Codebase list libmypaint / HEAD mypaint-tiled-surface.c
HEAD

Tree @HEAD (Download .tar.gz)

mypaint-tiled-surface.c @HEADraw · history · blame

   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
/* libmypaint - The MyPaint Brush Library
 * Copyright (C) 2007-2014 Martin Renold <martinxyz@gmx.ch> et. al.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "config.h"

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#ifdef _OPENMP
#include <omp.h>
#endif

#include "mypaint-config.h"
#include "mypaint-tiled-surface.h"
#include "tiled-surface-private.h"
#include "helpers.h"
#include "brushmodes.h"
#include "operationqueue.h"

#define NUM_BBOXES_DEFAULT 32


/**
 * MyPaintTiledSurface:
 *
 * Testing if this comment ends up in the gir.
 */
struct MyPaintTiledSurface;

void tiled_surface_process_tile(MyPaintTiledSurface *self, int tx, int ty);

void process_tile_internal(
    void* tiled_surface, void (*request_start)(void*, void*), void (*request_end)(void*, void*),
    OperationQueue* op_queue, int tx, int ty);

static void
begin_atomic_default(MyPaintSurface *surface)
{
    mypaint_tiled_surface_begin_atomic((MyPaintTiledSurface *)surface);
}

static void
end_atomic_default(MyPaintSurface *surface, MyPaintRectangle *roi)
{
    mypaint_tiled_surface_end_atomic((MyPaintTiledSurface *)surface, roi);
}

/**
 * mypaint_tiled_surface_begin_atomic: (skip)
 */
void
mypaint_tiled_surface_begin_atomic(MyPaintTiledSurface *self)
{
  self->dirty_bbox.x = 0;
  self->dirty_bbox.y = 0;
  self->dirty_bbox.width = 0;
  self->dirty_bbox.height = 0;
}

/**
 * mypaint_tiled_surface_end_atomic: (skip)
 *
 * Implementation of #MyPaintSurface::end_atomic vfunc
 * Note: Only intended to be used from #MyPaintTiledSurface subclasses, which should chain up to this
 * if implementing their own #MyPaintSurface::end_atomic vfunc.
 * Application code should only use mypaint_surface_end_atomic().
 */
void
mypaint_tiled_surface_end_atomic(MyPaintTiledSurface *self, MyPaintRectangle *roi)
{
    // Process tiles
    TileIndex *tiles;
    int tiles_n = operation_queue_get_dirty_tiles(self->operation_queue, &tiles);

    #pragma omp parallel for schedule(static) if(self->threadsafe_tile_requests && tiles_n > 3)
    for (int i = 0; i < tiles_n; i++) {
      tiled_surface_process_tile(self, tiles[i].x, tiles[i].y);
    }

    operation_queue_clear_dirty_tiles(self->operation_queue);

    if (roi) {
        *roi = self->dirty_bbox;
    }
}


/**
 * mypaint_tiled_surface_tile_request_start:
 */
void mypaint_tiled_surface_tile_request_start(MyPaintTiledSurface *self, MyPaintTileRequest *request)
{
    assert(self->tile_request_start);
    self->tile_request_start(self, request);
}

/**
 * mypaint_tiled_surface_tile_request_end:
 */
void mypaint_tiled_surface_tile_request_end(MyPaintTiledSurface *self, MyPaintTileRequest *request)
{
    assert(self->tile_request_end);
    self->tile_request_end(self, request);
}

/**
 * mypaint_tiled_surface_set_symmetry_state:
 * @active: TRUE to enable, FALSE to disable.
 * @center_x: X axis to mirror events across.
 *
 * Enable/Disable symmetric brush painting across an X axis.
 */
void
mypaint_tiled_surface_set_symmetry_state(MyPaintTiledSurface *self, gboolean active, float center_x)
{
    self->surface_do_symmetry = active;
    self->surface_center_x = center_x;
}

/**
 * mypaint_tile_request_init:
 *
 * Initialize a request for use with mypaint_tiled_surface_tile_request_start()
 * and mypaint_tiled_surface_tile_request_end()
 */
void
mypaint_tile_request_init(MyPaintTileRequest *data, int level,
                          int tx, int ty, gboolean readonly)
{
    data->tx = tx;
    data->ty = ty;
    data->readonly = readonly;
    data->buffer = NULL;
    data->context = NULL;
#ifdef _OPENMP
    data->thread_id = omp_get_thread_num();
#else
    data->thread_id = -1;
#endif
    data->mipmap_level = level;
}

// Must be threadsafe
static inline float
calculate_r_sample(float x, float y, float aspect_ratio,
                      float sn, float cs)
{
    const float yyr=(y*cs-x*sn)*aspect_ratio;
    const float xxr=y*sn+x*cs;
    const float r = (yyr*yyr + xxr*xxr);
    return r;
}

static inline float
calculate_rr(int xp, int yp, float x, float y, float aspect_ratio,
                      float sn, float cs, float one_over_radius2)
{
    // code duplication, see brush::count_dabs_to()
    const float yy = (yp + 0.5f - y);
    const float xx = (xp + 0.5f - x);
    const float yyr=(yy*cs-xx*sn)*aspect_ratio;
    const float xxr=yy*sn+xx*cs;
    const float rr = (yyr*yyr + xxr*xxr) * one_over_radius2;
    // rr is in range 0.0..1.0*sqrt(2)
    return rr;
}

static inline float
sign_point_in_line( float px, float py, float vx, float vy )
{
    return (px - vx) * (-vy) - (vx) * (py - vy);
}

static inline void
closest_point_to_line( float lx, float ly, float px, float py, float *ox, float *oy )
{
    const float l2 = lx*lx + ly*ly;
    const float ltp_dot = px*lx + py*ly;
    const float t = ltp_dot / l2;
    *ox = lx * t;
    *oy = ly * t;
}

