blender-archive/source/blender/editors/space_sequencer/sequencer_draw.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */

/** \file
 * \ingroup spseq
 */

#include <string.h>
#include <math.h>

#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_utildefines.h"
#include "BLI_threads.h"

#include "IMB_imbuf_types.h"

#include "DNA_scene_types.h"
#include "DNA_mask_types.h"
#include "DNA_object_types.h"
#include "DNA_screen_types.h"
#include "DNA_space_types.h"
#include "DNA_userdef_types.h"
#include "DNA_sound_types.h"
#include "DNA_anim_types.h"

#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_sequencer.h"
#include "BKE_sound.h"
#include "BKE_scene.h"
#include "BKE_fcurve.h"

#include "IMB_colormanagement.h"
#include "IMB_imbuf.h"

#include "GPU_immediate.h"
#include "GPU_immediate_util.h"
#include "GPU_matrix.h"
#include "GPU_state.h"
#include "GPU_framebuffer.h"
#include "GPU_vertex_buffer.h"

#include "ED_anim_api.h"
#include "ED_gpencil.h"
#include "ED_markers.h"
#include "ED_mask.h"
#include "ED_sequencer.h"
#include "ED_screen.h"
#include "ED_time_scrub_ui.h"
#include "ED_space_api.h"

#include "BIF_glutil.h"

#include "UI_interface.h"
#include "UI_resources.h"
#include "UI_view2d.h"

#include "WM_api.h"
#include "WM_types.h"

#include "MEM_guardedalloc.h"

/* own include */
#include "sequencer_intern.h"

#define SEQ_LEFTHANDLE 1
#define SEQ_RIGHTHANDLE 2

#define SEQ_HANDLE_SIZE_MIN 7.0f
#define SEQ_HANDLE_SIZE_MAX 40.0f

#define SEQ_SCROLLER_TEXT_OFFSET 8

/* Note, Don't use SEQ_BEGIN/SEQ_END while drawing!
 * it messes up transform, - Campbell */
#undef SEQ_BEGIN
#undef SEQP_BEGIN
#undef SEQ_END

static Sequence *special_seq_update = NULL;

void color3ubv_from_seq(Scene *curscene, Sequence *seq, unsigned char col[3])
{
  unsigned char blendcol[3];
  SolidColorVars *colvars = (SolidColorVars *)seq->effectdata;

  switch (seq->type) {
    case SEQ_TYPE_IMAGE:
      UI_GetThemeColor3ubv(TH_SEQ_IMAGE, col);
      break;

    case SEQ_TYPE_META:
      UI_GetThemeColor3ubv(TH_SEQ_META, col);
      break;

    case SEQ_TYPE_MOVIE:
      UI_GetThemeColor3ubv(TH_SEQ_MOVIE, col);
      break;

    case SEQ_TYPE_MOVIECLIP:
      UI_GetThemeColor3ubv(TH_SEQ_MOVIECLIP, col);
      break;

    case SEQ_TYPE_MASK:
      UI_GetThemeColor3ubv(TH_SEQ_MASK, col); /* TODO */
      break;

    case SEQ_TYPE_SCENE:
      UI_GetThemeColor3ubv(TH_SEQ_SCENE, col);

      if (seq->scene == curscene) {
        UI_GetColorPtrShade3ubv(col, col, 20);
      }
      break;

    /* transitions */
    case SEQ_TYPE_CROSS:
    case SEQ_TYPE_GAMCROSS:
    case SEQ_TYPE_WIPE:
      UI_GetThemeColor3ubv(TH_SEQ_TRANSITION, col);

      /* slightly offset hue to distinguish different effects */
      if (seq->type == SEQ_TYPE_CROSS) {
        rgb_byte_set_hue_float_offset(col, 0.04);
      }
      if (seq->type == SEQ_TYPE_GAMCROSS) {
        rgb_byte_set_hue_float_offset(col, 0.08);
      }
      if (seq->type == SEQ_TYPE_WIPE) {
        rgb_byte_set_hue_float_offset(col, 0.12);
      }
      break;

    /* effects */
    case SEQ_TYPE_TRANSFORM:
    case SEQ_TYPE_SPEED:
    case SEQ_TYPE_ADD:
    case SEQ_TYPE_SUB:
    case SEQ_TYPE_MUL:
    case SEQ_TYPE_ALPHAOVER:
    case SEQ_TYPE_ALPHAUNDER:
    case SEQ_TYPE_OVERDROP:
    case SEQ_TYPE_GLOW:
    case SEQ_TYPE_MULTICAM:
    case SEQ_TYPE_ADJUSTMENT:
    case SEQ_TYPE_GAUSSIAN_BLUR:
    case SEQ_TYPE_COLORMIX:
      UI_GetThemeColor3ubv(TH_SEQ_EFFECT, col);

