libdrawtext: 16879398fda7 src/font.c

libdrawtext

view src/font.c @ 65:16879398fda7

added dtx_line_height query

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sat, 25 Aug 2012 18:27:54 +0300
parents	10cfb642d0b8
children	b6ed6e9b4092

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);

91 }

93 return fnt;

94 }

96 void dtx_close_font(struct dtx_font *fnt)

97 {

98 if(!fnt) return;

100 FT_Done_Face(fnt->face);

101

102 /* destroy the glyphmaps */

103 while(fnt->gmaps) {

104 void *tmp = fnt->gmaps;

105 fnt->gmaps = fnt->gmaps->next;

106 dtx_free_glyphmap(tmp);

107 }

108

109 free(fnt);

110 }

111

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

113 {

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

115 }

116

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

118 {

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

120 }

121

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

123 {

124 struct dtx_glyphmap *gm;

125

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

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

128 return fnt->last_gmap;

129 }

130

131 /* otherwise search for the appropriate glyphmap */

132 gm = fnt->gmaps;

133 while(gm) {

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

135 fnt->last_gmap = gm;

136 return gm;

137 }

138 gm = gm->next;

139 }

140 return 0;

141 }

142

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

144 {

145 struct dtx_glyphmap *gm;

146

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

148 * the requested range

149 */

150 gm = fnt->gmaps;

151 while(gm) {

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

153 return gm;

154 }

155 gm = gm->next;

156 }

157

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

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

160 return 0;

161 }

162 return gm;

163 }

164

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

166 {

167 FT_Face face = fnt->face;

168 struct dtx_glyphmap *gmap;

169 int i, j;

170 int gx, gy;

171 int padding = 4;

172 int total_width = padding;

173 int max_height = 0;

174

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

176

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

178 return 0;

179 }

180

181 gmap->ptsize = sz;

182 gmap->cstart = cstart;

183 gmap->cend = cend;

184 gmap->crange = cend - cstart;

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

186

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

188 free(gmap);

189 return 0;

190 }

191

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

193 int h;

194

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

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

197

198 if(h > max_height) {

199 max_height = h;

200 }

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

202 }

203

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

205

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

207 free(gmap->glyphs);

208 free(gmap);

209 return 0;

210 }

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

212

213 gx = padding;

214 gy = padding;

215

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

217 float gwidth, gheight;

218 unsigned char *src, *dst;

219 FT_GlyphSlot glyph;

220

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

222 glyph = face->glyph;

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

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

225

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

227 gx = padding;

228 gy += max_height + padding;

229 }

230

231 src = glyph->bitmap.buffer;

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

233

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

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

236 dst += gmap->xsz;

237 src += glyph->bitmap.pitch;

238 }

239

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

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

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

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

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

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

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

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

248 /* also precalc normalized */

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

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

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

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

253

254 gx += gwidth + padding;

255 }

256

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

258 gmap->next = fnt->gmaps;

259 fnt->gmaps = gmap;

260

261 return gmap;

262 }

263 #endif /* USE_FREETYPE */

264

265 void dtx_free_glyphmap(struct dtx_glyphmap *gmap)

266 {

267 if(gmap) {

268 free(gmap->pixels);

269 free(gmap->glyphs);

270 free(gmap);

271 }

272 }

273

274 unsigned char *dtx_get_glyphmap_pixels(struct dtx_glyphmap *gmap)

275 {

276 return gmap->pixels;

277 }

278

279 int dtx_get_glyphmap_width(struct dtx_glyphmap *gmap)

280 {

281 return gmap->xsz;

282 }

283

284 int dtx_get_glyphmap_height(struct dtx_glyphmap *gmap)

285 {

286 return gmap->ysz;

287 }

288

289 struct dtx_glyphmap *dtx_load_glyphmap(const char *fname)

290 {

291 FILE *fp;

292 struct dtx_glyphmap *gmap;

293

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

295 return 0;

296 }

297 gmap = dtx_load_glyphmap_stream(fp);

298 fclose(fp);

299 return gmap;

300 }

301

302 struct dtx_glyphmap *dtx_load_glyphmap_stream(FILE *fp)

303 {

304 char buf[512];

305 int hdr_lines = 0;

306 struct dtx_glyphmap *gmap;

307 struct glyph *glyphs = 0;

308 int min_code = INT_MAX;

309 int max_code = INT_MIN;

310 int i, max_pixval, num_pixels;

311

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

313 fperror("failed to allocate glyphmap");

314 return 0;

315 }

316

317 while(hdr_lines < 3) {

318 char *line = buf;

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

320 fperror("unexpected end of file");

321 goto err;

322 }

323

324 while(isspace(*line)) {

325 line++;

326 }

327

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

329 struct glyph *g;

330 int c;

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

332

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

334 if(res != 5) {

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

336 goto err;

337 }

338

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

340 fperror("failed to allocate glyph");

341 goto err;

342 }

343 g->code = c;

344 g->x = x;

345 g->y = y;

346 g->width = xsz;

347 g->height = ysz;

348 g->next = glyphs;

349 glyphs = g;

350

351 if(c < min_code) {

352 min_code = c;

353 }

354 if(c > max_code) {

355 max_code = c;

