libdrawtext: 1c2c00d432da src/font.c

libdrawtext

view src/font.c @ 66:1c2c00d432da

made the open_font function automatically use the first font it loads

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sun, 26 Aug 2012 04:43:09 +0300
parents	365eba4dccec
children	baec6ad7b2dd

line source

1 /*

2 libdrawtext - a simple library for fast text rendering in OpenGL

5 This program is free software: you can redistribute it and/or modify

6 it under the terms of the GNU Lesser General Public License as published by

7 the Free Software Foundation, either version 3 of the License, or

8 (at your option) any later version.

10 This program is distributed in the hope that it will be useful,

11 but WITHOUT ANY WARRANTY; without even the implied warranty of

12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

13 GNU Lesser General Public License for more details.

15 You should have received a copy of the GNU Lesser General Public License

16 along with this program. If not, see <http://www.gnu.org/licenses/>.

17 */

18 #ifndef NO_FREETYPE

19 #define USE_FREETYPE

20 #endif

22 #include <stdio.h>

23 #include <stdlib.h>

24 #include <string.h>

25 #include <math.h>

26 #include <limits.h>

27 #include <ctype.h>

28 #include <float.h>

29 #include <errno.h>

30 #ifdef USE_FREETYPE

31 #include <ft2build.h>

32 #include FT_FREETYPE_H

33 #endif

34 #include "drawtext.h"

35 #include "drawtext_impl.h"

37 #define FTSZ_TO_PIXELS(x) ((x) / 64)

38 #define MAX_IMG_WIDTH 4096

41 #ifdef USE_FREETYPE

42 static int init_freetype(void);

43 static void cleanup(void);

45 static void calc_best_size(int total_width, int max_glyph_height, int padding, int pow2, int *imgw, int *imgh);

46 static int next_pow2(int x);

48 static FT_Library ft;

51 static int init_done;

53 static int init_freetype(void)

54 {

55 if(!init_done) {

56 if(FT_Init_FreeType(&ft) != 0) {

57 return -1;

58 }

59 atexit(cleanup);

60 init_done = 1;

61 }

62 return 0;

63 }

65 static void cleanup(void)

66 {

67 if(init_done) {

68 FT_Done_FreeType(ft);

69 }

70 }

72 struct dtx_font *dtx_open_font(const char *fname, int sz)

73 {

74 struct dtx_font *fnt;

76 init_freetype();

78 if(!(fnt = calloc(1, sizeof *fnt))) {

79 fperror("failed to allocate font structure");

80 return 0;

81 }

83 if(FT_New_Face(ft, fname, 0, (FT_Face*)&fnt->face) != 0) {

84 fprintf(stderr, "failed to open font file: %s\n", fname);

85 return 0;

86 }

88 /* pre-create the extended ASCII range glyphmap */

89 if(sz) {

90 dtx_prepare_range(fnt, sz, 0, 256);

92 if(!dtx_font) {

93 dtx_use_font(fnt, sz);

94 }

95 }

97 return fnt;

98 }

100 void dtx_close_font(struct dtx_font *fnt)

101 {

102 if(!fnt) return;

103

104 FT_Done_Face(fnt->face);

105

106 /* destroy the glyphmaps */

107 while(fnt->gmaps) {

108 void *tmp = fnt->gmaps;

109 fnt->gmaps = fnt->gmaps->next;

110 dtx_free_glyphmap(tmp);

111 }

112

113 free(fnt);

114 }

115

116 void dtx_prepare(struct dtx_font *fnt, int sz)

117 {

118 dtx_get_font_glyphmap_range(fnt, sz, 0, 256);

119 }

120

121 void dtx_prepare_range(struct dtx_font *fnt, int sz, int cstart, int cend)

122 {

123 dtx_get_font_glyphmap_range(fnt, sz, cstart, cend);

124 }

125

126 struct dtx_glyphmap *dtx_get_font_glyphmap(struct dtx_font *fnt, int sz, int code)

127 {

128 struct dtx_glyphmap *gm;

129

130 /* check to see if the last we've given out fits the bill */

131 if(fnt->last_gmap && code >= fnt->last_gmap->cstart && code < fnt->last_gmap->cend && fnt->last_gmap->ptsize == sz) {

132 return fnt->last_gmap;

133 }

134

135 /* otherwise search for the appropriate glyphmap */

136 gm = fnt->gmaps;