      /* slightly offset hue to distinguish different effects */
      if (seq->type == SEQ_TYPE_ADD) {
        rgb_byte_set_hue_float_offset(col, 0.04);
      }
      else if (seq->type == SEQ_TYPE_SUB) {
        rgb_byte_set_hue_float_offset(col, 0.08);
      }
      else if (seq->type == SEQ_TYPE_MUL) {
        rgb_byte_set_hue_float_offset(col, 0.12);
      }
      else if (seq->type == SEQ_TYPE_ALPHAOVER) {
        rgb_byte_set_hue_float_offset(col, 0.16);
      }
      else if (seq->type == SEQ_TYPE_ALPHAUNDER) {
        rgb_byte_set_hue_float_offset(col, 0.20);
      }
      else if (seq->type == SEQ_TYPE_OVERDROP) {
        rgb_byte_set_hue_float_offset(col, 0.24);
      }
      else if (seq->type == SEQ_TYPE_GLOW) {
        rgb_byte_set_hue_float_offset(col, 0.28);
      }
      else if (seq->type == SEQ_TYPE_TRANSFORM) {
        rgb_byte_set_hue_float_offset(col, 0.36);
      }
      else if (seq->type == SEQ_TYPE_MULTICAM) {
        rgb_byte_set_hue_float_offset(col, 0.32);
      }
      else if (seq->type == SEQ_TYPE_ADJUSTMENT) {
        rgb_byte_set_hue_float_offset(col, 0.40);
      }
      else if (seq->type == SEQ_TYPE_GAUSSIAN_BLUR) {
        rgb_byte_set_hue_float_offset(col, 0.42);
      }
      else if (seq->type == SEQ_TYPE_COLORMIX) {
        rgb_byte_set_hue_float_offset(col, 0.46);
      }
      break;

    case SEQ_TYPE_COLOR:
      rgb_float_to_uchar(col, colvars->col);
      break;

    case SEQ_TYPE_SOUND_RAM:
      UI_GetThemeColor3ubv(TH_SEQ_AUDIO, col);
      blendcol[0] = blendcol[1] = blendcol[2] = 128;
      if (seq->flag & SEQ_MUTE) {
        UI_GetColorPtrBlendShade3ubv(col, blendcol, col, 0.5, 20);
      }
      break;

    case SEQ_TYPE_TEXT:
      UI_GetThemeColor3ubv(TH_SEQ_TEXT, col);
      break;

    default:
      col[0] = 10;
      col[1] = 255;
      col[2] = 40;
      break;
  }
}

static void drawseqwave(View2D *v2d,
                        const bContext *C,
                        SpaceSeq *sseq,
                        Scene *scene,
                        Sequence *seq,
                        float x1,
                        float y1,
                        float x2,
                        float y2,
                        float stepsize)
{
  /*
   * x1 is the starting x value to draw the wave,
   * x2 the end x value, same for y1 and y2
   * stepsize is width of a pixel.
   */

  /* offset x1 and x2 values, to match view min/max, if strip is out of bounds */
  int x1_offset = max_ff(v2d->cur.xmin, x1);
  int x2_offset = min_ff(v2d->cur.xmax + 1.0f, x2);

  if (seq->sound && ((sseq->flag & SEQ_ALL_WAVEFORMS) || (seq->flag & SEQ_AUDIO_DRAW_WAVEFORM))) {
    int i, j, p;
    int length = floor((x2_offset - x1_offset) / stepsize) + 1;
    float ymid = (y1 + y2) / 2.0f;
    float yscale = (y2 - y1) / 2.0f;
    float samplestep;
    float startsample, endsample;
    float volume = seq->volume;
    float value1, value2;
    bSound *sound = seq->sound;
    FCurve *fcu = id_data_find_fcurve(&scene->id, seq, &RNA_Sequence, "volume", 0, NULL);

    SoundWaveform *waveform;

    if (length < 2) {
      return;
    }

    BLI_spin_lock(sound->spinlock);
    if (!sound->waveform) {
      if (!(sound->tags & SOUND_TAGS_WAVEFORM_LOADING)) {
        /* prevent sounds from reloading */
        sound->tags |= SOUND_TAGS_WAVEFORM_LOADING;
        BLI_spin_unlock(sound->spinlock);
        sequencer_preview_add_sound(C, seq);
      }
      else {
        BLI_spin_unlock(sound->spinlock);
      }
      return; /* nothing to draw */
    }
    BLI_spin_unlock(sound->spinlock);

    waveform = sound->waveform;

    if (waveform->length == 0) {
      /* BKE_sound_read_waveform() set an empty SoundWaveform data in case it cannot generate a
       * valid one. See T45726. */
      return;
    }

    startsample = floor((seq->startofs + seq->anim_startofs) / FPS *
                        SOUND_WAVE_SAMPLES_PER_SECOND);
    endsample = ceil((seq->startofs + seq->anim_startofs + seq->enddisp - seq->startdisp) / FPS *
                     SOUND_WAVE_SAMPLES_PER_SECOND);
    samplestep = (endsample - startsample) * stepsize / (x2 - x1);

    length = min_ii(
        floor((waveform->length - startsample) / samplestep - (x1_offset - x1) / stepsize),
        length);

    if (length < 2) {
      return;
    }

    GPU_blend(true);
    GPUVertFormat *format = immVertexFormat();
    uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
    uint col = GPU_vertformat_attr_add(format, "color", GPU_COMP_F32, 4, GPU_FETCH_FLOAT);
    immBindBuiltinProgram(GPU_SHADER_2D_FLAT_COLOR);
    immBegin(GPU_PRIM_TRI_STRIP, length * 2);

    for (i = 0; i < length; i++) {
      float sampleoffset = startsample + ((x1_offset - x1) / stepsize + i) * samplestep;
      p = sampleoffset;

      value1 = waveform->data[p * 3];
      value2 = waveform->data[p * 3 + 1];

      if (samplestep > 1.0f) {
        for (j = p + 1; (j < waveform->length) && (j < p + samplestep); j++) {
          if (value1 > waveform->data[j * 3]) {
            value1 = waveform->data[j * 3];
          }

          if (value2 < waveform->data[j * 3 + 1]) {
            value2 = waveform->data[j * 3 + 1];
          }
        }
      }
      else if (p + 1 < waveform->length) {
        /* use simple linear interpolation */
        float f = sampleoffset - p;
        value1 = (1.0f - f) * value1 + f * waveform->data[p * 3 + 3];
        value2 = (1.0f - f) * value2 + f * waveform->data[p * 3 + 4];
      }

      if (fcu && !BKE_fcurve_is_empty(fcu)) {
        float evaltime = x1_offset + (i * stepsize);
        volume = evaluate_fcurve(fcu, evaltime);
        CLAMP_MIN(volume, 0.0f);
      }
      value1 *= volume;
      value2 *= volume;

      if (value2 > 1 || value1 < -1) {
        immAttr4f(col, 1.0f, 0.0f, 0.0f, 0.5f);

