/usr/share/gtk-doc/html/libvips/libvips-generate.html is in libvips-doc 7.38.5-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>generate</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.78.1">
<link rel="home" href="index.html" title="VIPS Reference Manual">
<link rel="up" href="ch01.html" title="Core VIPS API">
<link rel="prev" href="VipsRegion.html" title="VipsRegion">
<link rel="next" href="libvips-header.html" title="header">
<meta name="generator" content="GTK-Doc V1.19 (XML mode)">
<link rel="stylesheet" href="style.css" type="text/css">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2">
<tr valign="middle">
<td><a accesskey="p" href="VipsRegion.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
<td><a accesskey="u" href="ch01.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
<td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
<th width="100%" align="center">VIPS Reference Manual</th>
<td><a accesskey="n" href="libvips-header.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
</tr>
<tr><td colspan="5" class="shortcuts">
<a href="#libvips-generate.synopsis" class="shortcut">Top</a>
|
<a href="#libvips-generate.description" class="shortcut">Description</a>
</td></tr>
</table>
<div class="refentry">
<a name="libvips-generate"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="libvips-generate.top_of_page"></a>generate</span></h2>
<p>generate — calculate pixels and pixel buffers</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="libvips-generate.stability-level"></a><h2>Stability Level</h2>
Stable, unless otherwise indicated
</div>
<div class="refsynopsisdiv">
<a name="libvips-generate.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#include <vips/vips.h>
<span class="returnvalue">int</span> (<a class="link" href="libvips-generate.html#VipsRegionWrite" title="VipsRegionWrite ()">*VipsRegionWrite</a>) (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *region</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *area</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-sink-disc" title="vips_sink_disc ()">vips_sink_disc</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsRegionWrite" title="VipsRegionWrite ()"><span class="type">VipsRegionWrite</span></a> write_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);
<span class="returnvalue">void</span> * (<a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()">*VipsStartFn</a>) (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> (<a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()">*VipsGenerateFn</a>) (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>,
<em class="parameter"><code><span class="type">gboolean</span> *stop</code></em>);
<span class="returnvalue">int</span> (<a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()">*VipsStopFn</a>) (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-sink" title="vips_sink ()">vips_sink</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-sink-tile" title="vips_sink_tile ()">vips_sink_tile</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_width</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_height</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">void</span> (<a class="link" href="libvips-generate.html#VipsSinkNotify" title="VipsSinkNotify ()">*VipsSinkNotify</a>) (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *rect</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-sink-screen" title="vips_sink_screen ()">vips_sink_screen</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *in</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *mask</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_width</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_height</code></em>,
<em class="parameter"><code><span class="type">int</span> max_tiles</code></em>,
<em class="parameter"><code><span class="type">int</span> priority</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsSinkNotify" title="VipsSinkNotify ()"><span class="type">VipsSinkNotify</span></a> notify</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-sink-memory" title="vips_sink_memory ()">vips_sink_memory</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-sink-memory2" title="vips_sink_memory2 ()">vips_sink_memory2</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>);
<span class="returnvalue">void</span> * <a class="link" href="libvips-generate.html#vips-start-one" title="vips_start_one ()">vips_start_one</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-stop-one" title="vips_stop_one ()">vips_stop_one</a> (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">void</span> * <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()">vips_start_many</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-stop-many" title="vips_stop_many ()">vips_stop_many</a> (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<a class="link" href="VipsImage.html" title="VipsImage"><span class="returnvalue">VipsImage</span></a> ** <a class="link" href="libvips-generate.html#vips-allocate-input-array" title="vips_allocate_input_array ()">vips_allocate_input_array</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code>...</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()">vips_image_generate</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-image-pipeline-array" title="vips_image_pipeline_array ()">vips_image_pipeline_array</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle" title="enum VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> **in</code></em>);
<span class="returnvalue">int</span> <a class="link" href="libvips-generate.html#vips-image-pipelinev" title="vips_image_pipelinev ()">vips_image_pipelinev</a> (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle" title="enum VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code>...</code></em>);
</pre>
</div>
<div class="refsect1">
<a name="libvips-generate.description"></a><h2>Description</h2>
<p>
These functions let you generate regions of pixels in an image
processing operation, and ask for regions of image to be calculated.
