| File: | draw.c |
| Location: | line 440, column 5 |
| Description: | Value stored to 'dx' is never read |
| 1 | /* |
| 2 | * |
| 3 | Copyright (c) 1991 X Consortium |
| 4 | |
| 5 | Permission is hereby granted, free of charge, to any person obtaining a copy |
| 6 | of this software and associated documentation files (the "Software"), to deal |
| 7 | in the Software without restriction, including without limitation the rights |
| 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 9 | copies of the Software, and to permit persons to whom the Software is |
| 10 | furnished to do so, subject to the following conditions: |
| 11 | |
| 12 | The above copyright notice and this permission notice shall be included in |
| 13 | all copies or substantial portions of the Software. |
| 14 | |
| 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 18 | X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN |
| 19 | AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| 20 | CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 21 | |
| 22 | Except as contained in this notice, the name of the X Consortium shall not be |
| 23 | used in advertising or otherwise to promote the sale, use or other dealings |
| 24 | in this Software without prior written authorization from the X Consortium. |
| 25 | * |
| 26 | */ |
| 27 | |
| 28 | /* |
| 29 | * draw.c |
| 30 | * |
| 31 | * accept dvi function calls and translate to X |
| 32 | */ |
| 33 | |
| 34 | /* |
| 35 | Support for ditroff drawing commands added: lines, circles, ellipses, |
| 36 | arcs and splines. Splines are approximated as short lines by iterating |
| 37 | a simple approximation algorithm. This seems good enough for previewing. |
| 38 | |
| 39 | David Evans <dre@cs.nott.ac.uk>, 14th March, 1990 |
| 40 | */ |
| 41 | |
| 42 | #include <X11/Xos.h> |
| 43 | #include <X11/IntrinsicP.h> |
| 44 | #include <X11/StringDefs.h> |
| 45 | #include <stdio.h> |
| 46 | #include <ctype.h> |
| 47 | #include <math.h> |
| 48 | #include "DviP.h" |
| 49 | #include <stdlib.h> |
| 50 | |
| 51 | #ifndef M_PI3.14159265358979323846264338327950288 |
| 52 | #define M_PI3.14159265358979323846264338327950288 3.14159265358979323846264338327950 |
| 53 | #endif |
| 54 | |
| 55 | /* the following are for use in the spline approximation algorithm */ |
| 56 | |
| 57 | typedef struct Point { |
| 58 | double x; |
| 59 | double y; |
| 60 | struct Point *next; |
| 61 | } Point; |
| 62 | |
| 63 | #define ITERATIONS10 10 /* iterations to approximate spline */ |
| 64 | |
| 65 | #define midx(p,q)((p->x + q->x) / 2) ((p->x + q->x) / 2) /* mid x point on pq */ |
| 66 | #define midy(p,q)((p->y + q->y) / 2) ((p->y + q->y) / 2) /* mid y point on pq */ |
| 67 | |
| 68 | #define length(p,q)sqrt(((q->x - p->x)*(q->x - p->x)) + ((q->y - p ->y)*(q->y - p->y))) sqrt(((q->x - p->x)*(q->x - p->x)) \ |
| 69 | + ((q->y - p->y)*(q->y - p->y))) /* length of pq */ |
| 70 | |
| 71 | static Point *spline = (Point *)NULL((void*)0); /* head of spline linked list */ |
| 72 | |
| 73 | static void ApproxSpline(int n); |
| 74 | static void DeletePoint(Point *p); |
| 75 | static void DrawSplineSegments(DviWidget dw); |
| 76 | static int GetSpline(const char *s); |
| 77 | static void InsertPoint(Point *p, Point *q); |
| 78 | static void LineApprox(Point *p1, Point *p2, Point *p3); |
| 79 | static Point * MakePoint(double x, double y); |
