summaryrefslogtreecommitdiffstats
path: root/gfx/wr/webrender/src/prepare.rs
blob: f32c94073e7e7c3ef6751b13b3351922b7c2f821 (plain)
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
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//! # Prepare pass
//!
//! TODO: document this!

use api::{ColorF, PremultipliedColorF, PropertyBinding};
use api::{BoxShadowClipMode, BorderStyle, ClipMode};
use api::units::*;
use euclid::Scale;
use smallvec::SmallVec;
use crate::composite::CompositorSurfaceKind;
use crate::command_buffer::{PrimitiveCommand, QuadFlags, CommandBufferIndex};
use crate::image_tiling::{self, Repetition};
use crate::border::{get_max_scale_for_border, build_border_instances};
use crate::clip::{ClipStore, ClipNodeRange};
use crate::spatial_tree::{SpatialNodeIndex, SpatialTree};
use crate::clip::{ClipDataStore, ClipNodeFlags, ClipChainInstance, ClipItemKind};
use crate::frame_builder::{FrameBuildingContext, FrameBuildingState, PictureContext, PictureState};
use crate::gpu_cache::{GpuCacheHandle, GpuDataRequest};
use crate::gpu_types::{BrushFlags, TransformPaletteId, QuadSegment};
use crate::internal_types::{FastHashMap, PlaneSplitAnchor, Filter};
use crate::picture::{PicturePrimitive, SliceId, ClusterFlags, PictureCompositeMode};
use crate::picture::{PrimitiveList, PrimitiveCluster, SurfaceIndex, TileCacheInstance, SubpixelMode, Picture3DContext};
use crate::prim_store::line_dec::MAX_LINE_DECORATION_RESOLUTION;
use crate::prim_store::*;
use crate::prim_store::gradient::GradientGpuBlockBuilder;
use crate::render_backend::DataStores;
use crate::render_task_graph::{RenderTaskId};
use crate::render_task_cache::RenderTaskCacheKeyKind;
use crate::render_task_cache::{RenderTaskCacheKey, to_cache_size, RenderTaskParent};
use crate::render_task::{RenderTaskKind, RenderTask, SubPass, MaskSubPass, EmptyTask};
use crate::renderer::{GpuBufferBuilder, GpuBufferAddress};
use crate::segment::{EdgeAaSegmentMask, SegmentBuilder};
use crate::space::SpaceMapper;
use crate::util::{clamp_to_scale_factor, pack_as_float, MaxRect};
use crate::visibility::{compute_conservative_visible_rect, PrimitiveVisibility, VisibilityState};


const MAX_MASK_SIZE: f32 = 4096.0;

const MIN_BRUSH_SPLIT_SIZE: f32 = 256.0;
const MIN_BRUSH_SPLIT_AREA: f32 = 128.0 * 128.0;

const MIN_AA_SEGMENTS_SIZE: f32 = 4.0;

pub fn prepare_primitives(
    store: &mut PrimitiveStore,
    prim_list: &mut PrimitiveList,
    pic_context: &PictureContext,
    pic_state: &mut PictureState,
    frame_context: &FrameBuildingContext,
    frame_state: &mut FrameBuildingState,
    data_stores: &mut DataStores,
    scratch: &mut PrimitiveScratchBuffer,
    tile_caches: &mut FastHashMap<SliceId, Box<TileCacheInstance>>,
    prim_instances: &mut Vec<PrimitiveInstance>,
) {
    profile_scope!("prepare_primitives");
    let mut cmd_buffer_targets = Vec::new();

    for cluster in &mut prim_list.clusters {
        if !cluster.flags.contains(ClusterFlags::IS_VISIBLE) {
            continue;
        }
        profile_scope!("cluster");
        pic_state.map_local_to_pic.set_target_spatial_node(
            cluster.spatial_node_index,
            frame_context.spatial_tree,
        );

        for prim_instance_index in cluster.prim_range() {
            if frame_state.surface_builder.get_cmd_buffer_targets_for_prim(
                &prim_instances[prim_instance_index].vis,
                &mut cmd_buffer_targets,
            ) {
                let plane_split_anchor = PlaneSplitAnchor::new(
                    cluster.spatial_node_index,
                    PrimitiveInstanceIndex(prim_instance_index as u32),
                );

                prepare_prim_for_render(
                    store,
                    prim_instance_index,
                    cluster,
                    pic_context,
                    pic_state,
                    frame_context,
                    frame_state,
                    plane_split_anchor,
                    data_stores,
                    scratch,
                    tile_caches,
                    prim_instances,
                    &cmd_buffer_targets,
                );

                frame_state.num_visible_primitives += 1;
                continue;
            }

            // TODO(gw): Technically no need to clear visibility here, since from this point it
            //           only matters if it got added to a command buffer. Kept here for now to
            //           make debugging simpler, but perhaps we can remove / tidy this up.
            prim_instances[prim_instance_index].clear_visibility();
        }
    }
}

fn can_use_clip_chain_for_quad_path(
    clip_chain: &ClipChainInstance,
    clip_store: &ClipStore,
    data_stores: &DataStores,
) -> bool {
    if !clip_chain.needs_mask {
        return true;
    }

    for i in 0 .. clip_chain.clips_range.count {
        let clip_instance = clip_store.get_instance_from_range(&clip_chain.clips_range, i);
        let clip_node = &data_stores.clip[clip_instance.handle];

        match clip_node.item.kind {
            ClipItemKind::Rectangle { mode: ClipMode::ClipOut, .. } |
            ClipItemKind::RoundedRectangle { mode: ClipMode::ClipOut, .. } => {
                return false;
            }
            ClipItemKind::RoundedRectangle { .. } | ClipItemKind::Rectangle { .. } => {}
            ClipItemKind::BoxShadow { .. } => {
                // legacy path for box-shadows for now (move them to a separate primitive next)
                return false;
            }
            ClipItemKind::Image { .. } => {
                panic!("bug: image-masks not expected on rect/quads");
            }
        }
    }

    true
}

#[derive(Debug, Copy, Clone)]
pub enum QuadRenderStrategy {
    Direct,
    Indirect,
    NinePatch {
        radius: LayoutVector2D,
        clip_rect: LayoutRect,
    },
    Tiled {
        x_tiles: u16,
        y_tiles: u16,
    }
}

fn get_prim_render_strategy(
    prim_spatial_node_index: SpatialNodeIndex,
    clip_chain: &ClipChainInstance,
    clip_store: &ClipStore,
    data_stores: &DataStores,
    can_use_nine_patch: bool,
    spatial_tree: &SpatialTree,
) -> QuadRenderStrategy {
    if clip_chain.needs_mask {
        fn tile_count_for_size(size: f32) -> u16 {
            (size / MIN_BRUSH_SPLIT_SIZE).min(4.0).max(1.0).ceil() as u16
        }

        let prim_coverage_size = clip_chain.pic_coverage_rect.size();
        let x_tiles = tile_count_for_size(prim_coverage_size.width);
        let y_tiles = tile_count_for_size(prim_coverage_size.height);
        let try_split_prim = x_tiles > 1 || y_tiles > 1;

        if try_split_prim {
            if can_use_nine_patch {
                if clip_chain.clips_range.count == 1 {
                    let clip_instance = clip_store.get_instance_from_range(&clip_chain.clips_range, 0);
                    let clip_node = &data_stores.clip[clip_instance.handle];

                    if let ClipItemKind::RoundedRectangle { ref radius, mode: ClipMode::Clip, rect, .. } = clip_node.item.kind {
                        let max_corner_width = radius.top_left.width
                                                    .max(radius.bottom_left.width)
                                                    .max(radius.top_right.width)
                                                    .max(radius.bottom_right.width);
                        let max_corner_height = radius.top_left.height
                                                    .max(radius.bottom_left.height)
                                                    .max(radius.top_right.height)
                                                    .max(radius.bottom_right.height);

                        if max_corner_width <= 0.5 * rect.size().width &&
                           max_corner_height <= 0.5 * rect.size().height {

                            let clip_prim_coords_match = spatial_tree.is_matching_coord_system(
                                prim_spatial_node_index,
                                clip_node.item.spatial_node_index,
                            );

                            if clip_prim_coords_match {
                                let map_clip_to_prim = SpaceMapper::new_with_target(
                                    prim_spatial_node_index,
                                    clip_node.item.spatial_node_index,
                                    LayoutRect::max_rect(),
                                    spatial_tree,
                                );

                                if let Some(rect) = map_clip_to_prim.map(&rect) {
                                    return QuadRenderStrategy::NinePatch {
                                        radius: LayoutVector2D::new(max_corner_width, max_corner_height),
                                        clip_rect: rect,
                                    };
                                }
                            }
                        }
                    }
                }
            }

            QuadRenderStrategy::Tiled {
                x_tiles,
                y_tiles,
            }
        } else {
            QuadRenderStrategy::Indirect
        }
    } else {
        QuadRenderStrategy::Direct
    }
}

fn prepare_prim_for_render(
    store: &mut PrimitiveStore,
    prim_instance_index: usize,
    cluster: &mut PrimitiveCluster,
    pic_context: &PictureContext,
    pic_state: &mut PictureState,
    frame_context: &FrameBuildingContext,
    frame_state: &mut FrameBuildingState,
    plane_split_anchor: PlaneSplitAnchor,
    data_stores: &mut DataStores,
    scratch: &mut PrimitiveScratchBuffer,
    tile_caches: &mut FastHashMap<SliceId, Box<TileCacheInstance>>,
    prim_instances: &mut Vec<PrimitiveInstance>,
    targets: &[CommandBufferIndex],
) {
    profile_scope!("prepare_prim_for_render");

    // If we have dependencies, we need to prepare them first, in order
    // to know the actual rect of this primitive.
    // For example, scrolling may affect the location of an item in
    // local space, which may force us to render this item on a larger
    // picture target, if being composited.
    let mut is_passthrough = false;
    if let PrimitiveInstanceKind::Picture { pic_index, .. } = prim_instances[prim_instance_index].kind {
        let pic = &mut store.pictures[pic_index.0];