// Must be threadsafe
//
// This works by taking the visibility at the nearest point
// and dividing by 1.0 + delta.
//
// - nearest point: point where the dab has more influence
// - farthest point: point at a fixed distance away from
//                   the nearest point
// - delta: how much occluded is the farthest point relative
//          to the nearest point
static inline float
calculate_rr_antialiased(int xp, int yp, float x, float y, float aspect_ratio,
                      float sn, float cs, float one_over_radius2,
                      float r_aa_start)
{
    // calculate pixel position and borders in a way
    // that the dab's center is always at zero
    float pixel_right = x - (float)xp;
    float pixel_bottom = y - (float)yp;
    float pixel_center_x = pixel_right - 0.5f;
    float pixel_center_y = pixel_bottom - 0.5f;
    float pixel_left = pixel_right - 1.0f;
    float pixel_top = pixel_bottom - 1.0f;

    float nearest_x, nearest_y; // nearest to origin, but still inside pixel
    float farthest_x, farthest_y; // farthest from origin, but still inside pixel
    float r_near, r_far, rr_near, rr_far;
    // Dab's center is inside pixel?
    if( pixel_left<0 && pixel_right>0 &&
        pixel_top<0 && pixel_bottom>0 )
    {
        nearest_x = 0;
        nearest_y = 0;
        r_near = rr_near = 0;
    }
    else
    {
        closest_point_to_line( cs, sn, pixel_center_x, pixel_center_y, &nearest_x, &nearest_y );
        nearest_x = CLAMP( nearest_x, pixel_left, pixel_right );
        nearest_y = CLAMP( nearest_y, pixel_top, pixel_bottom );
        // XXX: precision of "nearest" values could be improved
        // by intersecting the line that goes from nearest_x/Y to 0
        // with the pixel's borders here, however the improvements
        // would probably not justify the perdormance cost.
        r_near = calculate_r_sample( nearest_x, nearest_y, aspect_ratio, sn, cs );
        rr_near = r_near * one_over_radius2;
    }

    // out of dab's reach?
    if( rr_near > 1.0f )
        return rr_near;

    // check on which side of the dab's line is the pixel center
    float center_sign = sign_point_in_line( pixel_center_x, pixel_center_y, cs, -sn );

    // radius of a circle with area=1
    //   A = pi * r * r
    //   r = sqrt(1/pi)
    const float rad_area_1 = sqrtf( 1.0f / M_PI );

    // center is below dab
    if( center_sign < 0 )
    {
        farthest_x = nearest_x - sn*rad_area_1;
        farthest_y = nearest_y + cs*rad_area_1;
    }
    // above dab
    else
    {
        farthest_x = nearest_x + sn*rad_area_1;
        farthest_y = nearest_y - cs*rad_area_1;
    }

    r_far = calculate_r_sample( farthest_x, farthest_y, aspect_ratio, sn, cs );
    rr_far = r_far * one_over_radius2;

    // check if we can skip heavier AA
    if( r_far < r_aa_start )
        return (rr_far+rr_near) * 0.5f;

    // calculate AA approximate
    float visibilityNear = 1.0f - rr_near;
    float delta = rr_far - rr_near;
    float delta2 = 1.0f + delta;
    visibilityNear /= delta2;

    return 1.0f - visibilityNear;
}

static inline float
calculate_opa(float rr, float hardness,
              float segment1_offset, float segment1_slope,
              float segment2_offset, float segment2_slope) {

    const float fac = rr <= hardness ? segment1_slope : segment2_slope;
    float opa = rr <= hardness ? segment1_offset : segment2_offset;
    opa += rr*fac;

    if (rr > 1.0f) {
        opa = 0.0f;
    }
    #ifdef HEAVY_DEBUG
    assert(isfinite(opa));
    assert(opa >= 0.0f && opa <= 1.0f);
    #endif
    return opa;
}

// Must be threadsafe
void render_dab_mask (uint16_t * mask,
                        float x, float y,
                        float radius,
                        float hardness,
                        float aspect_ratio, float angle
                        )
{

    hardness = CLAMP(hardness, 0.0, 1.0);
    if (aspect_ratio<1.0) aspect_ratio=1.0;
    assert(hardness != 0.0); // assured by caller

    // For a graphical explanation, see:
    // http://wiki.mypaint.info/Development/Documentation/Brushlib
    //
    // The hardness calculation is explained below:
    //
    // Dab opacity gradually fades out from the center (rr=0) to
    // fringe (rr=1) of the dab. How exactly depends on the hardness.
    // We use two linear segments, for which we pre-calculate slope
    // and offset here.
    //
    // opa
    // ^
    // *   .
    // |        *
    // |          .
    // +-----------*> rr = (distance_from_center/radius)^2
    // 0           1
    //
    float segment1_offset = 1.0f;
    float segment1_slope  = -(1.0f/hardness - 1.0f);
    float segment2_offset = hardness/(1.0f-hardness);
    float segment2_slope  = -hardness/(1.0f-hardness);
    // for hardness == 1.0, segment2 will never be used

    float angle_rad=angle/360*2*M_PI;
    float cs=cos(angle_rad);
    float sn=sin(angle_rad);

    const float r_fringe = radius + 1.0f; // +1.0 should not be required, only to be sure
    int x0 = floor (x - r_fringe);
    int y0 = floor (y - r_fringe);
    int x1 = floor (x + r_fringe);
    int y1 = floor (y + r_fringe);
    if (x0 < 0) x0 = 0;
    if (y0 < 0) y0 = 0;
    if (x1 > MYPAINT_TILE_SIZE-1) x1 = MYPAINT_TILE_SIZE-1;
    if (y1 > MYPAINT_TILE_SIZE-1) y1 = MYPAINT_TILE_SIZE-1;
    const float one_over_radius2 = 1.0f/(radius*radius);

