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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449
//! Shared access to Cairo image surfaces.
use std::cmp::min;
use std::marker::PhantomData;
use std::ptr::NonNull;
use std::slice;
use cast::i32;
use cssparser::Color;
use nalgebra::{storage::Storage, Dim, Matrix};
use crate::color::color_to_rgba;
use crate::drawing_ctx::set_source_color_on_cairo;
use crate::error::*;
use crate::rect::{IRect, Rect};
use crate::surface_utils::srgb;
use crate::util::clamp;
use super::{
iterators::{PixelRectangle, Pixels},
AsCairoARGB, CairoARGB, EdgeMode, ImageSurfaceDataExt, Pixel, PixelOps, ToCairoARGB, ToPixel,
};
/// Interpolation when scaling images.
///
/// This is meant to be translated from the `ImageRendering` property. We don't use
/// `ImageRendering` directly here, because this module is supposed to be lower-level
/// than the main part of librsvg. Here, we take `Interpolation` and translate it
/// to Cairo's own values for pattern filtering.
///
/// This enum can be expanded to use more of Cairo's filtering modes.
pub enum Interpolation {
Nearest,
Smooth,
}
impl From<Interpolation> for cairo::Filter {
fn from(i: Interpolation) -> cairo::Filter {
// Cairo's default for interpolation is CAIRO_FILTER_GOOD. This happens in Cairo's internals, as
// CAIRO_FILTER_DEFAULT is an internal macro that expands to CAIRO_FILTER_GOOD.
match i {
Interpolation::Nearest => cairo::Filter::Nearest,
Interpolation::Smooth => cairo::Filter::Good,
}
}
}
/// Types of pixel data in a `ImageSurface`.
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub enum SurfaceType {
/// The pixel data is in the sRGB color space.
SRgb,
/// The pixel data is in the linear sRGB color space.
LinearRgb,
/// The pixel data is alpha-only (contains meaningful data only in the alpha channel).
///
/// A number of methods are optimized for alpha-only surfaces. For example, linearization and
/// unlinearization have no effect for alpha-only surfaces.
AlphaOnly,
}
impl SurfaceType {
/// Combines surface types
///
/// If combining two alpha-only surfaces, the result is alpha-only.
/// If one is alpha-only, the result is the other.
/// If none is alpha-only, the types should be the same.
///
/// # Panics
/// Panics if the surface types are not alpha-only and differ.
pub fn combine(self, other: SurfaceType) -> SurfaceType {
match (self, other) {
(SurfaceType::AlphaOnly, t) => t,
(t, SurfaceType::AlphaOnly) => t,
(t1, t2) if t1 == t2 => t1,
_ => panic!(),
}
}
}
/// Operators supported by `ImageSurface<Shared>::compose`.
pub enum Operator {
Over,
In,
Out,
Atop,
Xor,
Multiply,
Screen,
Darken,
Lighten,
Overlay,
ColorDodge,
ColorBurn,
HardLight,
SoftLight,
Difference,
Exclusion,
HslHue,
HslSaturation,
HslColor,
HslLuminosity,
}
/// Wrapper for a Cairo image surface that enforces exclusive access when modifying it.
///
/// Shared access to `cairo::ImageSurface` is tricky since a read-only borrowed reference
/// can still be cloned and then modified. We can't simply use `cairo::ImageSurface::data()`
/// because in the filter code we have surfaces referenced from multiple places and it would
/// probably add more complexity to remove that and start passing around references.
///
/// This wrapper asserts the uniqueness of its image surface.
///
/// It uses the typestate pattern to ensure that the surface can be modified only when
/// it is in the `Exclusive` state, while in the `Shared` state it only allows read-only access.
#[derive(Debug, Clone)]
pub struct ImageSurface<T> {
surface: cairo::ImageSurface,
data_ptr: NonNull<u8>, // *const.
width: i32,
height: i32,
stride: isize,
surface_type: SurfaceType,
_state: PhantomData<T>,
}
#[derive(Debug, Clone)]
pub struct Shared;
/// Shared state of `ImageSurface`
pub type SharedImageSurface = ImageSurface<Shared>;
#[derive(Debug, Clone)]
pub struct Exclusive;
/// Exclusive state of `ImageSurface`
pub type ExclusiveImageSurface = ImageSurface<Exclusive>;
// The access is read-only, the ref-counting on an `cairo::ImageSurface` is atomic.
unsafe impl Sync for SharedImageSurface {}
/// A compile-time blur direction variable.
pub trait BlurDirection {
const IS_VERTICAL: bool;
}
/// Vertical blur direction.
pub enum Vertical {}
/// Horizontal blur direction.
pub enum Horizontal {}
impl BlurDirection for Vertical {
const IS_VERTICAL: bool = true;
}
impl BlurDirection for Horizontal {
const IS_VERTICAL: bool = false;
}
/// A compile-time alpha-only marker variable.
pub trait IsAlphaOnly {
const IS_ALPHA_ONLY: bool;
}
/// Alpha-only.
pub enum AlphaOnly {}
/// Not alpha-only.
pub enum NotAlphaOnly {}
/// Iterator over the rows of a `SharedImageSurface`.
pub struct Rows<'a> {
surface: &'a SharedImageSurface,
next_row: i32,
}
/// Iterator over the mutable rows of an `ExclusiveImageSurface`.
pub struct RowsMut<'a> {
// Keep an ImageSurfaceData here instead of a raw mutable pointer to the bytes,
// so that the ImageSurfaceData will mark the surface as dirty when it is dropped.
data: cairo::ImageSurfaceData<'a>,
width: i32,
height: i32,
stride: i32,
next_row: i32,
}
impl IsAlphaOnly for AlphaOnly {
const IS_ALPHA_ONLY: bool = true;
}
impl IsAlphaOnly for NotAlphaOnly {
const IS_ALPHA_ONLY: bool = false;
}
impl<T> ImageSurface<T> {
/// Returns the surface width.
