 134 vpos += y1 + y2; 135 break; 136 case 'q': 137 drawspline(Bp, 1); 138 break; 139 case '~': 140 drawspline(Bp, 2); 141 break; 142 default: 143 error(FATAL, "unknown draw function <%c>\n", r); 144 break; 145 } 146 } 147 148 void 149 beginpath(char *buf, int copy) { 150 151 /* 152 * Called from devcntrl() whenever an "x X BeginPath" command is read. It's used 153 * to mark the start of a sequence of drawing commands that should be grouped 154 * together and treated as a single path. By default the drawing procedures in 155 * *drawfile treat each drawing command as a separate object, and usually start 156 * with a newpath (just as a precaution) and end with a stroke. The newpath and 157 * stroke isolate individual drawing commands and make it impossible to deal with 158 * composite objects. "x X BeginPath" can be used to mark the start of drawing 159 * commands that should be grouped together and treated as a single object, and 160 * part of what's done here ensures that the PostScript drawing commands defined 161 * in *drawfile skip the newpath and stroke, until after the next "x X DrawPath" 162 * command. At that point the path that's been built up can be manipulated in 163 * various ways (eg. filled and/or stroked with a different line width). 164 * 165 * Color selection is one of the options that's available in parsebuf(), 166 * so if we get here we add *colorfile to the output file before doing 167 * anything important. 168 * 169 */ 170 if (inpath == FALSE) { 171 endstring(); 172 /* getdraw(); */ 173 /* getcolor(); */ 174 Bprint(Bstdout, "gsave\n"); 175 Bprint(Bstdout, "newpath\n"); 176 Bprint(Bstdout, "%d %d m\n", hpos, vpos); 177 Bprint(Bstdout, "/inpath true def\n"); 178 if ( copy == TRUE ) 179 Bprint(Bstdout, "%s\n", buf); 180 inpath = TRUE; 181 } 182 } 183 184 static void parsebuf(char*); 185 186 void 187 drawpath(char *buf, int copy) { 188 189 /* 190 * 191 * Called from devcntrl() whenever an "x X DrawPath" command is read. It marks the 192 * end of the path started by the last "x X BeginPath" command and uses whatever 193 * has been passed along in *buf to manipulate the path (eg. fill and/or stroke 194 * the path). Once that's been done the drawing procedures are restored to their 195 * default behavior in which each drawing command is treated as an isolated path. 196 * The new version (called after "x X DrawPath") has copy set to FALSE, and calls 197 * parsebuf() to figure out what goes in the output file. It's a feeble attempt 198 * to free users and preprocessors (like pic) from having to know PostScript. The 199 * comments in parsebuf() describe what's handled. 200 * 201 * In the early version a path was started with "x X BeginObject" and ended with 202 * "x X EndObject". In both cases *buf was just copied to the output file, and 203 * was expected to be legitimate PostScript that manipulated the current path. 204 * The old escape sequence will be supported for a while (for Ravi), and always 205 * call this routine with copy set to TRUE. 206 * 207 * 208 */ 209 210 if ( inpath == TRUE ) { 211 if ( copy == TRUE ) 212 Bprint(Bstdout, "%s\n", buf); 213 else 214 parsebuf(buf); 215 Bprint(Bstdout, "grestore\n"); 216 Bprint(Bstdout, "/inpath false def\n"); 217 /* reset(); */ 218 inpath = FALSE; 219 } 220 } 221 222 223 static void 224 parsebuf(char *buf) 225 { 226 char *p; /* usually the next token */ 227 char *q; 228 int gsavelevel = 0; /* non-zero if we've done a gsave */ 229 230 /* 231 * Simple minded attempt at parsing the string that followed an "x X DrawPath" 232 * command. Everything not recognized here is simply ignored - there's absolutely 233 * no error checking and what was originally in buf is clobbered by strtok(). 