137 while(gm) {

138 if(code >= gm->cstart && code < gm->cend && sz == gm->ptsize) {

139 fnt->last_gmap = gm;

140 return gm;

141 }

142 gm = gm->next;

143 }

144 return 0;

145 }

146

147 struct dtx_glyphmap *dtx_get_font_glyphmap_range(struct dtx_font *fnt, int sz, int cstart, int cend)

148 {

149 struct dtx_glyphmap *gm;

150

151 /* search the available glyphmaps to see if we've got one that includes

152 * the requested range

153 */

154 gm = fnt->gmaps;

155 while(gm) {

156 if(gm->cstart <= cstart && gm->cend >= cend && gm->ptsize == sz) {

157 return gm;

158 }

159 gm = gm->next;

160 }

161

162 /* not found, create one and add it to the list */

163 if(!(gm = dtx_create_glyphmap_range(fnt, sz, cstart, cend))) {

164 return 0;

165 }

166 return gm;

167 }

168

169 struct dtx_glyphmap *dtx_create_glyphmap_range(struct dtx_font *fnt, int sz, int cstart, int cend)

170 {

171 FT_Face face = fnt->face;

172 struct dtx_glyphmap *gmap;

173 int i, j;

174 int gx, gy;

175 int padding = 4;

176 int total_width = padding;

177 int max_height = 0;

178

179 FT_Set_Char_Size(fnt->face, 0, sz * 64, 72, 72);

180

181 if(!(gmap = calloc(1, sizeof *gmap))) {

182 return 0;

183 }

184

185 gmap->ptsize = sz;

186 gmap->cstart = cstart;

187 gmap->cend = cend;

188 gmap->crange = cend - cstart;

189 gmap->line_advance = FTSZ_TO_PIXELS((float)face->size->metrics.height);

190

191 if(!(gmap->glyphs = malloc(gmap->crange * sizeof *gmap->glyphs))) {

192 free(gmap);

193 return 0;

194 }

195

196 for(i=0; i<gmap->crange; i++) {

197 int h;

198

199 FT_Load_Char(face, i + cstart, 0);

200 h = FTSZ_TO_PIXELS(face->glyph->metrics.height);

201

202 if(h > max_height) {

203 max_height = h;

204 }

205 total_width += FTSZ_TO_PIXELS(face->glyph->metrics.width) + padding;

206 }

207

208 calc_best_size(total_width, max_height, padding, 1, &gmap->xsz, &gmap->ysz);

209

210 if(!(gmap->pixels = malloc(gmap->xsz * gmap->ysz))) {

211 free(gmap->glyphs);

212 free(gmap);

213 return 0;

214 }

215 memset(gmap->pixels, 0, gmap->xsz * gmap->ysz);

216

217 gx = padding;

218 gy = padding;

219

220 for(i=0; i<gmap->crange; i++) {

221 float gwidth, gheight;

222 unsigned char *src, *dst;

223 FT_GlyphSlot glyph;

224

225 FT_Load_Char(face, i + cstart, FT_LOAD_RENDER);

226 glyph = face->glyph;

227 gwidth = FTSZ_TO_PIXELS((float)glyph->metrics.width);

228 gheight = FTSZ_TO_PIXELS((float)glyph->metrics.height);

229

230 if(gx > gmap->xsz - gwidth - padding) {

231 gx = padding;

232 gy += max_height + padding;

233 }

234

235 src = glyph->bitmap.buffer;

236 dst = gmap->pixels + gy * gmap->xsz + gx;

237

238 for(j=0; j<glyph->bitmap.rows; j++) {

239 memcpy(dst, src, glyph->bitmap.width);

240 dst += gmap->xsz;

241 src += glyph->bitmap.pitch;

242 }

243

244 gmap->glyphs[i].code = i;

245 gmap->glyphs[i].x = gx - 1;

246 gmap->glyphs[i].y = gy - 1;

247 gmap->glyphs[i].width = gwidth + 2;

248 gmap->glyphs[i].height = gheight + 2;

249 gmap->glyphs[i].orig_x = -FTSZ_TO_PIXELS((float)glyph->metrics.horiBearingX) + 1;

250 gmap->glyphs[i].orig_y = FTSZ_TO_PIXELS((float)glyph->metrics.height - glyph->metrics.horiBearingY) + 1;