        CLAMP_MAX(value2, 1.0f);
        CLAMP_MIN(value1, -1.0f);
      }
      else {
        immAttr4f(col, 1.0f, 1.0f, 1.0f, 0.5f);
      }

      immVertex2f(pos, x1_offset + i * stepsize, ymid + value1 * yscale);
      immVertex2f(pos, x1_offset + i * stepsize, ymid + value2 * yscale);
    }

    immEnd();
    immUnbindProgram();
    GPU_blend(false);
  }
}
static void drawmeta_contents(Scene *scene, Sequence *seqm, float x1, float y1, float x2, float y2)
{
  /* note: this used to use SEQ_BEGIN/SEQ_END, but it messes up the
   * seq->depth value, (needed by transform when doing overlap checks)
   * so for now, just use the meta's immediate children, could be fixed but
   * its only drawing - campbell */
  Sequence *seq;
  unsigned char col[4];

  int chan_min = MAXSEQ;
  int chan_max = 0;
  int chan_range = 0;
  float draw_range = y2 - y1;
  float draw_height;
  ListBase *seqbase;
  int offset;

  seqbase = BKE_sequence_seqbase_get(seqm, &offset);
  if (!seqbase || BLI_listbase_is_empty(seqbase)) {
    return;
  }

  if (seqm->type == SEQ_TYPE_SCENE) {
    offset = seqm->start - offset;
  }
  else {
    offset = 0;
  }

  GPU_blend(true);
  GPU_blend_set_func_separate(
      GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);

  for (seq = seqbase->first; seq; seq = seq->next) {
    chan_min = min_ii(chan_min, seq->machine);
    chan_max = max_ii(chan_max, seq->machine);
  }

  chan_range = (chan_max - chan_min) + 1;
  draw_height = draw_range / chan_range;

  col[3] = 196; /* alpha, used for all meta children */

  uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

  immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

  for (seq = seqbase->first; seq; seq = seq->next) {
    const int startdisp = seq->startdisp + offset;
    const int enddisp = seq->enddisp + offset;

    if ((startdisp > x2 || enddisp < x1) == 0) {
      float y_chan = (seq->machine - chan_min) / (float)(chan_range)*draw_range;
      float x1_chan = startdisp;
      float x2_chan = enddisp;
      float y1_chan, y2_chan;

      color3ubv_from_seq(scene, seq, col);

      if ((seqm->flag & SEQ_MUTE) || (seq->flag & SEQ_MUTE)) {
        col[3] = 64;
      }
      else {
        col[3] = 196;
      }

      immUniformColor4ubv(col);

      /* clamp within parent sequence strip bounds */
      if (x1_chan < x1) {
        x1_chan = x1;
      }
      if (x2_chan > x2) {
        x2_chan = x2;
      }

      y1_chan = y1 + y_chan + (draw_height * SEQ_STRIP_OFSBOTTOM);
      y2_chan = y1 + y_chan + (draw_height * SEQ_STRIP_OFSTOP);

      immRectf(pos, x1_chan, y1_chan, x2_chan, y2_chan);
    }
  }

  immUnbindProgram();

  GPU_blend(false);
}

/* clamp handles to defined size in pixel space */
float sequence_handle_size_get_clamped(Sequence *seq, const float pixelx)
{
  const float minhandle = pixelx * SEQ_HANDLE_SIZE_MIN;
  const float maxhandle = pixelx * SEQ_HANDLE_SIZE_MAX;
  float size = CLAMPIS(seq->handsize, minhandle, maxhandle);

  /* ensure we're not greater than half width */
  return min_ff(size, ((float)(seq->enddisp - seq->startdisp) / 2.0f) / pixelx);
}

/* draw a handle, for each end of a sequence strip */
static void draw_seq_handle(View2D *v2d,
                            Sequence *seq,
                            const float handsize_clamped,
                            const short direction,
                            unsigned int pos)
{
  float v1[2], v2[2], v3[2], rx1 = 0, rx2 = 0;  // for triangles and rect
  float x1, x2, y1, y2;
  unsigned int whichsel = 0;

  x1 = seq->startdisp;
  x2 = seq->enddisp;

  y1 = seq->machine + SEQ_STRIP_OFSBOTTOM;
  y2 = seq->machine + SEQ_STRIP_OFSTOP;

