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 typedef enum {
  31         ACOMP_ATTACK = 0,
  32         ACOMP_RELEASE,
  33         ACOMP_KNEE,
  34         ACOMP_RATIO,
  35         ACOMP_THRESHOLD,
  36         ACOMP_MAKEUP,
  37
  38         ACOMP_GAINR,
  39         ACOMP_OUTLEVEL,
  40         ACOMP_SIDECHAIN,
  41
  42         ACOMP_INPUT,
  43         ACOMP_SC,
  44         ACOMP_OUTPUT,
  45 } PortIndexMono;
  46
  47 typedef enum {
  48         ACOMP_STEREO_ATTACK = 0,
  49         ACOMP_STEREO_RELEASE,
  50         ACOMP_STEREO_KNEE,
  51         ACOMP_STEREO_RATIO,
  52         ACOMP_STEREO_THRESHOLD,
  53         ACOMP_STEREO_MAKEUP,
  54
  55         ACOMP_STEREO_GAINR,
  56         ACOMP_STEREO_OUTLEVEL,
  57         ACOMP_STEREO_SIDECHAIN,
  58
  59         ACOMP_STEREO_INPUT0,
  60         ACOMP_STEREO_INPUT1,
  61         ACOMP_STEREO_SC,
  62         ACOMP_STEREO_OUTPUT0,
  63         ACOMP_STEREO_OUTPUT1,
  64 } PortIndexStereo;
  65
  66 typedef struct {
  67         float* attack;
  68         float* release;
  69         float* knee;
  70         float* ratio;
  71         float* thresdb;
  72         float* makeup;
  73
  74         float* gainr;
  75         float* outlevel;
  76         float* sidechain;
  77
  78         float* input0;
  79         float* input1;
  80         float* sc;
  81         float* output0;
  82         float* output1;
  83
  84         float srate;
  85         float old_yl;
  86         float old_y1;
  87         float old_yg;
  88
  89 #ifdef LV2_EXTENDED
  90         LV2_Inline_Display_Image_Surface surf;
  91         bool                     need_expose;
  92         cairo_surface_t*         display;
  93         LV2_Inline_Display*      queue_draw;
  94         uint32_t                 w, h;
  95
  96         /* ports pointers are only valid during run so we'll
  97          * have to cache them for the display, besides
  98          * we do want to check for changes
  99          */
 100         float v_knee;
 101         float v_ratio;
 102         float v_thresdb;
 103         float v_lvl;
 104         float v_lvl_in;
 105         float v_lvl_out;
 106 #endif
 107 } AComp;
 108
 109 static LV2_Handle
 110 instantiate(const LV2_Descriptor* descriptor,
 111             double rate,
 112             const char* bundle_path,
 113             const LV2_Feature* const* features)
 114 {
 115         AComp* acomp = (AComp*)calloc(1, sizeof(AComp));
 116
 117         for (int i=0; features[i]; ++i) {
 118 #ifdef LV2_EXTENDED
 119                 if (!strcmp(features[i]->URI, LV2_INLINEDISPLAY__queue_draw)) {
 120                         acomp->queue_draw = (LV2_Inline_Display*) features[i]->data;
 121                 }
 122 #endif
 123         }
 124
 125         acomp->srate = rate;
 126         acomp->old_yl=acomp->old_y1=acomp->old_yg=0.f;
 127 #ifdef LV2_EXTENDED
 128         acomp->need_expose = true;
 129 #endif
 130
 131         return (LV2_Handle)acomp;
 132 }
 133
 134
 135 static void
 136 connect_port_mono(LV2_Handle instance,
 137              uint32_t port,
 138              void* data)
 139 {
 140         AComp* acomp = (AComp*)instance;
 141
 142         switch ((PortIndexMono)port) {
 143         case ACOMP_ATTACK:
 144                 acomp->attack = (float*)data;
 145                 break;
 146         case ACOMP_RELEASE:
 147                 acomp->release = (float*)data;
