src/cairo.sgl — sigil-cairo

1;;; (cairo) — Cairo 2D graphics bindings for Sigil

2;;;

3;;; Pure-Scheme bindings using the dynamic FFI. No native C code required.

4;;; Requires libcairo.so / libcairo.dylib to be installed on the system.

6(define-library (cairo)

7 (import (sigil core)

8 (sigil ffi))

10 (export

11 ;; Library handle

12 cairo-lib

14 ;; Constants — Format

15 CAIRO_FORMAT_INVALID

16 CAIRO_FORMAT_ARGB32

17 CAIRO_FORMAT_RGB24

18 CAIRO_FORMAT_A8

19 CAIRO_FORMAT_A1

21 ;; Constants — Status

22 CAIRO_STATUS_SUCCESS

23 CAIRO_STATUS_NO_MEMORY

24 CAIRO_STATUS_INVALID_RESTORE

25 CAIRO_STATUS_INVALID_POP_GROUP

26 CAIRO_STATUS_NO_CURRENT_POINT

27 CAIRO_STATUS_INVALID_MATRIX

28 CAIRO_STATUS_INVALID_STATUS

29 CAIRO_STATUS_NULL_POINTER

30 CAIRO_STATUS_INVALID_STRING

31 CAIRO_STATUS_INVALID_PATH_DATA

32 CAIRO_STATUS_READ_ERROR

33 CAIRO_STATUS_WRITE_ERROR

34 CAIRO_STATUS_SURFACE_FINISHED

35 CAIRO_STATUS_SURFACE_TYPE_MISMATCH

36 CAIRO_STATUS_PATTERN_TYPE_MISMATCH

38 ;; Constants — Operator

39 CAIRO_OPERATOR_CLEAR

40 CAIRO_OPERATOR_SOURCE

41 CAIRO_OPERATOR_OVER

42 CAIRO_OPERATOR_IN

43 CAIRO_OPERATOR_OUT

44 CAIRO_OPERATOR_ATOP

45 CAIRO_OPERATOR_DEST

46 CAIRO_OPERATOR_DEST_OVER

47 CAIRO_OPERATOR_DEST_IN

48 CAIRO_OPERATOR_DEST_OUT

49 CAIRO_OPERATOR_DEST_ATOP

50 CAIRO_OPERATOR_XOR

51 CAIRO_OPERATOR_ADD

52 CAIRO_OPERATOR_SATURATE

53 CAIRO_OPERATOR_MULTIPLY

54 CAIRO_OPERATOR_SCREEN

55 CAIRO_OPERATOR_OVERLAY

56 CAIRO_OPERATOR_DARKEN

57 CAIRO_OPERATOR_LIGHTEN

58 CAIRO_OPERATOR_COLOR_DODGE

59 CAIRO_OPERATOR_COLOR_BURN

60 CAIRO_OPERATOR_HARD_LIGHT

61 CAIRO_OPERATOR_SOFT_LIGHT

62 CAIRO_OPERATOR_DIFFERENCE

63 CAIRO_OPERATOR_EXCLUSION

65 ;; Constants — Line cap/join

66 CAIRO_LINE_CAP_BUTT

67 CAIRO_LINE_CAP_ROUND

68 CAIRO_LINE_CAP_SQUARE

69 CAIRO_LINE_JOIN_MITER

70 CAIRO_LINE_JOIN_ROUND

71 CAIRO_LINE_JOIN_BEVEL

73 ;; Constants — Fill rule

74 CAIRO_FILL_RULE_WINDING

75 CAIRO_FILL_RULE_EVEN_ODD

77 ;; Constants — Antialias

78 CAIRO_ANTIALIAS_DEFAULT

79 CAIRO_ANTIALIAS_NONE

80 CAIRO_ANTIALIAS_GRAY

81 CAIRO_ANTIALIAS_SUBPIXEL

82 CAIRO_ANTIALIAS_FAST

83 CAIRO_ANTIALIAS_GOOD

84 CAIRO_ANTIALIAS_BEST

86 ;; Constants — Font

87 CAIRO_FONT_SLANT_NORMAL

88 CAIRO_FONT_SLANT_ITALIC

89 CAIRO_FONT_SLANT_OBLIQUE

90 CAIRO_FONT_WEIGHT_NORMAL

91 CAIRO_FONT_WEIGHT_BOLD

93 ;; Constants — Extend

94 CAIRO_EXTEND_NONE

95 CAIRO_EXTEND_REPEAT

96 CAIRO_EXTEND_REFLECT

97 CAIRO_EXTEND_PAD

99 ;; Constants — Content

100 CAIRO_CONTENT_COLOR

101 CAIRO_CONTENT_ALPHA

102 CAIRO_CONTENT_COLOR_ALPHA

103

104 ;; Struct layouts

105 cairo-text-extents-layout

106 cairo-font-extents-layout

107 cairo-matrix-layout

108

109 ;; Surfaces

110 cairo-image-surface-create

111 cairo-image-surface-create-from-png

112 cairo-surface-destroy

113 cairo-surface-write-to-png

114 cairo-surface-flush

115 cairo-surface-finish

116 cairo-surface-status

117 cairo-surface-create-similar

118 cairo-image-surface-get-width

119 cairo-image-surface-get-height

120 cairo-image-surface-get-stride

121 cairo-image-surface-get-format

122 cairo-image-surface-get-data

123 cairo-pdf-surface-create

124 cairo-svg-surface-create

125 cairo-pdf-surface-set-size

126

127 ;; Context

128 cairo-create

129 cairo-destroy

130 cairo-save

131 cairo-restore

132 cairo-status

133 cairo-status-to-string

134 cairo-push-group

135 cairo-pop-group

136 cairo-pop-group-to-source

137 cairo-get-target

138

139 ;; Drawing state

140 cairo-set-source-rgb

141 cairo-set-source-rgba

142 cairo-set-source-surface

143 cairo-set-source

144 cairo-set-line-width

145 cairo-get-line-width

146 cairo-set-line-cap

147 cairo-set-line-join

148 cairo-set-miter-limit

149 cairo-set-dash

150 cairo-set-fill-rule

151 cairo-set-operator

152 cairo-set-antialias

153

154 ;; Paths

155 cairo-new-path

156 cairo-new-sub-path

157 cairo-close-path

158 cairo-move-to

159 cairo-line-to

160 cairo-curve-to

161 cairo-arc

162 cairo-arc-negative

163 cairo-rectangle

164 cairo-rel-move-to

165 cairo-rel-line-to

166 cairo-rel-curve-to

167

168 ;; Drawing ops

169 cairo-stroke

170 cairo-fill

171 cairo-paint

172 cairo-stroke-preserve

173 cairo-fill-preserve

174 cairo-paint-with-alpha

175 cairo-clip

176 cairo-clip-preserve

177 cairo-reset-clip

178 cairo-mask

