/usr/share/gtk-doc/html/libvips/VipsRegion.html is in libvips-doc 7.26.3-1build1.
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 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>VipsRegion</title>
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
<link rel="home" href="index.html" title="VIPS Reference Manual">
<link rel="up" href="ch01.html" title="Core VIPS API">
<link rel="prev" href="VipsImage.html" title="VipsImage">
<link rel="next" href="libvips-generate.html" title="generate">
<meta name="generator" content="GTK-Doc V1.17 (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="VipsImage.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-generate.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
</tr>
<tr><td colspan="5" class="shortcuts">
<a href="#VipsRegion.synopsis" class="shortcut">Top</a>
|
<a href="#VipsRegion.description" class="shortcut">Description</a>
|
<a href="#VipsRegion.object-hierarchy" class="shortcut">Object Hierarchy</a>
</td></tr>
</table>
<div class="refentry">
<a name="VipsRegion"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="VipsRegion.top_of_page"></a>VipsRegion</span></h2>
<p>VipsRegion — small, rectangular parts of images</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="VipsRegion.stability-level"></a><h2>Stability Level</h2>
Stable, unless otherwise indicated
</div>
<div class="refsynopsisdiv">
<a name="VipsRegion.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#include <vips/vips.h>
<a class="link" href="VipsRegion.html#VipsRegion-struct" title="VipsRegion">VipsRegion</a>;
<a class="link" href="VipsRegion.html#VipsRegionClass" title="VipsRegionClass">VipsRegionClass</a>;
<a class="link" href="VipsRegion.html" title="VipsRegion"><span class="returnvalue">VipsRegion</span></a> * <a class="link" href="VipsRegion.html#vips-region-new" title="vips_region_new ()">vips_region_new</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="VipsRegion.html#vips-region-buffer" title="vips_region_buffer ()">vips_region_buffer</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);
<span class="returnvalue">int</span> <a class="link" href="VipsRegion.html#vips-region-image" title="vips_region_image ()">vips_region_image</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);
<span class="returnvalue">int</span> <a class="link" href="VipsRegion.html#vips-region-region" title="vips_region_region ()">vips_region_region</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *dest</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);
<span class="returnvalue">int</span> <a class="link" href="VipsRegion.html#vips-region-equalsregion" title="vips_region_equalsregion ()">vips_region_equalsregion</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg1</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg2</code></em>);
<span class="returnvalue">int</span> <a class="link" href="VipsRegion.html#vips-region-position" title="vips_region_position ()">vips_region_position</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);
<span class="returnvalue">void</span> <a class="link" href="VipsRegion.html#vips-region-paint" title="vips_region_paint ()">vips_region_paint</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> value</code></em>);
<span class="returnvalue">void</span> <a class="link" href="VipsRegion.html#vips-region-black" title="vips_region_black ()">vips_region_black</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>);
<span class="returnvalue">void</span> <a class="link" href="VipsRegion.html#vips-region-copy" title="vips_region_copy ()">vips_region_copy</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *dest</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);
<span class="returnvalue">int</span> <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()">vips_region_prepare</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);
<span class="returnvalue">int</span> <a class="link" href="VipsRegion.html#vips-region-prepare-to" title="vips_region_prepare_to ()">vips_region_prepare_to</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *dest</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);
<span class="returnvalue">int</span> <a class="link" href="VipsRegion.html#vips-region-prepare-many" title="vips_region_prepare_many ()">vips_region_prepare_many</a> (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> **reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);
#define <a class="link" href="VipsRegion.html#VIPS-REGION-LSKIP:CAPS" title="VIPS_REGION_LSKIP()">VIPS_REGION_LSKIP</a> (R)
#define <a class="link" href="VipsRegion.html#VIPS-REGION-N-ELEMENTS:CAPS" title="VIPS_REGION_N_ELEMENTS()">VIPS_REGION_N_ELEMENTS</a> (R)
#define <a class="link" href="VipsRegion.html#VIPS-REGION-SIZEOF-LINE:CAPS" title="VIPS_REGION_SIZEOF_LINE()">VIPS_REGION_SIZEOF_LINE</a> (R)
#define <a class="link" href="VipsRegion.html#VIPS-REGION-ADDR:CAPS" title="VIPS_REGION_ADDR()">VIPS_REGION_ADDR</a> (R,
X,
Y)
#define <a class="link" href="VipsRegion.html#VIPS-REGION-ADDR-TOPLEFT:CAPS" title="VIPS_REGION_ADDR_TOPLEFT()">VIPS_REGION_ADDR_TOPLEFT</a> (R)
</pre>
</div>
<div class="refsect1">
<a name="VipsRegion.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="synopsis">
GObject
+----<a class="link" href="libvips-VipsArgument.html#VipsObject">VipsObject</a>
+----VipsRegion
</pre>
</div>
<div class="refsect1">
<a name="VipsRegion.description"></a><h2>Description</h2>
<p>
A <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> is a small part of an image and some pixels. You use regions to
read pixels out of images without having to have the whole image in memory
at once.