 148                 break;
 149         case ACOMP_KNEE:
 150                 acomp->knee = (float*)data;
 151                 break;
 152         case ACOMP_RATIO:
 153                 acomp->ratio = (float*)data;
 154                 break;
 155         case ACOMP_THRESHOLD:
 156                 acomp->thresdb = (float*)data;
 157                 break;
 158         case ACOMP_MAKEUP:
 159                 acomp->makeup = (float*)data;
 160                 break;
 161         case ACOMP_GAINR:
 162                 acomp->gainr = (float*)data;
 163                 break;
 164         case ACOMP_OUTLEVEL:
 165                 acomp->outlevel = (float*)data;
 166                 break;
 167         case ACOMP_SIDECHAIN:
 168                 acomp->sidechain = (float*)data;
 169                 break;
 170         case ACOMP_INPUT:
 171                 acomp->input0 = (float*)data;
 172                 break;
 173         case ACOMP_SC:
 174                 acomp->sc = (float*)data;
 175                 break;
 176         case ACOMP_OUTPUT:
 177                 acomp->output0 = (float*)data;
 178                 break;
 179         }
 180 }
 181
 182 static void
 183 connect_port_stereo(LV2_Handle instance,
 184              uint32_t port,
 185              void* data)
 186 {
 187         AComp* acomp = (AComp*)instance;
 188
 189         switch ((PortIndexStereo)port) {
 190         case ACOMP_STEREO_ATTACK:
 191                 acomp->attack = (float*)data;
 192                 break;
 193         case ACOMP_STEREO_RELEASE:
 194                 acomp->release = (float*)data;
 195                 break;
 196         case ACOMP_STEREO_KNEE:
 197                 acomp->knee = (float*)data;
 198                 break;
 199         case ACOMP_STEREO_RATIO:
 200                 acomp->ratio = (float*)data;
 201                 break;
 202         case ACOMP_STEREO_THRESHOLD:
 203                 acomp->thresdb = (float*)data;
 204                 break;
 205         case ACOMP_STEREO_MAKEUP:
 206                 acomp->makeup = (float*)data;
 207                 break;
 208         case ACOMP_STEREO_GAINR:
 209                 acomp->gainr = (float*)data;
 210                 break;
 211         case ACOMP_STEREO_OUTLEVEL:
 212                 acomp->outlevel = (float*)data;
 213                 break;
 214         case ACOMP_STEREO_SIDECHAIN:
 215                 acomp->sidechain = (float*)data;
 216                 break;
 217         case ACOMP_STEREO_INPUT0:
 218                 acomp->input0 = (float*)data;
 219                 break;
 220         case ACOMP_STEREO_INPUT1:
 221                 acomp->input1 = (float*)data;
 222                 break;
 223         case ACOMP_STEREO_SC:
 224                 acomp->sc = (float*)data;
 225                 break;
 226         case ACOMP_STEREO_OUTPUT0:
 227                 acomp->output0 = (float*)data;
 228                 break;
 229         case ACOMP_STEREO_OUTPUT1:
 230                 acomp->output1 = (float*)data;
 231                 break;
 232         }
 233 }
 234
 235 // Force already-denormal float value to zero
 236 static inline float
 237 sanitize_denormal(float value) {
 238         if (!isnormal(value)) {
 239                 value = 0.f;
 240         }
 241         return value;
 242 }
 243
 244 static inline float
 245 from_dB(float gdb) {
 246         return (exp(gdb/20.f*log(10.f)));
 247 }
 248