179 cairo-mask-surface

180

181 ;; Text

182 cairo-select-font-face

183 cairo-set-font-size

184 cairo-show-text

185 cairo-text-extents

186 cairo-font-extents

187

188 ;; Glyph rendering

189 cairo-glyph-layout

190 cairo-show-glyphs

191 cairo-glyph-path

192 cairo-ft-font-face-create

193 cairo-set-font-face

194 cairo-font-face-destroy

195

196 ;; Transforms

197 cairo-translate

198 cairo-scale

199 cairo-rotate

200 cairo-identity-matrix

201 cairo-get-matrix

202 cairo-set-matrix

203

204 ;; Patterns

205 cairo-pattern-create-rgb

206 cairo-pattern-create-rgba

207 cairo-pattern-create-linear

208 cairo-pattern-create-radial

209 cairo-pattern-add-color-stop-rgb

210 cairo-pattern-add-color-stop-rgba

211 cairo-pattern-destroy

212 cairo-pattern-set-extend

213 cairo-pattern-create-for-surface

214

215 ;; Convenience

216 with-cairo-surface

217 with-cairo-context)

218

219 (begin

220

221 ;; ============================================================

222 ;; Library Loading

223 ;; ============================================================

224

225 (define cairo-lib (c-library "libcairo"))

226

227 ;; ============================================================

228 ;; Constants

229 ;; ============================================================

230

231 ;; Format

232 (define CAIRO_FORMAT_INVALID -1)

233 (define CAIRO_FORMAT_ARGB32 0)

234 (define CAIRO_FORMAT_RGB24 1)

235 (define CAIRO_FORMAT_A8 2)

236 (define CAIRO_FORMAT_A1 3)

237

238 ;; Status

239 (define CAIRO_STATUS_SUCCESS 0)

240 (define CAIRO_STATUS_NO_MEMORY 1)

241 (define CAIRO_STATUS_INVALID_RESTORE 2)

242 (define CAIRO_STATUS_INVALID_POP_GROUP 3)

243 (define CAIRO_STATUS_NO_CURRENT_POINT 4)

244 (define CAIRO_STATUS_INVALID_MATRIX 5)

245 (define CAIRO_STATUS_INVALID_STATUS 6)

246 (define CAIRO_STATUS_NULL_POINTER 7)

247 (define CAIRO_STATUS_INVALID_STRING 8)

248 (define CAIRO_STATUS_INVALID_PATH_DATA 9)

249 (define CAIRO_STATUS_READ_ERROR 10)

250 (define CAIRO_STATUS_WRITE_ERROR 11)

251 (define CAIRO_STATUS_SURFACE_FINISHED 12)

252 (define CAIRO_STATUS_SURFACE_TYPE_MISMATCH 13)

253 (define CAIRO_STATUS_PATTERN_TYPE_MISMATCH 14)

254

255 ;; Operator

256 (define CAIRO_OPERATOR_CLEAR 0)

257 (define CAIRO_OPERATOR_SOURCE 1)

258 (define CAIRO_OPERATOR_OVER 2)

259 (define CAIRO_OPERATOR_IN 3)

260 (define CAIRO_OPERATOR_OUT 4)

261 (define CAIRO_OPERATOR_ATOP 5)

262 (define CAIRO_OPERATOR_DEST 6)

263 (define CAIRO_OPERATOR_DEST_OVER 7)

264 (define CAIRO_OPERATOR_DEST_IN 8)

265 (define CAIRO_OPERATOR_DEST_OUT 9)

266 (define CAIRO_OPERATOR_DEST_ATOP 10)

267 (define CAIRO_OPERATOR_XOR 11)

268 (define CAIRO_OPERATOR_ADD 12)

269 (define CAIRO_OPERATOR_SATURATE 13)

270 (define CAIRO_OPERATOR_MULTIPLY 14)

271 (define CAIRO_OPERATOR_SCREEN 15)

272 (define CAIRO_OPERATOR_OVERLAY 16)

273 (define CAIRO_OPERATOR_DARKEN 17)

274 (define CAIRO_OPERATOR_LIGHTEN 18)

275 (define CAIRO_OPERATOR_COLOR_DODGE 19)

276 (define CAIRO_OPERATOR_COLOR_BURN 20)

277 (define CAIRO_OPERATOR_HARD_LIGHT 21)

278 (define CAIRO_OPERATOR_SOFT_LIGHT 22)

279 (define CAIRO_OPERATOR_DIFFERENCE 23)

280 (define CAIRO_OPERATOR_EXCLUSION 24)

281

282 ;; Line cap

283 (define CAIRO_LINE_CAP_BUTT 0)

284 (define CAIRO_LINE_CAP_ROUND 1)

285 (define CAIRO_LINE_CAP_SQUARE 2)

286

287 ;; Line join

288 (define CAIRO_LINE_JOIN_MITER 0)

289 (define CAIRO_LINE_JOIN_ROUND 1)

290 (define CAIRO_LINE_JOIN_BEVEL 2)

291

292 ;; Fill rule

293 (define CAIRO_FILL_RULE_WINDING 0)

294 (define CAIRO_FILL_RULE_EVEN_ODD 1)

295

296 ;; Antialias

297 (define CAIRO_ANTIALIAS_DEFAULT 0)

298 (define CAIRO_ANTIALIAS_NONE 1)

299 (define CAIRO_ANTIALIAS_GRAY 2)

300 (define CAIRO_ANTIALIAS_SUBPIXEL 3)

301 (define CAIRO_ANTIALIAS_FAST 4)

302 (define CAIRO_ANTIALIAS_GOOD 5)

303 (define CAIRO_ANTIALIAS_BEST 6)

304

305 ;; Font slant/weight

306 (define CAIRO_FONT_SLANT_NORMAL 0)

307 (define CAIRO_FONT_SLANT_ITALIC 1)

308 (define CAIRO_FONT_SLANT_OBLIQUE 2)

309 (define CAIRO_FONT_WEIGHT_NORMAL 0)

310 (define CAIRO_FONT_WEIGHT_BOLD 1)

311

312 ;; Extend

313 (define CAIRO_EXTEND_NONE 0)

314 (define CAIRO_EXTEND_REPEAT 1)

315 (define CAIRO_EXTEND_REFLECT 2)

316 (define CAIRO_EXTEND_PAD 3)

317

318 ;; Content

319 (define CAIRO_CONTENT_COLOR #x1000)

320 (define CAIRO_CONTENT_ALPHA #x2000)