#[inline]
pub fn width(&self) -> i32 {
self.width
}
/// Returns the surface height.
#[inline]
pub fn height(&self) -> i32 {
self.height
}
/// Returns the surface stride.
#[inline]
pub fn stride(&self) -> isize {
self.stride
}
}
impl ImageSurface<Shared> {
/// Creates a `SharedImageSurface` from a unique `cairo::ImageSurface`.
///
/// # Panics
/// Panics if the surface format isn't `ARgb32` and if the surface is not unique, that is, its
/// reference count isn't 1.
#[inline]
pub fn wrap(
surface: cairo::ImageSurface,
surface_type: SurfaceType,
) -> Result<SharedImageSurface, cairo::Error> {
// get_pixel() assumes ARgb32.
assert_eq!(surface.format(), cairo::Format::ARgb32);
let reference_count =
unsafe { cairo::ffi::cairo_surface_get_reference_count(surface.to_raw_none()) };
assert_eq!(reference_count, 1);
let (width, height) = (surface.width(), surface.height());
// Cairo allows zero-sized surfaces, but it does malloc(0), whose result
// is implementation-defined. So, we can't assume NonNull below. This is
// why we disallow zero-sized surfaces here.
if !(width > 0 && height > 0) {
return Err(cairo::Error::InvalidSize);
}
surface.flush();
let data_ptr = NonNull::new(unsafe {
cairo::ffi::cairo_image_surface_get_data(surface.to_raw_none())
})
.unwrap();
let stride = surface.stride() as isize;
Ok(SharedImageSurface {
surface,
data_ptr,
width,
height,
stride,
surface_type,
_state: PhantomData,
})
}
/// Creates a `SharedImageSurface` copying from a `cairo::ImageSurface`, even if it
/// does not have a reference count of 1.
#[inline]
pub fn copy_from_surface(surface: &cairo::ImageSurface) -> Result<Self, cairo::Error> {
let copy =
cairo::ImageSurface::create(cairo::Format::ARgb32, surface.width(), surface.height())?;
{
let cr = cairo::Context::new(©)?;
cr.set_source_surface(surface, 0f64, 0f64)?;
cr.paint()?;
}
SharedImageSurface::wrap(copy, SurfaceType::SRgb)
}
/// Creates an empty `SharedImageSurface` of the given size and `type`.
#[inline]
pub fn empty(width: i32, height: i32, surface_type: SurfaceType) -> Result<Self, cairo::Error> {
let s = cairo::ImageSurface::create(cairo::Format::ARgb32, width, height)?;
SharedImageSurface::wrap(s, surface_type)
}
/// Converts this `SharedImageSurface` back into a Cairo image surface.
#[inline]
pub fn into_image_surface(self) -> Result<cairo::ImageSurface, cairo::Error> {
let reference_count =
unsafe { cairo::ffi::cairo_surface_get_reference_count(self.surface.to_raw_none()) };
if reference_count == 1 {
Ok(self.surface)
} else {
// If there are any other references, copy the underlying surface.
self.copy_surface(IRect::from_size(self.width, self.height))
}
}
pub fn from_image(
image: &image::DynamicImage,
content_type: Option<&str>,
mime_data: Option<Vec<u8>>,
) -> Result<SharedImageSurface, cairo::Error> {
let rgba_image = image.to_rgba8();
let width = i32(rgba_image.width()).map_err(|_| cairo::Error::InvalidSize)?;
let height = i32(rgba_image.height()).map_err(|_| cairo::Error::InvalidSize)?;
let mut surf = ExclusiveImageSurface::new(width, height, SurfaceType::SRgb)?;
rgba_image
.rows()
.zip(surf.rows_mut())
.flat_map(|(src_row, dest_row)| src_row.zip(dest_row.iter_mut()))
.for_each(|(src, dest)| *dest = src.to_pixel().premultiply().to_cairo_argb());
if let (Some(content_type), Some(bytes)) = (content_type, mime_data) {
surf.surface.set_mime_data(content_type, bytes)?;
}
surf.share()
}
/// Returns `true` if the surface contains meaningful data only in the alpha channel.
#[inline]
fn is_alpha_only(&self) -> bool {
self.surface_type == SurfaceType::AlphaOnly
}
/// Returns the type of this surface.
#[inline]
pub fn surface_type(&self) -> SurfaceType {
self.surface_type
}
/// Retrieves the pixel value at the given coordinates.
#[inline]
pub fn get_pixel(&self, x: u32, y: u32) -> Pixel {
assert!(x < self.width as u32);
assert!(y < self.height as u32);
#[allow(clippy::cast_ptr_alignment)]
let value = unsafe {
*(self
.data_ptr
.as_ptr()
.offset(y as isize * self.stride + x as isize * 4) as *const u32)
};
Pixel::from_u32(value)
}
/// Retrieves the pixel value by offset into the pixel data array.
