libs/plugins/a-comp.lv2/a-comp.c

   1 /* a-comp
   2  * Copyright (C) 2016 Damien Zammit <damien@zamaudio.com>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <math.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <stdbool.h>
  19
  20 #ifdef LV2_EXTENDED
  21 #include <cairo/cairo.h>
  22 #include "ardour/lv2_extensions.h"
  23 #endif
  24
  25 #include "lv2/lv2plug.in/ns/lv2core/lv2.h"
  26
  27 #define ACOMP_URI               "urn:ardour:a-comp"
  28 #define ACOMP_STEREO_URI        "urn:ardour:a-comp#stereo"
  29
  30 #ifndef M_PI
  31 #  define M_PI 3.14159265358979323846
  32 #endif
  33
  34 typedef enum {
  35         ACOMP_ATTACK = 0,
  36         ACOMP_RELEASE,
  37         ACOMP_KNEE,
  38         ACOMP_RATIO,
  39         ACOMP_THRESHOLD,
  40         ACOMP_MAKEUP,
  41
  42         ACOMP_GAINR,
  43         ACOMP_OUTLEVEL,
  44         ACOMP_SIDECHAIN,
  45         ACOMP_ENABLE,
  46
  47         ACOMP_INPUT,
  48         ACOMP_SC,
  49         ACOMP_OUTPUT,
  50         ACOMP_STEREO_INPUT,
  51         ACOMP_STEREO_OUTPUT,
  52 } PortIndex;
  53
  54 typedef struct {
  55         float* attack;
  56         float* release;
  57         float* knee;
  58         float* ratio;
  59         float* thresdb;
  60         float* makeup;
  61
  62         float* gainr;
  63         float* outlevel;
  64         float* sidechain;
  65         float* enable;
  66
  67         float* input0;
  68         float* input1;
  69         float* sc;
  70         float* output0;
  71         float* output1;
  72
  73         float srate;
  74         float old_yl;
  75         float old_y1;
  76         float old_yg;
  77
  78         float makeup_gain;
  79         float tau;
  80
  81 #ifdef LV2_EXTENDED
  82         LV2_Inline_Display_Image_Surface surf;
  83         bool                     need_expose;
  84         cairo_surface_t*         display;
  85         LV2_Inline_Display*      queue_draw;
  86         uint32_t                 w, h;
  87
  88         /* ports pointers are only valid during run so we'll
  89          * have to cache them for the display, besides
  90          * we do want to check for changes
  91          */
  92         float v_knee;
  93         float v_ratio;
  94         float v_thresdb;
  95         float v_lvl;
  96         float v_lvl_in;
  97         float v_lvl_out;
  98 #endif
  99 } AComp;
 100
 101 static LV2_Handle
 102 instantiate(const LV2_Descriptor* descriptor,
 103             double rate,
 104             const char* bundle_path,
 105             const LV2_Feature* const* features)
 106 {
 107         AComp* acomp = (AComp*)calloc(1, sizeof(AComp));
 108
 109         for (int i=0; features[i]; ++i) {
 110 #ifdef LV2_EXTENDED
 111                 if (!strcmp(features[i]->URI, LV2_INLINEDISPLAY__queue_draw)) {
 112                         acomp->queue_draw = (LV2_Inline_Display*) features[i]->data;
 113                 }
 114 #endif
 115         }
 116
 117         acomp->srate = rate;
 118         acomp->old_yl=acomp->old_y1=acomp->old_yg=0.f;
 119         acomp->tau = (1.0 - exp (-2.f * M_PI * 25.f / acomp->srate));
 120 #ifdef LV2_EXTENDED
 121         acomp->need_expose = true;
 122 #endif
 123
 124         return (LV2_Handle)acomp;
 125 }
 126
 127
 128 static void
 129 connect_port(LV2_Handle instance,
 130              uint32_t port,
 131              void* data)
 132 {
 133         AComp* acomp = (AComp*)instance;
 134
 135         switch ((PortIndex)port) {
 136         case ACOMP_ATTACK:
 137                 acomp->attack = (float*)data;
 138                 break;
 139         case ACOMP_RELEASE:
 140                 acomp->release = (float*)data;
 141                 break;
 142         case ACOMP_KNEE:
 143                 acomp->knee = (float*)data;
 144                 break;
 145         case ACOMP_RATIO:
 146                 acomp->ratio = (float*)data;
 147                 break;