    // Pre-calculate rr and put it in the mask.
    // This an optimization that makes use of auto-vectorization
    // OPTIMIZE: if using floats for the brush engine, store these directly in the mask
    float rr_mask[MYPAINT_TILE_SIZE*MYPAINT_TILE_SIZE+2*MYPAINT_TILE_SIZE];

    if (radius < 3.0f)
    {
      const float aa_border = 1.0f;
      float r_aa_start = ((radius>aa_border) ? (radius-aa_border) : 0);
      r_aa_start *= r_aa_start / aspect_ratio;

      for (int yp = y0; yp <= y1; yp++) {
        for (int xp = x0; xp <= x1; xp++) {
          const float rr = calculate_rr_antialiased(xp, yp,
                                  x, y, aspect_ratio,
                                  sn, cs, one_over_radius2,
                                  r_aa_start);
          rr_mask[(yp*MYPAINT_TILE_SIZE)+xp] = rr;
        }
      }
    }
    else
    {
      for (int yp = y0; yp <= y1; yp++) {
        for (int xp = x0; xp <= x1; xp++) {
          const float rr = calculate_rr(xp, yp,
                                  x, y, aspect_ratio,
                                  sn, cs, one_over_radius2);
          rr_mask[(yp*MYPAINT_TILE_SIZE)+xp] = rr;
        }
      }
    }

    // we do run length encoding: if opacity is zero, the next
    // value in the mask is the number of pixels that can be skipped.
    uint16_t * mask_p = mask;
    int skip=0;

    skip += y0*MYPAINT_TILE_SIZE;
    for (int yp = y0; yp <= y1; yp++) {
      skip += x0;

      int xp;
      for (xp = x0; xp <= x1; xp++) {
        const float rr = rr_mask[(yp*MYPAINT_TILE_SIZE)+xp];
        const float opa = calculate_opa(rr, hardness,
                                  segment1_offset, segment1_slope,
                                  segment2_offset, segment2_slope);
        const uint16_t opa_ = opa * (1<<15);
        if (!opa_) {
          skip++;
        } else {
          if (skip) {
            *mask_p++ = 0;
            *mask_p++ = skip*4;
            skip = 0;
          }
          *mask_p++ = opa_;
        }
      }
      skip += MYPAINT_TILE_SIZE-xp;
    }
    *mask_p++ = 0;
    *mask_p++ = 0;
  }

// Must be threadsafe
void
process_op(uint16_t *rgba_p, uint16_t *mask,
           int tx, int ty, OperationDataDrawDab *op)
{

    // first, we calculate the mask (opacity for each pixel)
    render_dab_mask(mask,
                    op->x - tx*MYPAINT_TILE_SIZE,
                    op->y - ty*MYPAINT_TILE_SIZE,
                    op->radius,
                    op->hardness,
                    op->aspect_ratio, op->angle
                    );

    // second, we use the mask to stamp a dab for each activated blend mode
    if (op->paint < 1.0) {
      if (op->normal) {
        if (op->color_a == 1.0) {
          draw_dab_pixels_BlendMode_Normal(mask, rgba_p,
                                           op->color_r, op->color_g, op->color_b, op->normal*op->opaque*(1 - op->paint)*(1<<15));
        } else {
          // normal case for brushes that use smudging (eg. watercolor)
          draw_dab_pixels_BlendMode_Normal_and_Eraser(mask, rgba_p,
                                                      op->color_r, op->color_g, op->color_b, op->color_a*(1<<15),
                                                      op->normal*op->opaque*(1 - op->paint)*(1<<15));
        }
      }

      if (op->lock_alpha && op->color_a != 0) {
        draw_dab_pixels_BlendMode_LockAlpha(mask, rgba_p,
                                            op->color_r, op->color_g, op->color_b,
                                            op->lock_alpha*op->opaque*(1 - op->colorize)*(1 - op->posterize)*(1 - op->paint)*(1<<15));
      }
    }

    if (op->paint > 0.0) {
      if (op->normal) {
        if (op->color_a == 1.0) {
          draw_dab_pixels_BlendMode_Normal_Paint(mask, rgba_p,
                                           op->color_r, op->color_g, op->color_b, op->normal*op->opaque*op->paint*(1<<15));
        } else {
          // normal case for brushes that use smudging (eg. watercolor)
          draw_dab_pixels_BlendMode_Normal_and_Eraser_Paint(mask, rgba_p,
                                                      op->color_r, op->color_g, op->color_b, op->color_a*(1<<15),
                                                      op->normal*op->opaque*op->paint*(1<<15));
        }
      }

      if (op->lock_alpha && op->color_a != 0) {
        draw_dab_pixels_BlendMode_LockAlpha_Paint(mask, rgba_p,
                                            op->color_r, op->color_g, op->color_b,
                                            op->lock_alpha*op->opaque*(1 - op->colorize)*(1 - op->posterize)*op->paint*(1<<15));
      }
    }

    if (op->colorize) {
      draw_dab_pixels_BlendMode_Color(mask, rgba_p,
                                      op->color_r, op->color_g, op->color_b,
                                      op->colorize*op->opaque*(1<<15));
    }
    if (op->posterize) {
      draw_dab_pixels_BlendMode_Posterize(mask, rgba_p,
                                      op->posterize*op->opaque*(1<<15),
                                      op->posterize_num);
    }
}

// Must be threadsafe
void
process_tile_internal(
  void *tiled_surface,
  void (*request_start) (void*, void*),
  void (*request_end) (void*, void*),
  OperationQueue* op_queue, int tx, int ty)
{
    TileIndex tile_index = {tx, ty};
    OperationDataDrawDab *op = operation_queue_pop(op_queue, tile_index);
    if (!op) {
        return;
    }