#[inline]
pub fn get_pixel_by_offset(&self, offset: isize) -> Pixel {
assert!(offset < self.stride * self.height as isize);
#[allow(clippy::cast_ptr_alignment)]
let value = unsafe { *(self.data_ptr.as_ptr().offset(offset) as *const u32) };
Pixel::from_u32(value)
}
/// Calls `set_source_surface()` on the given Cairo context.
#[inline]
pub fn set_as_source_surface(
&self,
cr: &cairo::Context,
x: f64,
y: f64,
) -> Result<(), cairo::Error> {
cr.set_source_surface(&self.surface, x, y)
}
/// Creates a Cairo surface pattern from the surface
pub fn to_cairo_pattern(&self) -> cairo::SurfacePattern {
cairo::SurfacePattern::create(&self.surface)
}
/// Returns a new `cairo::ImageSurface` with the same contents as the one stored in this
/// `SharedImageSurface` within the given bounds.
fn copy_surface(&self, bounds: IRect) -> Result<cairo::ImageSurface, cairo::Error> {
let output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
let cr = cairo::Context::new(&output_surface)?;
let r = cairo::Rectangle::from(bounds);
cr.rectangle(r.x(), r.y(), r.width(), r.height());
cr.clip();
cr.set_source_surface(&self.surface, 0f64, 0f64)?;
cr.paint()?;
Ok(output_surface)
}
/// Scales the given surface by `x` and `y` into a surface `width`×`height` in size, clipped by
/// `bounds`.
pub fn scale_to(
&self,
width: i32,
height: i32,
bounds: IRect,
x: f64,
y: f64,
) -> Result<SharedImageSurface, cairo::Error> {
let output_surface = cairo::ImageSurface::create(cairo::Format::ARgb32, width, height)?;
{
let cr = cairo::Context::new(&output_surface)?;
let r = cairo::Rectangle::from(bounds);
cr.rectangle(r.x(), r.y(), r.width(), r.height());
cr.clip();
cr.scale(x, y);
self.set_as_source_surface(&cr, 0.0, 0.0)?;
cr.paint()?;
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Returns a scaled version of a surface and bounds.
#[inline]
pub fn scale(
&self,
bounds: IRect,
x: f64,
y: f64,
) -> Result<(SharedImageSurface, IRect), cairo::Error> {
let new_width = (f64::from(self.width) * x).ceil() as i32;
let new_height = (f64::from(self.height) * y).ceil() as i32;
let new_bounds = bounds.scale(x, y);
Ok((
self.scale_to(new_width, new_height, new_bounds, x, y)?,
new_bounds,
))
}
/// Returns a surface with black background and alpha channel matching this surface.
pub fn extract_alpha(&self, bounds: IRect) -> Result<SharedImageSurface, cairo::Error> {
let mut output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
let output_stride = output_surface.stride() as usize;
{
let mut output_data = output_surface.data().unwrap();
for (x, y, Pixel { a, .. }) in Pixels::within(self, bounds) {
let output_pixel = Pixel {
r: 0,
g: 0,
b: 0,
a,
};
output_data.set_pixel(output_stride, output_pixel, x, y);
}
}
SharedImageSurface::wrap(output_surface, SurfaceType::AlphaOnly)
}
/// Returns a surface whose alpha channel for each pixel is equal to the
/// luminance of that pixel's unpremultiplied RGB values. The resulting
/// surface's RGB values are not meanignful; only the alpha channel has
/// useful luminance data.
///
/// This is to get a mask suitable for use with cairo_mask_surface().
pub fn to_luminance_mask(&self) -> Result<SharedImageSurface, cairo::Error> {
let bounds = IRect::from_size(self.width, self.height);
let mut output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
let stride = output_surface.stride() as usize;
{
let mut data = output_surface.data().unwrap();
for (x, y, pixel) in Pixels::within(self, bounds) {
data.set_pixel(stride, pixel.to_luminance_mask(), x, y);
}
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Returns a surface with pre-multiplication of color values undone.
///
/// HACK: this is storing unpremultiplied pixels in an ARGB32 image surface (which is supposed
/// to be premultiplied pixels).
pub fn unpremultiply(&self, bounds: IRect) -> Result<SharedImageSurface, cairo::Error> {
// Unpremultiplication doesn't affect the alpha channel.
if self.is_alpha_only() {
return Ok(self.clone());
}
let mut output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
let stride = output_surface.stride() as usize;
{
let mut data = output_surface.data().unwrap();
for (x, y, pixel) in Pixels::within(self, bounds) {
data.set_pixel(stride, pixel.unpremultiply(), x, y);
}
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Converts the surface to the linear sRGB color space.
#[inline]
pub fn to_linear_rgb(&self, bounds: IRect) -> Result<SharedImageSurface, cairo::Error> {
match self.surface_type {
SurfaceType::LinearRgb | SurfaceType::AlphaOnly => Ok(self.clone()),
_ => srgb::linearize_surface(self, bounds),
}
}
/// Converts the surface to the sRGB color space.
#[inline]
pub fn to_srgb(&self, bounds: IRect) -> Result<SharedImageSurface, cairo::Error> {
match self.surface_type {
SurfaceType::SRgb | SurfaceType::AlphaOnly => Ok(self.clone()),
_ => srgb::unlinearize_surface(self, bounds),
}
}
/// Performs a convolution.
///
/// Note that `kernel` is rotated 180 degrees.