 148         case ACOMP_THRESHOLD:
 149                 acomp->thresdb = (float*)data;
 150                 break;
 151         case ACOMP_MAKEUP:
 152                 acomp->makeup = (float*)data;
 153                 break;
 154         case ACOMP_GAINR:
 155                 acomp->gainr = (float*)data;
 156                 break;
 157         case ACOMP_OUTLEVEL:
 158                 acomp->outlevel = (float*)data;
 159                 break;
 160         case ACOMP_SIDECHAIN:
 161                 acomp->sidechain = (float*)data;
 162                 break;
 163         case ACOMP_ENABLE:
 164                 acomp->enable = (float*)data;
 165                 break;
 166         case ACOMP_INPUT:
 167                 acomp->input0 = (float*)data;
 168                 break;
 169         case ACOMP_SC:
 170                 acomp->sc = (float*)data;
 171                 break;
 172         case ACOMP_OUTPUT:
 173                 acomp->output0 = (float*)data;
 174                 break;
 175         case ACOMP_STEREO_INPUT:
 176                 acomp->input1 = (float*)data;
 177                 break;
 178         case ACOMP_STEREO_OUTPUT:
 179                 acomp->output1 = (float*)data;
 180                 break;
 181         }
 182 }
 183
 184 // Force already-denormal float value to zero
 185 static inline float
 186 sanitize_denormal(float value) {
 187         if (!isnormal(value)) {
 188                 value = 0.f;
 189         }
 190         return value;
 191 }
 192
 193 static inline float
 194 from_dB(float gdb) {
 195         return (exp(gdb/20.f*log(10.f)));
 196 }
 197
 198 static inline float
 199 to_dB(float g) {
 200         return (20.f*log10(g));
 201 }
 202
 203 static void
 204 activate(LV2_Handle instance)
 205 {
 206         AComp* acomp = (AComp*)instance;
 207
 208         *(acomp->gainr) = 0.0f;
 209         *(acomp->outlevel) = -45.0f;
 210         acomp->old_yl=acomp->old_y1=acomp->old_yg=0.f;
 211 }
 212
 213 static void
 214 run_mono(LV2_Handle instance, uint32_t n_samples)
 215 {
 216         AComp* acomp = (AComp*)instance;
 217
 218         const float* const input = acomp->input0;
 219         const float* const sc = acomp->sc;
 220         float* const output = acomp->output0;
 221
 222         float srate = acomp->srate;
 223         float width = (6.f * *(acomp->knee)) + 0.01;
 224         float cdb=0.f;
 225         float attack_coeff = exp(-1000.f/(*(acomp->attack) * srate));
 226         float release_coeff = exp(-1000.f/(*(acomp->release) * srate));
 227
 228         float max = 0.f;
 229         float lgaininp = 0.f;
 230         float Lgain = 1.f;
 231         float Lxg, Lxl, Lyg, Lyl, Ly1;
 232         int usesidechain = (*(acomp->sidechain) <= 0.f) ? 0 : 1;
 233         uint32_t i;
 234         float ingain;
 235         float in0;
 236         float sc0;
 237
 238         float ratio = *acomp->ratio;
 239         float thresdb = *acomp->thresdb;
 240         float makeup_target = from_dB(*acomp->makeup);
 241         float makeup_gain = acomp->makeup_gain;
 242
 243         const const float tau = acomp->tau;
 244
 245         if (*acomp->enable <= 0) {
 246                 ratio = 1.f;
 247                 thresdb = 0.f;
 248                 makeup_target = 1.f;
 249         }
 250
 251 #ifdef LV2_EXTENDED
 252         if (acomp->v_knee != *acomp->knee) {
 253                 acomp->v_knee = *acomp->knee;
 254                 acomp->need_expose = true;
 255         }
 256
 257         if (acomp->v_ratio != ratio) {
 258                 acomp->v_ratio = ratio;
 259                 acomp->need_expose = true;
 260         }
 261
 262         if (acomp->v_thresdb != thresdb) {
 263                 acomp->v_thresdb = thresdb;
 264                 acomp->need_expose = true;
 265         }
 266 #endif
 267
 268         float in_peak = 0;
 269
 270         for (i = 0; i < n_samples; i++) {