  /* set up co-ordinates/dimensions for either left or right handle */
  if (direction == SEQ_LEFTHANDLE) {
    rx1 = x1;
    rx2 = x1 + handsize_clamped * 0.75f;

    v1[0] = x1 + handsize_clamped / 4;
    v1[1] = y1 + (((y1 + y2) / 2.0f - y1) / 2);
    v2[0] = x1 + handsize_clamped / 4;
    v2[1] = y2 - (((y1 + y2) / 2.0f - y1) / 2);
    v3[0] = v2[0] + handsize_clamped / 4;
    v3[1] = (y1 + y2) / 2.0f;

    whichsel = SEQ_LEFTSEL;
  }
  else if (direction == SEQ_RIGHTHANDLE) {
    rx1 = x2 - handsize_clamped * 0.75f;
    rx2 = x2;

    v1[0] = x2 - handsize_clamped / 4;
    v1[1] = y1 + (((y1 + y2) / 2.0f - y1) / 2);
    v2[0] = x2 - handsize_clamped / 4;
    v2[1] = y2 - (((y1 + y2) / 2.0f - y1) / 2);
    v3[0] = v2[0] - handsize_clamped / 4;
    v3[1] = (y1 + y2) / 2.0f;

    whichsel = SEQ_RIGHTSEL;
  }

  /* draw! */
  if (!(seq->type & SEQ_TYPE_EFFECT) || BKE_sequence_effect_get_num_inputs(seq->type) == 0) {
    GPU_blend(true);

    GPU_blend_set_func_separate(
        GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);

    if (seq->flag & whichsel) {
      immUniformColor4ub(0, 0, 0, 80);
    }
    else if (seq->flag & SELECT) {
      immUniformColor4ub(255, 255, 255, 30);
    }
    else {
      immUniformColor4ub(0, 0, 0, 22);
    }

    immRectf(pos, rx1, y1, rx2, y2);

    if (seq->flag & whichsel) {
      immUniformColor4ub(255, 255, 255, 200);
    }
    else {
      immUniformColor4ub(0, 0, 0, 50);
    }

    immBegin(GPU_PRIM_TRIS, 3);
    immVertex2fv(pos, v1);
    immVertex2fv(pos, v2);
    immVertex2fv(pos, v3);
    immEnd();

    GPU_blend(false);
  }

  if ((G.moving & G_TRANSFORM_SEQ) || (seq->flag & whichsel)) {
    const uchar col[4] = {255, 255, 255, 255};
    char numstr[32];
    size_t numstr_len;

    if (direction == SEQ_LEFTHANDLE) {
      numstr_len = BLI_snprintf_rlen(numstr, sizeof(numstr), "%d", seq->startdisp);
      x1 = rx1;
      y1 -= 0.45f;
    }
    else {
      numstr_len = BLI_snprintf_rlen(numstr, sizeof(numstr), "%d", seq->enddisp - 1);
      x1 = x2 - handsize_clamped * 0.75f;
      y1 = y2 + 0.05f;
    }
    UI_view2d_text_cache_add(v2d, x1, y1, numstr, numstr_len, col);
  }
}

/* draw info text on a sequence strip */
static void draw_seq_text(View2D *v2d,
                          SpaceSeq *sseq,
                          Sequence *seq,
                          float x1,
                          float x2,
                          float y1,
                          float y2,
                          const unsigned char background_col[3])
{
  rctf rect;
  char str[32 + FILE_MAX];
  size_t str_len;
  const char *name = seq->name + 2;
  uchar col[4];

  /* note, all strings should include 'name' */
  if (name[0] == '\0') {
    name = BKE_sequence_give_name(seq);
  }

  if (seq->type == SEQ_TYPE_META || seq->type == SEQ_TYPE_ADJUSTMENT) {
    str_len = BLI_snprintf(str, sizeof(str), "%s | %d", name, seq->len);
  }
  else if (seq->type == SEQ_TYPE_SCENE) {
    if (seq->scene) {
      if (seq->scene_camera) {
        str_len = BLI_snprintf(str,
                               sizeof(str),
                               "%s: %s (%s) | %d",
                               name,
                               seq->scene->id.name + 2,
                               ((ID *)seq->scene_camera)->name + 2,
                               seq->len);
      }
      else {
        str_len = BLI_snprintf(
            str, sizeof(str), "%s: %s | %d", name, seq->scene->id.name + 2, seq->len);
      }
    }
    else {
      str_len = BLI_snprintf(str, sizeof(str), "%s | %d", name, seq->len);
    }
  }
  else if (seq->type == SEQ_TYPE_MOVIECLIP) {
    if (seq->clip && !STREQ(name, seq->clip->id.name + 2)) {
      str_len = BLI_snprintf(
          str, sizeof(str), "%s: %s | %d", name, seq->clip->id.name + 2, seq->len);
    }
    else {
      str_len = BLI_snprintf(str, sizeof(str), "%s | %d", name, seq->len);
    }
  }
  else if (seq->type == SEQ_TYPE_MASK) {
    if (seq->mask && !STREQ(name, seq->mask->id.name + 2)) {
      str_len = BLI_snprintf(
          str, sizeof(str), "%s: %s | %d", name, seq->mask->id.name + 2, seq->len);
    }
    else {
      str_len = BLI_snprintf(str, sizeof(str), "%s | %d", name, seq->len);
    }
  }
  else if (seq->type == SEQ_TYPE_MULTICAM) {
    str_len = BLI_snprintf(str, sizeof(str), "Cam %s: %d", name, seq->multicam_source);
  }
  else if (seq->type == SEQ_TYPE_IMAGE) {
    str_len = BLI_snprintf(str,
                           sizeof(str),
                           "%s: %s%s | %d",
                           name,
                           seq->strip->dir,
                           seq->strip->stripdata->name,
                           seq->len);
  }
  else if (seq->type == SEQ_TYPE_TEXT) {
    TextVars *textdata = seq->effectdata;
    str_len = BLI_snprintf(str, sizeof(str), "%s | %d", textdata->text, seq->startdisp);
  }
  else if (seq->type & SEQ_TYPE_EFFECT) {
    str_len = BLI_snprintf(str, sizeof(str), "%s | %d", name, seq->len);
  }
  else if (seq->type == SEQ_TYPE_SOUND_RAM) {
    /* If a waveform is drawn, we don't want to overlay it with text,
     * as it would make both hard to read. */
    if ((sseq->flag & SEQ_ALL_WAVEFORMS) || (seq->flag & SEQ_AUDIO_DRAW_WAVEFORM)) {
      str[0] = 0;
      str_len = 0;
    }
    else if (seq->sound) {
      str_len = BLI_snprintf(str, sizeof(str), "%s: %s | %d", name, seq->sound->name, seq->len);
    }
    else {
      str_len = BLI_snprintf(str, sizeof(str), "%s | %d", name, seq->len);
    }
  }
  else if (seq->type == SEQ_TYPE_MOVIE) {
    str_len = BLI_snprintf(str,
                           sizeof(str),
                           "%s: %s%s | %d",
                           name,
                           seq->strip->dir,
                           seq->strip->stripdata->name,
                           seq->len);
  }
  else {
    /* should never get here!, but might with files from future */
    BLI_assert(0);