 249 static inline float
 250 to_dB(float g) {
 251         return (20.f*log10(g));
 252 }
 253
 254 static void
 255 activate(LV2_Handle instance)
 256 {
 257         AComp* acomp = (AComp*)instance;
 258
 259         *(acomp->gainr) = 0.0f;
 260         *(acomp->outlevel) = -45.0f;
 261         acomp->old_yl=acomp->old_y1=acomp->old_yg=0.f;
 262 }
 263
 264 static void
 265 run_mono(LV2_Handle instance, uint32_t n_samples)
 266 {
 267         AComp* acomp = (AComp*)instance;
 268
 269         const float* const input = acomp->input0;
 270         const float* const sc = acomp->sc;
 271         float* const output = acomp->output0;
 272
 273         float srate = acomp->srate;
 274         float width = (6.f * *(acomp->knee)) + 0.01;
 275         float cdb=0.f;
 276         float attack_coeff = exp(-1000.f/(*(acomp->attack) * srate));
 277         float release_coeff = exp(-1000.f/(*(acomp->release) * srate));
 278
 279         float max = 0.f;
 280         float lgaininp = 0.f;
 281         float Lgain = 1.f;
 282         float Lxg, Lxl, Lyg, Lyl, Ly1;
 283         int usesidechain = (*(acomp->sidechain) < 0.5) ? 0 : 1;
 284         uint32_t i;
 285         float ingain;
 286         float in0;
 287         float sc0;
 288         float ratio = *(acomp->ratio);
 289         float thresdb = *(acomp->thresdb);
 290
 291 #ifdef LV2_EXTENDED
 292         if (acomp->v_knee != *acomp->knee) {
 293                 acomp->v_knee = *acomp->knee;
 294                 acomp->need_expose = true;
 295         }
 296
 297         if (acomp->v_ratio != *acomp->ratio) {
 298                 acomp->v_ratio = *acomp->ratio;
 299                 acomp->need_expose = true;
 300         }
 301
 302         if (acomp->v_thresdb != *acomp->thresdb) {
 303                 acomp->v_thresdb = *acomp->thresdb;
 304                 acomp->need_expose = true;
 305         }
 306 #endif
 307
 308         float in_peak = 0;
 309
 310         for (i = 0; i < n_samples; i++) {
 311                 in0 = input[i];
 312                 sc0 = sc[i];
 313                 ingain = usesidechain ? fabs(sc0) : fabs(in0);
 314                 in_peak = fmaxf (in_peak, ingain);
 315                 Lyg = 0.f;
 316                 Lxg = (ingain==0.f) ? -160.f : to_dB(ingain);
 317                 Lxg = sanitize_denormal(Lxg);
 318
 319
 320                 if (2.f*(Lxg-thresdb) < -width) {
 321                         Lyg = Lxg;
 322                 } else if (2.f*(Lxg-thresdb) > width) {
 323                         Lyg = thresdb + (Lxg-thresdb)/ratio;
 324                         Lyg = sanitize_denormal(Lyg);
 325                 } else {
 326                         Lyg = Lxg + (1.f/ratio-1.f)*(Lxg-thresdb+width/2.f)*(Lxg-thresdb+width/2.f)/(2.f*width);
 327                 }
 328
 329                 Lxl = Lxg - Lyg;
 330
 331                 acomp->old_y1 = sanitize_denormal(acomp->old_y1);
 332                 acomp->old_yl = sanitize_denormal(acomp->old_yl);
 333                 Ly1 = fmaxf(Lxl, release_coeff * acomp->old_y1+(1.f-release_coeff)*Lxl);
 334                 Lyl = attack_coeff * acomp->old_yl+(1.f-attack_coeff)*Ly1;
 335                 Ly1 = sanitize_denormal(Ly1);
 336                 Lyl = sanitize_denormal(Lyl);
 337
 338                 cdb = -Lyl;
 339                 Lgain = from_dB(cdb);
 340
 341                 *(acomp->gainr) = Lyl;
 342
 343                 lgaininp = in0 * Lgain;