    MyPaintTileRequest request_data;
    const int mipmap_level = 0;
    mypaint_tile_request_init(&request_data, mipmap_level, tx, ty, FALSE);

    request_start(tiled_surface, &request_data);
    uint16_t * rgba_p = request_data.buffer;
    if (!rgba_p) {
        printf("Warning: Unable to get tile!\n");
        return;
    }

    uint16_t mask[MYPAINT_TILE_SIZE*MYPAINT_TILE_SIZE+2*MYPAINT_TILE_SIZE];

    while (op) {
        process_op(rgba_p, mask, tile_index.x, tile_index.y, op);
        free(op);
        op = operation_queue_pop(op_queue, tile_index);
    }
    request_end(tiled_surface, &request_data);
}

void
update_dirty_bbox(MyPaintRectangle *bbox, OperationDataDrawDab *op)
{
    int bb_x, bb_y, bb_w, bb_h;
    float r_fringe = op->radius + 1.0f; // +1.0 should not be required, only to be sure
    bb_x = floor (op->x - r_fringe);
    bb_y = floor (op->y - r_fringe);
    bb_w = floor (op->x + r_fringe) - bb_x + 1;
    bb_h = floor (op->y + r_fringe) - bb_y + 1;

    mypaint_rectangle_expand_to_include_point(bbox, bb_x, bb_y);
    mypaint_rectangle_expand_to_include_point(bbox, bb_x+bb_w-1, bb_y+bb_h-1);
}

// returns TRUE if the surface was modified
gboolean draw_dab_internal (
  OperationQueue *op_queue, float x, float y,
  float radius,
  float color_r, float color_g, float color_b,
  float opaque, float hardness,
  float color_a,
  float aspect_ratio, float angle,
  float lock_alpha,
  float colorize,
  float posterize,
  float posterize_num,
  float paint,
  MyPaintRectangle *bbox
  )

{
    OperationDataDrawDab op_struct;
    OperationDataDrawDab *op = &op_struct;

    op->x = x;
    op->y = y;
    op->radius = radius;
    op->aspect_ratio = aspect_ratio;
    op->angle = angle;
    op->opaque = CLAMP(opaque, 0.0f, 1.0f);
    op->hardness = CLAMP(hardness, 0.0f, 1.0f);
    op->lock_alpha = CLAMP(lock_alpha, 0.0f, 1.0f);
    op->colorize = CLAMP(colorize, 0.0f, 1.0f);
    op->posterize = CLAMP(posterize, 0.0f, 1.0f);
    op->posterize_num= CLAMP(ROUND(posterize_num * 100.0), 1, 128);
    op->paint = CLAMP(paint, 0.0f, 1.0f);
    if (op->radius < 0.1f) return FALSE; // don't bother with dabs smaller than 0.1 pixel
    if (op->hardness == 0.0f) return FALSE; // infintly small center point, fully transparent outside
    if (op->opaque == 0.0f) return FALSE;

    color_r = CLAMP(color_r, 0.0f, 1.0f);
    color_g = CLAMP(color_g, 0.0f, 1.0f);
    color_b = CLAMP(color_b, 0.0f, 1.0f);
    color_a = CLAMP(color_a, 0.0f, 1.0f);

    op->color_r = color_r * (1<<15);
    op->color_g = color_g * (1<<15);
    op->color_b = color_b * (1<<15);
    op->color_a = color_a;

    // blending mode preparation
    op->normal = 1.0f;

    op->normal *= 1.0f-op->lock_alpha;
    op->normal *= 1.0f-op->colorize;
    op->normal *= 1.0f-op->posterize;

    if (op->aspect_ratio<1.0f) op->aspect_ratio=1.0f;

    // Determine the tiles influenced by operation, and queue it for processing for each tile
    float r_fringe = radius + 1.0f; // +1.0 should not be required, only to be sure

    int tx1 = floor(floor(x - r_fringe) / MYPAINT_TILE_SIZE);
    int tx2 = floor(floor(x + r_fringe) / MYPAINT_TILE_SIZE);
    int ty1 = floor(floor(y - r_fringe) / MYPAINT_TILE_SIZE);
    int ty2 = floor(floor(y + r_fringe) / MYPAINT_TILE_SIZE);

    for (int ty = ty1; ty <= ty2; ty++) {
        for (int tx = tx1; tx <= tx2; tx++) {
            const TileIndex tile_index = {tx, ty};
            OperationDataDrawDab *op_copy = (OperationDataDrawDab *)malloc(sizeof(OperationDataDrawDab));
            *op_copy = *op;
            operation_queue_add(op_queue, tile_index, op_copy);
        }
    }

    update_dirty_bbox(bbox, op);

    return TRUE;
}

// returns TRUE if the surface was modified
int draw_dab (MyPaintSurface *surface, float x, float y,
               float radius,
               float r, float g, float b,
               float opaque, float hardness,
               float color_a,
               float aspect_ratio, float angle,
               float lock_alpha,
               float colorize)
{
    MyPaintTiledSurface* self = (MyPaintTiledSurface*)surface;
    // Normal pass
    gboolean surface_modified = (draw_dab_internal(
        self->operation_queue, x, y, radius, r, g, b, opaque, hardness, color_a, aspect_ratio, angle, lock_alpha,
        colorize, 0.0, 0.0, 0.0, &self->dirty_bbox));
    // Symmetry pass
    if (surface_modified && self->surface_do_symmetry) {
        const float symm_x = self->surface_center_x + (self->surface_center_x - x);
        draw_dab_internal(
            self->operation_queue, symm_x, y, radius, r, g, b, opaque, hardness, color_a, aspect_ratio, -angle,
            lock_alpha, colorize, 0.0, 0.0, 0.0, &self->dirty_bbox);
    }
    return surface_modified;
}


void get_color_internal
(
 void *tiled_surface,
 void (*request_start) (void*, void*),
 void (*request_end) (void*, void*),
 gboolean threadsafe_tile_requests,
 OperationQueue *op_queue,
 float x, float y,
 float radius,
 float * color_r, float * color_g, float * color_b, float * color_a,
 float paint
  )
{
    if (radius < 1.0f) radius = 1.0f;
    const float hardness = 0.5f;
    const float aspect_ratio = 1.0f;
    const float angle = 0.0f;

    float sum_weight, sum_r, sum_g, sum_b, sum_a;
    sum_weight = sum_r = sum_g = sum_b = sum_a = 0.0f;