///
/// The `target` parameter determines the position of the kernel relative to each pixel of the
/// image. The value of `(0, 0)` indicates that the top left pixel of the (180-degrees-rotated)
/// kernel corresponds to the current pixel, and the rest of the kernel is to the right and
/// bottom of the pixel. The value of `(cols / 2, rows / 2)` centers a kernel with an odd
/// number of rows and columns.
///
/// # Panics
/// Panics if `kernel` has zero rows or columns.
pub fn convolve<R: Dim, C: Dim, S: Storage<f64, R, C>>(
&self,
bounds: IRect,
target: (i32, i32),
kernel: &Matrix<f64, R, C, S>,
edge_mode: EdgeMode,
) -> Result<SharedImageSurface, cairo::Error> {
assert!(kernel.nrows() >= 1);
assert!(kernel.ncols() >= 1);
let mut output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
let output_stride = output_surface.stride() as usize;
{
let mut output_data = output_surface.data().unwrap();
if self.is_alpha_only() {
for (x, y, _pixel) in Pixels::within(self, bounds) {
let kernel_bounds = IRect::new(
x as i32 - target.0,
y as i32 - target.1,
x as i32 - target.0 + kernel.ncols() as i32,
y as i32 - target.1 + kernel.nrows() as i32,
);
let mut a = 0.0;
for (x, y, pixel) in
PixelRectangle::within(self, bounds, kernel_bounds, edge_mode)
{
let kernel_x = (kernel_bounds.x1 - x - 1) as usize;
let kernel_y = (kernel_bounds.y1 - y - 1) as usize;
let factor = kernel[(kernel_y, kernel_x)];
a += f64::from(pixel.a) * factor;
}
let convert = |x: f64| (clamp(x, 0.0, 255.0) + 0.5) as u8;
let output_pixel = Pixel {
r: 0,
g: 0,
b: 0,
a: convert(a),
};
output_data.set_pixel(output_stride, output_pixel, x, y);
}
} else {
for (x, y, _pixel) in Pixels::within(self, bounds) {
let kernel_bounds = IRect::new(
x as i32 - target.0,
y as i32 - target.1,
x as i32 - target.0 + kernel.ncols() as i32,
y as i32 - target.1 + kernel.nrows() as i32,
);
let mut r = 0.0;
let mut g = 0.0;
let mut b = 0.0;
let mut a = 0.0;
for (x, y, pixel) in
PixelRectangle::within(self, bounds, kernel_bounds, edge_mode)
{
let kernel_x = (kernel_bounds.x1 - x - 1) as usize;
let kernel_y = (kernel_bounds.y1 - y - 1) as usize;
let factor = kernel[(kernel_y, kernel_x)];
r += f64::from(pixel.r) * factor;
g += f64::from(pixel.g) * factor;
b += f64::from(pixel.b) * factor;
a += f64::from(pixel.a) * factor;
}
let convert = |x: f64| (clamp(x, 0.0, 255.0) + 0.5) as u8;
let output_pixel = Pixel {
r: convert(r),
g: convert(g),
b: convert(b),
a: convert(a),
};
output_data.set_pixel(output_stride, output_pixel, x, y);
}
}
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Performs a horizontal or vertical box blur.
///
/// The `target` parameter determines the position of the kernel relative to each pixel of the
/// image. The value of `0` indicates that the first pixel of the kernel corresponds to the
/// current pixel, and the rest of the kernel is to the right or bottom of the pixel. The value
/// of `kernel_size / 2` centers a kernel with an odd size.
///
/// # Panics
/// Panics if `kernel_size` is `0` or if `target >= kernel_size`.
// This is public (and not inlined into box_blur()) for the purpose of accessing it from the
// benchmarks.
pub fn box_blur_loop<B: BlurDirection, A: IsAlphaOnly>(
&self,
output_surface: &mut cairo::ImageSurface,
bounds: IRect,
kernel_size: usize,
target: usize,
) {
assert_ne!(kernel_size, 0);
assert!(target < kernel_size);
assert_eq!(self.is_alpha_only(), A::IS_ALPHA_ONLY);
{
// The following code is needed for a parallel implementation of the blur loop. The
// blurring is done either for each row or for each column of pixels, depending on the
// value of `vertical`, independently of the others. Naturally, we want to run the
// outer loop on a thread pool.
//
// The case of `vertical == false` is simple since the input image slice can be
// partitioned into chunks for each row of pixels and processed in parallel with rayon.
// The case of `vertical == true`, however, is more involved because we can't just make
// mutable slices for all pixel columns (they would be overlapping which is forbidden
// by the aliasing rules).
//
// This is where the following struct comes into play: it stores a sub-slice of the
// pixel data and can be split at any row or column into two parts (similar to
// slice::split_at_mut()).
struct UnsafeSendPixelData<'a> {
width: u32,
height: u32,
stride: isize,
ptr: NonNull<u8>,
_marker: PhantomData<&'a mut ()>,
}
unsafe impl<'a> Send for UnsafeSendPixelData<'a> {}
impl<'a> UnsafeSendPixelData<'a> {
/// Creates a new `UnsafeSendPixelData`.
///
/// # Safety
/// You must call `cairo_surface_mark_dirty()` on the surface once all instances of
/// `UnsafeSendPixelData` are dropped to make sure the pixel changes are committed
/// to Cairo.