234 * A typical *buf might look like, 235 * 236 * gray .9 fill stroke 237 * 238 * to fill the current path with a gray level of .9 and follow that by stroking the 239 * outline of the path. Since unrecognized tokens are ignored the last example 240 * could also be written as, 241 * 242 * with gray .9 fill then stroke 243 * 244 * The "with" and "then" strings aren't recognized tokens and are simply discarded. 245 * The "stroke", "fill", and "wfill" force out appropriate PostScript code and are 246 * followed by a grestore. In otherwords changes to the grahics state (eg. a gray 247 * level or color) are reset to default values immediately after the stroke, fill, 248 * or wfill tokens. For now "fill" gets invokes PostScript's eofill operator and 249 * "wfill" calls fill (ie. the operator that uses the non-zero winding rule). 250 * 251 * The tokens that cause temporary changes to the graphics state are "gray" (for 252 * setting the gray level), "color" (for selecting a known color from the colordict 253 * dictionary defined in *colorfile), and "line" (for setting the line width). All 254 * three tokens can be extended since strncmp() makes the comparison. For example 255 * the strings "line" and "linewidth" accomplish the same thing. Colors are named 256 * (eg. "red"), but must be appropriately defined in *colorfile. For now all three 257 * tokens must be followed immediately by their single argument. The gray level 258 * (ie. the argument that follows "gray") should be a number between 0 and 1, with 259 * 0 for black and 1 for white. 260 * 261 * To pass straight PostScript through enclose the appropriate commands in double 262 * quotes. Straight PostScript is only bracketed by the outermost gsave/grestore 263 * pair (ie. the one from the initial "x X BeginPath") although that's probably 264 * a mistake. Suspect I may have to change the double quote delimiters. 265 */ 266 for(p = buf; p != nil; p = q) { 267 if( q = strchr(p, ' ') ) 268 *q++ = '\0'; 269 270 if ( gsavelevel == 0 ) { 271 Bprint(Bstdout, "gsave\n"); 272 gsavelevel++; 273 } 274 if ( strcmp(p, "stroke") == 0 ) { 275 Bprint(Bstdout, "closepath stroke\ngrestore\n"); 276 gsavelevel--; 277 } else if ( strcmp(p, "openstroke") == 0 ) { 278 Bprint(Bstdout, "stroke\ngrestore\n"); 279 gsavelevel--; 280 } else if ( strcmp(p, "fill") == 0 ) { 281 Bprint(Bstdout, "eofill\ngrestore\n"); 282 gsavelevel--; 283 } else if ( strcmp(p, "wfill") == 0 ) { 284 Bprint(Bstdout, "fill\ngrestore\n"); 285 gsavelevel--; 286 } else if ( strcmp(p, "sfill") == 0 ) { 287 Bprint(Bstdout, "eofill\ngrestore\ngsave\nstroke\ngrestore\n"); 288 gsavelevel--; 289 } else if ( strncmp(p, "gray", strlen("gray")) == 0 ) { 290 if( q ) { 291 p = q; 292 if ( q = strchr(p, ' ') ) 293 *q++ = '\0'; 294 Bprint(Bstdout, "%s setgray\n", p); 295 } 296 } else if ( strncmp(p, "color", strlen("color")) == 0 ) { 297 if( q ) { 298 p = q; 299 if ( q = strchr(p, ' ') ) 300 *q++ = '\0'; 301 Bprint(Bstdout, "/%s setcolor\n", p); 302 } 303 } else if ( strncmp(p, "line", strlen("line")) == 0 ) { 304 if( q ) { 305 p = q; 306 if ( q = strchr(p, ' ') ) 307 *q++ = '\0'; 308 Bprint(Bstdout, "%s resolution mul 2 div setlinewidth\n", p); 309 } 310 } else if ( strncmp(p, "reverse", strlen("reverse")) == 0 ) 311 Bprint(Bstdout, "reversepath\n"); 312 else if ( *p == '"' ) { 313 for ( ; gsavelevel > 0; gsavelevel-- ) 314 Bprint(Bstdout, "grestore\n"); 315 if ( q != nil ) 316 *--q = ' '; 317 if ( (q = strchr(p, '"')) != nil ) { 318 *q++ = '\0'; 319 Bprint(Bstdout, "%s\n", p); 320 } 321 } 322 } 323 324 for ( ; gsavelevel > 0; gsavelevel-- ) 325 Bprint(Bstdout, "grestore\n"); 326 327 } 328