</p>
</div>
<div class="refsect1">
<a name="libvips-generate.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="VipsRegionWrite"></a><h3>VipsRegionWrite ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> (*VipsRegionWrite) (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *region</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *area</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);</pre>
<p>
The function should write the pixels in <em class="parameter"><code>area</code></em> from <em class="parameter"><code>region</code></em>. <em class="parameter"><code>a</code></em> is the
value passed into <code class="function">vips_discsink()</code>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-sink-disc" title="vips_sink_disc ()"><code class="function">vips_sink_disc()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>region</code></em> :</span></p></td>
<td>get pixels from here</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>area</code></em> :</span></p></td>
<td>area to write</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>client data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-sink-disc"></a><h3>vips_sink_disc ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_sink_disc (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsRegionWrite" title="VipsRegionWrite ()"><span class="type">VipsRegionWrite</span></a> write_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);</pre>
<p>
<a class="link" href="libvips-generate.html#vips-sink-disc" title="vips_sink_disc ()"><code class="function">vips_sink_disc()</code></a> loops over <em class="parameter"><code>im</code></em>, top-to-bottom, generating it in sections.
As each section is produced, <em class="parameter"><code>write_fn</code></em> is called.
</p>
<p>
<em class="parameter"><code>write_fn</code></em> is always called single-threaded (though not always from the same
thread), it's always given image
sections in top-to-bottom order, and there are never any gaps.
</p>
<p>
This operation is handy for making image sinks which output to things like
disc files.
</p>
<p>
See also: <a class="link" href="VipsThreadState.html#vips-concurrency-set" title="vips_concurrency_set ()"><code class="function">vips_concurrency_set()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td>
<td>image to process</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>write_fn</code></em> :</span></p></td>
<td>called for every batch of pixels</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>client data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VipsStartFn"></a><h3>VipsStartFn ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> * (*VipsStartFn) (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Start a new processing sequence for this generate function. This allocates
per-thread state, such as an input region.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-start-one" title="vips_start_one ()"><code class="function">vips_start_one()</code></a>, <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()"><code class="function">vips_start_many()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>a new sequence value</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VipsGenerateFn"></a><h3>VipsGenerateFn ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> (*VipsGenerateFn) (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>,
<em class="parameter"><code><span class="type">gboolean</span> *stop</code></em>);</pre>
<p>
Fill <em class="parameter"><code>image->valid</code></em> with pixels. <em class="parameter"><code>seq</code></em> contains per-thread state, such as the
input regions.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>, <a class="link" href="libvips-generate.html#vips-stop-many" title="vips_stop_many ()"><code class="function">vips_stop_many()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VipsStopFn"></a><h3>VipsStopFn ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> (*VipsStopFn) (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Stop a processing sequence. This frees
per-thread state, such as an input region.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-stop-one" title="vips_stop_one ()"><code class="function">vips_stop_one()</code></a>, <a class="link" href="libvips-generate.html#vips-stop-many" title="vips_stop_many ()"><code class="function">vips_stop_many()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-sink"></a><h3>vips_sink ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_sink (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Loops over an image. <em class="parameter"><code>generate</code></em> is called for every pixel in the image, with
the <em class="parameter"><code>reg</code></em> argument being a region of pixels for processing. <a class="link" href="libvips-generate.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a> is
used to implement operations like <span class="type">VipsAvg</span> which have no image output.
</p>
<p>
Each set of pixels is sized according to the requirements of the image
pipeline that generated <em class="parameter"><code>im</code></em>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>, <a class="link" href="VipsImage.html#vips-image-new" title="vips_image_new ()"><code class="function">vips_image_new()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td>
<td>scan over this image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>start_fn</code></em> :</span></p></td>
<td>start sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>generate_fn</code></em> :</span></p></td>
<td>generate pixels with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stop_fn</code></em> :</span></p></td>
<td>stop sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-sink-tile"></a><h3>vips_sink_tile ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_sink_tile (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_width</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_height</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Loops over an image. <em class="parameter"><code>generate</code></em> is called for every pixel in the image, with
the <em class="parameter"><code>reg</code></em> argument being a region of pixels for processing.