</p>
<p>
A region can be a memory buffer, part of a memory-mapped file, part of some
other image, or part of some other region.
</p>
<p>
Regions must be created, used and freed all within the same thread, since
they can reference private per-thread caches. VIPS sanity-checks region
ownership in various places, so you are likely to see <code class="function">g_assert()</code> errors if
you don't follow this rule.
</p>
<p>
There
is API to transfer ownership of regions between threads, but hopefully this
is only needed within VIPS, so we don't expose it. Hopefully.
</p>
</div>
<div class="refsect1">
<a name="VipsRegion.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="VipsRegion-struct"></a><h3>VipsRegion</h3>
<pre class="programlisting">typedef struct {
/* Users may read these two fields.
*/
VipsImage *im; /* Link back to parent image */
VipsRect valid; /* Area of parent we can see */
/* The rest of VipsRegion is private.
*/
} VipsRegion;
</pre>
<p>
A small part of a <a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a>. <em class="parameter"><code>valid</code></em> holds the left/top/width/height of the
area of pixels that are available from the region.
</p>
<p>
See also: <a class="link" href="VipsRegion.html#VIPS-REGION-ADDR:CAPS" title="VIPS_REGION_ADDR()"><code class="function">VIPS_REGION_ADDR()</code></a>, <a class="link" href="VipsRegion.html#vips-region-new" title="vips_region_new ()"><code class="function">vips_region_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">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *<em class="structfield"><code><a name="VipsRegion-struct.im"></a>im</code></em>;</span></p></td>
<td>the <a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> that this region is defined on</td>
</tr>
<tr>
<td><p><span class="term"><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> <em class="structfield"><code><a name="VipsRegion-struct.valid"></a>valid</code></em>;</span></p></td>
<td>the <a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> of pixels that this region represents</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VipsRegionClass"></a><h3>VipsRegionClass</h3>
<pre class="programlisting">typedef struct {
VipsObjectClass parent_class;
} VipsRegionClass;
</pre>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-new"></a><h3>vips_region_new ()</h3>
<pre class="programlisting"><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="returnvalue">VipsRegion</span></a> * vips_region_new (<em class="parameter"><code><a class="link" href="VipsImage.html" title="VipsImage"><span class="type">VipsImage</span></a> *im</code></em>);</pre>
<p>
Create a region. <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> s start out empty, you need to call
<a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a> to fill them with pixels.
</p>
<p>
See also: <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">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>image</code></em> :</span></p></td>
<td>image to create this region on</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-buffer"></a><h3>vips_region_buffer ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_buffer (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);</pre>
<p>
The region is transformed so that at least <em class="parameter"><code>r</code></em> pixels are available as a
memory buffer.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to operate upon</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>r</code></em> :</span></p></td>
<td>
<a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> of pixels you need to be able to address</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 for error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-image"></a><h3>vips_region_image ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_image (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);</pre>
<p>
The region is transformed so that at least <em class="parameter"><code>r</code></em> pixels are available directly
from the image. The image needs to be a memory buffer or represent a file
on disc that has been mapped or can be mapped.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to operate upon</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>r</code></em> :</span></p></td>
<td>
<a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> of pixels you need to be able to address</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 for error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-region"></a><h3>vips_region_region ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_region (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *dest</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);</pre>
<p>
Make <a class="link" href="VipsRegion.html#VIPS-REGION-ADDR:CAPS" title="VIPS_REGION_ADDR()"><code class="function">VIPS_REGION_ADDR()</code></a> on <em class="parameter"><code>reg</code></em> go to <em class="parameter"><code>dest</code></em> instead.
</p>
<p>
<em class="parameter"><code>r</code></em> is the part of <em class="parameter"><code>reg</code></em> which you want to be able to address (this
effectively becomes the valid field), (<em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>) is the top LH corner of the
corresponding area in <em class="parameter"><code>dest</code></em>.
</p>
<p>
Performs all clipping necessary to ensure that <em class="parameter"><code>reg->valid</code></em> is indeed
valid.
</p>
<p>
If the region we attach to is modified, we can be left with dangling
pointers! If the region we attach to is on another image, the two images
must have
the same sizeof( pel ).
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to operate upon</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>dest</code></em> :</span></p></td>
<td>region to connect to</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>r</code></em> :</span></p></td>
<td>
<a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> of pixels you need to be able to address</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>postion of <em class="parameter"><code>r</code></em> in <em class="parameter"><code>dest</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>y</code></em> :</span></p></td>
<td>postion of <em class="parameter"><code>r</code></em> in <em class="parameter"><code>dest</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 for error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-equalsregion"></a><h3>vips_region_equalsregion ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_equalsregion (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg1</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg2</code></em>);</pre>
<p>
Do two regions point to the same piece of image? ie.