251 gmap->glyphs[i].advance = FTSZ_TO_PIXELS((float)glyph->metrics.horiAdvance);

252 /* also precalc normalized */

253 gmap->glyphs[i].nx = (float)gmap->glyphs[i].x / (float)gmap->xsz;

254 gmap->glyphs[i].ny = (float)gmap->glyphs[i].y / (float)gmap->ysz;

255 gmap->glyphs[i].nwidth = (float)gmap->glyphs[i].width / (float)gmap->xsz;

256 gmap->glyphs[i].nheight = (float)gmap->glyphs[i].height / (float)gmap->ysz;

257

258 gx += gwidth + padding;

259 }

260

261 /* add it to the glyphmaps list of the font */

262 gmap->next = fnt->gmaps;

263 fnt->gmaps = gmap;

264

265 return gmap;

266 }

267 #endif /* USE_FREETYPE */

268

269 void dtx_free_glyphmap(struct dtx_glyphmap *gmap)

270 {

271 if(gmap) {

272 free(gmap->pixels);

273 free(gmap->glyphs);

274 free(gmap);

275 }

276 }

277

278 unsigned char *dtx_get_glyphmap_pixels(struct dtx_glyphmap *gmap)

279 {

280 return gmap->pixels;

281 }

282

283 int dtx_get_glyphmap_width(struct dtx_glyphmap *gmap)

284 {

285 return gmap->xsz;

286 }

287

288 int dtx_get_glyphmap_height(struct dtx_glyphmap *gmap)

289 {

290 return gmap->ysz;

291 }

292

293 struct dtx_glyphmap *dtx_load_glyphmap(const char *fname)

294 {

295 FILE *fp;

296 struct dtx_glyphmap *gmap;

297

298 if(!(fp = fopen(fname, "r"))) {

299 return 0;

300 }

301 gmap = dtx_load_glyphmap_stream(fp);

302 fclose(fp);

303 return gmap;

304 }

305

306 struct dtx_glyphmap *dtx_load_glyphmap_stream(FILE *fp)

307 {

308 char buf[512];

309 int hdr_lines = 0;

310 struct dtx_glyphmap *gmap;

311 struct glyph *glyphs = 0;

312 int min_code = INT_MAX;

313 int max_code = INT_MIN;

314 int i, max_pixval, num_pixels;

315

316 if(!(gmap = calloc(1, sizeof *gmap))) {

317 fperror("failed to allocate glyphmap");

318 return 0;

319 }

320

321 while(hdr_lines < 3) {

322 char *line = buf;

323 if(!fgets(buf, sizeof buf, fp)) {

324 fperror("unexpected end of file");

325 goto err;

326 }

327

328 while(isspace(*line)) {

329 line++;

330 }

331

332 if(line[0] == '#') {

333 struct glyph *g;

334 int c;

335 float x, y, xsz, ysz, res;

336

337 res = sscanf(line + 1, "%d: %fx%f+%f+%f\n", &c, &xsz, &ysz, &x, &y);

338 if(res != 5) {

339 fprintf(stderr, "%s: invalid glyph info line\n", __func__);

340 goto err;

341 }

342

343 if(!(g = malloc(sizeof *g))) {

344 fperror("failed to allocate glyph");

345 goto err;

346 }

347 g->code = c;

348 g->x = x;

349 g->y = y;

350 g->width = xsz;

351 g->height = ysz;

352 g->next = glyphs;

353 glyphs = g;

354

355 if(c < min_code) {

356 min_code = c;

357 }

358 if(c > max_code) {

359 max_code = c;

360 }

361 } else {

362 switch(hdr_lines) {

363 case 0:

364 if(0[line] != 'P' || 1[line] != '6') {

365 fprintf(stderr, "%s: invalid file format (magic)\n", __func__);

366 goto err;

367 }

368 break;

369

370 case 1:

371 if(sscanf(line, "%d %d", &gmap->xsz, &gmap->ysz) != 2) {

372 fprintf(stderr, "%s: invalid file format (dim)\n", __func__);

373 goto err;

374 }

375 break;

376

377 case 2:

378 {

379 char *endp;

380 max_pixval = strtol(line, &endp, 10);

381 if(endp == line) {

382 fprintf(stderr, "%s: invalid file format (maxval)\n", __func__);

383 goto err;

384 }

385 }

386 break;

387

388 default:

389 break; /* can't happen */

390 }

391 hdr_lines++;