    // in case we return with an error
    *color_r = 0.0f;
    *color_g = 1.0f;
    *color_b = 0.0f;

    // WARNING: some code duplication with draw_dab

    float r_fringe = radius + 1.0f; // +1 should not be required, only to be sure

    int tx1 = floor(floor(x - r_fringe) / MYPAINT_TILE_SIZE);
    int tx2 = floor(floor(x + r_fringe) / MYPAINT_TILE_SIZE);
    int ty1 = floor(floor(y - r_fringe) / MYPAINT_TILE_SIZE);
    int ty2 = floor(floor(y + r_fringe) / MYPAINT_TILE_SIZE);
    #ifdef _OPENMP
    int tiles_n = (tx2 - tx1) * (ty2 - ty1);
    #endif

    // Calculate the `guaranteed sample` interval and
    // the percentage of pixels to sample for the dab.
    // The basic idea is to have larger intervals and
    // lower percentages for really large dabs, to
    // avoid accumulated rounding errors and heavier
    // calculations.
    //
    // The values are set so that the number of pixels
    // sampled is _bounded_ linearly by the radius.
    //
    // The constant factor 7 is chosen through manual
    // evaluation of results and gives us a total sample
    // rate bounded by '1/(r * 3.5)'
    // Other models may have better properties, some
    // more thinking needed here.
    //
    // For really small radii we'll sample every pixel
    // in the dab to avoid biasing.
    const int sample_interval = radius <= 2.0f ? 1 : (int)(radius * 7);
    const float random_sample_rate = 1.0f / (7 * radius);

    #ifdef _OPENMP
    #pragma omp parallel for schedule(static) if(threadsafe_tile_requests && tiles_n > 3)
    #endif
    for (int ty = ty1; ty <= ty2; ty++) {
      for (int tx = tx1; tx <= tx2; tx++) {

        // Flush queued draw_dab operations
        process_tile_internal(tiled_surface, request_start, request_end, op_queue, tx, ty);

        MyPaintTileRequest request_data;
        const int mipmap_level = 0;
        mypaint_tile_request_init(&request_data, mipmap_level, tx, ty, TRUE);
        request_start(tiled_surface, &request_data);
        uint16_t * rgba_p = request_data.buffer;
        if (!rgba_p) {
          printf("Warning: Unable to get tile!\n");
          break;
        }

        // first, we calculate the mask (opacity for each pixel)
        uint16_t mask[MYPAINT_TILE_SIZE*MYPAINT_TILE_SIZE+2*MYPAINT_TILE_SIZE];

        render_dab_mask(mask,
                        x - tx*MYPAINT_TILE_SIZE,
                        y - ty*MYPAINT_TILE_SIZE,
                        radius,
                        hardness,
                        aspect_ratio, angle
                        );

        // TODO: try atomic operations instead
        #pragma omp critical
        {
        get_color_pixels_accumulate (
          mask, rgba_p, &sum_weight, &sum_r, &sum_g, &sum_b, &sum_a, paint,
          sample_interval, random_sample_rate);
        }

        request_end(tiled_surface, &request_data);
      }
    }

    assert(sum_weight > 0.0f);
    sum_a /= sum_weight;

    // For legacy sampling, we need to divide
    // by the total after the accumulation.
    if (paint < 0.0) {
        sum_r /= sum_weight;
        sum_g /= sum_weight;
        sum_b /= sum_weight;
    }

    *color_a = CLAMP(sum_a, 0.0f, 1.0f);
    if (sum_a > 0.0f) {
      // Straighten the color channels if using legacy sampling.
      // Clamp to guard against rounding errors.
      const float demul = paint < 0.0 ? sum_a : 1.0;
      *color_r = CLAMP(sum_r / demul, 0.0f, 1.0f);
      *color_g = CLAMP(sum_g / demul, 0.0f, 1.0f);
      *color_b = CLAMP(sum_b / demul, 0.0f, 1.0f);
    } else {
      // it is all transparent, so don't care about the colors
      // (let's make them ugly so bugs will be visible)
      *color_r = 0.0f;
      *color_g = 1.0f;
      *color_b = 0.0f;
    }
}

/* Go-betweens for more clarity  */
void tsf1_request_start(void* surface, void* request) {
  MyPaintTiledSurface *self = (MyPaintTiledSurface*) surface;
  self->tile_request_start(self, (MyPaintTileRequest*) request);
}
void tsf1_request_end(void* surface, void* request) {
  MyPaintTiledSurface *self = (MyPaintTiledSurface*) surface;
  self->tile_request_end(self, (MyPaintTileRequest*) request);
}

void
get_color(
    MyPaintSurface* surface, float x, float y, float radius, float* color_r, float* color_g, float* color_b,
    float* color_a)
{
    MyPaintTiledSurface* self = (MyPaintTiledSurface*)surface;
    get_color_internal(
      surface, tsf1_request_start, tsf1_request_end, self->threadsafe_tile_requests, self->operation_queue, x, y,
      radius, color_r, color_g, color_b, color_a, -1.0);
}


float
mypaint_tiled_surface_get_alpha (MyPaintTiledSurface *self, float x, float y, float radius) {
  float r, g, b, a;
  get_color(&self->parent, x, y, radius, &r, &g, &b, &a);
  return a;
}

void tiled_surface_process_tile(MyPaintTiledSurface *self, int tx, int ty) {
  process_tile_internal(self, tsf1_request_start, tsf1_request_end, self->operation_queue, tx, ty);
}