    str_len = BLI_snprintf(str, sizeof(str), "%s | %d", name, seq->len);
  }

  if (seq->flag & SELECT) {
    col[0] = col[1] = col[2] = 255;
  }
  else if ((((int)background_col[0] + (int)background_col[1] + (int)background_col[2]) / 3) < 50) {
    col[0] = col[1] = col[2] = 80; /* use lighter text color for dark background */
  }
  else {
    col[0] = col[1] = col[2] = 0;
  }
  col[3] = 255;

  rect.xmin = x1;
  rect.ymin = y1;
  rect.xmax = x2;
  rect.ymax = y2;

  UI_view2d_text_cache_add_rectf(v2d, &rect, str, str_len, col);
}

static void draw_sequence_extensions(Scene *scene,
                                     ARegion *region,
                                     Sequence *seq,
                                     unsigned int pos)
{
  float x1, x2, y1, y2, pixely;
  unsigned char col[4], blendcol[3];
  View2D *v2d = &region->v2d;

  x1 = seq->startdisp;
  x2 = seq->enddisp;

  y1 = seq->machine + SEQ_STRIP_OFSBOTTOM;
  y2 = seq->machine + SEQ_STRIP_OFSTOP;

  pixely = BLI_rctf_size_y(&v2d->cur) / BLI_rcti_size_y(&v2d->mask);

  if (pixely <= 0) {
    return; /* can happen when the view is split/resized */
  }

  blendcol[0] = blendcol[1] = blendcol[2] = 120;

  if (seq->startofs || seq->endofs) {
    GPU_blend(true);
    GPU_blend_set_func_separate(
        GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);

    color3ubv_from_seq(scene, seq, col);

    if (seq->flag & SELECT) {
      UI_GetColorPtrShade3ubv(col, col, -50);
    }

    if (seq->flag & SEQ_MUTE) {
      col[3] = 64;
    }
    else {
      if (seq->flag & SELECT) {
        col[3] = 170;
      }
      else {
        col[3] = 80;
      }
    }
  }

  if (seq->startofs) {
    immUniformColor4ubv(col);
    immRectf(pos, (float)(seq->start), y1 - SEQ_STRIP_OFSBOTTOM, x1, y1);

    immUniformColor3ubvAlpha(col, col[3] + 50);

    /* outline */
    imm_draw_box_wire_2d(pos, (float)(seq->start), y1 - SEQ_STRIP_OFSBOTTOM, x1, y1);
  }
  if (seq->endofs) {
    immUniformColor4ubv(col);
    immRectf(pos, x2, y2, (float)(seq->start + seq->len), y2 + SEQ_STRIP_OFSBOTTOM);

    immUniformColor3ubvAlpha(col, col[3] + 50);

    /* outline */
    imm_draw_box_wire_2d(pos, x2, y2, (float)(seq->start + seq->len), y2 + SEQ_STRIP_OFSBOTTOM);
  }

  if (seq->startofs || seq->endofs) {
    GPU_blend(false);
  }

  if (seq->startstill || seq->endstill) {
    GPU_blend(true);
    GPU_blend_set_func_separate(
        GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);

    color3ubv_from_seq(scene, seq, col);
    UI_GetColorPtrBlendShade3ubv(col, blendcol, col, 0.5f, 60);

    if (seq->flag & SEQ_MUTE) {
      col[3] = 96;
    }
    else {
      if (seq->flag & SELECT) {
        col[3] = 255;
      }
      else {
        col[3] = 170;
      }
    }

    immUniformColor4ubv(col);
  }

  if (seq->startstill) {
    immRectf(pos, x1, y1, (float)(seq->start), y2);
  }
  if (seq->endstill) {
    immRectf(pos, (float)(seq->start + seq->len), y1, x2, y2);
  }

  if (seq->startstill || seq->endstill) {
    GPU_blend(false);
  }
}

/*
 * Draw a sequence strip, bounds check already made
 * ARegion is currently only used to get the windows width in pixels
 * so wave file sample drawing precision is zoom adjusted
 */
static void draw_seq_strip(const bContext *C,
                           SpaceSeq *sseq,
                           Scene *scene,
                           ARegion *region,
                           Sequence *seq,
                           int outline_tint,
                           float pixelx)
{
  View2D *v2d = &region->v2d;
  float x1, x2, y1, y2;
  unsigned char col[4], background_col[4], is_single_image;
  const float handsize_clamped = sequence_handle_size_get_clamped(seq, pixelx);

  /* we need to know if this is a single image/color or not for drawing */
  is_single_image = (char)BKE_sequence_single_check(seq);