</p>
<p>
Each set of pixels is <em class="parameter"><code>tile_width</code></em> by <em class="parameter"><code>tile_height</code></em> pixels (less at the
image edges). This is handy for things like writing a tiled TIFF image,
where tiles have to be generated with a certain size.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a>, <a class="link" href="VipsThreadState.html#vips-get-tile-size" title="vips_get_tile_size ()"><code class="function">vips_get_tile_size()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td>
<td>scan over this image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>tile_width</code></em> :</span></p></td>
<td>tile width</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>tile_height</code></em> :</span></p></td>
<td>tile height</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>start_fn</code></em> :</span></p></td>
<td>start sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>generate_fn</code></em> :</span></p></td>
<td>generate pixels with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stop_fn</code></em> :</span></p></td>
<td>stop sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VipsSinkNotify"></a><h3>VipsSinkNotify ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> (*VipsSinkNotify) (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *rect</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);</pre>
<p>
</p>
</div>
<hr>
<div class="refsect2">
<a name="vips-sink-screen"></a><h3>vips_sink_screen ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_sink_screen (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *in</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *mask</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_width</code></em>,
<em class="parameter"><code><span class="type">int</span> tile_height</code></em>,
<em class="parameter"><code><span class="type">int</span> max_tiles</code></em>,
<em class="parameter"><code><span class="type">int</span> priority</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsSinkNotify" title="VipsSinkNotify ()"><span class="type">VipsSinkNotify</span></a> notify</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>);</pre>
<p>
This operation renders <em class="parameter"><code>in</code></em> in the background, making pixels available on
<em class="parameter"><code>out</code></em> as they are calculated. The <em class="parameter"><code>notify</code></em> callback is run every time a new
set of pixels are available. Calculated pixels are kept in a cache with
tiles sized <em class="parameter"><code>tile_width</code></em> by <em class="parameter"><code>tile_height</code></em> pixels and with at most <em class="parameter"><code>max_tiles</code></em>
tiles.
If <em class="parameter"><code>max_tiles</code></em> is -1, the cache is of unlimited size (up to the maximum image
size).
The <em class="parameter"><code>mask</code></em> image is a one-band uchar image and has 255 for pixels which are
currently in cache and 0 for uncalculated pixels.
</p>
<p>
Only a single sink is calculated at any one time, though many may be
alive. Use <em class="parameter"><code>priority</code></em> to indicate which renders are more important:
zero means normal
priority, negative numbers are low priority, positive numbers high
priority.
</p>
<p>
Calls to <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a> on <em class="parameter"><code>out</code></em> return immediately and hold
whatever is
currently in cache for that <a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> (check <em class="parameter"><code>mask</code></em> to see which parts of the
<a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> are valid). Any pixels in the <a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> which are not in
cache are added
to a queue, and the <em class="parameter"><code>notify</code></em> callback will trigger when those pixels are
ready.
</p>
<p>
The <em class="parameter"><code>notify</code></em> callback is run from one of the background threads. In the
callback
you need to somehow send a message to the main thread that the pixels are
ready. In a glib-based application, this is easily done with <code class="function">g_idle_add()</code>.
</p>
<p>
If <em class="parameter"><code>notify</code></em> is <code class="literal">NULL</code> then <a class="link" href="libvips-generate.html#vips-sink-screen" title="vips_sink_screen ()"><code class="function">vips_sink_screen()</code></a> runs synchronously.
<a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a> on <em class="parameter"><code>out</code></em> will always block until the pixels have been
calculated.