</p>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
VIPS_REGION_ADDR( reg1, x, y ) == VIPS_REGION_ADDR( reg2, x, y ) &&
*VIPS_REGION_ADDR( reg1, x, y ) ==
*VIPS_REGION_ADDR( reg2, x, y ) for all x, y, reg1, reg2.
</pre></div>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg1</code></em> :</span></p></td>
<td>region to test</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg2</code></em> :</span></p></td>
<td>region to test</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>non-zero on equality.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-position"></a><h3>vips_region_position ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_position (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);</pre>
<p>
Set the position of a region. This only affects reg->valid, ie. the way
pixels are addressed, not reg->data, the pixels which are addressed. Clip
against the size of the image. Do not allow negative positions, or
positions outside the image.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to operate upon</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>position to move to</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>y</code></em> :</span></p></td>
<td>position to move to</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>0 on success, or -1 for error.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-paint"></a><h3>vips_region_paint ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> vips_region_paint (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> value</code></em>);</pre>
<p>
Paints <em class="parameter"><code>value</code></em> into <em class="parameter"><code>reg</code></em> covering rectangle <em class="parameter"><code>r</code></em>. <em class="parameter"><code>value</code></em> is passed to
<code class="function">memset()</code>, so it usually needs to be 0 or 255. <em class="parameter"><code>r</code></em> is clipped against
<em class="parameter"><code>reg->valid</code></em>.
</p>
<p>
See also: <a class="link" href="VipsRegion.html#vips-region-black" title="vips_region_black ()"><code class="function">vips_region_black()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to operate upon</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>r</code></em> :</span></p></td>
<td>area to paint</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>value</code></em> :</span></p></td>
<td>value to paint</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-black"></a><h3>vips_region_black ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> vips_region_black (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>);</pre>
<p>
Paints 0 into the valid part of <em class="parameter"><code>reg</code></em>.
</p>
<p>
See also: <a class="link" href="VipsRegion.html#vips-region-paint" title="vips_region_paint ()"><code class="function">vips_region_paint()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to operate upon</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-copy"></a><h3>vips_region_copy ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> vips_region_copy (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *dest</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);</pre>
<p>
Copy from one region to another. Copy area <em class="parameter"><code>r</code></em> from inside <em class="parameter"><code>reg</code></em> to <em class="parameter"><code>dest</code></em>,
positioning the area of pixels at <em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>. The two regions must have pixels
which are the same size.
</p>
<p>
See also: <a class="link" href="VipsRegion.html#vips-region-paint" title="vips_region_paint ()"><code class="function">vips_region_paint()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>source region</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>dest</code></em> :</span></p></td>
<td>destination region</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>r</code></em> :</span></p></td>
<td>
<a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> of pixels you need to copy</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>postion of <em class="parameter"><code>r</code></em> in <em class="parameter"><code>dest</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>y</code></em> :</span></p></td>
<td>postion of <em class="parameter"><code>r</code></em> in <em class="parameter"><code>dest</code></em>
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="vips-region-prepare"></a><h3>vips_region_prepare ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_prepare (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);</pre>
<p>
<a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a> fills <em class="parameter"><code>reg</code></em> with pixels. After calling,
you can address at least the area <em class="parameter"><code>r</code></em> with <a class="link" href="VipsRegion.html#VIPS-REGION-ADDR:CAPS" title="VIPS_REGION_ADDR()"><code class="function">VIPS_REGION_ADDR()</code></a> and get
valid pixels.
</p>
<p>
<a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a> runs in-line, that is, computation is done by
the calling thread, no new threads are involved, and computation
blocks until the pixels are ready.
</p>
<p>
Use <code class="function">vips_region_prepare_thread()</code> to calculate an area of pixels with many
threads. Use <a class="link" href="VipsThreadState.html#vips-sink-screen" title="vips_sink_screen ()"><code class="function">vips_sink_screen()</code></a> to calculate an area of pixels in the
background.
</p>
<p>
See also: <code class="function">vips_region_prepare_thread()</code>, <a class="link" href="VipsThreadState.html#vips-sink-screen" title="vips_sink_screen ()"><code class="function">vips_sink_screen()</code></a>,
<a class="link" href="VipsRegion.html#vips-region-prepare-to" title="vips_region_prepare_to ()"><code class="function">vips_region_prepare_to()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to prepare</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>r</code></em> :</span></p></td>
<td>
<a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> of pixels you need to be able to address</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-region-prepare-to"></a><h3>vips_region_prepare_to ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_prepare_to (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *reg</code></em>,
<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> *dest</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>,
<em class="parameter"><code><span class="type">int</span> x</code></em>,
<em class="parameter"><code><span class="type">int</span> y</code></em>);</pre>
<p>
Like <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a>: fill <em class="parameter"><code>reg</code></em> with data, ready to be read from by
our caller. Unlike <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a>, rather than allocating memory
local to <em class="parameter"><code>reg</code></em> for the result, we guarantee that we will fill the pixels
in <em class="parameter"><code>dest</code></em> at offset <em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>. In other words, we generate an extra copy
operation if necessary.