/**
 * mypaint_tiled_surface_init: (skip)
 *
 * Initialize the surface, passing in implementations of the tile backend.
 * Note: Only intended to be called from subclasses of #MyPaintTiledSurface
 **/
void
mypaint_tiled_surface_init(MyPaintTiledSurface *self,
                           MyPaintTileRequestStartFunction tile_request_start,
                           MyPaintTileRequestEndFunction tile_request_end)
{
    mypaint_surface_init(&self->parent);
    self->parent.draw_dab = draw_dab;
    self->parent.get_color = get_color;
    self->parent.begin_atomic = begin_atomic_default;
    self->parent.end_atomic = end_atomic_default;

    self->tile_request_end = tile_request_end;
    self->tile_request_start = tile_request_start;

    self->tile_size = MYPAINT_TILE_SIZE;
    self->threadsafe_tile_requests = FALSE;

    self->dirty_bbox.x = 0;
    self->dirty_bbox.y = 0;
    self->dirty_bbox.width = 0;
    self->dirty_bbox.height = 0;
    self->surface_do_symmetry = FALSE;
    self->surface_center_x = 0.0f;
    self->operation_queue = operation_queue_new();
}


/**
 * mypaint_tiled_surface_destroy: (skip)
 *
 * Deallocate resources set up by mypaint_tiled_surface_init()
 * Does not free the #MyPaintTiledSurface itself.
 * Note: Only intended to be called from subclasses of #MyPaintTiledSurface
 */
void
mypaint_tiled_surface_destroy(MyPaintTiledSurface *self)
{
    operation_queue_free(self->operation_queue);
}

/* -- Extended interface -- */

/**
  * MyPaintTiledSurface2: (skip)
  */
struct MyPaintTiledSurface2;


/**
 * mypaint_tiled_surface2_tile_request_start: (skip)
 */
void mypaint_tiled_surface2_tile_request_start(MyPaintTiledSurface2 *self, MyPaintTileRequest *request)
{
    assert(self->tile_request_start);
    self->tile_request_start(self, request);
}

/**
 * mypaint_tiled_surface2_tile_request_end: (skip)
 */
void mypaint_tiled_surface2_tile_request_end(MyPaintTiledSurface2 *self, MyPaintTileRequest *request)
{
    assert(self->tile_request_end);
    self->tile_request_end(self, request);
}

/* Go-betweens for more clarity  */
void tsf2_request_start(void* surface, void* request) {
  MyPaintTiledSurface2 *self = (MyPaintTiledSurface2*) surface;
  self->tile_request_start(self, (MyPaintTileRequest*) request);
}

void tsf2_request_end(void* surface, void* request) {
  MyPaintTiledSurface2 *self = (MyPaintTiledSurface2*) surface;
  self->tile_request_end(self, (MyPaintTileRequest*) request);
}

void tiled_surface2_process_tile(MyPaintTiledSurface2 *self, int tx, int ty) {
  process_tile_internal(self, tsf2_request_start, tsf2_request_end, self->operation_queue, tx, ty);
}

void
get_color_pigment(
    MyPaintSurface2* surface, float x, float y, float radius, float* color_r, float* color_g, float* color_b,
    float* color_a, float paint)
{
    MyPaintTiledSurface2* self = (MyPaintTiledSurface2*)surface;
    get_color_internal(
        surface, tsf2_request_start, tsf2_request_end, self->threadsafe_tile_requests, self->operation_queue, x, y,
        radius, color_r, color_g, color_b, color_a, paint);
}

static void
begin_atomic_default_2(MyPaintSurface *surface)
{
  mypaint_tiled_surface2_begin_atomic((MyPaintTiledSurface2 *)surface);
}

static void
end_atomic_default_2(MyPaintSurface2 *surface, MyPaintRectangles *roi)
{
    mypaint_tiled_surface2_end_atomic((MyPaintTiledSurface2 *)surface, roi);
}

void
prepare_bounding_boxes(MyPaintTiledSurface2 *self) {
    MyPaintSymmetryState symm_state = self->symmetry_data.state_current;
    const gboolean snowflake = symm_state.type == MYPAINT_SYMMETRY_TYPE_SNOWFLAKE;
    const int num_bboxes_desired = symm_state.num_lines * (snowflake ? 2 : 1);
    // If the bounding box array cannot fit one rectangle per symmetry dab,
    // try to allocate enough space for that to be possible.
    // Failure is ok, as the bounding box assignments will be functional anyway.
    if (num_bboxes_desired > self->num_bboxes) {
        const int margin = 10; // Add margin to avoid unnecessary reallocations.
        const int num_to_allocate = num_bboxes_desired + margin;
        int bytes_to_allocate = num_to_allocate * sizeof(MyPaintRectangle);
        MyPaintRectangle* new_bboxes = malloc(bytes_to_allocate);
        if (new_bboxes) {
            free(self->bboxes);
            // Initialize memory
            memset(new_bboxes, 0, bytes_to_allocate);
            self->bboxes = new_bboxes;
            self->num_bboxes = num_to_allocate;
            // No need to clear anything after the memset, so reset counter
            self->num_bboxes_dirtied = 0;
        }
    }
    // Clean up any previously populated bounding boxes and reset the counter
    for (int i = 0; i < MIN(self->num_bboxes, self->num_bboxes_dirtied); ++i) {
        self->bboxes[i].height = 0;
        self->bboxes[i].width = 0;
        self->bboxes[i].x = 0;
        self->bboxes[i].y = 0;
    }
    self->num_bboxes_dirtied = 0;
}

// returns TRUE if the surface was modified
int draw_dab_2 (MyPaintSurface2 *surface, float x, float y,
               float radius,
               float color_r, float color_g, float color_b,
               float opaque, float hardness,
               float color_a,
               float aspect_ratio, float angle,
               float lock_alpha,
               float colorize,
               float posterize,
               float posterize_num,
               float paint)
{
    MyPaintTiledSurface2* self = (MyPaintTiledSurface2*)surface;

    // These calls are repeated enough to warrant a local macro, for both readability and correctness.
#define DDI(x, y, angle, bb_idx) (draw_dab_internal(\
        self->operation_queue, (x), (y), radius, color_r, color_g, color_b, opaque, \
        hardness, color_a, aspect_ratio, (angle), \
        lock_alpha, colorize, posterize, posterize_num, paint, &self->bboxes[(bb_idx)]))