 344                 output[i] = lgaininp * from_dB(*(acomp->makeup));
 345
 346                 max = (fabsf(output[i]) > max) ? fabsf(output[i]) : sanitize_denormal(max);
 347
 348                 // TODO re-use local variables on stack
 349                 // store values back to acomp at the end of the inner-loop
 350                 acomp->old_yl = Lyl;
 351                 acomp->old_y1 = Ly1;
 352                 acomp->old_yg = Lyg;
 353         }
 354
 355         *(acomp->outlevel) = (max < 0.0056f) ? -45.f : to_dB(max);
 356
 357 #ifdef LV2_EXTENDED
 358         acomp->v_lvl += .1 * (in_peak - acomp->v_lvl);  // crude LPF TODO use n_samples/rate TC
 359         const float v_lvl_in = (acomp->v_lvl < 0.001f) ? -60.f : to_dB(acomp->v_lvl);
 360         const float v_lvl_out = (max < 0.001f) ? -60.f : to_dB(max);
 361         if (fabsf (acomp->v_lvl_out - v_lvl_out) >= 1 || fabsf (acomp->v_lvl_in - v_lvl_in) >= 1) {
 362                 // >= 1dB difference
 363                 acomp->need_expose = true;
 364                 acomp->v_lvl_in = v_lvl_in;
 365                 acomp->v_lvl_out = v_lvl_out - *acomp->makeup;
 366         }
 367         if (acomp->need_expose && acomp->queue_draw) {
 368                 acomp->need_expose = false;
 369                 acomp->queue_draw->queue_draw (acomp->queue_draw->handle);
 370         }
 371 #endif
 372 }
 373
 374 static void
 375 run_stereo(LV2_Handle instance, uint32_t n_samples)
 376 {
 377         AComp* acomp = (AComp*)instance;
 378
 379         const float* const input0 = acomp->input0;
 380         const float* const input1 = acomp->input1;
 381         const float* const sc = acomp->sc;
 382         float* const output0 = acomp->output0;
 383         float* const output1 = acomp->output1;
 384
 385         float srate = acomp->srate;
 386         float width = (6.f * *(acomp->knee)) + 0.01;
 387         float cdb=0.f;
 388         float attack_coeff = exp(-1000.f/(*(acomp->attack) * srate));
 389         float release_coeff = exp(-1000.f/(*(acomp->release) * srate));
 390
 391         float max = 0.f;
 392         float lgaininp = 0.f;
 393         float rgaininp = 0.f;
 394         float Lgain = 1.f;
 395         float Lxg, Lxl, Lyg, Lyl, Ly1;
 396         int usesidechain = (*(acomp->sidechain) < 0.5) ? 0 : 1;
 397         uint32_t i;
 398         float ingain;
 399         float in0;
 400         float in1;
 401         float sc0;
 402         float maxabslr;
 403         float ratio = *(acomp->ratio);
 404         float thresdb = *(acomp->thresdb);
 405
 406 #ifdef LV2_EXTENDED
 407         if (acomp->v_knee != *acomp->knee) {
 408                 acomp->v_knee = *acomp->knee;
 409                 acomp->need_expose = true;
 410         }
 411
 412         if (acomp->v_ratio != *acomp->ratio) {
 413                 acomp->v_ratio = *acomp->ratio;
 414                 acomp->need_expose = true;
 415         }
 416
 417         if (acomp->v_thresdb != *acomp->thresdb) {
 418                 acomp->v_thresdb = *acomp->thresdb;
 419                 acomp->need_expose = true;
 420         }
 421 #endif
 422
 423         float in_peak = 0;
 424
 425         for (i = 0; i < n_samples; i++) {
 426                 in0 = input0[i];
 427                 in1 = input1[i];
 428                 sc0 = sc[i];
 429                 maxabslr = fmaxf(fabs(in0), fabs(in1));
 430                 ingain = usesidechain ? fabs(sc0) : maxabslr;