  /* body */
  x1 = (seq->startstill) ? seq->start : seq->startdisp;
  y1 = seq->machine + SEQ_STRIP_OFSBOTTOM;
  x2 = (seq->endstill) ? (seq->start + seq->len) : seq->enddisp;
  y2 = seq->machine + SEQ_STRIP_OFSTOP;

  uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

  immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

  /* get the correct color per strip type*/
  // color3ubv_from_seq(scene, seq, col);
  color3ubv_from_seq(scene, seq, background_col);

  if (seq->flag & SEQ_MUTE) {
    background_col[3] = 128;

    GPU_blend(true);
    GPU_blend_set_func_separate(
        GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);
  }
  else {
    background_col[3] = 255;
  }

  if (seq->flag & SELECT) {
    UI_GetColorPtrShade3ubv(background_col, background_col, -50);
  }

  immUniformColor4ubv(background_col);

  /* draw the main strip body */
  if (is_single_image) { /* single image */
    immRectf(pos,
             BKE_sequence_tx_get_final_left(seq, false),
             y1,
             BKE_sequence_tx_get_final_right(seq, false),
             y2);
  }
  else { /* normal operation */
    immRectf(pos, x1, y1, x2, y2);
  }

  if (seq->flag & SEQ_MUTE) {
    GPU_blend(false);
  }

  if (!is_single_image) {
    if ((sseq->draw_flag & SEQ_DRAW_OFFSET_EXT) || (seq == special_seq_update)) {
      draw_sequence_extensions(scene, region, seq, pos);
    }
  }

  draw_seq_handle(v2d, seq, handsize_clamped, SEQ_LEFTHANDLE, pos);
  draw_seq_handle(v2d, seq, handsize_clamped, SEQ_RIGHTHANDLE, pos);

  x1 = seq->startdisp;
  x2 = seq->enddisp;

  immUnbindProgram();

  /* draw sound wave */
  if (seq->type == SEQ_TYPE_SOUND_RAM) {
    if (!(sseq->flag & SEQ_NO_WAVEFORMS)) {
      drawseqwave(v2d,
                  C,
                  sseq,
                  scene,
                  seq,
                  x1,
                  y1,
                  x2,
                  y2,
                  BLI_rctf_size_x(&region->v2d.cur) / region->winx);
    }
  }

  /* draw lock */
  if (seq->flag & SEQ_LOCK) {
    GPU_blend(true);

    pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
    immBindBuiltinProgram(GPU_SHADER_2D_DIAG_STRIPES);

    immUniform4f("color1", 1.0f, 1.0f, 1.0f, 0.125f);
    immUniform4f("color2", 0.0f, 0.0f, 0.0f, 0.125f);
    immUniform1i("size1", 8);
    immUniform1i("size2", 8);

    immRectf(pos, x1, y1, x2, y2);

    immUnbindProgram();

    GPU_blend(false);
  }

  if (!BKE_sequence_is_valid_check(seq)) {
    GPU_blend(true);

    pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
    immBindBuiltinProgram(GPU_SHADER_2D_DIAG_STRIPES);

    immUniform4f("color1", 1.0f, 0.0f, 0.0f, 1.0f);
    immUniform4f("color2", 0.0f, 0.0f, 0.0f, 0.0f);
    immUniform1i("size1", 8);
    immUniform1i("size2", 8);

    immRectf(pos, x1, y1, x2, y2);

    immUnbindProgram();

    GPU_blend(false);
  }

  color3ubv_from_seq(scene, seq, col);

  /* draw the strip outline */
  color3ubv_from_seq(scene, seq, col);
  if ((G.moving & G_TRANSFORM_SEQ) && (seq->flag & SELECT)) {
    if (seq->flag & SEQ_OVERLAP) {
      col[0] = 255;
      col[1] = col[2] = 40;
    }
    else {
      UI_GetColorPtrShade3ubv(col, col, 120 + outline_tint);
    }
  }
  else {
    UI_GetColorPtrShade3ubv(col, col, outline_tint);
  }

  if ((seq->type == SEQ_TYPE_META) ||
      ((seq->type == SEQ_TYPE_SCENE) && (seq->flag & SEQ_SCENE_STRIPS))) {
    drawmeta_contents(scene, seq, x1, y1, x2, y2);
  }

  pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

  /* TODO: add back stippled line for muted strips? */
  immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

  if (seq->flag & SEQ_MUTE) {
    col[3] = 96;

    GPU_blend(true);
    GPU_blend_set_func_separate(
        GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);

    immUniformColor4ubv(col);
  }
  else {
    immUniformColor3ubv(col);
  }

  imm_draw_box_wire_2d(pos, x1, y1, x2, y2); /* outline */

  immUnbindProgram();

  /* calculate if seq is long enough to print a name */
  x1 = seq->startdisp + handsize_clamped;
  x2 = seq->enddisp - handsize_clamped;

  float scroller_vert_xoffs = (V2D_SCROLL_HANDLE_WIDTH + SEQ_SCROLLER_TEXT_OFFSET) * pixelx;

  /* info text on the strip */
  if (x1 < v2d->cur.xmin + scroller_vert_xoffs) {
    x1 = v2d->cur.xmin + scroller_vert_xoffs;
  }
  else if (x1 > v2d->cur.xmax) {
    x1 = v2d->cur.xmax;
  }
  if (x2 < v2d->cur.xmin) {
    x2 = v2d->cur.xmin;
  }
  else if (x2 > v2d->cur.xmax) {
    x2 = v2d->cur.xmax;
  }