| 80 | |
| 81 | void |
| 82 | HorizontalMove(DviWidget dw, int delta) |
| 83 | { |
| 84 | dw->dvi.state->x += delta; |
| 85 | } |
| 86 | |
| 87 | void |
| 88 | HorizontalGoto(DviWidget dw, int NewPosition) |
| 89 | { |
| 90 | dw->dvi.state->x = NewPosition; |
| 91 | } |
| 92 | |
| 93 | void |
| 94 | VerticalMove(DviWidget dw, int delta) |
| 95 | { |
| 96 | dw->dvi.state->y += delta; |
| 97 | } |
| 98 | |
| 99 | void |
| 100 | VerticalGoto(DviWidget dw, int NewPosition) |
| 101 | { |
| 102 | dw->dvi.state->y = NewPosition; |
| 103 | } |
| 104 | |
| 105 | #ifdef USE_XFT |
| 106 | static void |
| 107 | DrawText (DviWidget dw) |
| 108 | { |
| 109 | int i; |
| 110 | XftFont *font; |
| 111 | |
| 112 | font = dw->dvi.cache.font; |
| 113 | for (i = 0; i <= dw->dvi.cache.index; i++) |
| 114 | { |
| 115 | if (dw->dvi.cache.cache[i].font) |
| 116 | font = dw->dvi.cache.cache[i].font; |
| 117 | XftDrawString8 (dw->dvi.draw, &dw->dvi.black, |
| 118 | font, |
| 119 | dw->dvi.cache.cache[i].x, |
| 120 | dw->dvi.cache.start_y, |
| 121 | (unsigned char *) dw->dvi.cache.cache[i].chars, |
| 122 | dw->dvi.cache.cache[i].nchars); |
| 123 | } |
| 124 | } |
| 125 | #endif |
| 126 | |
| 127 | void |
| 128 | FlushCharCache (DviWidget dw) |
| 129 | { |
| 130 | int xx, yx; |
| 131 | |
| 132 | xx = ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)); |
| 133 | yx = ToX(dw, dw->dvi.state->y)((int) ((dw->dvi.state->y) * (dw)->dvi.scale + 0.5)); |
| 134 | if (dw->dvi.cache.char_index != 0) |
| 135 | { |
| 136 | #ifdef USE_XFT |
| 137 | DrawText (dw); |
| 138 | #else |
| 139 | XDrawText (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
| 140 | dw->dvi.cache.start_x, dw->dvi.cache.start_y, |
| 141 | dw->dvi.cache.cache, dw->dvi.cache.index + 1); |
| 142 | #endif |
| 143 | } |
| 144 | dw->dvi.cache.index = 0; |
| 145 | dw->dvi.cache.max = DVI_TEXT_CACHE_SIZE256; |
| 146 | if (dw->dvi.noPolyText) |
| 147 | dw->dvi.cache.max = 1; |
| 148 | dw->dvi.cache.char_index = 0; |
| 149 | dw->dvi.cache.cache[0].nchars = 0; |
| 150 | dw->dvi.cache.start_x = dw->dvi.cache.x = xx; |
| 151 | dw->dvi.cache.start_y = dw->dvi.cache.y = yx; |
| 152 | } |
| 153 | |
| 154 | void |
| 155 | SetGCForDraw (DviWidget dw) |
| 156 | { |
| 157 | int lw; |
| 158 | if (dw->dvi.state->line_style != dw->dvi.line_style || |
| 159 | dw->dvi.state->line_width != dw->dvi.line_width) |
| 160 | { |
| 161 | lw = ToX(dw, dw->dvi.state->line_width)((int) ((dw->dvi.state->line_width) * (dw)->dvi.scale + 0.5)); |
| 162 | if (lw <= 1) |
| 163 | lw = 0; |
| 164 | XSetLineAttributes (XtDisplay (dw)(((dw)->core.screen)->display), dw->dvi.normal_GC, |
| 165 | lw, LineSolid0, CapButt1, JoinMiter0); |
| 166 | dw->dvi.line_style = dw->dvi.state->line_style; |
| 167 | dw->dvi.line_width = dw->dvi.state->line_width; |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | void |
| 172 | DrawLine (DviWidget dw, int x, int y) |
| 173 | { |
| 174 | if (dw->dvi.display_enable) |
| 175 | XDrawLine (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
| 176 | ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)), ToX(dw, dw->dvi.state->y)((int) ((dw->dvi.state->y) * (dw)->dvi.scale + 0.5)), |
| 177 | ToX(dw, dw->dvi.state->x + x)((int) ((dw->dvi.state->x + x) * (dw)->dvi.scale + 0.5 )), ToX(dw,dw->dvi.state->y + y)((int) ((dw->dvi.state->y + y) * (dw)->dvi.scale + 0.5 ))); |