 431                 in_peak = fmaxf (in_peak, ingain);
 432                 Lyg = 0.f;
 433                 Lxg = (ingain==0.f) ? -160.f : to_dB(ingain);
 434                 Lxg = sanitize_denormal(Lxg);
 435
 436
 437                 if (2.f*(Lxg-thresdb) < -width) {
 438                         Lyg = Lxg;
 439                 } else if (2.f*(Lxg-thresdb) > width) {
 440                         Lyg = thresdb + (Lxg-thresdb)/ratio;
 441                         Lyg = sanitize_denormal(Lyg);
 442                 } else {
 443                         Lyg = Lxg + (1.f/ratio-1.f)*(Lxg-thresdb+width/2.f)*(Lxg-thresdb+width/2.f)/(2.f*width);
 444                 }
 445
 446                 Lxl = Lxg - Lyg;
 447
 448                 acomp->old_y1 = sanitize_denormal(acomp->old_y1);
 449                 acomp->old_yl = sanitize_denormal(acomp->old_yl);
 450                 Ly1 = fmaxf(Lxl, release_coeff * acomp->old_y1+(1.f-release_coeff)*Lxl);
 451                 Lyl = attack_coeff * acomp->old_yl+(1.f-attack_coeff)*Ly1;
 452                 Ly1 = sanitize_denormal(Ly1);
 453                 Lyl = sanitize_denormal(Lyl);
 454
 455                 cdb = -Lyl;
 456                 Lgain = from_dB(cdb);
 457
 458                 *(acomp->gainr) = Lyl;
 459
 460                 lgaininp = in0 * Lgain;
 461                 rgaininp = in1 * Lgain;
 462                 output0[i] = lgaininp * from_dB(*(acomp->makeup));
 463                 output1[i] = rgaininp * from_dB(*(acomp->makeup));
 464
 465                 max = (fmaxf(fabs(output0[i]), fabs(output1[i])) > max) ? fmaxf(fabs(output0[i]), fabs(output1[i])) : sanitize_denormal(max);
 466
 467                 // TODO re-use local variables on stack
 468                 // store values back to acomp at the end of the inner-loop
 469                 acomp->old_yl = Lyl;
 470                 acomp->old_y1 = Ly1;
 471                 acomp->old_yg = Lyg;
 472         }
 473
 474         *(acomp->outlevel) = (max < 0.0056f) ? -45.f : to_dB(max);
 475
 476 #ifdef LV2_EXTENDED
 477         acomp->v_lvl += .1 * (in_peak - acomp->v_lvl);  // crude LPF TODO use n_samples/rate TC
 478         const float v_lvl_in = (acomp->v_lvl < 0.001f) ? -60.f : to_dB(acomp->v_lvl);
 479         const float v_lvl_out = (max < 0.001f) ? -60.f : to_dB(max);
 480         if (fabsf (acomp->v_lvl_out - v_lvl_out) >= 1 || fabsf (acomp->v_lvl_in - v_lvl_in) >= 1) {
 481                 // >= 1dB difference
 482                 acomp->need_expose = true;
 483                 acomp->v_lvl_in = v_lvl_in;
 484                 acomp->v_lvl_out = v_lvl_out - *acomp->makeup;
 485         }
 486         if (acomp->need_expose && acomp->queue_draw) {
 487                 acomp->need_expose = false;
 488                 acomp->queue_draw->queue_draw (acomp->queue_draw->handle);
 489         }
 490 #endif
 491 }
 492
 493 static void
 494 deactivate(LV2_Handle instance)
 495 {
 496         activate(instance);
 497 }
 498
 499 static void
 500 cleanup(LV2_Handle instance)
 501 {
 502 #ifdef LV2_EXTENDED
 503         AComp* acomp = (AComp*)instance;
 504         if (acomp->display) {
 505                 cairo_surface_destroy (acomp->display);
 506         }
 507 #endif
 508
 509         free(instance);
 510 }
 511
 512
 513 #ifndef MIN
 514 #define MIN(A,B) ((A) < (B)) ? (A) : (B)
 515 #endif
 516
 517 #ifdef LV2_EXTENDED
 518 static float