        // TODO(gw): Plan to remove pictures with no composite mode, so that we don't need
        //           to special case for pass through pictures.
        is_passthrough = pic.composite_mode.is_none();

        match pic.take_context(
            pic_index,
            Some(pic_context.surface_index),
            pic_context.subpixel_mode,
            frame_state,
            frame_context,
            scratch,
            tile_caches,
        ) {
            Some((pic_context_for_children, mut pic_state_for_children, mut prim_list)) => {
                prepare_primitives(
                    store,
                    &mut prim_list,
                    &pic_context_for_children,
                    &mut pic_state_for_children,
                    frame_context,
                    frame_state,
                    data_stores,
                    scratch,
                    tile_caches,
                    prim_instances,
                );

                // Restore the dependencies (borrow check dance)
                store.pictures[pic_context_for_children.pic_index.0]
                    .restore_context(
                        pic_context_for_children.pic_index,
                        prim_list,
                        pic_context_for_children,
                        prim_instances,
                        frame_context,
                        frame_state,
                    );
            }
            None => {
                return;
            }
        }
    }

    let prim_instance = &mut prim_instances[prim_instance_index];

    if !is_passthrough {

        // In this initial patch, we only support non-masked primitives through the new
        // quad rendering path. Follow up patches will extend this to support masks, and
        // then use by other primitives. In the new quad rendering path, we'll still want
        // to skip the entry point to `update_clip_task` as that does old-style segmenting
        // and mask generation.
        let should_update_clip_task = match prim_instance.kind {
            PrimitiveInstanceKind::Rectangle { ref mut use_legacy_path, .. } => {
                *use_legacy_path = !can_use_clip_chain_for_quad_path(
                    &prim_instance.vis.clip_chain,
                    frame_state.clip_store,
                    data_stores,
                );

                *use_legacy_path
            }
            PrimitiveInstanceKind::Picture { .. } => {
                false
            }
            _ => true,
        };

        if should_update_clip_task {
            let prim_rect = data_stores.get_local_prim_rect(
                prim_instance,
                &store.pictures,
                frame_state.surfaces,
            );

            if !update_clip_task(
                prim_instance,
                &prim_rect.min,
                cluster.spatial_node_index,
                pic_context.raster_spatial_node_index,
                pic_context,
                pic_state,
                frame_context,
                frame_state,
                store,
                data_stores,
                scratch,
            ) {
                return;
            }
        }
    }

    prepare_interned_prim_for_render(
        store,
        PrimitiveInstanceIndex(prim_instance_index as u32),
        prim_instance,
        cluster,
        plane_split_anchor,
        pic_context,
        pic_state,
        frame_context,
        frame_state,
        data_stores,
        scratch,
        targets,
    )
}

/// Prepare an interned primitive for rendering, by requesting
/// resources, render tasks etc. This is equivalent to the
/// prepare_prim_for_render_inner call for old style primitives.
fn prepare_interned_prim_for_render(
    store: &mut PrimitiveStore,
    prim_instance_index: PrimitiveInstanceIndex,
    prim_instance: &mut PrimitiveInstance,
    cluster: &mut PrimitiveCluster,
    plane_split_anchor: PlaneSplitAnchor,
    pic_context: &PictureContext,
    pic_state: &mut PictureState,
    frame_context: &FrameBuildingContext,
    frame_state: &mut FrameBuildingState,
    data_stores: &mut DataStores,
    scratch: &mut PrimitiveScratchBuffer,
    targets: &[CommandBufferIndex],
) {
    let prim_spatial_node_index = cluster.spatial_node_index;
    let device_pixel_scale = frame_state.surfaces[pic_context.surface_index.0].device_pixel_scale;

    match &mut prim_instance.kind {
        PrimitiveInstanceKind::LineDecoration { data_handle, ref mut render_task, .. } => {
            profile_scope!("LineDecoration");
            let prim_data = &mut data_stores.line_decoration[*data_handle];
            let common_data = &mut prim_data.common;
            let line_dec_data = &mut prim_data.kind;

            // Update the template this instane references, which may refresh the GPU
            // cache with any shared template data.
            line_dec_data.update(common_data, frame_state);

            // Work out the device pixel size to be used to cache this line decoration.

            // If we have a cache key, it's a wavy / dashed / dotted line. Otherwise, it's
            // a simple solid line.
            if let Some(cache_key) = line_dec_data.cache_key.as_ref() {
                // TODO(gw): These scale factors don't do a great job if the world transform
                //           contains perspective
                let scale = frame_context
                    .spatial_tree
                    .get_world_transform(prim_spatial_node_index)
                    .scale_factors();

                // Scale factors are normalized to a power of 2 to reduce the number of
                // resolution changes.
                // For frames with a changing scale transform round scale factors up to
                // nearest power-of-2 boundary so that we don't keep having to redraw
                // the content as it scales up and down. Rounding up to nearest
                // power-of-2 boundary ensures we never scale up, only down --- avoiding
                // jaggies. It also ensures we never scale down by more than a factor of
                // 2, avoiding bad downscaling quality.
                let scale_width = clamp_to_scale_factor(scale.0, false);
                let scale_height = clamp_to_scale_factor(scale.1, false);
                // Pick the maximum dimension as scale
                let world_scale = LayoutToWorldScale::new(scale_width.max(scale_height));

                let scale_factor = world_scale * Scale::new(1.0);
                let task_size_f = (LayoutSize::from_au(cache_key.size) * scale_factor).ceil();
                let mut task_size = if task_size_f.width > MAX_LINE_DECORATION_RESOLUTION as f32 ||
                   task_size_f.height > MAX_LINE_DECORATION_RESOLUTION as f32 {
                     let max_extent = task_size_f.width.max(task_size_f.height);
                     let task_scale_factor = Scale::new(MAX_LINE_DECORATION_RESOLUTION as f32 / max_extent);
                     let task_size = (LayoutSize::from_au(cache_key.size) * scale_factor * task_scale_factor)
                                    .ceil().to_i32();
                    task_size
                } else {
                    task_size_f.to_i32()
                };

                // It's plausible, due to float accuracy issues that the line decoration may be considered
                // visible even if the scale factors are ~0. However, the render task allocation below requires
                // that the size of the task is > 0. To work around this, ensure that the task size is at least
                // 1x1 pixels
                task_size.width = task_size.width.max(1);
                task_size.height = task_size.height.max(1);

                // Request a pre-rendered image task.
                // TODO(gw): This match is a bit untidy, but it should disappear completely
                //           once the prepare_prims and batching are unified. When that
                //           happens, we can use the cache handle immediately, and not need
                //           to temporarily store it in the primitive instance.
                *render_task = Some(frame_state.resource_cache.request_render_task(
                    RenderTaskCacheKey {
                        size: task_size,
                        kind: RenderTaskCacheKeyKind::LineDecoration(cache_key.clone()),
                    },
                    frame_state.gpu_cache,
                    frame_state.frame_gpu_data,
                    frame_state.rg_builder,
                    None,
                    false,
                    RenderTaskParent::Surface(pic_context.surface_index),
                    &mut frame_state.surface_builder,
                    |rg_builder, _| {
                        rg_builder.add().init(RenderTask::new_dynamic(
                            task_size,
                            RenderTaskKind::new_line_decoration(
                                cache_key.style,
                                cache_key.orientation,
                                cache_key.wavy_line_thickness.to_f32_px(),
                                LayoutSize::from_au(cache_key.size),
                            ),
                        ))
                    }
                ));
            }
        }
        PrimitiveInstanceKind::TextRun { run_index, data_handle, .. } => {
            profile_scope!("TextRun");
            let prim_data = &mut data_stores.text_run[*data_handle];
            let run = &mut store.text_runs[*run_index];

            prim_data.common.may_need_repetition = false;

            // The glyph transform has to match `glyph_transform` in "ps_text_run" shader.
            // It's relative to the rasterizing space of a glyph.
            let transform = frame_context.spatial_tree
                .get_relative_transform(
                    prim_spatial_node_index,
                    pic_context.raster_spatial_node_index,
                )
                .into_fast_transform();
            let prim_offset = prim_data.common.prim_rect.min.to_vector() - run.reference_frame_relative_offset;

            let surface = &frame_state.surfaces[pic_context.surface_index.0];

            // If subpixel AA is disabled due to the backing surface the glyphs
            // are being drawn onto, disable it (unless we are using the
            // specifial subpixel mode that estimates background color).
            let allow_subpixel = match prim_instance.vis.state {
                VisibilityState::Culled |
                VisibilityState::Unset |
                VisibilityState::PassThrough => {
                    panic!("bug: invalid visibility state");
                }
                VisibilityState::Visible { sub_slice_index, .. } => {
                    // For now, we only allow subpixel AA on primary sub-slices. In future we
                    // may support other sub-slices if we find content that does this.
                    if sub_slice_index.is_primary() {
                        match pic_context.subpixel_mode {
                            SubpixelMode::Allow => true,
                            SubpixelMode::Deny => false,
                            SubpixelMode::Conditional { allowed_rect, prohibited_rect } => {
                                // Conditional mode allows subpixel AA to be enabled for this
                                // text run, so long as it's inside the allowed rect.
                                allowed_rect.contains_box(&prim_instance.vis.clip_chain.pic_coverage_rect) &&
                                !prohibited_rect.intersects(&prim_instance.vis.clip_chain.pic_coverage_rect)
                            }
                        }
                    } else {
                        false
                    }
                }
            };

            run.request_resources(
                prim_offset,
                &prim_data.font,
                &prim_data.glyphs,
                &transform.to_transform().with_destination::<_>(),
                surface,
                prim_spatial_node_index,
                allow_subpixel,
                frame_context.fb_config.low_quality_pinch_zoom,
                frame_state.resource_cache,
                frame_state.gpu_cache,
                frame_context.spatial_tree,
                scratch,
            );