321 (define CAIRO_CONTENT_COLOR_ALPHA #x3000)

322

323 ;; ============================================================

324 ;; Struct Layouts

325 ;; ============================================================

326

327 (define cairo-text-extents-layout

328 (c-struct-layout

329 x-bearing: ffi/double

330 y-bearing: ffi/double

331 width: ffi/double

332 height: ffi/double

333 x-advance: ffi/double

334 y-advance: ffi/double))

335

336 (define cairo-font-extents-layout

337 (c-struct-layout

338 ascent: ffi/double

339 descent: ffi/double

340 height: ffi/double

341 max-x-advance: ffi/double

342 max-y-advance: ffi/double))

343

344 (define cairo-matrix-layout

345 (c-struct-layout

346 xx: ffi/double

347 yx: ffi/double

348 xy: ffi/double

349 yy: ffi/double

350 x0: ffi/double

351 y0: ffi/double))

352

353 ;; cairo_glyph_t — for glyph-level text rendering

354 (define cairo-glyph-layout

355 (c-struct-layout

356 index: ffi/ulong

357 x: ffi/double

358 y: ffi/double))

359

360 ;; ============================================================

361 ;; Finalizer Pointers (looked up once)

362 ;; ============================================================

363

364 (define %cairo-destroy-ptr (c-symbol cairo-lib "cairo_destroy"))

365 (define %surface-destroy-ptr (c-symbol cairo-lib "cairo_surface_destroy"))

366 (define %pattern-destroy-ptr (c-symbol cairo-lib "cairo_pattern_destroy"))

367 (define %font-face-destroy-ptr (c-symbol cairo-lib "cairo_font_face_destroy"))

368

369 ;; ============================================================

370 ;; Raw Function Bindings

371 ;; ============================================================

372

373 ;; Surfaces

374 (define %image-surface-create

375 (c-function cairo-lib "cairo_image_surface_create"

376 (list ffi/int ffi/int ffi/int) ffi/pointer))

377

378 (define %image-surface-create-from-png

379 (c-function cairo-lib "cairo_image_surface_create_from_png"

380 (list ffi/string) ffi/pointer))

381

382 (define %surface-destroy

383 (c-function cairo-lib "cairo_surface_destroy"

384 (list ffi/pointer) ffi/void))

385

386 (define %surface-write-to-png

387 (c-function cairo-lib "cairo_surface_write_to_png"

388 (list ffi/pointer ffi/string) ffi/int))

389

390 (define %surface-flush

391 (c-function cairo-lib "cairo_surface_flush"

392 (list ffi/pointer) ffi/void))

393

394 (define %surface-finish

395 (c-function cairo-lib "cairo_surface_finish"

396 (list ffi/pointer) ffi/void))

397

398 (define %surface-status

399 (c-function cairo-lib "cairo_surface_status"

400 (list ffi/pointer) ffi/int))

401

402 (define %surface-create-similar

403 (c-function cairo-lib "cairo_surface_create_similar"

404 (list ffi/pointer ffi/int ffi/int ffi/int) ffi/pointer))

405

406 (define %image-surface-get-width

407 (c-function cairo-lib "cairo_image_surface_get_width"

408 (list ffi/pointer) ffi/int))

409

410 (define %image-surface-get-height

411 (c-function cairo-lib "cairo_image_surface_get_height"

412 (list ffi/pointer) ffi/int))

413

414 (define %image-surface-get-stride

415 (c-function cairo-lib "cairo_image_surface_get_stride"

416 (list ffi/pointer) ffi/int))

417

418 (define %image-surface-get-format

419 (c-function cairo-lib "cairo_image_surface_get_format"

420 (list ffi/pointer) ffi/int))

421

422 (define %image-surface-get-data

423 (c-function cairo-lib "cairo_image_surface_get_data"

424 (list ffi/pointer) ffi/pointer))

425

426 ;; PDF/SVG surfaces (may not be available on all systems)

427 (define %pdf-surface-create

428 (c-function cairo-lib "cairo_pdf_surface_create"

429 (list ffi/string ffi/double ffi/double) ffi/pointer))

430

431 (define %svg-surface-create

432 (c-function cairo-lib "cairo_svg_surface_create"

433 (list ffi/string ffi/double ffi/double) ffi/pointer))

434

435 (define %pdf-surface-set-size

436 (c-function cairo-lib "cairo_pdf_surface_set_size"

437 (list ffi/pointer ffi/double ffi/double) ffi/void))

438

439 ;; Context

440 (define %cairo-create

441 (c-function cairo-lib "cairo_create"

442 (list ffi/pointer) ffi/pointer))

443

444 (define %cairo-destroy

445 (c-function cairo-lib "cairo_destroy"

446 (list ffi/pointer) ffi/void))

447

448 (define %cairo-save

449 (c-function cairo-lib "cairo_save"

450 (list ffi/pointer) ffi/void))

451

452 (define %cairo-restore

453 (c-function cairo-lib "cairo_restore"

454 (list ffi/pointer) ffi/void))

455

456 (define %cairo-status

457 (c-function cairo-lib "cairo_status"

458 (list ffi/pointer) ffi/int))

459

460 (define %cairo-status-to-string

461 (c-function cairo-lib "cairo_status_to_string"

462 (list ffi/int) ffi/string))

463

464 (define %cairo-push-group

465 (c-function cairo-lib "cairo_push_group"

466 (list ffi/pointer) ffi/void))

467

468 (define %cairo-pop-group

469 (c-function cairo-lib "cairo_pop_group"

470 (list ffi/pointer) ffi/pointer))

471

472 (define %cairo-pop-group-to-source

473 (c-function cairo-lib "cairo_pop_group_to_source"

474 (list ffi/pointer) ffi/void))

475

476 (define %cairo-get-target

477 (c-function cairo-lib "cairo_get_target"

478 (list ffi/pointer) ffi/pointer))

479

480 ;; Drawing state

481 (define %set-source-rgb

482 (c-function cairo-lib "cairo_set_source_rgb"

483 (list ffi/pointer ffi/double ffi/double ffi/double) ffi/void))

484

485 (define %set-source-rgba

486 (c-function cairo-lib "cairo_set_source_rgba"

487 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double) ffi/void))

488

489 (define %set-source-surface

490 (c-function cairo-lib "cairo_set_source_surface"

491 (list ffi/pointer ffi/pointer ffi/double ffi/double) ffi/void))

492

493 (define %set-source

494 (c-function cairo-lib "cairo_set_source"

495 (list ffi/pointer ffi/pointer) ffi/void))

496

497 (define %set-line-width

498 (c-function cairo-lib "cairo_set_line_width"

499 (list ffi/pointer ffi/double) ffi/void))