 271                 in0 = input[i];
 272                 sc0 = sc[i];
 273                 ingain = usesidechain ? fabs(sc0) : fabs(in0);
 274                 in_peak = fmaxf (in_peak, ingain);
 275                 Lyg = 0.f;
 276                 Lxg = (ingain==0.f) ? -160.f : to_dB(ingain);
 277                 Lxg = sanitize_denormal(Lxg);
 278
 279
 280                 if (2.f*(Lxg-thresdb) < -width) {
 281                         Lyg = Lxg;
 282                 } else if (2.f*(Lxg-thresdb) > width) {
 283                         Lyg = thresdb + (Lxg-thresdb)/ratio;
 284                         Lyg = sanitize_denormal(Lyg);
 285                 } else {
 286                         Lyg = Lxg + (1.f/ratio-1.f)*(Lxg-thresdb+width/2.f)*(Lxg-thresdb+width/2.f)/(2.f*width);
 287                 }
 288
 289                 Lxl = Lxg - Lyg;
 290
 291                 acomp->old_y1 = sanitize_denormal(acomp->old_y1);
 292                 acomp->old_yl = sanitize_denormal(acomp->old_yl);
 293                 Ly1 = fmaxf(Lxl, release_coeff * acomp->old_y1+(1.f-release_coeff)*Lxl);
 294                 Lyl = attack_coeff * acomp->old_yl+(1.f-attack_coeff)*Ly1;
 295                 Ly1 = sanitize_denormal(Ly1);
 296                 Lyl = sanitize_denormal(Lyl);
 297
 298                 cdb = -Lyl;
 299                 Lgain = from_dB(cdb);
 300
 301                 *(acomp->gainr) = Lyl;
 302
 303                 lgaininp = in0 * Lgain;
 304
 305                 makeup_gain += tau * (makeup_target - makeup_gain) + 1e-12;
 306                 output[i] = lgaininp * makeup_gain;
 307
 308                 max = (fabsf(output[i]) > max) ? fabsf(output[i]) : sanitize_denormal(max);
 309
 310                 // TODO re-use local variables on stack
 311                 // store values back to acomp at the end of the inner-loop
 312                 acomp->old_yl = Lyl;
 313                 acomp->old_y1 = Ly1;
 314                 acomp->old_yg = Lyg;
 315         }
 316
 317         *(acomp->outlevel) = (max < 0.0056f) ? -45.f : to_dB(max);
 318         acomp->makeup_gain = makeup_gain;
 319
 320 #ifdef LV2_EXTENDED
 321         acomp->v_lvl += .1 * (in_peak - acomp->v_lvl);  // crude LPF TODO use n_samples/rate TC
 322         const float v_lvl_in = (acomp->v_lvl < 0.001f) ? -60.f : to_dB(acomp->v_lvl);
 323         const float v_lvl_out = (max < 0.001f) ? -60.f : to_dB(max);
 324         if (fabsf (acomp->v_lvl_out - v_lvl_out) >= 1 || fabsf (acomp->v_lvl_in - v_lvl_in) >= 1) {
 325                 // >= 1dB difference
 326                 acomp->need_expose = true;
 327                 acomp->v_lvl_in = v_lvl_in;
 328                 acomp->v_lvl_out = v_lvl_out - to_dB(makeup_gain);
 329         }
 330         if (acomp->need_expose && acomp->queue_draw) {
 331                 acomp->need_expose = false;
 332                 acomp->queue_draw->queue_draw (acomp->queue_draw->handle);
 333         }
 334 #endif
 335 }
 336
 337 static void
 338 run_stereo(LV2_Handle instance, uint32_t n_samples)
 339 {
 340         AComp* acomp = (AComp*)instance;
 341
 342         const float* const input0 = acomp->input0;
 343         const float* const input1 = acomp->input1;
 344         const float* const sc = acomp->sc;
 345         float* const output0 = acomp->output0;
 346         float* const output1 = acomp->output1;
 347
 348         float srate = acomp->srate;
 349         float width = (6.f * *(acomp->knee)) + 0.01;
 350         float cdb=0.f;
 351         float attack_coeff = exp(-1000.f/(*(acomp->attack) * srate));
 352         float release_coeff = exp(-1000.f/(*(acomp->release) * srate));
 353
 354         float max = 0.f;
 355         float lgaininp = 0.f;
 356         float rgaininp = 0.f;
 357         float Lgain = 1.f;
 358         float Lxg, Lxl, Lyg, Lyl, Ly1;
 359         int usesidechain = (*(acomp->sidechain) <= 0.f) ? 0 : 1;
 360         uint32_t i;