    // Normal pass
    gboolean surface_modified = DDI(x, y, angle, 0);

    int num_bboxes_used = surface_modified ? 1 : 0;

    // Symmetry pass

    // OPTIMIZATION: skip the symmetry pass if surface was not modified by the initial dab;
    // at current if the initial dab does not modify the surface, none of the symmetry dabs
    // will either. If/when selection masks are added, this optimization _must_ be removed,
    // and `surface_modified` must be or'ed with the result of each call to draw_dab_internal.
    MyPaintSymmetryData *symm_data = &self->symmetry_data;
    if (surface_modified && symm_data->active && symm_data->num_symmetry_matrices) {
        const MyPaintSymmetryState symm = symm_data->state_current;
        const int num_bboxes = self->num_bboxes;
        const float rot_angle = 360.0 / symm.num_lines;
        const MyPaintTransform* const matrices = symm_data->symmetry_matrices;
        float x_out, y_out;

        switch (symm.type) {
        case MYPAINT_SYMMETRY_TYPE_VERTICAL: {
            mypaint_transform_point(&matrices[0], x, y, &x_out, &y_out);
            DDI(x_out, y_out, -2.0 * (90 + symm.angle) - angle, 1);
            num_bboxes_used = 2;
            break;
        }
        case MYPAINT_SYMMETRY_TYPE_HORIZONTAL: {
            mypaint_transform_point(&matrices[0], x, y, &x_out, &y_out);
            DDI(x_out, y_out, -2.0 * symm.angle - angle, 1);
            num_bboxes_used = 2;
            break;
        }
        case MYPAINT_SYMMETRY_TYPE_VERTHORZ: {
            // Reflect across horizontal line
            mypaint_transform_point(&matrices[0], x, y, &x_out, &y_out);
            DDI(x_out, y_out, -2.0 * symm.angle - angle, 1);
            // Then across the vertical line (diagonal)
            mypaint_transform_point(&matrices[1], x, y, &x_out, &y_out);
            DDI(x_out, y_out, angle, 2);
            // Then back across the horizontal line
            mypaint_transform_point(&matrices[2], x, y, &x_out, &y_out);
            DDI(x_out, y_out, -2.0 * symm.angle - angle, 3);
            num_bboxes_used = 4;
            break;
        }
        case MYPAINT_SYMMETRY_TYPE_SNOWFLAKE: {

            // These dabs will occupy the bboxes after the last bbox used by the rotational dabs.
            const int offset = MIN(num_bboxes / 2, symm.num_lines);
            const float dabs_per_bbox = MAX(1, (float)symm.num_lines * 2.0 / num_bboxes);
            const int base_idx = symm.num_lines - 1;
            const float base_angle = -2 * symm.angle - angle;
            // draw snowflake dabs for _all_ symmetry lines as we need to reflect the initial dab.
            for (int dab_count = 0; dab_count < symm.num_lines; dab_count++) {
                // If the number of bboxes cannot fit all snowflake dabs, use half for the rotational dabs
                // and the other half for the reflected dabs. This is not always optimal, but seldom bad.
                const int bbox_idx = offset + MIN(roundf(dab_count / dabs_per_bbox), num_bboxes - 1);
                mypaint_transform_point(&matrices[base_idx + dab_count], x, y, &x_out, &y_out);
                DDI(x_out, y_out, base_angle - dab_count * rot_angle, bbox_idx);
            }
            num_bboxes_used = MIN(self->num_bboxes, symm.num_lines * 2);
            // fall through to rotational to finish the process
        }
        case MYPAINT_SYMMETRY_TYPE_ROTATIONAL: {

            // Set the dab bbox distribution factor based on whether the pass is only
            // rotational, or following a snowflake pass. For the latter, we compress
            // the available range (unimportant if there are enough bboxes to go around).
            const gboolean snowflake = symm.type == MYPAINT_SYMMETRY_TYPE_SNOWFLAKE;
            float dabs_per_bbox = MAX(1, (float)(symm.num_lines * (snowflake ? 2 : 1)) / num_bboxes);

            // draw self->rot_symmetry_lines - 1 rotational dabs since initial pass handles the first dab
            for (int dab_count = 1; dab_count < symm.num_lines; dab_count++) {
                const int bbox_index = MIN(roundf(dab_count / dabs_per_bbox), num_bboxes - 1);
                mypaint_transform_point(&matrices[dab_count - 1], x, y, &x_out, &y_out);
                DDI(x_out, y_out, angle - dab_count * rot_angle, bbox_index);
            }

            // Use existing (larger) number of bboxes if it was set (in a snowflake pass)
            num_bboxes_used = MIN(self->num_bboxes, MAX(symm.num_lines, num_bboxes_used));
            break;
        }
        default:
            fprintf(stderr, "Warning: Unhandled symmetry type: %d\n", symm.type);
            break;
        }
    }
    self->num_bboxes_dirtied = MIN(self->num_bboxes, num_bboxes_used);
    return surface_modified;
#undef DDI
}

int
draw_dab_wrapper(
    MyPaintSurface* surface, float x, float y, float radius, float r, float g, float b, float opaque, float hardness,
    float color_a, float aspect_ratio, float angle, float lock_alpha, float colorize)
{
    const float posterize = 0.0;
    const float posterize_num = 1.0;
    const float pigment = 0.0;
    return draw_dab_2(
        (MyPaintSurface2*)surface, x, y, radius, r, g, b, opaque, hardness, color_a, aspect_ratio, angle, lock_alpha,
        colorize, posterize, posterize_num, pigment);
}

void
get_color_wrapper(
    MyPaintSurface* surface, float x, float y, float radius, float* color_r, float* color_g, float* color_b,
    float* color_a)
{
    MyPaintTiledSurface2* self = (MyPaintTiledSurface2*)surface;
    return get_color_internal(
        surface, tsf2_request_start, tsf2_request_end, self->threadsafe_tile_requests, self->operation_queue, x, y,
        radius, color_r, color_g, color_b, color_a, -1.0);
}

static void
end_atomic_wrapper(MyPaintSurface *surface, MyPaintRectangle *roi)
{
  MyPaintRectangles rois = {1, roi};
  mypaint_tiled_surface2_end_atomic((MyPaintTiledSurface2*)surface, &rois);
}