            // Update the template this instane references, which may refresh the GPU
            // cache with any shared template data.
            prim_data.update(frame_state);
        }
        PrimitiveInstanceKind::Clear { data_handle, .. } => {
            profile_scope!("Clear");
            let prim_data = &mut data_stores.prim[*data_handle];

            prim_data.common.may_need_repetition = false;

            // Update the template this instane references, which may refresh the GPU
            // cache with any shared template data.
            prim_data.update(frame_state, frame_context.scene_properties);
        }
        PrimitiveInstanceKind::NormalBorder { data_handle, ref mut render_task_ids, .. } => {
            profile_scope!("NormalBorder");
            let prim_data = &mut data_stores.normal_border[*data_handle];
            let common_data = &mut prim_data.common;
            let border_data = &mut prim_data.kind;

            common_data.may_need_repetition =
                matches!(border_data.border.top.style, BorderStyle::Dotted | BorderStyle::Dashed) ||
                matches!(border_data.border.right.style, BorderStyle::Dotted | BorderStyle::Dashed) ||
                matches!(border_data.border.bottom.style, BorderStyle::Dotted | BorderStyle::Dashed) ||
                matches!(border_data.border.left.style, BorderStyle::Dotted | BorderStyle::Dashed);


            // Update the template this instance references, which may refresh the GPU
            // cache with any shared template data.
            border_data.update(common_data, frame_state);

            // TODO(gw): For now, the scale factors to rasterize borders at are
            //           based on the true world transform of the primitive. When
            //           raster roots with local scale are supported in future,
            //           that will need to be accounted for here.
            let scale = frame_context
                .spatial_tree
                .get_world_transform(prim_spatial_node_index)
                .scale_factors();

            // Scale factors are normalized to a power of 2 to reduce the number of
            // resolution changes.
            // For frames with a changing scale transform round scale factors up to
            // nearest power-of-2 boundary so that we don't keep having to redraw
            // the content as it scales up and down. Rounding up to nearest
            // power-of-2 boundary ensures we never scale up, only down --- avoiding
            // jaggies. It also ensures we never scale down by more than a factor of
            // 2, avoiding bad downscaling quality.
            let scale_width = clamp_to_scale_factor(scale.0, false);
            let scale_height = clamp_to_scale_factor(scale.1, false);
            // Pick the maximum dimension as scale
            let world_scale = LayoutToWorldScale::new(scale_width.max(scale_height));
            let mut scale = world_scale * device_pixel_scale;
            let max_scale = get_max_scale_for_border(border_data);
            scale.0 = scale.0.min(max_scale.0);

            // For each edge and corner, request the render task by content key
            // from the render task cache. This ensures that the render task for
            // this segment will be available for batching later in the frame.
            let mut handles: SmallVec<[RenderTaskId; 8]> = SmallVec::new();

            for segment in &border_data.border_segments {
                // Update the cache key device size based on requested scale.
                let cache_size = to_cache_size(segment.local_task_size, &mut scale);
                let cache_key = RenderTaskCacheKey {
                    kind: RenderTaskCacheKeyKind::BorderSegment(segment.cache_key.clone()),
                    size: cache_size,
                };

                handles.push(frame_state.resource_cache.request_render_task(
                    cache_key,
                    frame_state.gpu_cache,
                    frame_state.frame_gpu_data,
                    frame_state.rg_builder,
                    None,
                    false,          // TODO(gw): We don't calculate opacity for borders yet!
                    RenderTaskParent::Surface(pic_context.surface_index),
                    &mut frame_state.surface_builder,
                    |rg_builder, _| {
                        rg_builder.add().init(RenderTask::new_dynamic(
                            cache_size,
                            RenderTaskKind::new_border_segment(
                                build_border_instances(
                                    &segment.cache_key,
                                    cache_size,
                                    &border_data.border,
                                    scale,
                                )
                            ),
                        ))
                    }
                ));
            }

            *render_task_ids = scratch
                .border_cache_handles
                .extend(handles);
        }
        PrimitiveInstanceKind::ImageBorder { data_handle, .. } => {
            profile_scope!("ImageBorder");
            let prim_data = &mut data_stores.image_border[*data_handle];

            // TODO: get access to the ninepatch and to check whether we need support
            // for repetitions in the shader.

            // Update the template this instance references, which may refresh the GPU
            // cache with any shared template data.
            prim_data.kind.update(
                &mut prim_data.common,
                frame_state
            );
        }
        PrimitiveInstanceKind::Rectangle { data_handle, segment_instance_index, color_binding_index, use_legacy_path, .. } => {
            profile_scope!("Rectangle");

            if *use_legacy_path {
                let prim_data = &mut data_stores.prim[*data_handle];
                prim_data.common.may_need_repetition = false;

                // TODO(gw): Legacy rect rendering path - remove once we support masks on quad prims
                if *color_binding_index != ColorBindingIndex::INVALID {
                    match store.color_bindings[*color_binding_index] {
                        PropertyBinding::Binding(..) => {
                            // We explicitly invalidate the gpu cache
                            // if the color is animating.
                            let gpu_cache_handle =
                                if *segment_instance_index == SegmentInstanceIndex::INVALID {
                                    None
                                } else if *segment_instance_index == SegmentInstanceIndex::UNUSED {
                                    Some(&prim_data.common.gpu_cache_handle)
                                } else {
                                    Some(&scratch.segment_instances[*segment_instance_index].gpu_cache_handle)
                                };
                            if let Some(gpu_cache_handle) = gpu_cache_handle {
                                frame_state.gpu_cache.invalidate(gpu_cache_handle);
                            }
                        }
                        PropertyBinding::Value(..) => {},
                    }
                }

                // Update the template this instane references, which may refresh the GPU
                // cache with any shared template data.
                prim_data.update(
                    frame_state,
                    frame_context.scene_properties,
                );

                write_segment(
                    *segment_instance_index,
                    frame_state,
                    &mut scratch.segments,
                    &mut scratch.segment_instances,
                    |request| {
                        prim_data.kind.write_prim_gpu_blocks(
                            request,
                            frame_context.scene_properties,
                        );
                    }
                );
            } else {
                let map_prim_to_surface = frame_context.spatial_tree.get_relative_transform(
                    prim_spatial_node_index,
                    pic_context.raster_spatial_node_index,
                );
                let prim_is_2d_scale_translation = map_prim_to_surface.is_2d_scale_translation();
                let prim_is_2d_axis_aligned = map_prim_to_surface.is_2d_axis_aligned();

                let strategy = get_prim_render_strategy(
                    prim_spatial_node_index,
                    &prim_instance.vis.clip_chain,
                    frame_state.clip_store,
                    data_stores,
                    prim_is_2d_scale_translation,
                    frame_context.spatial_tree,
                );

                let prim_data = &data_stores.prim[*data_handle];

                let (color, is_opaque) = match prim_data.kind {
                    PrimitiveTemplateKind::Clear => {
                        // Opaque black with operator dest out
                        (ColorF::BLACK, false)
                    }
                    PrimitiveTemplateKind::Rectangle { ref color, .. } => {
                        let color = frame_context.scene_properties.resolve_color(color);

                        (color, color.a >= 1.0)
                    }
                };

                let premul_color = color.premultiplied();

                let mut quad_flags = QuadFlags::empty();

                // Only use AA edge instances if the primitive is large enough to require it
                let prim_size = prim_data.common.prim_rect.size();
                if prim_size.width > MIN_AA_SEGMENTS_SIZE && prim_size.height > MIN_AA_SEGMENTS_SIZE {
                    quad_flags |= QuadFlags::USE_AA_SEGMENTS;
                }

                if is_opaque {
                    quad_flags |= QuadFlags::IS_OPAQUE;
                }
                let needs_scissor = !prim_is_2d_scale_translation;
                if !needs_scissor {
                    quad_flags |= QuadFlags::APPLY_DEVICE_CLIP;
                }

                // TODO(gw): For now, we don't select per-edge AA at all if the primitive
                //           has a 2d transform, which matches existing behavior. However,
                //           as a follow up, we can now easily check if we have a 2d-aligned
                //           primitive on a subpixel boundary, and enable AA along those edge(s).
                let aa_flags = if prim_is_2d_axis_aligned {
                    EdgeAaSegmentMask::empty()
                } else {
                    EdgeAaSegmentMask::all()
                };

                let transform_id = frame_state.transforms.get_id(
                    prim_spatial_node_index,
                    pic_context.raster_spatial_node_index,
                    frame_context.spatial_tree,
                );

                // TODO(gw): Perhaps rather than writing untyped data here (we at least do validate
                //           the written block count) to gpu-buffer, we could add a trait for
                //           writing typed data?
                let main_prim_address = write_prim_blocks(
                    frame_state.frame_gpu_data,
                    prim_data.common.prim_rect,
                    prim_instance.vis.clip_chain.local_clip_rect,
                    premul_color,
                    &[],
                );

                match strategy {
                    QuadRenderStrategy::Direct => {
                        frame_state.push_prim(
                            &PrimitiveCommand::quad(
                                prim_instance_index,
                                main_prim_address,
                                transform_id,
                                quad_flags,
                                aa_flags,
                            ),
                            prim_spatial_node_index,
                            targets,
                        );
                    }
                    QuadRenderStrategy::Indirect => {
                        let surface = &frame_state.surfaces[pic_context.surface_index.0];
                        let clipped_surface_rect = surface.get_surface_rect(
                            &prim_instance.vis.clip_chain.pic_coverage_rect,
                            frame_context.spatial_tree,
                        ).expect("bug: what can cause this?");

                        let p0 = clipped_surface_rect.min.floor();
                        let p1 = clipped_surface_rect.max.ceil();