</p>
<p>
See also: <a class="link" href="libvips-conversion.html#vips-tilecache" title="vips_tilecache ()"><code class="function">vips_tilecache()</code></a>, <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a>,
<a class="link" href="libvips-generate.html#vips-sink-disc" title="vips_sink_disc ()"><code class="function">vips_sink_disc()</code></a>, <a class="link" href="libvips-generate.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>in</code></em> :</span></p></td>
<td>input image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td>
<td>output image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>mask</code></em> :</span></p></td>
<td>mask image indicating valid pixels</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>tile_width</code></em> :</span></p></td>
<td>tile width</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>tile_height</code></em> :</span></p></td>
<td>tile height</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>max_tiles</code></em> :</span></p></td>
<td>maximum tiles to cache</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>priority</code></em> :</span></p></td>
<td>rendering priority</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>notify</code></em> :</span></p></td>
<td>pixels are ready notification callback</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>client data for callback</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on sucess, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-sink-memory"></a><h3>vips_sink_memory ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_sink_memory (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>);</pre>
<p>
Loops over an image, generating it to a memory buffer attached to the
image.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a>, <a class="link" href="VipsThreadState.html#vips-get-tile-size" title="vips_get_tile_size ()"><code class="function">vips_get_tile_size()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>im</code></em> :</span></p></td>
<td>generate this image to memory</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-sink-memory2"></a><h3>vips_sink_memory2 ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_sink_memory2 (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>);</pre>
<p>
</p>
</div>
<hr>
<div class="refsect2">
<a name="vips-start-one"></a><h3>vips_start_one ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> * vips_start_one (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Start function for one image in. Input image is <em class="parameter"><code>a</code></em>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td>
<td>image to generate</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-stop-one"></a><h3>vips_stop_one ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_stop_one (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Stop function for one image in. Input image is <em class="parameter"><code>a</code></em>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-start-many"></a><h3>vips_start_many ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> * vips_start_many (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Start function for many images in. <em class="parameter"><code>a</code></em> is a pointer to
a <code class="literal">NULL</code>-terminated array of input images.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>, <a class="link" href="libvips-generate.html#vips-allocate-input-array" title="vips_allocate_input_array ()"><code class="function">vips_allocate_input_array()</code></a>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>out</code></em> :</span></p></td>
<td>image to generate</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-stop-many"></a><h3>vips_stop_many ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_stop_many (<em class="parameter"><code><span class="type">void</span> *seq</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Stop function for many images in. <em class="parameter"><code>a</code></em> is a pointer to
a <code class="literal">NULL</code>-terminated array of input images.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>seq</code></em> :</span></p></td>
<td>sequence value</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-allocate-input-array"></a><h3>vips_allocate_input_array ()</h3>
<pre class="programlisting"><a class="link" href="VipsImage.html" title="VipsImage"><span class="returnvalue">VipsImage</span></a> ** vips_allocate_input_array (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *out</code></em>,
<em class="parameter"><code>...</code></em>);</pre>
<p>
Convenience function --- make a <code class="literal">NULL</code>-terminated array of input images.
Use with <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()"><code class="function">vips_start_many()</code></a>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>, <a class="link" href="libvips-generate.html#vips-start-many" title="vips_start_many ()"><code class="function">vips_start_many()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<code class="literal">NULL</code>-terminated array of images. Do not free the result.</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-image-generate"></a><h3>vips_image_generate ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_image_generate (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStartFn" title="VipsStartFn ()"><span class="type">VipsStartFn</span></a> start_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsGenerateFn" title="VipsGenerateFn ()"><span class="type">VipsGenerateFn</span></a> generate_fn</code></em>,
<em class="parameter"><code><a class="link" href="libvips-generate.html#VipsStopFn" title="VipsStopFn ()"><span class="type">VipsStopFn</span></a> stop_fn</code></em>,
<em class="parameter"><code><span class="type">void</span> *a</code></em>,
<em class="parameter"><code><span class="type">void</span> *b</code></em>);</pre>
<p>
Generates an image. The action depends on the image type.
</p>
<p>
For images opened with "p", <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a> just attaches the
start/generate/stop callbacks and returns.
</p>
<p>
For "t" images, memory is allocated for the whole image and it is entirely
generated using <a class="link" href="libvips-generate.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a>.