  /* nice text here would require changing the view matrix for texture text */
  if ((x2 - x1) / pixelx > 32) {
    draw_seq_text(v2d, sseq, seq, x1, x2, y1, y2, background_col);
  }
}

void sequencer_special_update_set(Sequence *seq)
{
  special_seq_update = seq;
}

Sequence *ED_sequencer_special_preview_get(void)
{
  return special_seq_update;
}

void ED_sequencer_special_preview_set(bContext *C, const int mval[2])
{
  Scene *scene = CTX_data_scene(C);
  ARegion *region = CTX_wm_region(C);
  int hand;
  Sequence *seq;
  seq = find_nearest_seq(scene, &region->v2d, &hand, mval);
  sequencer_special_update_set(seq);
}

void ED_sequencer_special_preview_clear(void)
{
  sequencer_special_update_set(NULL);
}

ImBuf *sequencer_ibuf_get(struct Main *bmain,
                          struct Depsgraph *depsgraph,
                          Scene *scene,
                          SpaceSeq *sseq,
                          int cfra,
                          int frame_ofs,
                          const char *viewname)
{
  SeqRenderData context = {0};
  ImBuf *ibuf;
  int rectx, recty;
  double render_size;
  short is_break = G.is_break;

  if (sseq->render_size == SEQ_PROXY_RENDER_SIZE_NONE) {
    return NULL;
  }

  if (sseq->render_size == SEQ_PROXY_RENDER_SIZE_SCENE) {
    render_size = scene->r.size / 100.0;
  }
  else {
    render_size = BKE_sequencer_rendersize_to_scale_factor(sseq->render_size);
  }

  rectx = render_size * scene->r.xsch + 0.5;
  recty = render_size * scene->r.ysch + 0.5;

  BKE_sequencer_new_render_data(
      bmain, depsgraph, scene, rectx, recty, sseq->render_size, false, &context);
  context.view_id = BKE_scene_multiview_view_id_get(&scene->r, viewname);

  /* Sequencer could start rendering, in this case we need to be sure it wouldn't be canceled
   * by Escape pressed somewhere in the past. */
  G.is_break = false;

  /* Rendering can change OGL context. Save & Restore framebuffer. */
  GPUFrameBuffer *fb = GPU_framebuffer_active_get();
  GPU_framebuffer_restore();

  if (special_seq_update) {
    ibuf = BKE_sequencer_give_ibuf_direct(&context, cfra + frame_ofs, special_seq_update);
  }
  else {
    ibuf = BKE_sequencer_give_ibuf(&context, cfra + frame_ofs, sseq->chanshown);
  }

  if (fb) {
    GPU_framebuffer_bind(fb);
  }

  /* restore state so real rendering would be canceled (if needed) */
  G.is_break = is_break;

  return ibuf;
}

static void sequencer_check_scopes(SequencerScopes *scopes, ImBuf *ibuf)
{
  if (scopes->reference_ibuf != ibuf) {
    if (scopes->zebra_ibuf) {
      IMB_freeImBuf(scopes->zebra_ibuf);
      scopes->zebra_ibuf = NULL;
    }

    if (scopes->waveform_ibuf) {
      IMB_freeImBuf(scopes->waveform_ibuf);
      scopes->waveform_ibuf = NULL;
    }

    if (scopes->sep_waveform_ibuf) {
      IMB_freeImBuf(scopes->sep_waveform_ibuf);
      scopes->sep_waveform_ibuf = NULL;
    }

    if (scopes->vector_ibuf) {
      IMB_freeImBuf(scopes->vector_ibuf);
      scopes->vector_ibuf = NULL;
    }

    if (scopes->histogram_ibuf) {
      IMB_freeImBuf(scopes->histogram_ibuf);
      scopes->histogram_ibuf = NULL;
    }
  }
}

static ImBuf *sequencer_make_scope(Scene *scene, ImBuf *ibuf, ImBuf *(*make_scope_cb)(ImBuf *ibuf))
{
  ImBuf *display_ibuf = IMB_dupImBuf(ibuf);
  ImBuf *scope;

  IMB_colormanagement_imbuf_make_display_space(
      display_ibuf, &scene->view_settings, &scene->display_settings);

  scope = make_scope_cb(display_ibuf);

  IMB_freeImBuf(display_ibuf);

  return scope;
}

static void sequencer_display_size(Scene *scene, float r_viewrect[2])
{
  r_viewrect[0] = (float)scene->r.xsch;
  r_viewrect[1] = (float)scene->r.ysch;

  r_viewrect[0] *= scene->r.xasp / scene->r.yasp;
}

static void sequencer_draw_gpencil(const bContext *C)
{
  /* draw grease-pencil (image aligned) */
  ED_annotation_draw_2dimage(C);

  /* ortho at pixel level */
  UI_view2d_view_restore(C);

  /* draw grease-pencil (screen aligned) */
  ED_annotation_draw_view2d(C, 0);
}

/* draws content borders plus safety borders if needed */
static void sequencer_draw_borders(const SpaceSeq *sseq, const View2D *v2d, const Scene *scene)
{
  float x1 = v2d->tot.xmin;
  float y1 = v2d->tot.ymin;
  float x2 = v2d->tot.xmax;
  float y2 = v2d->tot.ymax;

  GPU_line_width(1.0f);