                        let x0 = p0.x;
                        let y0 = p0.y;
                        let x1 = p1.x;
                        let y1 = p1.y;

                        let segment = add_segment(
                            x0,
                            y0,
                            x1,
                            y1,
                            true,
                            prim_instance,
                            prim_spatial_node_index,
                            pic_context.raster_spatial_node_index,
                            main_prim_address,
                            transform_id,
                            aa_flags,
                            quad_flags,
                            device_pixel_scale,
                            needs_scissor,
                            frame_state,
                        );

                        add_composite_prim(
                            prim_instance_index,
                            LayoutRect::new(LayoutPoint::new(x0, y0), LayoutPoint::new(x1, y1)),
                            premul_color,
                            quad_flags,
                            frame_state,
                            targets,
                            &[segment],
                        );
                    }
                    QuadRenderStrategy::Tiled { x_tiles, y_tiles } => {
                        let surface = &frame_state.surfaces[pic_context.surface_index.0];

                        let clipped_surface_rect = surface.get_surface_rect(
                            &prim_instance.vis.clip_chain.pic_coverage_rect,
                            frame_context.spatial_tree,
                        ).expect("bug: what can cause this?");

                        let unclipped_surface_rect = surface.map_to_device_rect(
                            &prim_instance.vis.clip_chain.pic_coverage_rect,
                            frame_context.spatial_tree,
                        );

                        scratch.quad_segments.clear();

                        let mut x_coords = vec![clipped_surface_rect.min.x.round()];
                        let mut y_coords = vec![clipped_surface_rect.min.y.round()];

                        let dx = (clipped_surface_rect.max.x - clipped_surface_rect.min.x) / x_tiles as f32;
                        let dy = (clipped_surface_rect.max.y - clipped_surface_rect.min.y) / y_tiles as f32;

                        for x in 1 .. x_tiles {
                            x_coords.push((clipped_surface_rect.min.x + x as f32 * dx).round());
                        }
                        for y in 1 .. y_tiles {
                            y_coords.push((clipped_surface_rect.min.y + y as f32 * dy).round());
                        }

                        x_coords.push(clipped_surface_rect.max.x.round());
                        y_coords.push(clipped_surface_rect.max.y.round());

                        for y in 0 .. y_coords.len()-1 {
                            let y0 = y_coords[y];
                            let y1 = y_coords[y+1];

                            if y1 <= y0 {
                                continue;
                            }

                            for x in 0 .. x_coords.len()-1 {
                                let x0 = x_coords[x];
                                let x1 = x_coords[x+1];

                                if x1 <= x0 {
                                    continue;
                                }

                                let create_task = true;

                                let r = DeviceRect::new(DevicePoint::new(x0, y0), DevicePoint::new(x1, y1));

                                let x0 = r.min.x;
                                let y0 = r.min.y;
                                let x1 = r.max.x;
                                let y1 = r.max.y;

                                let segment = add_segment(
                                    x0,
                                    y0,
                                    x1,
                                    y1,
                                    create_task,
                                    prim_instance,
                                    prim_spatial_node_index,
                                    pic_context.raster_spatial_node_index,
                                    main_prim_address,
                                    transform_id,
                                    aa_flags,
                                    quad_flags,
                                    device_pixel_scale,
                                    needs_scissor,
                                    frame_state,
                                );
                                scratch.quad_segments.push(segment);
                            }
                        }

                        add_composite_prim(
                            prim_instance_index,
                            unclipped_surface_rect.cast_unit(),
                            premul_color,
                            quad_flags,
                            frame_state,
                            targets,
                            &scratch.quad_segments,
                        );
                    }
                    QuadRenderStrategy::NinePatch { clip_rect, radius } => {
                        let surface = &frame_state.surfaces[pic_context.surface_index.0];
                        let clipped_surface_rect = surface.get_surface_rect(
                            &prim_instance.vis.clip_chain.pic_coverage_rect,
                            frame_context.spatial_tree,
                        ).expect("bug: what can cause this?");

                        let unclipped_surface_rect = surface.map_to_device_rect(
                            &prim_instance.vis.clip_chain.pic_coverage_rect,
                            frame_context.spatial_tree,
                        );

                        let local_corner_0 = LayoutRect::new(
                            clip_rect.min,
                            clip_rect.min + radius,
                        );

                        let local_corner_1 = LayoutRect::new(
                            clip_rect.max - radius,
                            clip_rect.max,
                        );

                        let pic_corner_0 = pic_state.map_local_to_pic.map(&local_corner_0).unwrap();
                        let pic_corner_1 = pic_state.map_local_to_pic.map(&local_corner_1).unwrap();

                        let surface_rect_0 = surface.map_to_device_rect(
                            &pic_corner_0,
                            frame_context.spatial_tree,
                        );

                        let surface_rect_1 = surface.map_to_device_rect(
                            &pic_corner_1,
                            frame_context.spatial_tree,
                        );

                        let p0 = surface_rect_0.min.floor();
                        let p1 = surface_rect_0.max.ceil();
                        let p2 = surface_rect_1.min.floor();
                        let p3 = surface_rect_1.max.ceil();

                        let mut x_coords = [p0.x, p1.x, p2.x, p3.x];
                        let mut y_coords = [p0.y, p1.y, p2.y, p3.y];

                        x_coords.sort_by(|a, b| a.partial_cmp(b).unwrap());
                        y_coords.sort_by(|a, b| a.partial_cmp(b).unwrap());

                        scratch.quad_segments.clear();

                        for y in 0 .. y_coords.len()-1 {
                            let y0 = y_coords[y];
                            let y1 = y_coords[y+1];

                            if y1 <= y0 {
                                continue;
                            }

                            for x in 0 .. x_coords.len()-1 {
                                let x0 = x_coords[x];
                                let x1 = x_coords[x+1];

                                if x1 <= x0 {
                                    continue;
                                }

                                let create_task = if x == 1 || y == 1 {
                                    false
                                } else {
                                    true
                                };

                                let r = DeviceRect::new(DevicePoint::new(x0, y0), DevicePoint::new(x1, y1));

                                let r = match r.intersection(&clipped_surface_rect) {
                                    Some(r) => r,
                                    None => {
                                        continue;
                                    }
                                };

                                let x0 = r.min.x;
                                let y0 = r.min.y;
                                let x1 = r.max.x;
                                let y1 = r.max.y;

                                let segment = add_segment(
                                    x0,
                                    y0,
                                    x1,
                                    y1,
                                    create_task,
                                    prim_instance,
                                    prim_spatial_node_index,
                                    pic_context.raster_spatial_node_index,
                                    main_prim_address,
                                    transform_id,
                                    aa_flags,
                                    quad_flags,
                                    device_pixel_scale,
                                    false,
                                    frame_state,
                                );
                                scratch.quad_segments.push(segment);
                            }
                        }

                        add_composite_prim(
                            prim_instance_index,
                            unclipped_surface_rect.cast_unit(),
                            premul_color,
                            quad_flags,
                            frame_state,
                            targets,
                            &scratch.quad_segments,
                        );
                    }
                }

                return;
            }
        }
        PrimitiveInstanceKind::YuvImage { data_handle, segment_instance_index, .. } => {
            profile_scope!("YuvImage");
            let prim_data = &mut data_stores.yuv_image[*data_handle];
            let common_data = &mut prim_data.common;
            let yuv_image_data = &mut prim_data.kind;

            common_data.may_need_repetition = false;

            // Update the template this instane references, which may refresh the GPU
            // cache with any shared template data.
            yuv_image_data.update(common_data, frame_state);

            write_segment(
                *segment_instance_index,
                frame_state,
                &mut scratch.segments,
                &mut scratch.segment_instances,
                |request| {
                    yuv_image_data.write_prim_gpu_blocks(request);
                }
            );
        }
        PrimitiveInstanceKind::Image { data_handle, image_instance_index, .. } => {
            profile_scope!("Image");

            let prim_data = &mut data_stores.image[*data_handle];
            let common_data = &mut prim_data.common;
            let image_data = &mut prim_data.kind;
            let image_instance = &mut store.images[*image_instance_index];

            // Update the template this instance references, which may refresh the GPU
            // cache with any shared template data.
            image_data.update(
                common_data,
                image_instance,
                pic_context.surface_index,
                prim_spatial_node_index,
                frame_state,
                frame_context,
                &mut prim_instance.vis,
            );

            write_segment(
                image_instance.segment_instance_index,
                frame_state,
                &mut scratch.segments,
                &mut scratch.segment_instances,
                |request| {
                    image_data.write_prim_gpu_blocks(request);
                },
            );
        }
        PrimitiveInstanceKind::LinearGradient { data_handle, ref mut visible_tiles_range, .. } => {
            profile_scope!("LinearGradient");
            let prim_data = &mut data_stores.linear_grad[*data_handle];

            // Update the template this instane references, which may refresh the GPU
            // cache with any shared template data.
            prim_data.update(frame_state, pic_context.surface_index);

            if prim_data.stretch_size.width >= prim_data.common.prim_rect.width() &&
                prim_data.stretch_size.height >= prim_data.common.prim_rect.height() {

                prim_data.common.may_need_repetition = false;
            }

            if prim_data.tile_spacing != LayoutSize::zero() {
                // We are performing the decomposition on the CPU here, no need to
                // have it in the shader.
                prim_data.common.may_need_repetition = false;

                *visible_tiles_range = decompose_repeated_gradient(
                    &prim_instance.vis,
                    &prim_data.common.prim_rect,
                    prim_spatial_node_index,
                    &prim_data.stretch_size,
                    &prim_data.tile_spacing,
                    frame_state,
                    &mut scratch.gradient_tiles,
                    &frame_context.spatial_tree,
                    Some(&mut |_, mut request| {
                        request.push([
                            prim_data.start_point.x,
                            prim_data.start_point.y,
                            prim_data.end_point.x,
                            prim_data.end_point.y,
                        ]);
                        request.push([
                            pack_as_float(prim_data.extend_mode as u32),
                            prim_data.stretch_size.width,
                            prim_data.stretch_size.height,
                            0.0,
                        ]);
                    }),
                );

                if visible_tiles_range.is_empty() {
                    prim_instance.clear_visibility();
                }
            }

            let stops_address = GradientGpuBlockBuilder::build(
                prim_data.reverse_stops,
                frame_state.frame_gpu_data,
                &prim_data.stops,
            );