500

501 (define %get-line-width

502 (c-function cairo-lib "cairo_get_line_width"

503 (list ffi/pointer) ffi/double))

504

505 (define %set-line-cap

506 (c-function cairo-lib "cairo_set_line_cap"

507 (list ffi/pointer ffi/int) ffi/void))

508

509 (define %set-line-join

510 (c-function cairo-lib "cairo_set_line_join"

511 (list ffi/pointer ffi/int) ffi/void))

512

513 (define %set-miter-limit

514 (c-function cairo-lib "cairo_set_miter_limit"

515 (list ffi/pointer ffi/double) ffi/void))

516

517 (define %set-dash

518 (c-function cairo-lib "cairo_set_dash"

519 (list ffi/pointer ffi/pointer ffi/int ffi/double) ffi/void))

520

521 (define %set-fill-rule

522 (c-function cairo-lib "cairo_set_fill_rule"

523 (list ffi/pointer ffi/int) ffi/void))

524

525 (define %set-operator

526 (c-function cairo-lib "cairo_set_operator"

527 (list ffi/pointer ffi/int) ffi/void))

528

529 (define %set-antialias

530 (c-function cairo-lib "cairo_set_antialias"

531 (list ffi/pointer ffi/int) ffi/void))

532

533 ;; Paths

534 (define %new-path

535 (c-function cairo-lib "cairo_new_path"

536 (list ffi/pointer) ffi/void))

537

538 (define %new-sub-path

539 (c-function cairo-lib "cairo_new_sub_path"

540 (list ffi/pointer) ffi/void))

541

542 (define %close-path

543 (c-function cairo-lib "cairo_close_path"

544 (list ffi/pointer) ffi/void))

545

546 (define %move-to

547 (c-function cairo-lib "cairo_move_to"

548 (list ffi/pointer ffi/double ffi/double) ffi/void))

549

550 (define %line-to

551 (c-function cairo-lib "cairo_line_to"

552 (list ffi/pointer ffi/double ffi/double) ffi/void))

553

554 (define %curve-to

555 (c-function cairo-lib "cairo_curve_to"

556 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double ffi/double ffi/double) ffi/void))

557

558 (define %arc

559 (c-function cairo-lib "cairo_arc"

560 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double ffi/double) ffi/void))

561

562 (define %arc-negative

563 (c-function cairo-lib "cairo_arc_negative"

564 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double ffi/double) ffi/void))

565

566 (define %rectangle

567 (c-function cairo-lib "cairo_rectangle"

568 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double) ffi/void))

569

570 (define %rel-move-to

571 (c-function cairo-lib "cairo_rel_move_to"

572 (list ffi/pointer ffi/double ffi/double) ffi/void))

573

574 (define %rel-line-to

575 (c-function cairo-lib "cairo_rel_line_to"

576 (list ffi/pointer ffi/double ffi/double) ffi/void))

577

578 (define %rel-curve-to

579 (c-function cairo-lib "cairo_rel_curve_to"

580 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double ffi/double ffi/double) ffi/void))

581

582 ;; Drawing ops

583 (define %stroke

584 (c-function cairo-lib "cairo_stroke"

585 (list ffi/pointer) ffi/void))

586

587 (define %fill

588 (c-function cairo-lib "cairo_fill"

589 (list ffi/pointer) ffi/void))

590

591 (define %paint

592 (c-function cairo-lib "cairo_paint"

593 (list ffi/pointer) ffi/void))

594

595 (define %stroke-preserve

596 (c-function cairo-lib "cairo_stroke_preserve"

597 (list ffi/pointer) ffi/void))

598

599 (define %fill-preserve

600 (c-function cairo-lib "cairo_fill_preserve"

601 (list ffi/pointer) ffi/void))

602

603 (define %paint-with-alpha

604 (c-function cairo-lib "cairo_paint_with_alpha"

605 (list ffi/pointer ffi/double) ffi/void))

606

607 (define %clip

608 (c-function cairo-lib "cairo_clip"

609 (list ffi/pointer) ffi/void))

610

611 (define %clip-preserve

612 (c-function cairo-lib "cairo_clip_preserve"

613 (list ffi/pointer) ffi/void))

614

615 (define %reset-clip

616 (c-function cairo-lib "cairo_reset_clip"

617 (list ffi/pointer) ffi/void))

618

619 (define %mask

620 (c-function cairo-lib "cairo_mask"

621 (list ffi/pointer ffi/pointer) ffi/void))

622

623 (define %mask-surface

624 (c-function cairo-lib "cairo_mask_surface"

625 (list ffi/pointer ffi/pointer ffi/double ffi/double) ffi/void))

626

627 ;; Text

628 (define %select-font-face

629 (c-function cairo-lib "cairo_select_font_face"

630 (list ffi/pointer ffi/string ffi/int ffi/int) ffi/void))

631

632 (define %set-font-size

633 (c-function cairo-lib "cairo_set_font_size"

634 (list ffi/pointer ffi/double) ffi/void))

635

636 (define %show-text

637 (c-function cairo-lib "cairo_show_text"

638 (list ffi/pointer ffi/string) ffi/void))

639

640 (define %text-extents

641 (c-function cairo-lib "cairo_text_extents"

642 (list ffi/pointer ffi/string ffi/pointer) ffi/void))

643

644 (define %font-extents

645 (c-function cairo-lib "cairo_font_extents"

646 (list ffi/pointer ffi/pointer) ffi/void))

647

648 ;; Glyph rendering

649 (define %show-glyphs

650 (c-function cairo-lib "cairo_show_glyphs"

651 (list ffi/pointer ffi/pointer ffi/int) ffi/void))

652

653 (define %set-font-face

654 (c-function cairo-lib "cairo_set_font_face"

655 (list ffi/pointer ffi/pointer) ffi/void))

656

657 (define %font-face-destroy

658 (c-function cairo-lib "cairo_font_face_destroy"

659 (list ffi/pointer) ffi/void))

660

661 (define %ft-font-face-create

662 (c-function cairo-lib "cairo_ft_font_face_create_for_ft_face"

663 (list ffi/pointer ffi/int) ffi/pointer))

664

665 ;; Transforms

666 (define %translate

667 (c-function cairo-lib "cairo_translate"

668 (list ffi/pointer ffi/double ffi/double) ffi/void))

669

670 (define %scale

671 (c-function cairo-lib "cairo_scale"

672 (list ffi/pointer ffi/double ffi/double) ffi/void))

673

674 (define %rotate

675 (c-function cairo-lib "cairo_rotate"

676 (list ffi/pointer ffi/double) ffi/void))

677

678 (define %identity-matrix

679 (c-function cairo-lib "cairo_identity_matrix"