| 178 | dw->dvi.state->x += x; |
| 179 | dw->dvi.state->y += y; |
| 180 | } |
| 181 | |
| 182 | void |
| 183 | DrawCircle (DviWidget dw, int diameter) |
| 184 | { |
| 185 | if (dw->dvi.display_enable) |
| 186 | XDrawArc (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
| 187 | ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)), |
| 188 | ToX(dw, dw->dvi.state->y - (diameter / 2))((int) ((dw->dvi.state->y - (diameter / 2)) * (dw)-> dvi.scale + 0.5)), |
| 189 | ToX(dw, diameter)((int) ((diameter) * (dw)->dvi.scale + 0.5)), ToX(dw, diameter)((int) ((diameter) * (dw)->dvi.scale + 0.5)), 0, 360 * 64); |
| 190 | dw->dvi.state->x += diameter; |
| 191 | } |
| 192 | |
| 193 | void |
| 194 | DrawEllipse (DviWidget dw, int a, int b) |
| 195 | { |
| 196 | if (dw->dvi.display_enable) |
| 197 | XDrawArc (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
| 198 | ToX(dw, dw->dvi.state->x)((int) ((dw->dvi.state->x) * (dw)->dvi.scale + 0.5)), ToX(dw, dw->dvi.state->y - (b / 2))((int) ((dw->dvi.state->y - (b / 2)) * (dw)->dvi.scale + 0.5)), |
| 199 | ToX(dw,a)((int) ((a) * (dw)->dvi.scale + 0.5)), ToX(dw,b)((int) ((b) * (dw)->dvi.scale + 0.5)), 0, 360 * 64); |
| 200 | dw->dvi.state->x += a; |
| 201 | } |
| 202 | |
| 203 | |
| 204 | /* Convert angle in degrees to 64ths of a degree */ |
| 205 | |
| 206 | static int |
| 207 | ConvertAngle(int theta) |
| 208 | { |
| 209 | return(theta * 64); |
| 210 | } |
| 211 | |
| 212 | void |
| 213 | DrawArc (DviWidget dw, int x0, int y0, int x1, int y1) |
| 214 | { |
| 215 | int xc, yc, x2, y2, r; |
| 216 | int angle1, angle2; |
| 217 | |
| 218 | /* centre */ |
| 219 | xc = dw->dvi.state->x + x0; |
| 220 | yc = dw->dvi.state->y + y0; |
| 221 | |
| 222 | /* to */ |
| 223 | x2 = xc + x1; |
| 224 | y2 = yc + y1; |
| 225 | |
| 226 | dw->dvi.state->x = x2; |
| 227 | dw->dvi.state->y = y2; |
| 228 | |
| 229 | if (dw->dvi.display_enable) { |
| 230 | |
| 231 | /* radius */ |
| 232 | r = (int)sqrt((float) x1 * x1 + (float) y1 * y1); |
| 233 | |
| 234 | /* start and finish angles */ |
| 235 | if (x0 == 0) { |
| 236 | if (y0 >= 0) |
| 237 | angle1 = 90; |
| 238 | else |
| 239 | angle1 = 270; |
| 240 | } |
| 241 | else { |
| 242 | angle1 = (int) (atan((double)(y0) / (double)(x0)) * 180 / M_PI3.14159265358979323846264338327950288); |
| 243 | if (x0 > 0) |
| 244 | angle1 = 180 - angle1; |
| 245 | else |
| 246 | angle1 = -angle1; |
| 247 | } |
| 248 | |
| 249 | if (x1 == 0) { |
| 250 | if (y1 <= 0) |
| 251 | angle2 = 90; |
| 252 | else |
| 253 | angle2 = 270; |
| 254 | } |
| 255 | else { |
| 256 | angle2 = (int) (atan((double)(y1) / (double)(x1)) * 180 / M_PI3.14159265358979323846264338327950288); |
| 257 | if (x1 < 0) |
| 258 | angle2 = 180 - angle2; |
| 259 | else |
| 260 | angle2 = -angle2; |
| 261 | } |
| 262 | |
| 263 | if (angle1 < 0) |
| 264 | angle1 += 360; |
| 265 | if (angle2 < 0) |
| 266 | angle2 += 360; |
| 267 | |
| 268 | if (angle2 < angle1) |
| 269 | angle1 -= 360; |
| 270 | angle2 = angle2 - angle1; |
| 271 | |
| 272 | angle1 = ConvertAngle(angle1); |
| 273 | angle2 = ConvertAngle(angle2); |
| 274 | |
| 275 | XDrawArc (XtDisplay (dw)(((dw)->core.screen)->display), XtWindow (dw)((dw)->core.window), dw->dvi.normal_GC, |
| 276 | ToX(dw, xc - r)((int) ((xc - r) * (dw)->dvi.scale + 0.5)), ToX(dw, yc - r)((int) ((yc - r) * (dw)->dvi.scale + 0.5)), |