#[inline]
unsafe fn new(surface: &mut cairo::ImageSurface) -> Self {
assert_eq!(surface.format(), cairo::Format::ARgb32);
let ptr = surface.data().unwrap().as_mut_ptr();
Self {
width: surface.width() as u32,
height: surface.height() as u32,
stride: surface.stride() as isize,
ptr: NonNull::new(ptr).unwrap(),
_marker: PhantomData,
}
}
/// Sets a pixel value at the given coordinates.
#[inline]
fn set_pixel(&mut self, pixel: Pixel, x: u32, y: u32) {
assert!(x < self.width);
assert!(y < self.height);
let value = pixel.to_u32();
#[allow(clippy::cast_ptr_alignment)]
unsafe {
let ptr = self
.ptr
.as_ptr()
.offset(y as isize * self.stride + x as isize * 4)
as *mut u32;
*ptr = value;
}
}
/// Splits this `UnsafeSendPixelData` into two at the given row.
///
/// The first one contains rows `0..index` (`index` not included) and the second one
/// contains rows `index..height`.
#[inline]
fn split_at_row(self, index: u32) -> (Self, Self) {
assert!(index <= self.height);
(
UnsafeSendPixelData {
width: self.width,
height: index,
stride: self.stride,
ptr: self.ptr,
_marker: PhantomData,
},
UnsafeSendPixelData {
width: self.width,
height: self.height - index,
stride: self.stride,
ptr: NonNull::new(unsafe {
self.ptr.as_ptr().offset(index as isize * self.stride)
})
.unwrap(),
_marker: PhantomData,
},
)
}
/// Splits this `UnsafeSendPixelData` into two at the given column.
///
/// The first one contains columns `0..index` (`index` not included) and the second
/// one contains columns `index..width`.
#[inline]
fn split_at_column(self, index: u32) -> (Self, Self) {
assert!(index <= self.width);
(
UnsafeSendPixelData {
width: index,
height: self.height,
stride: self.stride,
ptr: self.ptr,
_marker: PhantomData,
},
UnsafeSendPixelData {
width: self.width - index,
height: self.height,
stride: self.stride,
ptr: NonNull::new(unsafe {
self.ptr.as_ptr().offset(index as isize * 4)
})
.unwrap(),
_marker: PhantomData,
},
)
}
}
let output_data = unsafe { UnsafeSendPixelData::new(output_surface) };
// Shift is target into the opposite direction.
let shift = (kernel_size - target) as i32;
let target = target as i32;
// Convert to f64 once since we divide by it.
let kernel_size_f64 = kernel_size as f64;
let compute = |x: u32| (f64::from(x) / kernel_size_f64 + 0.5) as u8;
// Depending on `vertical`, we're blurring either horizontally line-by-line, or
// vertically column-by-column. In the code below, the main axis is the axis along
// which the blurring happens (so if `vertical` is false, the main axis is the
// horizontal axis). The other axis is the outer loop axis. The code uses `i` and `j`
// for the other axis and main axis coordinates, respectively.
let (main_axis_min, main_axis_max, other_axis_min, other_axis_max) = if B::IS_VERTICAL {
(bounds.y0, bounds.y1, bounds.x0, bounds.x1)
} else {
(bounds.x0, bounds.x1, bounds.y0, bounds.y1)
};
// Helper function for getting the pixels.
let pixel = |i, j| {
let (x, y) = if B::IS_VERTICAL { (i, j) } else { (j, i) };
self.get_pixel(x as u32, y as u32)
};
// The following loop assumes the first row or column of `output_data` is the first row
// or column inside `bounds`.
let mut output_data = if B::IS_VERTICAL {
output_data.split_at_column(bounds.x0 as u32).1
} else {
output_data.split_at_row(bounds.y0 as u32).1
};
rayon::scope(|s| {
for i in other_axis_min..other_axis_max {
// Split off one row or column and launch its processing on another thread.
// Thanks to the initial split before the loop, there's no special case for the
// very first split.
let (mut current, remaining) = if B::IS_VERTICAL {
output_data.split_at_column(1)
} else {
output_data.split_at_row(1)
};
output_data = remaining;
s.spawn(move |_| {
// Helper function for setting the pixels.
let mut set_pixel = |j, pixel| {
// We're processing rows or columns one-by-one, so the other coordinate
// is always 0.
let (x, y) = if B::IS_VERTICAL { (0, j) } else { (j, 0) };
current.set_pixel(pixel, x, y);
};
// The idea is that since all weights of the box blur kernel are equal, for
// each step along the main axis, instead of recomputing the full sum, we
// can take the previous sum, subtract the "oldest" pixel value and add the
// "newest" pixel value.
//
// The sum is u32 so that it can fit MAXIMUM_KERNEL_SIZE * 255.
let mut sum_r = 0;
let mut sum_g = 0;
let mut sum_b = 0;
let mut sum_a = 0;
// The whole sum needs to be computed for the first pixel. However, we know
// that values outside of bounds are transparent, so the loop starts on the
// first pixel in bounds.
for j in main_axis_min..min(main_axis_max, main_axis_min + shift) {
let Pixel { r, g, b, a } = pixel(i, j);
if !A::IS_ALPHA_ONLY {
sum_r += u32::from(r);
sum_g += u32::from(g);
sum_b += u32::from(b);
}
sum_a += u32::from(a);
}
set_pixel(
main_axis_min as u32,
Pixel {
r: compute(sum_r),
g: compute(sum_g),
b: compute(sum_b),
a: compute(sum_a),
},
);
// Now, go through all the other pixels.