392 }

393 }

394

395 num_pixels = gmap->xsz * gmap->ysz;

396 if(!(gmap->pixels = malloc(num_pixels))) {

397 fperror("failed to allocate pixels");

398 goto err;

399 }

400

401 for(i=0; i<num_pixels; i++) {

402 long c = fgetc(fp);

403 if(c == -1) {

404 fprintf(stderr, "unexpected end of file while reading pixels\n");

405 goto err;

406 }

407 gmap->pixels[i] = 255 * c / max_pixval;

408 fseek(fp, 2, SEEK_CUR);

409 }

410

411 gmap->cstart = min_code;

412 gmap->cend = max_code + 1;

413 gmap->crange = gmap->cend - gmap->cstart;

414

415 if(!(gmap->glyphs = calloc(gmap->crange, sizeof *gmap->glyphs))) {

416 fperror("failed to allocate glyph info");

417 goto err;

418 }

419

420 while(glyphs) {

421 struct glyph *g = glyphs;

422 glyphs = glyphs->next;

423

424 gmap->glyphs[g->code - gmap->cstart] = *g;

425 free(g);

426 }

427 return gmap;

428

429 err:

430 dtx_free_glyphmap(gmap);

431 while(glyphs) {

432 void *tmp = glyphs;

433 glyphs = glyphs->next;

434 free(tmp);

435 }

436 return 0;

437 }

438

439 int dtx_save_glyphmap(const char *fname, const struct dtx_glyphmap *gmap)

440 {

441 FILE *fp;

442 int res;

443

444 if(!(fp = fopen(fname, "wb"))) {

445 fprintf(stderr, "%s: failed to open file: %s: %s\n", __func__, fname, strerror(errno));

446 return -1;

447 }

448 res = dtx_save_glyphmap_stream(fp, gmap);

449 fclose(fp);

450 return res;

451 }

452

453 int dtx_save_glyphmap_stream(FILE *fp, const struct dtx_glyphmap *gmap)

454 {

455 int i, num_pixels;

456 struct glyph *g = gmap->glyphs;

457

458 fprintf(fp, "P6\n%d %d\n", gmap->xsz, gmap->ysz);

459 for(i=0; i<gmap->crange; i++) {

460 fprintf(fp, "# %d: %fx%f+%f+%f\n", g->code, g->width, g->height, g->x, g->y);

461 g++;

462 }

463 fprintf(fp, "255\n");

464

465 num_pixels = gmap->xsz * gmap->ysz;

466 for(i=0; i<num_pixels; i++) {

467 int c = gmap->pixels[i];

468 fputc(c, fp);

469 fputc(c, fp);

470 fputc(c, fp);

471 }

472 return 0;

473 }

474

475

476 void dtx_use_font(struct dtx_font *fnt, int sz)

477 {

478 dtx_gl_init();

479

480 dtx_font = fnt;

481 dtx_font_sz = sz;

482 }

483

484 float dtx_line_height(void)

485 {

486 struct dtx_glyphmap *gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, '\n');

487

488 return gmap->line_advance;

489 }

490

491 void dtx_glyph_box(int code, struct dtx_box *box)

492 {

493 int cidx;

494 struct dtx_glyphmap *gmap;

495 gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code);

496

497 cidx = code - gmap->cstart;

498

499 box->x = gmap->glyphs[cidx].orig_x;

500 box->y = gmap->glyphs[cidx].orig_y;

501 box->width = gmap->glyphs[cidx].width;

502 box->height = gmap->glyphs[cidx].height;

503 }

504

505 float dtx_glyph_width(int code)

506 {

507 struct dtx_box box;

508 dtx_glyph_box(code, &box);

509 return box.width;

510 }

511

512 float dtx_glyph_height(int code)

513 {

514 struct dtx_box box;

515 dtx_glyph_box(code, &box);

516 return box.height;

517 }

518

519 void dtx_string_box(const char *str, struct dtx_box *box)

520 {

521 int code;

522 float pos_x = 0.0f, pos_y = 0.0f;

523 struct glyph *g = 0;

524 float x0, y0, x1, y1;

525

526 x0 = y0 = FLT_MAX;

527 x1 = y1 = -FLT_MAX;

528

529 while(*str) {

530 float px, py;

531 struct dtx_glyphmap *gmap;

532

533 code = dtx_utf8_char_code(str);