| 277 | ToX(dw, 2 * r)((int) ((2 * r) * (dw)->dvi.scale + 0.5)), ToX(dw, 2 * r)((int) ((2 * r) * (dw)->dvi.scale + 0.5)), |
| 278 | angle1, angle2); |
| 279 | } |
| 280 | } |
| 281 | |
| 282 | /* copy next non-blank string from p to temp, update p */ |
| 283 | |
| 284 | static const char * |
| 285 | getstr(const char *p, char *temp) |
| 286 | { |
| 287 | while (*p == ' ' || *p == '\t' || *p == '\n') |
| 288 | p++; |
| 289 | if (*p == '\0') { |
| 290 | temp[0] = 0; |
| 291 | return((char *)NULL((void*)0)); |
| 292 | } |
| 293 | while (*p != ' ' && *p != '\t' && *p != '\n' && *p != '\0') |
| 294 | *temp++ = *p++; |
| 295 | *temp = '\0'; |
| 296 | return(p); |
| 297 | } |
| 298 | |
| 299 | |
| 300 | /* Draw a spline by approximating with short lines. */ |
| 301 | |
| 302 | /*ARGSUSED*/ |
| 303 | void |
| 304 | DrawSpline (DviWidget dw, const char *s, int len) |
| 305 | { |
| 306 | int n; |
| 307 | |
| 308 | /* get coordinate pairs into spline linked list */ |
| 309 | if ((n = GetSpline(s)) <= 0) |
| 310 | return; |
| 311 | |
| 312 | ApproxSpline(n); |
| 313 | |
| 314 | DrawSplineSegments(dw); |
| 315 | } |
| 316 | |
| 317 | |
| 318 | /* Parse string s to create a linked list of Point's with spline */ |
| 319 | /* as its head. Return the number of coordinate pairs found. */ |
| 320 | |
| 321 | static int |
| 322 | GetSpline(const char *s) |
| 323 | { |
| 324 | double x, y, x1, y1; |
| 325 | int n = 0; |
| 326 | Point *pt; |
| 327 | const char *p = s; |
| 328 | char d[10]; |
| 329 | |
| 330 | if (!*p) |
| 331 | return(n); |
| 332 | |
| 333 | pt = spline = MakePoint(0.0, 0.0); |
| 334 | n = 1; |
| 335 | x = y = 0.0; |
| 336 | p = s; |
| 337 | while (p && *p) { |
| 338 | if ((p = getstr(p, d)) == (const char *)NULL((void*)0)) |
| 339 | break; |
| 340 | x1 = x + atof(d); |
| 341 | if ((p = getstr(p, d)) == (const char *)NULL((void*)0)) |
| 342 | break; |
| 343 | y1 = y + atof(d); |
| 344 | pt->next = MakePoint(x1, y1); |
| 345 | pt = pt->next; |
| 346 | x = pt->x; |
| 347 | y = pt->y; |
| 348 | n++; |
| 349 | } |
| 350 | |
| 351 | /* number of pairs of points */ |
| 352 | |
| 353 | return(n); |
| 354 | } |
| 355 | |
| 356 | /* Approximate a spline by lines generated by iterations of the */ |
| 357 | /* approximation algorithm from the original n points in the spline. */ |
| 358 | |
| 359 | static void |
| 360 | ApproxSpline(int n) |
| 361 | { |
| 362 | int mid, j; |
| 363 | Point *p1, *p2, *p3, *p; |
| 364 | |
| 365 | if (n < 3) |
| 366 | return; |
| 367 | |
| 368 | /* number of mid-points to calculate */ |
| 369 | mid = n - 3; |
| 370 | |
| 371 | /* remember original points are stored as an array of n points */ |
| 372 | /* so I can index it directly to calculate mid-points only. */ |
| 373 | if (mid > 0) { |
| 374 | p = spline->next; |
| 375 | j = 1; |
| 376 | while (j < n-2) { |
| 377 | p1 = p; |
| 378 | p = p->next; |
| 379 | p2 = p; |
| 380 | InsertPoint(p1, MakePoint(midx(p1, p2)((p1->x + p2->x) / 2), midy(p1, p2)((p1->y + p2->y) / 2))); |
| 381 | j++; |
| 382 | } |
| 383 | } |
| 384 | |
| 385 | /* Now approximate curve by line segments. */ |
| 386 | /* There *should* be the correct number of points now! */ |
| 387 | |
| 388 | p = spline; |
| 389 | while (p != (Point *)NULL((void*)0)) { |
| 390 | p1 = p; |
| 391 | if ((p = p->next) == (Point *)NULL((void*)0)) |
| 392 | break; |
| 393 | p2 = p; |