356 }

357 } else {

358 switch(hdr_lines) {

359 case 0:

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

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

362 goto err;

363 }

364 break;

365

366 case 1:

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

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

369 goto err;

370 }

371 break;

372

373 case 2:

374 {

375 char *endp;

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

377 if(endp == line) {

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

379 goto err;

380 }

381 }

382 break;

383

384 default:

385 break; /* can't happen */

386 }

387 hdr_lines++;

388 }

389 }

390

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

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

393 fperror("failed to allocate pixels");

394 goto err;

395 }

396

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

398 long c = fgetc(fp);

399 if(c == -1) {

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

401 goto err;

402 }

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

404 fseek(fp, 2, SEEK_CUR);

405 }

406

407 gmap->cstart = min_code;

408 gmap->cend = max_code + 1;

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

410

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

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

413 goto err;

414 }

415

416 while(glyphs) {

417 struct glyph *g = glyphs;

418 glyphs = glyphs->next;

419

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

421 free(g);

422 }

423 return gmap;

424

425 err:

426 dtx_free_glyphmap(gmap);

427 while(glyphs) {

428 void *tmp = glyphs;

429 glyphs = glyphs->next;

430 free(tmp);

431 }

432 return 0;

433 }

434

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

436 {

437 FILE *fp;

438 int res;

439

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

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

442 return -1;

443 }

444 res = dtx_save_glyphmap_stream(fp, gmap);

445 fclose(fp);

446 return res;

447 }

448

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

450 {

451 int i, num_pixels;

452 struct glyph *g = gmap->glyphs;

453

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

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

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

457 g++;

458 }

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

460

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

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

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

464 fputc(c, fp);

465 fputc(c, fp);

466 fputc(c, fp);

467 }

468 return 0;

469 }

470

471

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

473 {

474 dtx_gl_init();

475

476 dtx_font = fnt;

477 dtx_font_sz = sz;

478 }

479

480 float dtx_line_height(void)

481 {

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

483

484 return gmap->line_advance;

485 }

486

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

488 {

489 int cidx;

490 struct dtx_glyphmap *gmap;

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

492

493 cidx = code - gmap->cstart;

494

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

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

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

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

499 }

500

501 float dtx_glyph_width(int code)

502 {

503 struct dtx_box box;

504 dtx_glyph_box(code, &box);

505 return box.width;

506 }

507

508 float dtx_glyph_height(int code)

509 {

510 struct dtx_box box;

511 dtx_glyph_box(code, &box);

512 return box.height;

513 }

514

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

516 {

517 int code;

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

519 struct glyph *g = 0;

520 float x0, y0, x1, y1;

521

522 x0 = y0 = FLT_MAX;

523 x1 = y1 = -FLT_MAX;

524

525 while(*str) {

526 float px, py;

527 struct dtx_glyphmap *gmap;

528

529 code = dtx_utf8_char_code(str);

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

531

532 px = pos_x;

533 py = pos_y;

534

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

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

537

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

539 x0 = px + g->orig_x;

540 }

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

542 y0 = py - g->orig_y;

543 }

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

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

546 }

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

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

549 }

550 }

551 }

552

553 box->x = x0;

554 box->y = y0;

555 box->width = x1 - x0;

556 box->height = y1 - y0;

557 }

558

559 float dtx_string_width(const char *str)

560 {

561 struct dtx_box box;

562

563 dtx_string_box(str, &box);

564 return box.width;

565 }

566

567 float dtx_string_height(const char *str)

568 {

569 struct dtx_box box;

570

571 dtx_string_box(str, &box);

572 return box.height;

573 }

574

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

576 {

577 int i;

578 float pos = 0.0;

579 struct dtx_glyphmap *gmap;

580

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

582 int code = dtx_utf8_char_code(str);

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

584

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

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

587 }

588 return pos;

589 }

590

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

592 {

593 int i;

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

595 struct dtx_glyphmap *gmap;

596

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

598 int code = dtx_utf8_char_code(str);

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

600

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

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

603

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

605 break;

606 }

607 prev_pos = pos;

608 }

609 return i;

610 }

611

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

613 {

614 struct dtx_glyphmap *gmap;

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

616

617 switch(code) {

618 case '\n':

619 *xpos = 0.0;

620 if(gmap) {

621 *ypos -= gmap->line_advance;

622 }

623 return 0;

624

625 case '\t':

626 if(gmap) {

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

628 }

629 return 0;

630

631 case '\r':

632 *xpos = 0.0;

633 return 0;

634

635 default:

636 break;

637 }

638

639 if(gmap) {

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

641 }

642 return gmap;

643 }

644

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

646 {

647 int xsz, ysz, num_rows;

648 float aspect;

649

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

651 num_rows = total_width / xsz + 1;

652

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

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

655

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

657 if(pow2) {

658 ysz = next_pow2(ysz);

659 }

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

661

662 if(aspect >= 1.0) {

663 break;

664 }

665 }

666

667 if(xsz > MAX_IMG_WIDTH) {

668 xsz = MAX_IMG_WIDTH;

669 }

670

671 *imgw = xsz;

672 *imgh = ysz;

673 }

674

675

676 static int next_pow2(int x)

677 {

678 x--;

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

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

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

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

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

684 return x + 1;

685 }