            // TODO(gw): Consider whether it's worth doing segment building
            //           for gradient primitives.
            frame_state.push_prim(
                &PrimitiveCommand::instance(prim_instance_index, stops_address),
                prim_spatial_node_index,
                targets,
            );
            return;
        }
        PrimitiveInstanceKind::CachedLinearGradient { data_handle, ref mut visible_tiles_range, .. } => {
            profile_scope!("CachedLinearGradient");
            let prim_data = &mut data_stores.linear_grad[*data_handle];
            prim_data.common.may_need_repetition = prim_data.stretch_size.width < prim_data.common.prim_rect.width()
                || prim_data.stretch_size.height < prim_data.common.prim_rect.height();

            // Update the template this instance references, which may refresh the GPU
            // cache with any shared template data.
            prim_data.update(frame_state, pic_context.surface_index);

            if prim_data.tile_spacing != LayoutSize::zero() {
                prim_data.common.may_need_repetition = false;

                *visible_tiles_range = decompose_repeated_gradient(
                    &prim_instance.vis,
                    &prim_data.common.prim_rect,
                    prim_spatial_node_index,
                    &prim_data.stretch_size,
                    &prim_data.tile_spacing,
                    frame_state,
                    &mut scratch.gradient_tiles,
                    &frame_context.spatial_tree,
                    None,
                );

                if visible_tiles_range.is_empty() {
                    prim_instance.clear_visibility();
                }
            }
        }
        PrimitiveInstanceKind::RadialGradient { data_handle, ref mut visible_tiles_range, .. } => {
            profile_scope!("RadialGradient");
            let prim_data = &mut data_stores.radial_grad[*data_handle];

            prim_data.common.may_need_repetition = prim_data.stretch_size.width < prim_data.common.prim_rect.width()
                || prim_data.stretch_size.height < prim_data.common.prim_rect.height();

            // Update the template this instane references, which may refresh the GPU
            // cache with any shared template data.
            prim_data.update(frame_state, pic_context.surface_index);

            if prim_data.tile_spacing != LayoutSize::zero() {
                prim_data.common.may_need_repetition = false;

                *visible_tiles_range = decompose_repeated_gradient(
                    &prim_instance.vis,
                    &prim_data.common.prim_rect,
                    prim_spatial_node_index,
                    &prim_data.stretch_size,
                    &prim_data.tile_spacing,
                    frame_state,
                    &mut scratch.gradient_tiles,
                    &frame_context.spatial_tree,
                    None,
                );

                if visible_tiles_range.is_empty() {
                    prim_instance.clear_visibility();
                }
            }

            // TODO(gw): Consider whether it's worth doing segment building
            //           for gradient primitives.
        }
        PrimitiveInstanceKind::ConicGradient { data_handle, ref mut visible_tiles_range, .. } => {
            profile_scope!("ConicGradient");
            let prim_data = &mut data_stores.conic_grad[*data_handle];

            prim_data.common.may_need_repetition = prim_data.stretch_size.width < prim_data.common.prim_rect.width()
                || prim_data.stretch_size.height < prim_data.common.prim_rect.height();

            // Update the template this instane references, which may refresh the GPU
            // cache with any shared template data.
            prim_data.update(frame_state, pic_context.surface_index);

            if prim_data.tile_spacing != LayoutSize::zero() {
                prim_data.common.may_need_repetition = false;

                *visible_tiles_range = decompose_repeated_gradient(
                    &prim_instance.vis,
                    &prim_data.common.prim_rect,
                    prim_spatial_node_index,
                    &prim_data.stretch_size,
                    &prim_data.tile_spacing,
                    frame_state,
                    &mut scratch.gradient_tiles,
                    &frame_context.spatial_tree,
                    None,
                );

                if visible_tiles_range.is_empty() {
                    prim_instance.clear_visibility();
                }
            }

            // TODO(gw): Consider whether it's worth doing segment building
            //           for gradient primitives.
        }
        PrimitiveInstanceKind::Picture { pic_index, .. } => {
            profile_scope!("Picture");
            let pic = &mut store.pictures[pic_index.0];

            if prim_instance.vis.clip_chain.needs_mask {
                // TODO(gw): Much of the code in this branch could be moved in to a common
                //           function as we move more primitives to the new clip-mask paths.

                // We are going to split the clip mask tasks in to a list to be rendered
                // on the source picture, and those to be rendered in to a mask for
                // compositing the picture in to the target.
                let mut source_masks = Vec::new();
                let mut target_masks = Vec::new();

                // For some composite modes, we force target mask due to limitations. That
                // might results in artifacts for these modes (which are already an existing
                // problem) but we can handle these cases as follow ups.
                let force_target_mask = match pic.composite_mode {
                    // We can't currently render over top of these filters as their size
                    // may have changed due to downscaling. We could handle this separate
                    // case as a follow up.
                    Some(PictureCompositeMode::Filter(Filter::Blur { .. })) |
                    Some(PictureCompositeMode::Filter(Filter::DropShadows { .. })) => {
                        true
                    }
                    _ => {
                        false
                    }
                };

                // Work out which clips get drawn in to the source / target mask
                for i in 0 .. prim_instance.vis.clip_chain.clips_range.count {
                    let clip_instance = frame_state.clip_store.get_instance_from_range(&prim_instance.vis.clip_chain.clips_range, i);

                    if !force_target_mask && clip_instance.flags.contains(ClipNodeFlags::SAME_COORD_SYSTEM) {
                        source_masks.push(i);
                    } else {
                        target_masks.push(i);
                    }
                }

                let pic_surface_index = pic.raster_config.as_ref().unwrap().surface_index;
                let prim_local_rect = frame_state
                    .surfaces[pic_surface_index.0]
                    .clipped_local_rect
                    .cast_unit();

                let main_prim_address = write_prim_blocks(
                    frame_state.frame_gpu_data,
                    prim_local_rect,
                    prim_instance.vis.clip_chain.local_clip_rect,
                    PremultipliedColorF::WHITE,
                    &[],
                );

                // Handle masks on the source. This is the common case, and occurs for:
                // (a) Any masks in the same coord space as the surface
                // (b) All masks if the surface and parent are axis-aligned
                if !source_masks.is_empty() {
                    let first_clip_node_index = frame_state.clip_store.clip_node_instances.len() as u32;
                    let parent_task_id = pic.primary_render_task_id.expect("bug: no composite mode");

                    // Construct a new clip node range, also add image-mask dependencies as needed
                    for instance in source_masks {
                        let clip_instance = frame_state.clip_store.get_instance_from_range(&prim_instance.vis.clip_chain.clips_range, instance);

                        for tile in frame_state.clip_store.visible_mask_tiles(clip_instance) {
                            frame_state.rg_builder.add_dependency(
                                parent_task_id,
                                tile.task_id,
                            );
                        }

                        frame_state.clip_store.clip_node_instances.push(clip_instance.clone());
                    }

                    let clip_node_range = ClipNodeRange {
                        first: first_clip_node_index,
                        count: frame_state.clip_store.clip_node_instances.len() as u32 - first_clip_node_index,
                    };

                    let masks = MaskSubPass {
                        clip_node_range,
                        prim_spatial_node_index,
                        main_prim_address,
                    };

                    // Add the mask as a sub-pass of the picture
                    let pic_task_id = pic.primary_render_task_id.expect("uh oh");
                    let pic_task = frame_state.rg_builder.get_task_mut(pic_task_id);
                    pic_task.add_sub_pass(SubPass::Masks {
                        masks,
                    });
                }

                // Handle masks on the target. This is the rare case, and occurs for:
                // Masks in parent space when non-axis-aligned to source space
                if !target_masks.is_empty() {
                    let surface = &frame_state.surfaces[pic_context.surface_index.0];
                    let coverage_rect = prim_instance.vis.clip_chain.pic_coverage_rect;

                    let device_pixel_scale = surface.device_pixel_scale;
                    let raster_spatial_node_index = surface.raster_spatial_node_index;

                    let clipped_surface_rect = surface.get_surface_rect(
                        &coverage_rect,
                        frame_context.spatial_tree,
                    ).expect("bug: what can cause this?");

                    let p0 = clipped_surface_rect.min.floor();
                    let x0 = p0.x;
                    let y0 = p0.y;

                    let content_origin = DevicePoint::new(x0, y0);

                    // Draw a normal screens-space mask to an alpha target that
                    // can be sampled when compositing this picture.
                    let empty_task = EmptyTask {
                        content_origin,
                        device_pixel_scale,
                        raster_spatial_node_index,
                    };

                    let p1 = clipped_surface_rect.max.ceil();
                    let x1 = p1.x;
                    let y1 = p1.y;

                    let task_size = DeviceSize::new(x1 - x0, y1 - y0).round().to_i32();

                    let clip_task_id = frame_state.rg_builder.add().init(RenderTask::new_dynamic(
                        task_size,
                        RenderTaskKind::Empty(empty_task),
                    ));

                    // Construct a new clip node range, also add image-mask dependencies as needed
                    let first_clip_node_index = frame_state.clip_store.clip_node_instances.len() as u32;
                    for instance in target_masks {
                        let clip_instance = frame_state.clip_store.get_instance_from_range(&prim_instance.vis.clip_chain.clips_range, instance);

                        for tile in frame_state.clip_store.visible_mask_tiles(clip_instance) {
                            frame_state.rg_builder.add_dependency(
                                clip_task_id,
                                tile.task_id,
                            );
                        }