| 394 | if ((p = p->next) == (Point *)NULL((void*)0)) |
| 395 | break; |
| 396 | p3 = p; /* This point becomes first point of next curve */ |
| 397 | |
| 398 | LineApprox(p1, p2, p3); |
| 399 | } |
| 400 | } |
| 401 | |
| 402 | |
| 403 | /* p1, p2, and p3 are initially 3 *consecutive* points on the curve. */ |
| 404 | /* For each adjacent pair of points find the mid-point, insert this */ |
| 405 | /* in the linked list, delete the first of the two used (unless it */ |
| 406 | /* is the first for this curve). Repeat this ITERATIONS times. */ |
| 407 | |
| 408 | /*ARGSUSED*/ |
| 409 | static void |
| 410 | LineApprox(Point *p1, Point *p2, Point *p3) |
| 411 | { |
| 412 | Point *p4, *p; |
| 413 | int reps = ITERATIONS10; |
| 414 | |
| 415 | while (reps) { |
| 416 | for (p = p1; p != (Point *)NULL((void*)0) && p != p3; ) { |
| 417 | InsertPoint(p, p4 = MakePoint( midx(p,p->next)((p->x + p->next->x) / 2), midy(p,p->next)((p->y + p->next->y) / 2) )); |
| 418 | if (p != p1) |
| 419 | DeletePoint(p); |
| 420 | p = p4->next; /* skip inserted point! */ |
| 421 | } |
| 422 | reps--; |
| 423 | } |
| 424 | } |
| 425 | |
| 426 | |
| 427 | /* Traverse the linked list, calling DrawLine to approximate the */ |
| 428 | /* spline curve. Rounding errors are taken into account so that */ |
| 429 | /* the "curve" is continuous, and ends up where expected. */ |
| 430 | |
| 431 | static void |
| 432 | DrawSplineSegments(DviWidget dw) |
| 433 | { |
| 434 | Point *p, *q; |
| 435 | double x1, y1; |
| 436 | int dx, dy; |
| 437 | double xpos, ypos; |
| 438 | |
| 439 | p = spline; |
| 440 | dx = dy = 0; |
Value stored to 'dx' is never read | |
| 441 | |
| 442 | /* save the start position */ |
| 443 | |
| 444 | xpos = dw->dvi.state->x; |
| 445 | ypos = dw->dvi.state->y; |
| 446 | |
| 447 | x1 = y1 = 0.0; |
| 448 | |
| 449 | while (p != (Point *)NULL((void*)0)) { |
| 450 | dx = p->x - x1 + 0.5; |
| 451 | dy = p->y - y1 + 0.5; |
| 452 | DrawLine (dw, dx, dy); |
| 453 | |
| 454 | x1 = p->x; |
| 455 | y1 = p->y; |
| 456 | dw->dvi.state->x = xpos + x1; |
| 457 | dw->dvi.state->y = ypos + y1; |
| 458 | |
| 459 | q = p; |
| 460 | p = p->next; |
| 461 | XtFree((char *)q); |
| 462 | } |
| 463 | spline = (Point *)NULL((void*)0); |
| 464 | } |
| 465 | |
| 466 | |
| 467 | /* Malloc memory for a Point, and initialise the elements to x, y, NULL */ |
| 468 | /* Return a pointer to the new Point. */ |
| 469 | |
| 470 | static Point * |
| 471 | MakePoint(double x, double y) |
| 472 | { |
| 473 | Point *p; |
| 474 | |
| 475 | p = (Point *) XtMalloc (sizeof (Point)); |
| 476 | p->x = x; |
| 477 | p->y = y; |
| 478 | p->next = (Point *)NULL((void*)0); |
| 479 | |
| 480 | return(p); |
| 481 | } |
| 482 | |
| 483 | |
| 484 | /* Insert point q in linked list after point p. */ |
| 485 | |
| 486 | static void |
| 487 | InsertPoint(Point *p, Point *q) |
| 488 | { |
| 489 | /* point q to the next point */ |
| 490 | q->next = p->next; |
| 491 | |
| 492 | /* point p to new inserted one */ |
| 493 | p->next = q; |
| 494 | } |
| 495 | |
| 496 | /* Delete point p from the linked list. */ |
| 497 | |
| 498 | static void |
| 499 | DeletePoint(Point *p) |
| 500 | { |
| 501 | Point *tmp; |
| 502 | |
| 503 | tmp = p->next; |
| 504 | p->x = p->next->x; |
| 505 | p->y = p->next->y; |
| 506 | p->next = p->next->next; |
| 507 | XtFree((char *)tmp); |
| 508 | } |