/**
 * mypaint_tiled_surface2_init: (skip)
 *
 * Initialize the surface, passing in implementations of the tile backend.
 * Note: Only intended to be called from subclasses of #MyPaintTiledSurface
 **/
void
mypaint_tiled_surface2_init(MyPaintTiledSurface2 *self,
                           MyPaintTileRequestStartFunction2 tile_request_start,
                           MyPaintTileRequestEndFunction2 tile_request_end)
{
    mypaint_surface_init(&self->parent.parent);

    self->tile_request_end = tile_request_end;
    self->tile_request_start = tile_request_start;
    self->tile_size = MYPAINT_TILE_SIZE;
    self->threadsafe_tile_requests = FALSE;
    self->operation_queue = operation_queue_new();

    MyPaintSurface2 *s = &self->parent;

    s->draw_dab_pigment = draw_dab_2;
    s->get_color_pigment = get_color_pigment;
    s->end_atomic_multi = end_atomic_default_2;
    s->parent.begin_atomic = begin_atomic_default_2;

    // Adapters supporting the base interface
    s->parent.draw_dab = draw_dab_wrapper;
    s->parent.get_color = get_color_wrapper;
    s->parent.end_atomic = end_atomic_wrapper;

    self->num_bboxes = NUM_BBOXES_DEFAULT;
    self->bboxes = malloc(sizeof(MyPaintRectangle) * NUM_BBOXES_DEFAULT);
    memset(self->bboxes, 0, sizeof(MyPaintRectangle) * NUM_BBOXES_DEFAULT);
    self->symmetry_data = mypaint_default_symmetry_data();
}

void
mypaint_tiled_surface2_begin_atomic(MyPaintTiledSurface2 *self)
{
    mypaint_update_symmetry_state(&self->symmetry_data);
    prepare_bounding_boxes(self);
}

/**
 * mypaint_tiled_surface_end_atomic_2: (skip)
 *
 * Implementation of #MyPaintSurface::end_atomic vfunc
 * Note: Only intended to be used from #MyPaintTiledSurface subclasses, which should chain up to this
 * if implementing their own #MyPaintSurface::end_atomic vfunc.
 * Application code should only use mypaint_surface_end_atomic().
 */
void
mypaint_tiled_surface2_end_atomic(MyPaintTiledSurface2 *self, MyPaintRectangles *roi)
{
    // Process tiles
    TileIndex *tiles;
    int tiles_n = operation_queue_get_dirty_tiles(self->operation_queue, &tiles);

    #pragma omp parallel for schedule(static) if(self->threadsafe_tile_requests && tiles_n > 3)
    for (int i = 0; i < tiles_n; i++) {
      tiled_surface2_process_tile(self, tiles[i].x, tiles[i].y);
    }

    operation_queue_clear_dirty_tiles(self->operation_queue);

    if (roi) {
        const int roi_rects = roi->num_rectangles;
        const int num_dirty = self->num_bboxes_dirtied;
        // Clear out the input rectangles that will be overwritten
        for (int i = 0; i < MIN(roi_rects, num_dirty); ++i) {
            roi->rectangles[i].x = 0;
            roi->rectangles[i].y = 0;
            roi->rectangles[i].width = 0;
            roi->rectangles[i].height = 0;
        }
        // Write bounding box rectangles to the output array
        const float bboxes_per_output = MAX(1, (float)num_dirty / roi_rects);
        for (int i = 0; i < num_dirty; ++i) {
            int out_index;
            // If there is not enough space for all rectangles in the output,
            // merge some of the rectangles with their list-adjacent neighbours.
            if (num_dirty > roi_rects) {
                out_index = (int)MIN(roi_rects - 1, roundf((float)i / bboxes_per_output));
            } else {
                out_index = i;
            }
            mypaint_rectangle_expand_to_include_rect(&(roi->rectangles[out_index]), &(self->bboxes[i]));
        }
        // Set the number of rectangles written to, so the caller knows which ones to act on.
        roi->num_rectangles = MIN(roi_rects, num_dirty);
    }
}

/**
 * mypaint_tiled_surface_set_symmetry_state_2: (skip)
 * @active: TRUE to enable, FALSE to disable.
 * @center_x: X axis to mirror events across.
 * @center_y: Y axis to mirror events across.
 * @symmetry_angle: Angle to rotate the symmetry lines
 * @symmetry_type: Symmetry type to activate.
 * @rot_symmetry_lines: Number of rotational symmetry lines.
 *
 * Enable/Disable symmetric brush painting across an X axis.
 *
 */
void
mypaint_tiled_surface2_set_symmetry_state(MyPaintTiledSurface2 *self, gboolean active,
                                         float center_x, float center_y,
                                         float symmetry_angle,
                                         MyPaintSymmetryType symmetry_type,
                                         int rot_symmetry_lines)
{
    mypaint_symmetry_set_pending( // Only write to the pending new state, nothing gets recalculated here
        &self->symmetry_data, active, center_x, center_y, symmetry_angle, symmetry_type, rot_symmetry_lines);
}

/**
 * mypaint_tiled_surface2_destroy: (skip)
 *
 * Deallocate resources set up by mypaint_tiled_surface2_init()
 * Does not free the #MyPaintTiledSurface itself.
 * Note: Only intended to be called from subclasses of #MyPaintTiledSurface
 */
void
mypaint_tiled_surface2_destroy(MyPaintTiledSurface2 *self)
{
    operation_queue_free(self->operation_queue);
    free(self->bboxes);
    mypaint_symmetry_data_destroy(&self->symmetry_data);
}