680 (list ffi/pointer) ffi/void))

681

682 (define %get-matrix

683 (c-function cairo-lib "cairo_get_matrix"

684 (list ffi/pointer ffi/pointer) ffi/void))

685

686 (define %set-matrix

687 (c-function cairo-lib "cairo_set_matrix"

688 (list ffi/pointer ffi/pointer) ffi/void))

689

690 ;; Patterns

691 (define %pattern-create-rgb

692 (c-function cairo-lib "cairo_pattern_create_rgb"

693 (list ffi/double ffi/double ffi/double) ffi/pointer))

694

695 (define %pattern-create-rgba

696 (c-function cairo-lib "cairo_pattern_create_rgba"

697 (list ffi/double ffi/double ffi/double ffi/double) ffi/pointer))

698

699 (define %pattern-create-linear

700 (c-function cairo-lib "cairo_pattern_create_linear"

701 (list ffi/double ffi/double ffi/double ffi/double) ffi/pointer))

702

703 (define %pattern-create-radial

704 (c-function cairo-lib "cairo_pattern_create_radial"

705 (list ffi/double ffi/double ffi/double ffi/double ffi/double ffi/double) ffi/pointer))

706

707 (define %pattern-add-color-stop-rgb

708 (c-function cairo-lib "cairo_pattern_add_color_stop_rgb"

709 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double) ffi/void))

710

711 (define %pattern-add-color-stop-rgba

712 (c-function cairo-lib "cairo_pattern_add_color_stop_rgba"

713 (list ffi/pointer ffi/double ffi/double ffi/double ffi/double ffi/double) ffi/void))

714

715 (define %pattern-destroy

716 (c-function cairo-lib "cairo_pattern_destroy"

717 (list ffi/pointer) ffi/void))

718

719 (define %pattern-set-extend

720 (c-function cairo-lib "cairo_pattern_set_extend"

721 (list ffi/pointer ffi/int) ffi/void))

722

723 (define %pattern-create-for-surface

724 (c-function cairo-lib "cairo_pattern_create_for_surface"

725 (list ffi/pointer) ffi/pointer))

726

727 ;; ============================================================

728 ;; Public API — Surfaces

729 ;; ============================================================

730

731 ;;; Create an image surface with the given format and dimensions.

732 (define (cairo-image-surface-create format width height)

733 (: integer? integer? integer? -> pointer?)

734 (let ((surface (%image-surface-create format width height)))

735 (set-pointer-finalizer! surface %surface-destroy-ptr)

736 surface))

737

738 ;;; Create an image surface from a PNG file.

739 (define (cairo-image-surface-create-from-png filename)

740 (: string? -> pointer?)

741 (let ((surface (%image-surface-create-from-png filename)))

742 (set-pointer-finalizer! surface %surface-destroy-ptr)

743 surface))

744

745 ;;; Destroy a surface, freeing its resources.

746 (define (cairo-surface-destroy surface)

747 (: pointer? -> void?)

748 (set-pointer-finalizer! surface #f)

749 (%surface-destroy surface))

750

751 ;;; Write surface contents to a PNG file.

752 (define (cairo-surface-write-to-png surface filename)

753 (: pointer? string? -> integer?)

754 (%surface-write-to-png surface filename))

755

756 ;;; Flush pending drawing operations to the surface.

757 (define (cairo-surface-flush surface)

758 (: pointer? -> void?)

759 (%surface-flush surface))

760

761 ;;; Finish the surface, preventing further drawing.

762 (define (cairo-surface-finish surface)

763 (: pointer? -> void?)

764 (%surface-finish surface))

765

766 ;;; Get the status of a surface.

767 (define (cairo-surface-status surface)

768 (: pointer? -> integer?)

769 (%surface-status surface))

770

771 ;;; Create a new surface similar to an existing one.

772 (define (cairo-surface-create-similar surface content width height)

773 (: pointer? integer? integer? integer? -> pointer?)

774 (let ((s (%surface-create-similar surface content width height)))

775 (set-pointer-finalizer! s %surface-destroy-ptr)

776 s))

777

778 ;;; Get the width of an image surface in pixels.

779 (define (cairo-image-surface-get-width surface)

780 (: pointer? -> integer?)

781 (%image-surface-get-width surface))

782

783 ;;; Get the height of an image surface in pixels.

784 (define (cairo-image-surface-get-height surface)

785 (: pointer? -> integer?)

786 (%image-surface-get-height surface))

787

788 ;;; Get the stride of an image surface in bytes.

789 (define (cairo-image-surface-get-stride surface)

790 (: pointer? -> integer?)

791 (%image-surface-get-stride surface))

792

793 ;;; Get the pixel format of an image surface.

794 (define (cairo-image-surface-get-format surface)

795 (: pointer? -> integer?)

796 (%image-surface-get-format surface))

797

798 ;;; Get a pointer to the raw pixel data of an image surface.

799 (define (cairo-image-surface-get-data surface)

800 (: pointer? -> pointer?)

801 (%image-surface-get-data surface))

802

803 ;;; Create a PDF surface that writes to a file.

804 (define (cairo-pdf-surface-create filename width-pts height-pts)

805 (: string? number? number? -> pointer?)

806 (let ((surface (%pdf-surface-create filename width-pts height-pts)))

807 (set-pointer-finalizer! surface %surface-destroy-ptr)

808 surface))

809

810 ;;; Create an SVG surface that writes to a file.

811 (define (cairo-svg-surface-create filename width-pts height-pts)

812 (: string? number? number? -> pointer?)

813 (let ((surface (%svg-surface-create filename width-pts height-pts)))

814 (set-pointer-finalizer! surface %surface-destroy-ptr)

815 surface))

816

817 ;;; Set the size of a PDF surface page in points.

818 (define (cairo-pdf-surface-set-size surface width-pts height-pts)

819 (: pointer? number? number? -> void?)

820 (%pdf-surface-set-size surface width-pts height-pts))

821

822 ;; ============================================================

823 ;; Public API — Context

824 ;; ============================================================

825

826 ;;; Create a new drawing context for a surface.

827 (define (cairo-create surface)

828 (: pointer? -> pointer?)

829 (let ((cr (%cairo-create surface)))

830 (set-pointer-finalizer! cr %cairo-destroy-ptr)

831 cr))

832

833 ;;; Destroy a drawing context.

834 (define (cairo-destroy cr)

835 (: pointer? -> void?)

836 (set-pointer-finalizer! cr #f)

837 (%cairo-destroy cr))

838

839 ;;; Save the current drawing state.

840 (define (cairo-save cr)

841 (: pointer? -> void?)

842 (%cairo-save cr))

843

844 ;;; Restore a previously saved drawing state.