534 str = dtx_utf8_next_char((char*)str);

535

536 px = pos_x;

537 py = pos_y;

538

539 if((gmap = dtx_proc_char(code, &pos_x, &pos_y))) {

540 g = gmap->glyphs + code - gmap->cstart;

541

542 if(px + g->orig_x < x0) {

543 x0 = px + g->orig_x;

544 }

545 if(py - g->orig_y < y0) {

546 y0 = py - g->orig_y;

547 }

548 if(px + g->orig_x + g->width > x1) {

549 x1 = px + g->orig_x + g->width;

550 }

551 if(py - g->orig_y + g->height > y1) {

552 y1 = py - g->orig_y + g->height;

553 }

554 }

555 }

556

557 box->x = x0;

558 box->y = y0;

559 box->width = x1 - x0;

560 box->height = y1 - y0;

561 }

562

563 float dtx_string_width(const char *str)

564 {

565 struct dtx_box box;

566

567 dtx_string_box(str, &box);

568 return box.width;

569 }

570

571 float dtx_string_height(const char *str)

572 {

573 struct dtx_box box;

574

575 dtx_string_box(str, &box);

576 return box.height;

577 }

578

579 float dtx_char_pos(const char *str, int n)

580 {

581 int i;

582 float pos = 0.0;

583 struct dtx_glyphmap *gmap;

584

585 for(i=0; i<n; i++) {

586 int code = dtx_utf8_char_code(str);

587 str = dtx_utf8_next_char((char*)str);

588

589 gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code);

590 pos += gmap->glyphs[i].advance;

591 }

592 return pos;

593 }

594

595 int dtx_char_at_pt(const char *str, float pt)

596 {

597 int i;

598 float prev_pos = 0.0f, pos = 0.0f;

599 struct dtx_glyphmap *gmap;

600

601 for(i=0; *str; i++) {

602 int code = dtx_utf8_char_code(str);

603 str = dtx_utf8_next_char((char*)str);

604

605 gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code);

606 pos += gmap->glyphs[i].advance;

607

608 if(fabs(pt - prev_pos) < fabs(pt - pos)) {

609 break;

610 }

611 prev_pos = pos;

612 }

613 return i;

614 }

615

616 struct dtx_glyphmap *dtx_proc_char(int code, float *xpos, float *ypos)

617 {

618 struct dtx_glyphmap *gmap;

619 gmap = dtx_get_font_glyphmap(dtx_font, dtx_font_sz, code);

620

621 switch(code) {

622 case '\n':

623 *xpos = 0.0;

624 if(gmap) {

625 *ypos -= gmap->line_advance;

626 }

627 return 0;

628

629 case '\t':

630 if(gmap) {

631 *xpos = (fmod(*xpos, 4.0) + 4.0) * gmap->glyphs[0].advance;

632 }

633 return 0;

634

635 case '\r':

636 *xpos = 0.0;

637 return 0;

638

639 default:

640 break;

641 }

642

643 if(gmap) {

644 *xpos += gmap->glyphs[code - gmap->cstart].advance;

645 }

646 return gmap;

647 }

648

649 static void calc_best_size(int total_width, int max_glyph_height, int padding, int pow2, int *imgw, int *imgh)

650 {

651 int xsz, ysz, num_rows;

652 float aspect;

653

654 for(xsz=2; xsz<=MAX_IMG_WIDTH; xsz *= 2) {

655 num_rows = total_width / xsz + 1;

656

657 /* take into account the one extra padding for each row after the first */

658 num_rows = (total_width + padding * (num_rows - 1)) / xsz + 1;

659

660 ysz = num_rows * (max_glyph_height + padding) + padding;

661 if(pow2) {

662 ysz = next_pow2(ysz);

663 }

664 aspect = (float)xsz / (float)ysz;

665

666 if(aspect >= 1.0) {

667 break;

668 }

669 }

670

671 if(xsz > MAX_IMG_WIDTH) {

672 xsz = MAX_IMG_WIDTH;

673 }

674

675 *imgw = xsz;

676 *imgh = ysz;

677 }

678

679

680 static int next_pow2(int x)

681 {

682 x--;

683 x = (x >> 1) | x;

684 x = (x >> 2) | x;

685 x = (x >> 4) | x;

686 x = (x >> 8) | x;

687 x = (x >> 16) | x;

688 return x + 1;

689 }