                        frame_state.clip_store.clip_node_instances.push(clip_instance.clone());
                    }

                    let clip_node_range = ClipNodeRange {
                        first: first_clip_node_index,
                        count: frame_state.clip_store.clip_node_instances.len() as u32 - first_clip_node_index,
                    };

                    let masks = MaskSubPass {
                        clip_node_range,
                        prim_spatial_node_index,
                        main_prim_address,
                    };

                    let clip_task = frame_state.rg_builder.get_task_mut(clip_task_id);
                    clip_task.add_sub_pass(SubPass::Masks {
                        masks,
                    });

                    let clip_task_index = ClipTaskIndex(scratch.clip_mask_instances.len() as _);
                    scratch.clip_mask_instances.push(ClipMaskKind::Mask(clip_task_id));
                    prim_instance.vis.clip_task_index = clip_task_index;
                    frame_state.surface_builder.add_child_render_task(
                        clip_task_id,
                        frame_state.rg_builder,
                    );
                }
            }

            if pic.prepare_for_render(
                frame_state,
                data_stores,
            ) {
                if let Picture3DContext::In { root_data: None, plane_splitter_index, .. } = pic.context_3d {
                    let dirty_rect = frame_state.current_dirty_region().combined;
                    let splitter = &mut frame_state.plane_splitters[plane_splitter_index.0];
                    let surface_index = pic.raster_config.as_ref().unwrap().surface_index;
                    let surface = &frame_state.surfaces[surface_index.0];
                    let local_prim_rect = surface.clipped_local_rect.cast_unit();

                    PicturePrimitive::add_split_plane(
                        splitter,
                        frame_context.spatial_tree,
                        prim_spatial_node_index,
                        local_prim_rect,
                        &prim_instance.vis.clip_chain.local_clip_rect,
                        dirty_rect,
                        plane_split_anchor,
                    );
                }
            } else {
                prim_instance.clear_visibility();
            }
        }
        PrimitiveInstanceKind::BackdropCapture { .. } => {
            // Register the owner picture of this backdrop primitive as the
            // target for resolve of the sub-graph
            frame_state.surface_builder.register_resolve_source();
        }
        PrimitiveInstanceKind::BackdropRender { pic_index, .. } => {
            match frame_state.surface_builder.sub_graph_output_map.get(pic_index).cloned() {
                Some(sub_graph_output_id) => {
                    frame_state.surface_builder.add_child_render_task(
                        sub_graph_output_id,
                        frame_state.rg_builder,
                    );
                }
                None => {
                    // Backdrop capture was found not visible, didn't produce a sub-graph
                    // so we can just skip drawing
                    prim_instance.clear_visibility();
                }
            }
        }
    }

    match prim_instance.vis.state {
        VisibilityState::Unset => {
            panic!("bug: invalid vis state");
        }
        VisibilityState::Visible { .. } => {
            frame_state.push_prim(
                &PrimitiveCommand::simple(prim_instance_index),
                prim_spatial_node_index,
                targets,
            );
        }
        VisibilityState::PassThrough | VisibilityState::Culled => {}
    }
}


fn write_segment<F>(
    segment_instance_index: SegmentInstanceIndex,
    frame_state: &mut FrameBuildingState,
    segments: &mut SegmentStorage,
    segment_instances: &mut SegmentInstanceStorage,
    f: F,
) where F: Fn(&mut GpuDataRequest) {
    debug_assert_ne!(segment_instance_index, SegmentInstanceIndex::INVALID);
    if segment_instance_index != SegmentInstanceIndex::UNUSED {
        let segment_instance = &mut segment_instances[segment_instance_index];

        if let Some(mut request) = frame_state.gpu_cache.request(&mut segment_instance.gpu_cache_handle) {
            let segments = &segments[segment_instance.segments_range];

            f(&mut request);

            for segment in segments {
                request.write_segment(
                    segment.local_rect,
                    [0.0; 4],
                );
            }
        }
    }
}

fn decompose_repeated_gradient(
    prim_vis: &PrimitiveVisibility,
    prim_local_rect: &LayoutRect,
    prim_spatial_node_index: SpatialNodeIndex,
    stretch_size: &LayoutSize,
    tile_spacing: &LayoutSize,
    frame_state: &mut FrameBuildingState,
    gradient_tiles: &mut GradientTileStorage,
    spatial_tree: &SpatialTree,
    mut callback: Option<&mut dyn FnMut(&LayoutRect, GpuDataRequest)>,
) -> GradientTileRange {
    let tile_range = gradient_tiles.open_range();

    // Tighten the clip rect because decomposing the repeated image can
    // produce primitives that are partially covering the original image
    // rect and we want to clip these extra parts out.
    if let Some(tight_clip_rect) = prim_vis
        .clip_chain
        .local_clip_rect
        .intersection(prim_local_rect) {

        let visible_rect = compute_conservative_visible_rect(
            &prim_vis.clip_chain,
            frame_state.current_dirty_region().combined,
            prim_spatial_node_index,
            spatial_tree,
        );
        let stride = *stretch_size + *tile_spacing;

        let repetitions = image_tiling::repetitions(prim_local_rect, &visible_rect, stride);
        gradient_tiles.reserve(repetitions.num_repetitions());
        for Repetition { origin, .. } in repetitions {
            let mut handle = GpuCacheHandle::new();
            let rect = LayoutRect::from_origin_and_size(
                origin,
                *stretch_size,
            );

            if let Some(callback) = &mut callback {
                if let Some(request) = frame_state.gpu_cache.request(&mut handle) {
                    callback(&rect, request);
                }
            }

            gradient_tiles.push(VisibleGradientTile {
                local_rect: rect,
                local_clip_rect: tight_clip_rect,
                handle
            });
        }
    }

    // At this point if we don't have tiles to show it means we could probably
    // have done a better a job at culling during an earlier stage.
    gradient_tiles.close_range(tile_range)
}


fn update_clip_task_for_brush(
    instance: &PrimitiveInstance,
    prim_origin: &LayoutPoint,
    prim_spatial_node_index: SpatialNodeIndex,
    root_spatial_node_index: SpatialNodeIndex,
    pic_context: &PictureContext,
    pic_state: &mut PictureState,
    frame_context: &FrameBuildingContext,
    frame_state: &mut FrameBuildingState,
    prim_store: &PrimitiveStore,
    data_stores: &mut DataStores,
    segments_store: &mut SegmentStorage,
    segment_instances_store: &mut SegmentInstanceStorage,
    clip_mask_instances: &mut Vec<ClipMaskKind>,
    device_pixel_scale: DevicePixelScale,
) -> Option<ClipTaskIndex> {
    let segments = match instance.kind {
        PrimitiveInstanceKind::Picture { .. } |
        PrimitiveInstanceKind::TextRun { .. } |
        PrimitiveInstanceKind::Clear { .. } |
        PrimitiveInstanceKind::LineDecoration { .. } |
        PrimitiveInstanceKind::BackdropCapture { .. } |
        PrimitiveInstanceKind::BackdropRender { .. } => {
            return None;
        }
        PrimitiveInstanceKind::Image { image_instance_index, .. } => {
            let segment_instance_index = prim_store
                .images[image_instance_index]
                .segment_instance_index;

            if segment_instance_index == SegmentInstanceIndex::UNUSED {
                return None;
            }

            let segment_instance = &segment_instances_store[segment_instance_index];

            &segments_store[segment_instance.segments_range]
        }
        PrimitiveInstanceKind::YuvImage { segment_instance_index, .. } => {
            debug_assert!(segment_instance_index != SegmentInstanceIndex::INVALID);

            if segment_instance_index == SegmentInstanceIndex::UNUSED {
                return None;
            }

            let segment_instance = &segment_instances_store[segment_instance_index];

            &segments_store[segment_instance.segments_range]
        }
        PrimitiveInstanceKind::Rectangle { use_legacy_path, segment_instance_index, .. } => {
            assert!(use_legacy_path);
            debug_assert!(segment_instance_index != SegmentInstanceIndex::INVALID);

            if segment_instance_index == SegmentInstanceIndex::UNUSED {
                return None;
            }

            let segment_instance = &segment_instances_store[segment_instance_index];

            &segments_store[segment_instance.segments_range]
        }
        PrimitiveInstanceKind::ImageBorder { data_handle, .. } => {
            let border_data = &data_stores.image_border[data_handle].kind;

            // TODO: This is quite messy - once we remove legacy primitives we
            //       can change this to be a tuple match on (instance, template)
            border_data.brush_segments.as_slice()
        }
        PrimitiveInstanceKind::NormalBorder { data_handle, .. } => {
            let border_data = &data_stores.normal_border[data_handle].kind;

            // TODO: This is quite messy - once we remove legacy primitives we
            //       can change this to be a tuple match on (instance, template)
            border_data.brush_segments.as_slice()
        }
        PrimitiveInstanceKind::LinearGradient { data_handle, .. }
        | PrimitiveInstanceKind::CachedLinearGradient { data_handle, .. } => {
            let prim_data = &data_stores.linear_grad[data_handle];

            // TODO: This is quite messy - once we remove legacy primitives we
            //       can change this to be a tuple match on (instance, template)
            if prim_data.brush_segments.is_empty() {
                return None;
            }

            prim_data.brush_segments.as_slice()
        }
        PrimitiveInstanceKind::RadialGradient { data_handle, .. } => {
            let prim_data = &data_stores.radial_grad[data_handle];

            // TODO: This is quite messy - once we remove legacy primitives we
            //       can change this to be a tuple match on (instance, template)
            if prim_data.brush_segments.is_empty() {
                return None;
            }

            prim_data.brush_segments.as_slice()
        }
        PrimitiveInstanceKind::ConicGradient { data_handle, .. } => {
            let prim_data = &data_stores.conic_grad[data_handle];