845 (define (cairo-restore cr)

846 (: pointer? -> void?)

847 (%cairo-restore cr))

848

849 ;;; Get the status of a drawing context.

850 (define (cairo-status cr)

851 (: pointer? -> integer?)

852 (%cairo-status cr))

853

854 ;;; Convert a status code to a human-readable string.

855 (define (cairo-status-to-string status)

856 (: integer? -> string?)

857 (%cairo-status-to-string status))

858

859 ;;; Push a temporary group for compositing.

860 (define (cairo-push-group cr)

861 (: pointer? -> void?)

862 (%cairo-push-group cr))

863

864 ;;; Pop a group and return as a pattern.

865 (define (cairo-pop-group cr)

866 (: pointer? -> pointer?)

867 (let ((pat (%cairo-pop-group cr)))

868 (set-pointer-finalizer! pat %pattern-destroy-ptr)

869 pat))

870

871 ;;; Pop a group and set it as the source.

872 (define (cairo-pop-group-to-source cr)

873 (: pointer? -> void?)

874 (%cairo-pop-group-to-source cr))

875

876 ;;; Get the target surface for a context.

877 (define (cairo-get-target cr)

878 (: pointer? -> pointer?)

879 (%cairo-get-target cr))

880

881 ;; ============================================================

882 ;; Public API — Drawing State

883 ;; ============================================================

884

885 ;;; Set the source color as RGB (each component 0.0 to 1.0).

886 (define (cairo-set-source-rgb cr r g b)

887 (: pointer? number? number? number? -> void?)

888 (%set-source-rgb cr r g b))

889

890 ;;; Set the source color as RGBA (each component 0.0 to 1.0).

891 (define (cairo-set-source-rgba cr r g b a)

892 (: pointer? number? number? number? number? -> void?)

893 (%set-source-rgba cr r g b a))

894

895 ;;; Set a surface as the source pattern with origin offset.

896 (define (cairo-set-source-surface cr surface x y)

897 (: pointer? pointer? number? number? -> void?)

898 (%set-source-surface cr surface x y))

899

900 ;;; Set a pattern as the source.

901 (define (cairo-set-source cr pattern)

902 (: pointer? pointer? -> void?)

903 (%set-source cr pattern))

904

905 ;;; Set the line width for stroking.

906 (define (cairo-set-line-width cr width)

907 (: pointer? number? -> void?)

908 (%set-line-width cr width))

909

910 ;;; Get the current line width.

911 (define (cairo-get-line-width cr)

912 (: pointer? -> number?)

913 (%get-line-width cr))

914

915 ;;; Set the line cap style.

916 (define (cairo-set-line-cap cr cap)

917 (: pointer? integer? -> void?)

918 (%set-line-cap cr cap))

919

920 ;;; Set the line join style.

921 (define (cairo-set-line-join cr join)

922 (: pointer? integer? -> void?)

923 (%set-line-join cr join))

924

925 ;;; Set the miter limit for line joins.

926 (define (cairo-set-miter-limit cr limit)

927 (: pointer? number? -> void?)

928 (%set-miter-limit cr limit))

929

930 ;;; Set the dash pattern from a list of doubles.

931 (define (cairo-set-dash cr dashes offset)

932 (: pointer? list? number? -> void?)

933 (let* ((n (length dashes))

934 (buf (c-alloc (* n 8))))

935 (let loop ((i 0) (ds dashes))

936 (when (pair? ds)

937 (pointer-set! buf ffi/double (* i 8) (car ds))

938 (loop (+ i 1) (cdr ds))))

939 (%set-dash cr buf n offset)

940 (c-free buf)))

941

942 ;;; Set the fill rule.

943 (define (cairo-set-fill-rule cr rule)

944 (: pointer? integer? -> void?)

945 (%set-fill-rule cr rule))

946

947 ;;; Set the compositing operator.

948 (define (cairo-set-operator cr op)

949 (: pointer? integer? -> void?)

950 (%set-operator cr op))

951

952 ;;; Set the antialiasing mode.

953 (define (cairo-set-antialias cr antialias)

954 (: pointer? integer? -> void?)

955 (%set-antialias cr antialias))

956

957 ;; ============================================================

958 ;; Public API — Paths

959 ;; ============================================================

960

961 ;;; Clear the current path.

962 (define (cairo-new-path cr)

963 (: pointer? -> void?)

964 (%new-path cr))

965

966 ;;; Start a new sub-path.

967 (define (cairo-new-sub-path cr)

968 (: pointer? -> void?)

969 (%new-sub-path cr))

970

971 ;;; Close the current sub-path.

972 (define (cairo-close-path cr)

973 (: pointer? -> void?)

974 (%close-path cr))

975

976 ;;; Move to a point without drawing.

977 (define (cairo-move-to cr x y)

978 (: pointer? number? number? -> void?)

979 (%move-to cr x y))

980

981 ;;; Draw a line from the current point.

982 (define (cairo-line-to cr x y)

983 (: pointer? number? number? -> void?)

984 (%line-to cr x y))

985

986 ;;; Draw a cubic Bezier curve.

987 (define (cairo-curve-to cr x1 y1 x2 y2 x3 y3)

988 (: pointer? number? number? number? number? number? number? -> void?)

989 (%curve-to cr x1 y1 x2 y2 x3 y3))

990

991 ;;; Draw a circular arc.

992 (define (cairo-arc cr xc yc radius angle1 angle2)

993 (: pointer? number? number? number? number? number? -> void?)

994 (%arc cr xc yc radius angle1 angle2))

995

996 ;;; Draw a circular arc in the negative direction.

997 (define (cairo-arc-negative cr xc yc radius angle1 angle2)

998 (: pointer? number? number? number? number? number? -> void?)

999 (%arc-negative cr xc yc radius angle1 angle2))

1000

1001 ;;; Add a rectangle sub-path.

1002 (define (cairo-rectangle cr x y width height)

1003 (: pointer? number? number? number? number? -> void?)

1004 (%rectangle cr x y width height))

1005

1006 ;;; Move by a relative offset.

1007 (define (cairo-rel-move-to cr dx dy)

1008 (: pointer? number? number? -> void?)

1009 (%rel-move-to cr dx dy))

1010

1011 ;;; Draw a line by a relative offset.

1012 (define (cairo-rel-line-to cr dx dy)

1013 (: pointer? number? number? -> void?)

1014 (%rel-line-to cr dx dy))

1015

1016 ;;; Draw a curve by relative offsets.

1017 (define (cairo-rel-curve-to cr dx1 dy1 dx2 dy2 dx3 dy3)

1018 (: pointer? number? number? number? number? number? number? -> void?)