</p>
<p>
Also unlike <a class="link" href="VipsRegion.html#vips-region-prepare" title="vips_region_prepare ()"><code class="function">vips_region_prepare()</code></a>, <em class="parameter"><code>dest</code></em> is not set up for writing for
you with
<a class="link" href="VipsRegion.html#vips-region-buffer" title="vips_region_buffer ()"><code class="function">vips_region_buffer()</code></a>. You can
point <em class="parameter"><code>dest</code></em> at anything, and pixels really will be written there.
This makes <code class="function">vips_prepare_to()</code> useful for making the ends of pipelines, since
it (effectively) makes a break in the pipe.
</p>
<p>
See also: <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="VipsThreadState.html#vips-sink-disc" title="vips_sink_disc ()"><code class="function">vips_sink_disc()</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>reg</code></em> :</span></p></td>
<td>region to prepare</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>dest</code></em> :</span></p></td>
<td>region to write to</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>r</code></em> :</span></p></td>
<td>
<a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> of pixels you need to be able to address</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>postion of <em class="parameter"><code>r</code></em> in <em class="parameter"><code>dest</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>y</code></em> :</span></p></td>
<td>postion of <em class="parameter"><code>r</code></em> in <em class="parameter"><code>dest</code></em>
</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-region-prepare-many"></a><h3>vips_region_prepare_many ()</h3>
<pre class="programlisting"><span class="returnvalue">int</span> vips_region_prepare_many (<em class="parameter"><code><a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a> **reg</code></em>,
<em class="parameter"><code><a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> *r</code></em>);</pre>
</div>
<hr>
<div class="refsect2">
<a name="VIPS-REGION-LSKIP:CAPS"></a><h3>VIPS_REGION_LSKIP()</h3>
<pre class="programlisting">#define VIPS_REGION_LSKIP( R )</pre>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>R</code></em> :</span></p></td>
<td>a <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The number of bytes to add to move down a scanline.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VIPS-REGION-N-ELEMENTS:CAPS"></a><h3>VIPS_REGION_N_ELEMENTS()</h3>
<pre class="programlisting">#define VIPS_REGION_N_ELEMENTS( R )</pre>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>R</code></em> :</span></p></td>
<td>a <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The number of band elements across a region.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VIPS-REGION-SIZEOF-LINE:CAPS"></a><h3>VIPS_REGION_SIZEOF_LINE()</h3>
<pre class="programlisting">#define VIPS_REGION_SIZEOF_LINE( R )</pre>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>R</code></em> :</span></p></td>
<td>a <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The number of bytes across a region.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VIPS-REGION-ADDR:CAPS"></a><h3>VIPS_REGION_ADDR()</h3>
<pre class="programlisting">#define VIPS_REGION_ADDR( R, X, Y )</pre>
<p>
This macro returns a pointer to a pixel in a region. The (x, y) coordinates
need to be within the <a class="link" href="libvips-rect.html#VipsRect" title="VipsRect"><span class="type">VipsRect</span></a> (<em class="parameter"><code>R->valid</code></em>).
</p>
<p>
If DEBUG is defined, you get a version that checks bounds for you.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>R</code></em> :</span></p></td>
<td>a <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>X</code></em> :</span></p></td>
<td>x coordinate</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>Y</code></em> :</span></p></td>
<td>y coordinate</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The address of pixel (x,y) in the region.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="VIPS-REGION-ADDR-TOPLEFT:CAPS"></a><h3>VIPS_REGION_ADDR_TOPLEFT()</h3>
<pre class="programlisting">#define VIPS_REGION_ADDR_TOPLEFT( R ) ((R)->data)
</pre>
<p>
This macro returns a pointer to the top-left pixel in the <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a>, that
is, the pixel at (<em class="parameter"><code>R->valid.left</code></em>, <em class="parameter"><code>R->valid.top</code></em>).
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>R</code></em> :</span></p></td>
<td>a <a class="link" href="VipsRegion.html" title="VipsRegion"><span class="type">VipsRegion</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The address of the top-left pixel in the region.</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<div class="refsect1">
<a name="VipsRegion.see-also"></a><h2>See Also</h2>
image,
<a class="link" href="libvips-generate.html" title="generate">generate</a>
</div>
</div>
<div class="footer">
<hr>
Generated by GTK-Doc V1.17</div>
</body>
</html>
|