            // TODO: This is quite messy - once we remove legacy primitives we
            //       can change this to be a tuple match on (instance, template)
            if prim_data.brush_segments.is_empty() {
                return None;
            }

            prim_data.brush_segments.as_slice()
        }
    };

    // If there are no segments, early out to avoid setting a valid
    // clip task instance location below.
    if segments.is_empty() {
        return None;
    }

    // Set where in the clip mask instances array the clip mask info
    // can be found for this primitive. Each segment will push the
    // clip mask information for itself in update_clip_task below.
    let clip_task_index = ClipTaskIndex(clip_mask_instances.len() as _);

    // If we only built 1 segment, there is no point in re-running
    // the clip chain builder. Instead, just use the clip chain
    // instance that was built for the main primitive. This is a
    // significant optimization for the common case.
    if segments.len() == 1 {
        let clip_mask_kind = update_brush_segment_clip_task(
            &segments[0],
            Some(&instance.vis.clip_chain),
            root_spatial_node_index,
            pic_context.surface_index,
            frame_context,
            frame_state,
            &mut data_stores.clip,
            device_pixel_scale,
        );
        clip_mask_instances.push(clip_mask_kind);
    } else {
        let dirty_world_rect = frame_state.current_dirty_region().combined;

        for segment in segments {
            // Build a clip chain for the smaller segment rect. This will
            // often manage to eliminate most/all clips, and sometimes
            // clip the segment completely.
            frame_state.clip_store.set_active_clips_from_clip_chain(
                &instance.vis.clip_chain,
                prim_spatial_node_index,
                &frame_context.spatial_tree,
                &data_stores.clip,
            );

            let segment_clip_chain = frame_state
                .clip_store
                .build_clip_chain_instance(
                    segment.local_rect.translate(prim_origin.to_vector()),
                    &pic_state.map_local_to_pic,
                    &pic_state.map_pic_to_world,
                    &frame_context.spatial_tree,
                    frame_state.gpu_cache,
                    frame_state.resource_cache,
                    device_pixel_scale,
                    &dirty_world_rect,
                    &mut data_stores.clip,
                    frame_state.rg_builder,
                    false,
                );

            let clip_mask_kind = update_brush_segment_clip_task(
                &segment,
                segment_clip_chain.as_ref(),
                root_spatial_node_index,
                pic_context.surface_index,
                frame_context,
                frame_state,
                &mut data_stores.clip,
                device_pixel_scale,
            );
            clip_mask_instances.push(clip_mask_kind);
        }
    }

    Some(clip_task_index)
}

pub fn update_clip_task(
    instance: &mut PrimitiveInstance,
    prim_origin: &LayoutPoint,
    prim_spatial_node_index: SpatialNodeIndex,
    root_spatial_node_index: SpatialNodeIndex,
    pic_context: &PictureContext,
    pic_state: &mut PictureState,
    frame_context: &FrameBuildingContext,
    frame_state: &mut FrameBuildingState,
    prim_store: &mut PrimitiveStore,
    data_stores: &mut DataStores,
    scratch: &mut PrimitiveScratchBuffer,
) -> bool {
    let device_pixel_scale = frame_state.surfaces[pic_context.surface_index.0].device_pixel_scale;

    build_segments_if_needed(
        instance,
        frame_state,
        prim_store,
        data_stores,
        &mut scratch.segments,
        &mut scratch.segment_instances,
    );

    // First try to  render this primitive's mask using optimized brush rendering.
    instance.vis.clip_task_index = if let Some(clip_task_index) = update_clip_task_for_brush(
        instance,
        prim_origin,
        prim_spatial_node_index,
        root_spatial_node_index,
        pic_context,
        pic_state,
        frame_context,
        frame_state,
        prim_store,
        data_stores,
        &mut scratch.segments,
        &mut scratch.segment_instances,
        &mut scratch.clip_mask_instances,
        device_pixel_scale,
    ) {
        clip_task_index
    } else if instance.vis.clip_chain.needs_mask {
        // Get a minimal device space rect, clipped to the screen that we
        // need to allocate for the clip mask, as well as interpolated
        // snap offsets.
        let unadjusted_device_rect = match frame_state.surfaces[pic_context.surface_index.0].get_surface_rect(
            &instance.vis.clip_chain.pic_coverage_rect,
            frame_context.spatial_tree,
        ) {
            Some(rect) => rect,
            None => return false,
        };

        let (device_rect, device_pixel_scale) = adjust_mask_scale_for_max_size(
            unadjusted_device_rect,
            device_pixel_scale,
        );
        let clip_task_id = RenderTaskKind::new_mask(
            device_rect,
            instance.vis.clip_chain.clips_range,
            root_spatial_node_index,
            frame_state.clip_store,
            frame_state.gpu_cache,
            frame_state.frame_gpu_data,
            frame_state.resource_cache,
            frame_state.rg_builder,
            &mut data_stores.clip,
            device_pixel_scale,
            frame_context.fb_config,
            &mut frame_state.surface_builder,
        );
        // Set the global clip mask instance for this primitive.
        let clip_task_index = ClipTaskIndex(scratch.clip_mask_instances.len() as _);
        scratch.clip_mask_instances.push(ClipMaskKind::Mask(clip_task_id));
        instance.vis.clip_task_index = clip_task_index;
        frame_state.surface_builder.add_child_render_task(
            clip_task_id,
            frame_state.rg_builder,
        );
        clip_task_index
    } else {
        ClipTaskIndex::INVALID
    };

    true
}

/// Write out to the clip mask instances array the correct clip mask
/// config for this segment.
pub fn update_brush_segment_clip_task(
    segment: &BrushSegment,
    clip_chain: Option<&ClipChainInstance>,
    root_spatial_node_index: SpatialNodeIndex,
    surface_index: SurfaceIndex,
    frame_context: &FrameBuildingContext,
    frame_state: &mut FrameBuildingState,
    clip_data_store: &mut ClipDataStore,
    device_pixel_scale: DevicePixelScale,
) -> ClipMaskKind {
    let clip_chain = match clip_chain {
        Some(chain) => chain,
        None => return ClipMaskKind::Clipped,
    };
    if !clip_chain.needs_mask ||
       (!segment.may_need_clip_mask && !clip_chain.has_non_local_clips) {
        return ClipMaskKind::None;
    }

    let device_rect = match frame_state.surfaces[surface_index.0].get_surface_rect(
        &clip_chain.pic_coverage_rect,
        frame_context.spatial_tree,
    ) {
        Some(rect) => rect,
        None => return ClipMaskKind::Clipped,
    };

    let (device_rect, device_pixel_scale) = adjust_mask_scale_for_max_size(device_rect, device_pixel_scale);

    let clip_task_id = RenderTaskKind::new_mask(
        device_rect,
        clip_chain.clips_range,
        root_spatial_node_index,
        frame_state.clip_store,
        frame_state.gpu_cache,
        frame_state.frame_gpu_data,
        frame_state.resource_cache,
        frame_state.rg_builder,
        clip_data_store,
        device_pixel_scale,
        frame_context.fb_config,
        &mut frame_state.surface_builder,
    );

    frame_state.surface_builder.add_child_render_task(
        clip_task_id,
        frame_state.rg_builder,
    );
    ClipMaskKind::Mask(clip_task_id)
}


fn write_brush_segment_description(
    prim_local_rect: LayoutRect,
    prim_local_clip_rect: LayoutRect,
    clip_chain: &ClipChainInstance,
    segment_builder: &mut SegmentBuilder,
    clip_store: &ClipStore,
    data_stores: &DataStores,
) -> bool {
    // If the brush is small, we want to skip building segments
    // and just draw it as a single primitive with clip mask.
    if prim_local_rect.area() < MIN_BRUSH_SPLIT_AREA {
        return false;
    }

    // NOTE: The local clip rect passed to the segment builder must be the unmodified
    //       local clip rect from the clip leaf, not the local_clip_rect from the
    //       clip-chain instance. The clip-chain instance may have been reduced by
    //       clips that are in the same coordinate system, but not the same spatial
    //       node as the primitive. This can result in the clip for the segment building
    //       being affected by scrolling clips, which we can't handle (since the segments
    //       are not invalidated during frame building after being built).
    segment_builder.initialize(
        prim_local_rect,
        None,
        prim_local_clip_rect,
    );

    // Segment the primitive on all the local-space clip sources that we can.
    for i in 0 .. clip_chain.clips_range.count {
        let clip_instance = clip_store
            .get_instance_from_range(&clip_chain.clips_range, i);
        let clip_node = &data_stores.clip[clip_instance.handle];

        // If this clip item is positioned by another positioning node, its relative position
        // could change during scrolling. This means that we would need to resegment. Instead
        // of doing that, only segment with clips that have the same positioning node.
        // TODO(mrobinson, #2858): It may make sense to include these nodes, resegmenting only
        // when necessary while scrolling.
        if !clip_instance.flags.contains(ClipNodeFlags::SAME_SPATIAL_NODE) {
            continue;
        }

        let (local_clip_rect, radius, mode) = match clip_node.item.kind {
            ClipItemKind::RoundedRectangle { rect, radius, mode } => {
                (rect, Some(radius), mode)
            }
            ClipItemKind::Rectangle { rect, mode } => {
                (rect, None, mode)
            }
            ClipItemKind::BoxShadow { ref source } => {
                // For inset box shadows, we can clip out any
                // pixels that are inside the shadow region
                // and are beyond the inner rect, as they can't
                // be affected by the blur radius.
                let inner_clip_mode = match source.clip_mode {
                    BoxShadowClipMode::Outset => None,
                    BoxShadowClipMode::Inset => Some(ClipMode::ClipOut),
                };