 361         float ingain;
 362         float in0;
 363         float in1;
 364         float sc0;
 365         float maxabslr;
 366
 367         float ratio = *acomp->ratio;
 368         float thresdb = *acomp->thresdb;
 369         float makeup_target = from_dB(*acomp->makeup);
 370         float makeup_gain = acomp->makeup_gain;
 371
 372         const const float tau = acomp->tau;
 373
 374         if (*acomp->enable <= 0) {
 375                 ratio = 1.f;
 376                 thresdb = 0.f;
 377                 makeup_target = 1.f;
 378         }
 379
 380 #ifdef LV2_EXTENDED
 381         if (acomp->v_knee != *acomp->knee) {
 382                 acomp->v_knee = *acomp->knee;
 383                 acomp->need_expose = true;
 384         }
 385
 386         if (acomp->v_ratio != ratio) {
 387                 acomp->v_ratio = ratio;
 388                 acomp->need_expose = true;
 389         }
 390
 391         if (acomp->v_thresdb != thresdb) {
 392                 acomp->v_thresdb = thresdb;
 393                 acomp->need_expose = true;
 394         }
 395 #endif
 396
 397         float in_peak = 0;
 398
 399         for (i = 0; i < n_samples; i++) {
 400                 in0 = input0[i];
 401                 in1 = input1[i];
 402                 sc0 = sc[i];
 403                 maxabslr = fmaxf(fabs(in0), fabs(in1));
 404                 ingain = usesidechain ? fabs(sc0) : maxabslr;
 405                 in_peak = fmaxf (in_peak, ingain);
 406                 Lyg = 0.f;
 407                 Lxg = (ingain==0.f) ? -160.f : to_dB(ingain);
 408                 Lxg = sanitize_denormal(Lxg);
 409
 410
 411                 if (2.f*(Lxg-thresdb) < -width) {
 412                         Lyg = Lxg;
 413                 } else if (2.f*(Lxg-thresdb) > width) {
 414                         Lyg = thresdb + (Lxg-thresdb)/ratio;
 415                         Lyg = sanitize_denormal(Lyg);
 416                 } else {
 417                         Lyg = Lxg + (1.f/ratio-1.f)*(Lxg-thresdb+width/2.f)*(Lxg-thresdb+width/2.f)/(2.f*width);
 418                 }
 419
 420                 Lxl = Lxg - Lyg;
 421
 422                 acomp->old_y1 = sanitize_denormal(acomp->old_y1);
 423                 acomp->old_yl = sanitize_denormal(acomp->old_yl);
 424                 Ly1 = fmaxf(Lxl, release_coeff * acomp->old_y1+(1.f-release_coeff)*Lxl);
 425                 Lyl = attack_coeff * acomp->old_yl+(1.f-attack_coeff)*Ly1;
 426                 Ly1 = sanitize_denormal(Ly1);
 427                 Lyl = sanitize_denormal(Lyl);
 428
 429                 cdb = -Lyl;
 430                 Lgain = from_dB(cdb);
 431
 432                 *(acomp->gainr) = Lyl;
 433
 434                 lgaininp = in0 * Lgain;
 435                 rgaininp = in1 * Lgain;
 436
 437                 makeup_gain += tau * (makeup_target - makeup_gain) + 1e-12;
 438
 439                 output0[i] = lgaininp * makeup_gain;
 440                 output1[i] = rgaininp * makeup_gain;
 441
 442                 max = (fmaxf(fabs(output0[i]), fabs(output1[i])) > max) ? fmaxf(fabs(output0[i]), fabs(output1[i])) : sanitize_denormal(max);
 443
 444                 // TODO re-use local variables on stack
 445                 // store values back to acomp at the end of the inner-loop
 446                 acomp->old_yl = Lyl;
 447                 acomp->old_y1 = Ly1;
 448                 acomp->old_yg = Lyg;
 449         }
 450
 451         *(acomp->outlevel) = (max < 0.0056f) ? -45.f : to_dB(max);
 452         acomp->makeup_gain = makeup_gain;
 453
 454 #ifdef LV2_EXTENDED
 455         acomp->v_lvl += .1 * (in_peak - acomp->v_lvl);  // crude LPF TODO use n_samples/rate TC
 456         const float v_lvl_in = (acomp->v_lvl < 0.001f) ? -60.f : to_dB(acomp->v_lvl);
 457         const float v_lvl_out = (max < 0.001f) ? -60.f : to_dB(max);
 458         if (fabsf (acomp->v_lvl_out - v_lvl_out) >= 1 || fabsf (acomp->v_lvl_in - v_lvl_in) >= 1) {