</p>
<p>
For "w" images, memory for a few scanlines is allocated and
<a class="link" href="libvips-generate.html#vips-sink-disc" title="vips_sink_disc ()"><code class="function">vips_sink_disc()</code></a> used to generate the image in small chunks. As each
chunk is generated, it is written to disc.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-sink" title="vips_sink ()"><code class="function">vips_sink()</code></a>, <a class="link" href="VipsImage.html#vips-image-new" title="vips_image_new ()"><code class="function">vips_image_new()</code></a>, <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>start_fn</code></em> :</span></p></td>
<td>start sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>generate_fn</code></em> :</span></p></td>
<td>generate pixels with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>stop_fn</code></em> :</span></p></td>
<td>stop sequences with this function</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>a</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>b</code></em> :</span></p></td>
<td>user data</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-image-pipeline-array"></a><h3>vips_image_pipeline_array ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_image_pipeline_array (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle" title="enum VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> **in</code></em>);</pre>
<p>
Add an image to a pipeline. <em class="parameter"><code>image</code></em> depends on all of the images in <em class="parameter"><code>in</code></em>,
<em class="parameter"><code>image</code></em> prefers to supply pixels according to <em class="parameter"><code>hint</code></em>.
</p>
<p>
Operations can set demand hints, that is, hints to the VIPS IO system about
the type of region geometry this operation works best with. For example,
operations which transform coordinates will usually work best with
<a class="link" href="VipsImage.html#VIPS-DEMAND-STYLE-SMALLTILE:CAPS"><code class="literal">VIPS_DEMAND_STYLE_SMALLTILE</code></a>, operations which work on local windows of
pixels will like <a class="link" href="VipsImage.html#VIPS-DEMAND-STYLE-FATSTRIP:CAPS"><code class="literal">VIPS_DEMAND_STYLE_FATSTRIP</code></a>.
</p>
<p>
Header fields in <em class="parameter"><code>image</code></em> are set from the fields in <em class="parameter"><code>in</code></em>, with lower-numbered
images in <em class="parameter"><code>in</code></em> taking priority.
For example, if <em class="parameter"><code>in</code></em>[0] and <em class="parameter"><code>in</code></em>[1] both have an item
called "icc-profile", it's the profile attached to <em class="parameter"><code>in</code></em>[0] that will end up
on <em class="parameter"><code>image</code></em>.
Image history is completely copied from all <em class="parameter"><code>in</code></em>. <em class="parameter"><code>image</code></em> will have the history
of all the input images.
The array of input images can be empty, meaning <em class="parameter"><code>image</code></em> is at the start of a
pipeline.
</p>
<p>
VIPS uses the list of input images to build the tree of operations it needs
for the cache invalidation system.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-pipelinev" title="vips_image_pipelinev ()"><code class="function">vips_image_pipelinev()</code></a>, <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>output image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>hint</code></em> :</span></p></td>
<td>demand hint for <em class="parameter"><code>image</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>in</code></em> :</span></p></td>
<td>
<code class="literal">NULL</code>-terminated array of input images</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, -1 on error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-image-pipelinev"></a><h3>vips_image_pipelinev ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_image_pipelinev (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *image</code></em>,
<em class="parameter"><code><a class="link" href="VipsImage.html#VipsDemandStyle" title="enum VipsDemandStyle"><span class="type">VipsDemandStyle</span></a> hint</code></em>,
<em class="parameter"><code>...</code></em>);</pre>
<p>
Build an array and call <a class="link" href="libvips-generate.html#vips-image-pipeline-array" title="vips_image_pipeline_array ()"><code class="function">vips_image_pipeline_array()</code></a>.
</p>
<p>
See also: <a class="link" href="libvips-generate.html#vips-image-generate" title="vips_image_generate ()"><code class="function">vips_image_generate()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>output image of pipeline</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>hint</code></em> :</span></p></td>
<td>hint for this image</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>...</code></em> :</span></p></td>
<td>
<code class="literal">NULL</code>-terminated list of input images</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<div class="refsect1">
<a name="libvips-generate.see-also"></a><h2>See Also</h2>
image,
region
</div>
</div>
<div class="footer">
<hr>
Generated by GTK-Doc V1.19</div>
</body>
</html>
|