//
// j - target - 1 >= main_axis_min
// j >= main_axis_min + target + 1
let start_subtracting_at = main_axis_min + target + 1;
// j + shift - 1 < main_axis_max
// j < main_axis_max - shift + 1
let stop_adding_at = main_axis_max - shift + 1;
for j in main_axis_min + 1..main_axis_max {
if j >= start_subtracting_at {
let old_pixel = pixel(i, j - target - 1);
if !A::IS_ALPHA_ONLY {
sum_r -= u32::from(old_pixel.r);
sum_g -= u32::from(old_pixel.g);
sum_b -= u32::from(old_pixel.b);
}
sum_a -= u32::from(old_pixel.a);
}
if j < stop_adding_at {
let new_pixel = pixel(i, j + shift - 1);
if !A::IS_ALPHA_ONLY {
sum_r += u32::from(new_pixel.r);
sum_g += u32::from(new_pixel.g);
sum_b += u32::from(new_pixel.b);
}
sum_a += u32::from(new_pixel.a);
}
set_pixel(
j as u32,
Pixel {
r: compute(sum_r),
g: compute(sum_g),
b: compute(sum_b),
a: compute(sum_a),
},
);
}
});
}
});
}
// Don't forget to manually mark the surface as dirty (due to usage of
// `UnsafeSendPixelData`).
unsafe { cairo::ffi::cairo_surface_mark_dirty(output_surface.to_raw_none()) }
}
/// Performs a horizontal or vertical box blur.
///
/// The `target` parameter determines the position of the kernel relative to each pixel of the
/// image. The value of `0` indicates that the first pixel of the kernel corresponds to the
/// current pixel, and the rest of the kernel is to the right or bottom of the pixel. The value
/// of `kernel_size / 2` centers a kernel with an odd size.
///
/// # Panics
/// Panics if `kernel_size` is `0` or if `target >= kernel_size`.
#[inline]
pub fn box_blur<B: BlurDirection>(
&self,
bounds: IRect,
kernel_size: usize,
target: usize,
) -> Result<SharedImageSurface, cairo::Error> {
let mut output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
if self.is_alpha_only() {
self.box_blur_loop::<B, AlphaOnly>(&mut output_surface, bounds, kernel_size, target);
} else {
self.box_blur_loop::<B, NotAlphaOnly>(&mut output_surface, bounds, kernel_size, target);
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Fills the with a specified color.
#[inline]
pub fn flood(&self, bounds: IRect, color: Color) -> Result<SharedImageSurface, cairo::Error> {
let output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
let rgba = color_to_rgba(&color);
if rgba.alpha.unwrap_or(0.0) > 0.0 {
let cr = cairo::Context::new(&output_surface)?;
let r = cairo::Rectangle::from(bounds);
cr.rectangle(r.x(), r.y(), r.width(), r.height());
cr.clip();
set_source_color_on_cairo(&cr, &color);
cr.paint()?;
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Offsets the image of the specified amount.
#[inline]
pub fn offset(
&self,
bounds: Rect,
dx: f64,
dy: f64,
) -> Result<SharedImageSurface, cairo::Error> {
let output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
// output_bounds contains all pixels within bounds,
// for which (x - ox) and (y - oy) also lie within bounds.
if let Some(output_bounds) = bounds.translate((dx, dy)).intersection(&bounds) {
let cr = cairo::Context::new(&output_surface)?;
let r = cairo::Rectangle::from(output_bounds);
cr.rectangle(r.x(), r.y(), r.width(), r.height());
cr.clip();
self.set_as_source_surface(&cr, dx, dy)?;
cr.paint()?;
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Returns a new surface of the same size, with the contents of the
/// specified image, optionally transformed to match a given box
#[inline]
pub fn paint_image(
&self,
bounds: Rect,
image: &SharedImageSurface,
rect: Option<Rect>,
interpolation: Interpolation,
) -> Result<SharedImageSurface, cairo::Error> {
let output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
if rect.is_none() || !rect.unwrap().is_empty() {
let cr = cairo::Context::new(&output_surface)?;
let r = cairo::Rectangle::from(bounds);
cr.rectangle(r.x(), r.y(), r.width(), r.height());
cr.clip();
image.set_as_source_surface(&cr, 0f64, 0f64)?;
if let Some(rect) = rect {
let mut matrix = cairo::Matrix::new(
rect.width() / f64::from(image.width()),
0.0,
0.0,
rect.height() / f64::from(image.height()),
rect.x0,
rect.y0,
);
matrix.invert();
cr.source().set_matrix(matrix);
cr.source().set_filter(cairo::Filter::from(interpolation));
}
cr.paint()?;
}
SharedImageSurface::wrap(output_surface, image.surface_type)
}
/// Creates a new surface with the size and content specified in `bounds`
///
/// # Panics
/// Panics if `bounds` is an empty rectangle, since `SharedImageSurface` cannot
/// represent zero-sized images.
#[inline]
pub fn tile(&self, bounds: IRect) -> Result<SharedImageSurface, cairo::Error> {
// Cairo lets us create zero-sized surfaces, but the call to SharedImageSurface::wrap()
// below will panic in that case. So, disallow requesting a zero-sized subregion.
assert!(!bounds.is_empty());
let output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, bounds.width(), bounds.height())?;
{
let cr = cairo::Context::new(&output_surface)?;
self.set_as_source_surface(&cr, f64::from(-bounds.x0), f64::from(-bounds.y0))?;
cr.paint()?;
}
SharedImageSurface::wrap(output_surface, self.surface_type)
}
/// Returns a new surface of the same size, with the contents of the specified
/// image repeated to fill the bounds and starting from the given position.