 519 comp_curve (AComp* self, float xg) {
 520         const float knee = self->v_knee;
 521         const float ratio = self->v_ratio;
 522         const float thresdb = self->v_thresdb;
 523
 524         const float width = 6.f * knee + 0.01f;
 525         float yg = 0.f;
 526
 527         if (2.f * (xg - thresdb) < -width) {
 528                 yg = xg;
 529         } else if (2.f * (xg - thresdb) > width) {
 530                 yg = thresdb + (xg - thresdb) / ratio;
 531         } else {
 532                 yg = xg + (1.f / ratio - 1.f ) * (xg - thresdb + width / 2.f) * (xg - thresdb + width / 2.f) / (2.f * width);
 533         }
 534         return yg;
 535 }
 536
 537 static LV2_Inline_Display_Image_Surface *
 538 render_inline (LV2_Handle instance, uint32_t w, uint32_t max_h)
 539 {
 540         AComp* self = (AComp*)instance;
 541         uint32_t h = MIN (w, max_h);
 542
 543         if (!self->display || self->w != w || self->h != h) {
 544                 if (self->display) cairo_surface_destroy(self->display);
 545                 self->display = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, w, h);
 546                 self->w = w;
 547                 self->h = h;
 548         }
 549
 550         cairo_t* cr = cairo_create (self->display);
 551
 552         // clear background
 553         cairo_rectangle (cr, 0, 0, w, h);
 554         cairo_set_source_rgba (cr, .2, .2, .2, 1.0);
 555         cairo_fill (cr);
 556
 557         cairo_set_line_width(cr, 1.0);
 558
 559         // draw grid 10dB steps
 560         const double dash1[] = {1, 2};
 561         const double dash2[] = {1, 3};
 562         cairo_save (cr);
 563         cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
 564         cairo_set_dash(cr, dash2, 2, 2);
 565         cairo_set_source_rgba (cr, 0.5, 0.5, 0.5, 0.5);
 566
 567         for (uint32_t d = 1; d < 6; ++d) {
 568                 const float x = -.5 + floorf (w * (d * 10.f / 60.f));
 569                 const float y = -.5 + floorf (h * (d * 10.f / 60.f));
 570
 571                 cairo_move_to (cr, x, 0);
 572                 cairo_line_to (cr, x, h);
 573                 cairo_stroke (cr);
 574
 575                 cairo_move_to (cr, 0, y);
 576                 cairo_line_to (cr, w, y);
 577                 cairo_stroke (cr);
 578         }
 579         if (self->v_thresdb < 0) {
 580                 cairo_set_source_rgba (cr, 0.5, 0.5, 0.5, 1.0);
 581                 const float y = -.5 + floorf (h * (self->v_thresdb / -60.f));
 582                 cairo_set_dash(cr, dash1, 2, 2);
 583                 cairo_move_to (cr, 0, y);
 584                 cairo_line_to (cr, w, y);
 585                 cairo_stroke (cr);
 586                 cairo_move_to (cr, 0, h);
 587                 cairo_line_to (cr, w, 0);
 588                 cairo_stroke (cr);
 589         }
 590         cairo_restore (cr);
 591
 592
 593         // draw curve
 594         cairo_set_source_rgba (cr, .8, .8, .8, 1.0);
 595         cairo_move_to (cr, 0, h);
 596
 597         for (uint32_t x = 0; x < w; ++x) {
 598                 // plot -60..0  dB
 599                 const float x_db = 60.f * (-1.f + x / (float)w);
 600                 const float y_db = comp_curve (self, x_db);
 601                 const float y = h * (y_db / -60.f);
 602                 cairo_line_to (cr, x, y);
 603         }
 604         cairo_stroke_preserve (cr);