1019 (%rel-curve-to cr dx1 dy1 dx2 dy2 dx3 dy3))

1020

1021 ;; ============================================================

1022 ;; Public API — Drawing Operations

1023 ;; ============================================================

1024

1025 ;;; Stroke the current path.

1026 (define (cairo-stroke cr)

1027 (: pointer? -> void?)

1028 (%stroke cr))

1029

1030 ;;; Fill the current path.

1031 (define (cairo-fill cr)

1032 (: pointer? -> void?)

1033 (%fill cr))

1034

1035 ;;; Paint the entire surface with the source.

1036 (define (cairo-paint cr)

1037 (: pointer? -> void?)

1038 (%paint cr))

1039

1040 ;;; Stroke the current path, preserving it.

1041 (define (cairo-stroke-preserve cr)

1042 (: pointer? -> void?)

1043 (%stroke-preserve cr))

1044

1045 ;;; Fill the current path, preserving it.

1046 (define (cairo-fill-preserve cr)

1047 (: pointer? -> void?)

1048 (%fill-preserve cr))

1049

1050 ;;; Paint with a given alpha transparency.

1051 (define (cairo-paint-with-alpha cr alpha)

1052 (: pointer? number? -> void?)

1053 (%paint-with-alpha cr alpha))

1054

1055 ;;; Set the clip region to the current path.

1056 (define (cairo-clip cr)

1057 (: pointer? -> void?)

1058 (%clip cr))

1059

1060 ;;; Set the clip region, preserving the path.

1061 (define (cairo-clip-preserve cr)

1062 (: pointer? -> void?)

1063 (%clip-preserve cr))

1064

1065 ;;; Reset the clip region to the entire surface.

1066 (define (cairo-reset-clip cr)

1067 (: pointer? -> void?)

1068 (%reset-clip cr))

1069

1070 ;;; Mask with a pattern (paint where pattern has alpha).

1071 (define (cairo-mask cr pattern)

1072 (: pointer? pointer? -> void?)

1073 (%mask cr pattern))

1074

1075 ;;; Mask with a surface at the given offset.

1076 (define (cairo-mask-surface cr surface x y)

1077 (: pointer? pointer? number? number? -> void?)

1078 (%mask-surface cr surface x y))

1079

1080 ;; ============================================================

1081 ;; Public API — Text

1082 ;; ============================================================

1083

1084 ;;; Select a font by family, slant, and weight.

1085 (define (cairo-select-font-face cr family slant weight)

1086 (: pointer? string? integer? integer? -> void?)

1087 (%select-font-face cr family slant weight))

1088

1089 ;;; Set the font size.

1090 (define (cairo-set-font-size cr size)

1091 (: pointer? number? -> void?)

1092 (%set-font-size cr size))

1093

1094 ;;; Show text at the current position.

1095 (define (cairo-show-text cr text)

1096 (: pointer? string? -> void?)

1097 (%show-text cr text))

1098

1099 ;;; Get text extents as a dict with keys: x-bearing, y-bearing, width, height, x-advance, y-advance.

1100 (define (cairo-text-extents cr text)

1101 (: pointer? string? -> any?)

1102 (with-c-alloc cairo-text-extents-layout

1103 (lambda (extents)

1104 (%text-extents cr text extents)

1105 (c-struct->dict extents cairo-text-extents-layout))))

1106

1107 ;;; Get font extents as a dict with keys: ascent, descent, height, max-x-advance, max-y-advance.

1108 (define (cairo-font-extents cr)

1109 (: pointer? -> any?)

1110 (with-c-alloc cairo-font-extents-layout

1111 (lambda (extents)

1112 (%font-extents cr extents)

1113 (c-struct->dict extents cairo-font-extents-layout))))

1114

1115 ;; ============================================================

1116 ;; Public API — Glyph Rendering

1117 ;; ============================================================

1118

1119 ;;; Render glyphs at specified positions on a Cairo context.

1120 ;;;

1121 ;;; GLYPHS is a list of dicts with keys: index: (glyph index),

1122 ;;; x: (x position), y: (y position).

1123 (define (cairo-show-glyphs cr glyphs)

1124 (: pointer? list? -> void?)

1125 (let* ((n (length glyphs))

1126 (glyph-size (c-struct-size cairo-glyph-layout))

1127 (buf (c-alloc (* n glyph-size))))

1128 (let loop ((i 0) (gs glyphs))

1129 (when (pair? gs)

1130 (let ((g (car gs))

1131 (ptr (pointer+ buf (* i glyph-size))))

1132 (c-struct-set! ptr cairo-glyph-layout index: (dict-ref g index:))

1133 (c-struct-set! ptr cairo-glyph-layout x: (dict-ref g x:))

1134 (c-struct-set! ptr cairo-glyph-layout y: (dict-ref g y:))

1135 (loop (+ i 1) (cdr gs)))))

1136 (%show-glyphs cr buf n)

1137 (c-free buf)))

1138

1139 ;;; Add glyphs to the current path without rendering.

1140 ;;;

1141 ;;; GLYPHS is a list of dicts with keys: index: (glyph index),

1142 ;;; x: (x position), y: (y position).

1143 (define (cairo-glyph-path cr glyphs)

1144 (: pointer? list? -> void?)

1145 (let* ((gp (c-function cairo-lib "cairo_glyph_path"

1146 (list ffi/pointer ffi/pointer ffi/int) ffi/void))

1147 (n (length glyphs))

1148 (glyph-size (c-struct-size cairo-glyph-layout))

1149 (buf (c-alloc (* n glyph-size))))

1150 (let loop ((i 0) (gs glyphs))

1151 (when (pair? gs)

1152 (let ((g (car gs))

1153 (ptr (pointer+ buf (* i glyph-size))))

1154 (c-struct-set! ptr cairo-glyph-layout index: (dict-ref g index:))

1155 (c-struct-set! ptr cairo-glyph-layout x: (dict-ref g x:))

1156 (c-struct-set! ptr cairo-glyph-layout y: (dict-ref g y:))

1157 (loop (+ i 1) (cdr gs)))))

1158 (gp cr buf n)

1159 (c-free buf)))

1160

1161 ;;; Create a Cairo font face from a FreeType face.

1162 ;;;

1163 ;;; Requires Cairo to be built with FreeType support.

1164 (define (cairo-ft-font-face-create ft-face load-flags)

1165 (: pointer? integer? -> pointer?)

1166 (let ((face (%ft-font-face-create ft-face load-flags)))

1167 (set-pointer-finalizer! face %font-face-destroy-ptr)

1168 face))

1169

1170 ;;; Set the font face for a Cairo context.

1171 (define (cairo-set-font-face cr face)

1172 (: pointer? pointer? -> void?)