#[inline]
pub fn paint_image_tiled(
&self,
bounds: IRect,
image: &SharedImageSurface,
x: i32,
y: i32,
) -> Result<SharedImageSurface, cairo::Error> {
let output_surface =
cairo::ImageSurface::create(cairo::Format::ARgb32, self.width, self.height)?;
{
let cr = cairo::Context::new(&output_surface)?;
let ptn = image.to_cairo_pattern();
ptn.set_extend(cairo::Extend::Repeat);
let mut mat = cairo::Matrix::identity();
mat.translate(f64::from(-x), f64::from(-y));
ptn.set_matrix(mat);
let r = cairo::Rectangle::from(bounds);
cr.rectangle(r.x(), r.y(), r.width(), r.height());
cr.clip();
cr.set_source(&ptn)?;
cr.paint()?;
}
SharedImageSurface::wrap(output_surface, image.surface_type)
}
/// Performs the combination of two input surfaces using Porter-Duff
/// compositing operators.
///
/// # Panics
/// Panics if the two surface types are not compatible.
#[inline]
pub fn compose(
&self,
other: &SharedImageSurface,
bounds: IRect,
operator: Operator,
) -> Result<SharedImageSurface, cairo::Error> {
let output_surface = other.copy_surface(bounds)?;
{
let cr = cairo::Context::new(&output_surface)?;
let r = cairo::Rectangle::from(bounds);
cr.rectangle(r.x(), r.y(), r.width(), r.height());
cr.clip();
self.set_as_source_surface(&cr, 0.0, 0.0)?;
cr.set_operator(operator.into());
cr.paint()?;
}
SharedImageSurface::wrap(
output_surface,
self.surface_type.combine(other.surface_type),
)
}
/// Performs the combination of two input surfaces.
///
/// Each pixel of the resulting image is computed using the following formula:
/// `res = k1*i1*i2 + k2*i1 + k3*i2 + k4`
///
/// # Panics
/// Panics if the two surface types are not compatible.
#[inline]
pub fn compose_arithmetic(
&self,
other: &SharedImageSurface,
bounds: IRect,
k1: f64,
k2: f64,
k3: f64,
k4: f64,
) -> Result<SharedImageSurface, cairo::Error> {
let mut output_surface = ExclusiveImageSurface::new(
self.width,
self.height,
self.surface_type.combine(other.surface_type),
)?;
composite_arithmetic(self, other, &mut output_surface, bounds, k1, k2, k3, k4);
output_surface.share()
}
pub fn rows(&self) -> Rows<'_> {
Rows {
surface: self,
next_row: 0,
}
}
}
impl<'a> Iterator for Rows<'a> {
type Item = &'a [CairoARGB];
fn next(&mut self) -> Option<Self::Item> {
if self.next_row == self.surface.height {
return None;
}
let row = self.next_row;
self.next_row += 1;
// SAFETY: this code assumes that cairo image surface data is correctly
// aligned for u32. This assumption is justified by the Cairo docs,
// which say this:
//
// https://cairographics.org/manual/cairo-Image-Surfaces.html#cairo-image-surface-create-for-data
//
// > This pointer must be suitably aligned for any kind of variable,
// > (for example, a pointer returned by malloc).
unsafe {
let row_ptr: *const u8 = self
.surface
.data_ptr
.as_ptr()
.offset(row as isize * self.surface.stride);
let row_of_u32: &[u32] =
slice::from_raw_parts(row_ptr as *const u32, self.surface.width as usize);
let pixels = row_of_u32.as_cairo_argb();
assert!(pixels.len() == self.surface.width as usize);
Some(pixels)
}
}
}
impl<'a> Iterator for RowsMut<'a> {
type Item = &'a mut [CairoARGB];
fn next(&mut self) -> Option<Self::Item> {
if self.next_row == self.height {
return None;
}
let row = self.next_row as usize;
self.next_row += 1;
// SAFETY: this code assumes that cairo image surface data is correctly
// aligned for u32. This assumption is justified by the Cairo docs,
// which say this:
//
// https://cairographics.org/manual/cairo-Image-Surfaces.html#cairo-image-surface-create-for-data
//
// > This pointer must be suitably aligned for any kind of variable,
// > (for example, a pointer returned by malloc).
unsafe {
// We do this with raw pointers, instead of re-slicing the &mut self.data[....],
// because with the latter we can't synthesize an appropriate lifetime for
// the return value.
let data_ptr = self.data.as_mut_ptr();
let row_ptr: *mut u8 = data_ptr.offset(row as isize * self.stride as isize);
let row_of_u32: &mut [u32] =
slice::from_raw_parts_mut(row_ptr as *mut u32, self.width as usize);
let pixels = row_of_u32.as_cairo_argb_mut();
assert!(pixels.len() == self.width as usize);
Some(pixels)
}
}
}
/// Performs the arithmetic composite operation. Public for benchmarking.