                // Push a region into the segment builder where the
                // box-shadow can have an effect on the result. This
                // ensures clip-mask tasks get allocated for these
                // pixel regions, even if no other clips affect them.
                segment_builder.push_mask_region(
                    source.prim_shadow_rect,
                    source.prim_shadow_rect.inflate(
                        -0.5 * source.original_alloc_size.width,
                        -0.5 * source.original_alloc_size.height,
                    ),
                    inner_clip_mode,
                );

                continue;
            }
            ClipItemKind::Image { .. } => {
                panic!("bug: masks not supported on old segment path");
            }
        };

        segment_builder.push_clip_rect(local_clip_rect, radius, mode);
    }

    true
}

fn build_segments_if_needed(
    instance: &mut PrimitiveInstance,
    frame_state: &mut FrameBuildingState,
    prim_store: &mut PrimitiveStore,
    data_stores: &DataStores,
    segments_store: &mut SegmentStorage,
    segment_instances_store: &mut SegmentInstanceStorage,
) {
    let prim_clip_chain = &instance.vis.clip_chain;

    // Usually, the primitive rect can be found from information
    // in the instance and primitive template.
    let prim_local_rect = data_stores.get_local_prim_rect(
        instance,
        &prim_store.pictures,
        frame_state.surfaces,
    );

    let segment_instance_index = match instance.kind {
        PrimitiveInstanceKind::Rectangle { use_legacy_path, ref mut segment_instance_index, .. } => {
            assert!(use_legacy_path);
            segment_instance_index
        }
        PrimitiveInstanceKind::YuvImage { ref mut segment_instance_index, compositor_surface_kind, .. } => {
            // Only use segments for YUV images if not drawing as a compositor surface
            if !compositor_surface_kind.supports_segments() {
                *segment_instance_index = SegmentInstanceIndex::UNUSED;
                return;
            }

            segment_instance_index
        }
        PrimitiveInstanceKind::Image { data_handle, image_instance_index, compositor_surface_kind, .. } => {
            let image_data = &data_stores.image[data_handle].kind;
            let image_instance = &mut prim_store.images[image_instance_index];

            //Note: tiled images don't support automatic segmentation,
            // they strictly produce one segment per visible tile instead.
            if !compositor_surface_kind.supports_segments() ||
                frame_state.resource_cache
                    .get_image_properties(image_data.key)
                    .and_then(|properties| properties.tiling)
                    .is_some()
            {
                image_instance.segment_instance_index = SegmentInstanceIndex::UNUSED;
                return;
            }
            &mut image_instance.segment_instance_index
        }
        PrimitiveInstanceKind::Picture { .. } |
        PrimitiveInstanceKind::TextRun { .. } |
        PrimitiveInstanceKind::NormalBorder { .. } |
        PrimitiveInstanceKind::ImageBorder { .. } |
        PrimitiveInstanceKind::Clear { .. } |
        PrimitiveInstanceKind::LinearGradient { .. } |
        PrimitiveInstanceKind::CachedLinearGradient { .. } |
        PrimitiveInstanceKind::RadialGradient { .. } |
        PrimitiveInstanceKind::ConicGradient { .. } |
        PrimitiveInstanceKind::LineDecoration { .. } |
        PrimitiveInstanceKind::BackdropCapture { .. } |
        PrimitiveInstanceKind::BackdropRender { .. } => {
            // These primitives don't support / need segments.
            return;
        }
    };

    if *segment_instance_index == SegmentInstanceIndex::INVALID {
        let mut segments: SmallVec<[BrushSegment; 8]> = SmallVec::new();
        let clip_leaf = frame_state.clip_tree.get_leaf(instance.clip_leaf_id);

        if write_brush_segment_description(
            prim_local_rect,
            clip_leaf.local_clip_rect,
            prim_clip_chain,
            &mut frame_state.segment_builder,
            frame_state.clip_store,
            data_stores,
        ) {
            frame_state.segment_builder.build(|segment| {
                segments.push(
                    BrushSegment::new(
                        segment.rect.translate(-prim_local_rect.min.to_vector()),
                        segment.has_mask,
                        segment.edge_flags,
                        [0.0; 4],
                        BrushFlags::PERSPECTIVE_INTERPOLATION,
                    ),
                );
            });
        }

        // If only a single segment is produced, there is no benefit to writing
        // a segment instance array. Instead, just use the main primitive rect
        // written into the GPU cache.
        // TODO(gw): This is (sortof) a bandaid - due to a limitation in the current
        //           brush encoding, we can only support a total of up to 2^16 segments.
        //           This should be (more than) enough for any real world case, so for
        //           now we can handle this by skipping cases where we were generating
        //           segments where there is no benefit. The long term / robust fix
        //           for this is to move the segment building to be done as a more
        //           limited nine-patch system during scene building, removing arbitrary
        //           segmentation during frame-building (see bug #1617491).
        if segments.len() <= 1 {
            *segment_instance_index = SegmentInstanceIndex::UNUSED;
        } else {
            let segments_range = segments_store.extend(segments);

            let instance = SegmentedInstance {
                segments_range,
                gpu_cache_handle: GpuCacheHandle::new(),
            };

            *segment_instance_index = segment_instances_store.push(instance);
        };
    }
}

// Ensures that the size of mask render tasks are within MAX_MASK_SIZE.
fn adjust_mask_scale_for_max_size(device_rect: DeviceRect, device_pixel_scale: DevicePixelScale) -> (DeviceRect, DevicePixelScale) {
    if device_rect.width() > MAX_MASK_SIZE || device_rect.height() > MAX_MASK_SIZE {
        // round_out will grow by 1 integer pixel if origin is on a
        // fractional position, so keep that margin for error with -1:
        let scale = (MAX_MASK_SIZE - 1.0) /
            f32::max(device_rect.width(), device_rect.height());
        let new_device_pixel_scale = device_pixel_scale * Scale::new(scale);
        let new_device_rect = (device_rect.to_f32() * Scale::new(scale))
            .round_out();
        (new_device_rect, new_device_pixel_scale)
    } else {
        (device_rect, device_pixel_scale)
    }
}

pub fn write_prim_blocks(
    builder: &mut GpuBufferBuilder,
    prim_rect: LayoutRect,
    clip_rect: LayoutRect,
    color: PremultipliedColorF,
    segments: &[QuadSegment],
) -> GpuBufferAddress {
    let mut writer = builder.write_blocks(3 + segments.len() * 2);

    writer.push_one(prim_rect);
    writer.push_one(clip_rect);
    writer.push_one(color);

    for segment in segments {
        writer.push_one(segment.rect);
        match segment.task_id {
            RenderTaskId::INVALID => {
                writer.push_one([0.0; 4]);
            }
            task_id => {
                writer.push_render_task(task_id);
            }
        }
    }

    writer.finish()
}

fn add_segment(
    x0: f32,
    y0: f32,
    x1: f32,
    y1: f32,
    create_task: bool,
    prim_instance: &PrimitiveInstance,
    prim_spatial_node_index: SpatialNodeIndex,
    raster_spatial_node_index: SpatialNodeIndex,
    main_prim_address: GpuBufferAddress,
    transform_id: TransformPaletteId,
    aa_flags: EdgeAaSegmentMask,
    quad_flags: QuadFlags,
    device_pixel_scale: DevicePixelScale,
    needs_scissor_rect: bool,
    frame_state: &mut FrameBuildingState,
) -> QuadSegment {
    let task_size = DeviceSize::new(x1 - x0, y1 - y0).round().to_i32();
    let content_origin = DevicePoint::new(x0, y0);

    let rect = LayoutRect::new(
        LayoutPoint::new(x0, y0),
        LayoutPoint::new(x1, y1),
    );

    let task_id = if create_task {
        let task_id = frame_state.rg_builder.add().init(RenderTask::new_dynamic(
            task_size,
            RenderTaskKind::new_prim(
                prim_spatial_node_index,
                raster_spatial_node_index,
                device_pixel_scale,
                content_origin,
                main_prim_address,
                transform_id,
                aa_flags,
                quad_flags,
                prim_instance.vis.clip_chain.clips_range,
                needs_scissor_rect,
            ),
        ));

        let masks = MaskSubPass {
            clip_node_range: prim_instance.vis.clip_chain.clips_range,
            prim_spatial_node_index,
            main_prim_address,
        };

        let task = frame_state.rg_builder.get_task_mut(task_id);
        task.add_sub_pass(SubPass::Masks {
            masks,
        });

        frame_state.surface_builder.add_child_render_task(
            task_id,
            frame_state.rg_builder,
        );

        task_id
    } else {
        RenderTaskId::INVALID
    };

    QuadSegment {
        rect,
        task_id,
    }
}

fn add_composite_prim(
    prim_instance_index: PrimitiveInstanceIndex,
    rect: LayoutRect,
    color: PremultipliedColorF,
    quad_flags: QuadFlags,
    frame_state: &mut FrameBuildingState,
    targets: &[CommandBufferIndex],
    segments: &[QuadSegment],
) {
    let composite_prim_address = write_prim_blocks(
        frame_state.frame_gpu_data,
        rect,
        rect,
        color,
        segments,
    );

    frame_state.set_segments(
        segments,
        targets,
    );

    let mut composite_quad_flags = QuadFlags::IGNORE_DEVICE_PIXEL_SCALE | QuadFlags::APPLY_DEVICE_CLIP;
    if quad_flags.contains(QuadFlags::IS_OPAQUE) {
        composite_quad_flags |= QuadFlags::IS_OPAQUE;
    }

    frame_state.push_cmd(
        &PrimitiveCommand::quad(
            prim_instance_index,
            composite_prim_address,
            TransformPaletteId::IDENTITY,
            composite_quad_flags,
            // TODO(gw): No AA on composite, unless we use it to apply 2d clips
            EdgeAaSegmentMask::empty(),
        ),
        targets,
    );
}

impl CompositorSurfaceKind {
    /// Returns true if the compositor surface strategy supports segment rendering
    fn supports_segments(&self) -> bool {
        match self {
            CompositorSurfaceKind::Underlay | CompositorSurfaceKind::Overlay => false,
            CompositorSurfaceKind::Blit => true,
        }
    }
}