1173 (%set-font-face cr face))

1174

1175 ;;; Destroy a Cairo font face.

1176 (define (cairo-font-face-destroy face)

1177 (: pointer? -> void?)

1178 (set-pointer-finalizer! face #f)

1179 (%font-face-destroy face))

1180

1181 ;; ============================================================

1182 ;; Public API — Transforms

1183 ;; ============================================================

1184

1185 ;;; Translate the coordinate origin.

1186 (define (cairo-translate cr tx ty)

1187 (: pointer? number? number? -> void?)

1188 (%translate cr tx ty))

1189

1190 ;;; Scale the coordinate system.

1191 (define (cairo-scale cr sx sy)

1192 (: pointer? number? number? -> void?)

1193 (%scale cr sx sy))

1194

1195 ;;; Rotate the coordinate system by angle in radians.

1196 (define (cairo-rotate cr angle)

1197 (: pointer? number? -> void?)

1198 (%rotate cr angle))

1199

1200 ;;; Reset the transformation matrix to identity.

1201 (define (cairo-identity-matrix cr)

1202 (: pointer? -> void?)

1203 (%identity-matrix cr))

1204

1205 ;;; Get the current transformation matrix.

1206 ;;; Returns a dict with xx: yx: xy: yy: x0: y0: fields.

1207 (define (cairo-get-matrix cr)

1208 (: pointer? -> dict?)

1209 (let* ((matrix-size (c-struct-size cairo-matrix-layout))

1210 (buf (c-alloc matrix-size)))

1211 (%get-matrix cr buf)

1212 (let ((result (dict xx: (c-struct-ref buf cairo-matrix-layout xx:)

1213 yx: (c-struct-ref buf cairo-matrix-layout yx:)

1214 xy: (c-struct-ref buf cairo-matrix-layout xy:)

1215 yy: (c-struct-ref buf cairo-matrix-layout yy:)

1216 x0: (c-struct-ref buf cairo-matrix-layout x0:)

1217 y0: (c-struct-ref buf cairo-matrix-layout y0:))))

1218 (c-free buf)

1219 result)))

1220

1221 ;;; Set the transformation matrix from a dict with xx: yx: xy: yy: x0: y0:.

1222 (define (cairo-set-matrix cr matrix)

1223 (: pointer? dict? -> void?)

1224 (let* ((matrix-size (c-struct-size cairo-matrix-layout))

1225 (buf (c-alloc matrix-size)))

1226 (c-struct-set! buf cairo-matrix-layout xx: (dict-ref matrix xx:))

1227 (c-struct-set! buf cairo-matrix-layout yx: (dict-ref matrix yx:))

1228 (c-struct-set! buf cairo-matrix-layout xy: (dict-ref matrix xy:))

1229 (c-struct-set! buf cairo-matrix-layout yy: (dict-ref matrix yy:))

1230 (c-struct-set! buf cairo-matrix-layout x0: (dict-ref matrix x0:))

1231 (c-struct-set! buf cairo-matrix-layout y0: (dict-ref matrix y0:))

1232 (%set-matrix cr buf)

1233 (c-free buf)))

1234

1235 ;; ============================================================

1236 ;; Public API — Patterns

1237 ;; ============================================================

1238

1239 ;;; Create a solid RGB pattern.

1240 (define (cairo-pattern-create-rgb r g b)

1241 (: number? number? number? -> pointer?)

1242 (let ((pat (%pattern-create-rgb r g b)))

1243 (set-pointer-finalizer! pat %pattern-destroy-ptr)

1244 pat))

1245

1246 ;;; Create a solid RGBA pattern.

1247 (define (cairo-pattern-create-rgba r g b a)

1248 (: number? number? number? number? -> pointer?)

1249 (let ((pat (%pattern-create-rgba r g b a)))

1250 (set-pointer-finalizer! pat %pattern-destroy-ptr)

1251 pat))

1252

1253 ;;; Create a linear gradient pattern between two points.

1254 (define (cairo-pattern-create-linear x0 y0 x1 y1)

1255 (: number? number? number? number? -> pointer?)

1256 (let ((pat (%pattern-create-linear x0 y0 x1 y1)))

1257 (set-pointer-finalizer! pat %pattern-destroy-ptr)

1258 pat))

1259

1260 ;;; Create a radial gradient pattern between two circles.

1261 (define (cairo-pattern-create-radial cx0 cy0 r0 cx1 cy1 r1)

1262 (: number? number? number? number? number? number? -> pointer?)

1263 (let ((pat (%pattern-create-radial cx0 cy0 r0 cx1 cy1 r1)))

1264 (set-pointer-finalizer! pat %pattern-destroy-ptr)

1265 pat))

1266

1267 ;;; Add an RGB color stop to a gradient pattern.

1268 (define (cairo-pattern-add-color-stop-rgb pattern offset r g b)

1269 (: pointer? number? number? number? number? -> void?)

1270 (%pattern-add-color-stop-rgb pattern offset r g b))

1271

1272 ;;; Add an RGBA color stop to a gradient pattern.

1273 (define (cairo-pattern-add-color-stop-rgba pattern offset r g b a)

1274 (: pointer? number? number? number? number? number? -> void?)

1275 (%pattern-add-color-stop-rgba pattern offset r g b a))

1276

1277 ;;; Destroy a pattern.

1278 (define (cairo-pattern-destroy pattern)

1279 (: pointer? -> void?)

1280 (set-pointer-finalizer! pattern #f)

1281 (%pattern-destroy pattern))

1282

1283 ;;; Set the extend mode for a pattern.

1284 (define (cairo-pattern-set-extend pattern extend)

1285 (: pointer? integer? -> void?)

1286 (%pattern-set-extend pattern extend))

1287

1288 ;;; Create a pattern from a surface.

1289 (define (cairo-pattern-create-for-surface surface)

1290 (: pointer? -> pointer?)

1291 (let ((pat (%pattern-create-for-surface surface)))

1292 (set-pointer-finalizer! pat %pattern-destroy-ptr)

1293 pat))

1294

1295 ;; ============================================================

1296 ;; Convenience

1297 ;; ============================================================

1298

1299 ;;; Create a surface, call proc with it, then destroy it.

1300 (define (with-cairo-surface surface proc)

1301 (: pointer? procedure? -> any?)

1302 (let ((result (proc surface)))

1303 (cairo-surface-destroy surface)

1304 result))

1305

1306 ;;; Create a context for a surface, call proc with it, then destroy it.

1307 (define (with-cairo-context surface proc)

1308 (: pointer? procedure? -> any?)

1309 (let* ((cr (cairo-create surface))

1310 (result (proc cr)))

1311 (cairo-destroy cr)

1312 result))))