 459                 // >= 1dB difference
 460                 acomp->need_expose = true;
 461                 acomp->v_lvl_in = v_lvl_in;
 462                 acomp->v_lvl_out = v_lvl_out - to_dB(makeup_gain);
 463         }
 464         if (acomp->need_expose && acomp->queue_draw) {
 465                 acomp->need_expose = false;
 466                 acomp->queue_draw->queue_draw (acomp->queue_draw->handle);
 467         }
 468 #endif
 469 }
 470
 471 static void
 472 deactivate(LV2_Handle instance)
 473 {
 474         activate(instance);
 475 }
 476
 477 static void
 478 cleanup(LV2_Handle instance)
 479 {
 480 #ifdef LV2_EXTENDED
 481         AComp* acomp = (AComp*)instance;
 482         if (acomp->display) {
 483                 cairo_surface_destroy (acomp->display);
 484         }
 485 #endif
 486
 487         free(instance);
 488 }
 489
 490
 491 #ifndef MIN
 492 #define MIN(A,B) ((A) < (B)) ? (A) : (B)
 493 #endif
 494
 495 #ifdef LV2_EXTENDED
 496 static float
 497 comp_curve (AComp* self, float xg) {
 498         const float knee = self->v_knee;
 499         const float ratio = self->v_ratio;
 500         const float thresdb = self->v_thresdb;
 501
 502         const float width = 6.f * knee + 0.01f;
 503         float yg = 0.f;
 504
 505         if (2.f * (xg - thresdb) < -width) {
 506                 yg = xg;
 507         } else if (2.f * (xg - thresdb) > width) {
 508                 yg = thresdb + (xg - thresdb) / ratio;
 509         } else {
 510                 yg = xg + (1.f / ratio - 1.f ) * (xg - thresdb + width / 2.f) * (xg - thresdb + width / 2.f) / (2.f * width);
 511         }
 512         return yg;
 513 }
 514
 515 static LV2_Inline_Display_Image_Surface *
 516 render_inline (LV2_Handle instance, uint32_t w, uint32_t max_h)
 517 {
 518         AComp* self = (AComp*)instance;
 519         uint32_t h = MIN (w, max_h);
 520
 521         if (!self->display || self->w != w || self->h != h) {
 522                 if (self->display) cairo_surface_destroy(self->display);
 523                 self->display = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, w, h);
 524                 self->w = w;
 525                 self->h = h;
 526         }
 527
 528         cairo_t* cr = cairo_create (self->display);
 529
 530         // clear background
 531         cairo_rectangle (cr, 0, 0, w, h);
 532         cairo_set_source_rgba (cr, .2, .2, .2, 1.0);
 533         cairo_fill (cr);
 534
 535         cairo_set_line_width(cr, 1.0);
 536
 537         // draw grid 10dB steps
 538         const double dash1[] = {1, 2};
 539         const double dash2[] = {1, 3};
 540         cairo_save (cr);
 541         cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
 542         cairo_set_dash(cr, dash2, 2, 2);
 543         cairo_set_source_rgba (cr, 0.5, 0.5, 0.5, 0.5);
 544
 545         for (uint32_t d = 1; d < 6; ++d) {
 546                 const float x = -.5 + floorf (w * (d * 10.f / 60.f));
 547                 const float y = -.5 + floorf (h * (d * 10.f / 60.f));
 548
 549                 cairo_move_to (cr, x, 0);
 550                 cairo_line_to (cr, x, h);
 551                 cairo_stroke (cr);
 552
 553                 cairo_move_to (cr, 0, y);
 554                 cairo_line_to (cr, w, y);
 555                 cairo_stroke (cr);
 556         }
 557         if (self->v_thresdb < 0) {
 558                 cairo_set_source_rgba (cr, 0.5, 0.5, 0.5, 1.0);
 559                 const float y = -.5 + floorf (h * (self->v_thresdb / -60.f));
 560                 cairo_set_dash(cr, dash1, 2, 2);
 561                 cairo_move_to (cr, 0, y);
 562                 cairo_line_to (cr, w, y);
 563                 cairo_stroke (cr);
 564                 cairo_move_to (cr, 0, h);
 565                 cairo_line_to (cr, w, 0);
 566                 cairo_stroke (cr);
 567         }
 568         cairo_restore (cr);
 569
 570