#[inline]
pub fn composite_arithmetic(
surface1: &SharedImageSurface,
surface2: &SharedImageSurface,
output_surface: &mut ExclusiveImageSurface,
bounds: IRect,
k1: f64,
k2: f64,
k3: f64,
k4: f64,
) {
output_surface.modify(&mut |data, stride| {
for (x, y, pixel, pixel_2) in
Pixels::within(surface1, bounds).map(|(x, y, p)| (x, y, p, surface2.get_pixel(x, y)))
{
let i1a = f64::from(pixel.a) / 255f64;
let i2a = f64::from(pixel_2.a) / 255f64;
let oa = k1 * i1a * i2a + k2 * i1a + k3 * i2a + k4;
let oa = clamp(oa, 0f64, 1f64);
// Contents of image surfaces are transparent by default, so if the resulting pixel is
// transparent there's no need to do anything.
if oa > 0f64 {
let compute = |i1, i2| {
let i1 = f64::from(i1) / 255f64;
let i2 = f64::from(i2) / 255f64;
let o = k1 * i1 * i2 + k2 * i1 + k3 * i2 + k4;
let o = clamp(o, 0f64, oa);
((o * 255f64) + 0.5) as u8
};
let output_pixel = Pixel {
r: compute(pixel.r, pixel_2.r),
g: compute(pixel.g, pixel_2.g),
b: compute(pixel.b, pixel_2.b),
a: ((oa * 255f64) + 0.5) as u8,
};
data.set_pixel(stride, output_pixel, x, y);
}
}
});
}
impl ImageSurface<Exclusive> {
#[inline]
pub fn new(
width: i32,
height: i32,
surface_type: SurfaceType,
) -> Result<ExclusiveImageSurface, cairo::Error> {
let surface = cairo::ImageSurface::create(cairo::Format::ARgb32, width, height)?;
let (width, height) = (surface.width(), surface.height());
// Cairo allows zero-sized surfaces, but it does malloc(0), whose result
// is implementation-defined. So, we can't assume NonNull below. This is
// why we disallow zero-sized surfaces here.
if !(width > 0 && height > 0) {
return Err(cairo::Error::InvalidSize);
}
let data_ptr = NonNull::new(unsafe {
cairo::ffi::cairo_image_surface_get_data(surface.to_raw_none())
})
.unwrap();
let stride = surface.stride() as isize;
Ok(ExclusiveImageSurface {
surface,
data_ptr,
width,
height,
stride,
surface_type,
_state: PhantomData,
})
}
#[inline]
pub fn share(self) -> Result<SharedImageSurface, cairo::Error> {
SharedImageSurface::wrap(self.surface, self.surface_type)
}
/// Raw access to the image data as a slice
#[inline]
pub fn data(&mut self) -> cairo::ImageSurfaceData<'_> {
self.surface.data().unwrap()
}
/// Modify the image data
#[inline]
pub fn modify(&mut self, draw_fn: &mut dyn FnMut(&mut cairo::ImageSurfaceData<'_>, usize)) {
let stride = self.stride() as usize;
let mut data = self.data();
draw_fn(&mut data, stride)
}
/// Draw on the surface using cairo
#[inline]
pub fn draw(
&mut self,
draw_fn: &mut dyn FnMut(cairo::Context) -> Result<(), InternalRenderingError>,
) -> Result<(), InternalRenderingError> {
let cr = cairo::Context::new(&self.surface)?;
draw_fn(cr)
}
pub fn rows_mut(&mut self) -> RowsMut<'_> {
let width = self.surface.width();
let height = self.surface.height();
let stride = self.surface.stride();
let data = self.surface.data().unwrap();
RowsMut {
width,
height,
stride,
data,
next_row: 0,
}
}
}
impl From<Operator> for cairo::Operator {
fn from(op: Operator) -> cairo::Operator {
use cairo::Operator as Cairo;
use Operator::*;
match op {
Over => Cairo::Over,
In => Cairo::In,
Out => Cairo::Out,
Atop => Cairo::Atop,
Xor => Cairo::Xor,
Multiply => Cairo::Multiply,
Screen => Cairo::Screen,
Darken => Cairo::Darken,
Lighten => Cairo::Lighten,
Overlay => Cairo::Overlay,
ColorDodge => Cairo::ColorDodge,
ColorBurn => Cairo::ColorBurn,
HardLight => Cairo::HardLight,
SoftLight => Cairo::SoftLight,
Difference => Cairo::Difference,
Exclusion => Cairo::Exclusion,
HslHue => Cairo::HslHue,
HslSaturation => Cairo::HslSaturation,
HslColor => Cairo::HslColor,
HslLuminosity => Cairo::HslLuminosity,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::surface_utils::iterators::Pixels;
#[test]
fn test_extract_alpha() {
const WIDTH: i32 = 32;
const HEIGHT: i32 = 64;
let bounds = IRect::new(8, 24, 16, 48);
let full_bounds = IRect::from_size(WIDTH, HEIGHT);
let mut surface = ExclusiveImageSurface::new(WIDTH, HEIGHT, SurfaceType::SRgb).unwrap();
// Fill the surface with some data.
{
let mut data = surface.data();
let mut counter = 0u16;
for x in data.iter_mut() {
*x = counter as u8;
counter = (counter + 1) % 256;
}
}
let surface = surface.share().unwrap();
let alpha = surface.extract_alpha(bounds).unwrap();
for (x, y, p, pa) in
Pixels::within(&surface, full_bounds).map(|(x, y, p)| (x, y, p, alpha.get_pixel(x, y)))
{
assert_eq!(pa.r, 0);
assert_eq!(pa.g, 0);
assert_eq!(pa.b, 0);
if !bounds.contains(x as i32, y as i32) {
assert_eq!(pa.a, 0);
} else {
assert_eq!(pa.a, p.a);
}
}
}
}