 605
 606         cairo_line_to (cr, w, h);
 607         cairo_close_path (cr);
 608         cairo_clip (cr);
 609
 610         // draw signal level & reduction/gradient
 611         const float top = comp_curve (self, 0);
 612         cairo_pattern_t* pat = cairo_pattern_create_linear (0.0, 0.0, 0.0, h);
 613         if (top > self->v_thresdb) {
 614                 cairo_pattern_add_color_stop_rgba (pat, 0.0, 0.8, 0.1, 0.1, 0.5);
 615                 cairo_pattern_add_color_stop_rgba (pat, top / -60.f, 0.8, 0.1, 0.1, 0.5);
 616         }
 617         if (self->v_knee > 0) {
 618                 cairo_pattern_add_color_stop_rgba (pat, (self->v_thresdb / -60.f), 0.7, 0.7, 0.2, 0.5);
 619                 cairo_pattern_add_color_stop_rgba (pat, ((self->v_thresdb - self->v_knee) / -60.f), 0.5, 0.5, 0.5, 0.5);
 620         } else {
 621                 cairo_pattern_add_color_stop_rgba (pat, (self->v_thresdb / -60.f), 0.7, 0.7, 0.2, 0.5);
 622                 cairo_pattern_add_color_stop_rgba (pat, ((self->v_thresdb - .01) / -60.f), 0.5, 0.5, 0.5, 0.5);
 623         }
 624         cairo_pattern_add_color_stop_rgba (pat, 1.0, 0.5, 0.5, 0.5, 0.5);
 625
 626         // maybe cut off at x-position?
 627         const float x = w * (self->v_lvl_in + 60) / 60.f;
 628         //const float y = h * (self->v_lvl_out + 60) / 60.f;
 629         cairo_rectangle (cr, 0, h - x, x, h);
 630         if (self->v_ratio > 1.0) {
 631                 cairo_set_source (cr, pat);
 632         } else {
 633                 cairo_set_source_rgba (cr, 0.5, 0.5, 0.5, 0.5);
 634         }
 635         cairo_fill (cr);
 636
 637         cairo_pattern_destroy (pat); // TODO cache pattern
 638
 639
 640         // create RGBA surface
 641         cairo_destroy (cr);
 642         cairo_surface_flush (self->display);
 643         self->surf.width = cairo_image_surface_get_width (self->display);
 644         self->surf.height = cairo_image_surface_get_height (self->display);
 645         self->surf.stride = cairo_image_surface_get_stride (self->display);
 646         self->surf.data = cairo_image_surface_get_data  (self->display);
 647
 648         return &self->surf;
 649 }
 650 #endif
 651
 652 static const void*
 653 extension_data(const char* uri)
 654 {
 655 #ifdef LV2_EXTENDED
 656         static const LV2_Inline_Display_Interface display  = { render_inline };
 657         if (!strcmp(uri, LV2_INLINEDISPLAY__interface)) {
 658                 return &display;
 659         }
 660 #endif
 661         return NULL;
 662 }
 663
 664 static const LV2_Descriptor descriptor_mono = {
 665         ACOMP_URI,
 666         instantiate,
 667         connect_port_mono,
 668         activate,
 669         run_mono,
 670         deactivate,
 671         cleanup,
 672         extension_data
 673 };
 674
 675 static const LV2_Descriptor descriptor_stereo = {
 676         ACOMP_STEREO_URI,
 677         instantiate,
 678         connect_port_stereo,
 679         activate,
 680         run_stereo,
 681         deactivate,
 682         cleanup,
 683         extension_data
 684 };
 685
 686 LV2_SYMBOL_EXPORT
 687 const LV2_Descriptor*
 688 lv2_descriptor(uint32_t index)
 689 {
 690         switch (index) {
 691         case 0:
 692                 return &descriptor_mono;
 693         case 1:
 694                 return &descriptor_stereo;
 695         default:
 696                 return NULL;
 697         }
 698 }