 571         // draw curve
 572         cairo_set_source_rgba (cr, .8, .8, .8, 1.0);
 573         cairo_move_to (cr, 0, h);
 574
 575         for (uint32_t x = 0; x < w; ++x) {
 576                 // plot -60..0  dB
 577                 const float x_db = 60.f * (-1.f + x / (float)w);
 578                 const float y_db = comp_curve (self, x_db);
 579                 const float y = h * (y_db / -60.f);
 580                 cairo_line_to (cr, x, y);
 581         }
 582         cairo_stroke_preserve (cr);
 583
 584         cairo_line_to (cr, w, h);
 585         cairo_close_path (cr);
 586         cairo_clip (cr);
 587
 588         // draw signal level & reduction/gradient
 589         const float top = comp_curve (self, 0);
 590         cairo_pattern_t* pat = cairo_pattern_create_linear (0.0, 0.0, 0.0, h);
 591         if (top > self->v_thresdb) {
 592                 cairo_pattern_add_color_stop_rgba (pat, 0.0, 0.8, 0.1, 0.1, 0.5);
 593                 cairo_pattern_add_color_stop_rgba (pat, top / -60.f, 0.8, 0.1, 0.1, 0.5);
 594         }
 595         if (self->v_knee > 0) {
 596                 cairo_pattern_add_color_stop_rgba (pat, (self->v_thresdb / -60.f), 0.7, 0.7, 0.2, 0.5);
 597                 cairo_pattern_add_color_stop_rgba (pat, ((self->v_thresdb - self->v_knee) / -60.f), 0.5, 0.5, 0.5, 0.5);
 598         } else {
 599                 cairo_pattern_add_color_stop_rgba (pat, (self->v_thresdb / -60.f), 0.7, 0.7, 0.2, 0.5);
 600                 cairo_pattern_add_color_stop_rgba (pat, ((self->v_thresdb - .01) / -60.f), 0.5, 0.5, 0.5, 0.5);
 601         }
 602         cairo_pattern_add_color_stop_rgba (pat, 1.0, 0.5, 0.5, 0.5, 0.5);
 603
 604         // maybe cut off at x-position?
 605         const float x = w * (self->v_lvl_in + 60) / 60.f;
 606         //const float y = h * (self->v_lvl_out + 60) / 60.f;
 607         cairo_rectangle (cr, 0, h - x, x, h);
 608         if (self->v_ratio > 1.0) {
 609                 cairo_set_source (cr, pat);
 610         } else {
 611                 cairo_set_source_rgba (cr, 0.5, 0.5, 0.5, 0.5);
 612         }
 613         cairo_fill (cr);
 614
 615         cairo_pattern_destroy (pat); // TODO cache pattern
 616
 617
 618         // create RGBA surface
 619         cairo_destroy (cr);
 620         cairo_surface_flush (self->display);
 621         self->surf.width = cairo_image_surface_get_width (self->display);
 622         self->surf.height = cairo_image_surface_get_height (self->display);
 623         self->surf.stride = cairo_image_surface_get_stride (self->display);
 624         self->surf.data = cairo_image_surface_get_data  (self->display);
 625
 626         return &self->surf;
 627 }
 628 #endif
 629
 630 static const void*
 631 extension_data(const char* uri)
 632 {
 633 #ifdef LV2_EXTENDED
 634         static const LV2_Inline_Display_Interface display  = { render_inline };
 635         if (!strcmp(uri, LV2_INLINEDISPLAY__interface)) {
 636                 return &display;
 637         }
 638 #endif
 639         return NULL;
 640 }
 641
 642 static const LV2_Descriptor descriptor_mono = {
 643         ACOMP_URI,
 644         instantiate,
 645         connect_port,
 646         activate,
 647         run_mono,
 648         deactivate,
 649         cleanup,
 650         extension_data
 651 };
 652
 653 static const LV2_Descriptor descriptor_stereo = {
 654         ACOMP_STEREO_URI,
 655         instantiate,
 656         connect_port,
 657         activate,
 658         run_stereo,
 659         deactivate,
 660         cleanup,
 661         extension_data
 662 };
 663
 664 LV2_SYMBOL_EXPORT
 665 const LV2_Descriptor*
 666 lv2_descriptor(uint32_t index)
 667 {
 668         switch (index) {
 669         case 0:
 670                 return &descriptor_mono;
 671         case 1:
 672                 return &descriptor_stereo;
 673         default:
 674                 return NULL;
 675         }
 676 }