  /* border */
  const uint shdr_pos = GPU_vertformat_attr_add(
      immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

  immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_UNIFORM_COLOR);

  float viewport_size[4];
  GPU_viewport_size_get_f(viewport_size);
  immUniform2f("viewport_size", viewport_size[2] / UI_DPI_FAC, viewport_size[3] / UI_DPI_FAC);

  immUniformThemeColor(TH_BACK);
  immUniform1i("colors_len", 0); /* Simple dashes. */
  immUniform1f("dash_width", 6.0f);
  immUniform1f("dash_factor", 0.5f);

  imm_draw_box_wire_2d(shdr_pos, x1 - 0.5f, y1 - 0.5f, x2 + 0.5f, y2 + 0.5f);

  /* safety border */
  if (sseq->flag & SEQ_SHOW_SAFE_MARGINS) {
    immUniformThemeColorBlend(TH_VIEW_OVERLAY, TH_BACK, 0.25f);

    UI_draw_safe_areas(
        shdr_pos, x1, x2, y1, y2, scene->safe_areas.title, scene->safe_areas.action);

    if (sseq->flag & SEQ_SHOW_SAFE_CENTER) {
      UI_draw_safe_areas(shdr_pos,
                         x1,
                         x2,
                         y1,
                         y2,
                         scene->safe_areas.title_center,
                         scene->safe_areas.action_center);
    }
  }

  immUnbindProgram();
}

#if 0
void sequencer_draw_maskedit(const bContext *C, Scene *scene, ARegion *region, SpaceSeq *sseq)
{
  /* NOTE: sequencer mask editing isnt finished, the draw code is working but editing not,
   * for now just disable drawing since the strip frame will likely be offset */

  // if (sc->mode == SC_MODE_MASKEDIT)
  if (0 && sseq->mainb == SEQ_DRAW_IMG_IMBUF) {
    Mask *mask = BKE_sequencer_mask_get(scene);

    if (mask) {
      int width, height;
      float aspx = 1.0f, aspy = 1.0f;
      // ED_mask_get_size(C, &width, &height);

      //Scene *scene = CTX_data_scene(C);
      width = (scene->r.size * scene->r.xsch) / 100;
      height = (scene->r.size * scene->r.ysch) / 100;

      ED_mask_draw_region(mask,
                          region,
                          0,
                          0,
                          0, /* TODO */
                          width,
                          height,
                          aspx,
                          aspy,
                          false,
                          true,
                          NULL,
                          C);
    }
  }
}
#endif

/* Force redraw, when prefetching and using cache view. */
static void seq_prefetch_wm_notify(const bContext *C, Scene *scene)
{
  if (BKE_sequencer_prefetch_need_redraw(CTX_data_main(C), scene)) {
    WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER, NULL);
  }
}

static void *sequencer_OCIO_transform_ibuf(
    const bContext *C, ImBuf *ibuf, bool *glsl_used, int *format, int *type)
{
  void *display_buffer;
  void *cache_handle = NULL;
  bool force_fallback = false;
  *glsl_used = false;
  force_fallback |= (ED_draw_imbuf_method(ibuf) != IMAGE_DRAW_METHOD_GLSL);
  force_fallback |= (ibuf->dither != 0.0f);

  if (force_fallback) {
    /* Fallback to CPU based color space conversion */
    *glsl_used = false;
    *format = GL_RGBA;
    *type = GL_UNSIGNED_BYTE;
    display_buffer = NULL;
  }
  else if (ibuf->rect_float) {
    display_buffer = ibuf->rect_float;

    if (ibuf->channels == 4) {
      *format = GL_RGBA;
    }
    else if (ibuf->channels == 3) {
      *format = GL_RGB;
    }
    else {
      BLI_assert(!"Incompatible number of channels for float buffer in sequencer");
      *format = GL_RGBA;
      display_buffer = NULL;
    }

    *type = GL_FLOAT;

    if (ibuf->float_colorspace) {
      *glsl_used = IMB_colormanagement_setup_glsl_draw_from_space_ctx(
          C, ibuf->float_colorspace, ibuf->dither, true);
    }
    else {
      *glsl_used = IMB_colormanagement_setup_glsl_draw_ctx(C, ibuf->dither, true);
    }
  }
  else if (ibuf->rect) {
    display_buffer = ibuf->rect;
    *format = GL_RGBA;
    *type = GL_UNSIGNED_BYTE;

    *glsl_used = IMB_colormanagement_setup_glsl_draw_from_space_ctx(
        C, ibuf->rect_colorspace, ibuf->dither, false);
  }
  else {
    *format = GL_RGBA;
    *type = GL_UNSIGNED_BYTE;
    display_buffer = NULL;
  }

  /* there's a data to be displayed, but GLSL is not initialized
   * properly, in this case we fallback to CPU-based display transform
   */
  if ((ibuf->rect || ibuf->rect_float) && !*glsl_used) {
    display_buffer = IMB_display_buffer_acquire_ctx(C, ibuf, &cache_handle);
    *format = GL_RGBA;
    *type = GL_UNSIGNED_BYTE;
  }
  if (cache_handle) {
    IMB_display_buffer_release(cache_handle);
  }

  return display_buffer;
}

static void sequencer_stop_running_jobs(const bContext *C, Scene *scene)
{
  if (G.is_rendering == false && (scene->r.seq_prev_type) == OB_RENDER) {
    /* stop all running jobs, except screen one. currently previews frustrate Render
     * needed to make so sequencer's rendering doesn't conflict with compositor
     */
    WM_jobs_kill_type(CTX_wm_manager(C), NULL, WM_JOB_TYPE_COMPOSITE);

    /* in case of final rendering used for preview, kill all previews,
     * otherwise threading conflict will happen in rendering module
     */
    WM_jobs_kill_type(CTX_wm_manager(C), NULL, WM_JOB_TYPE_RENDER_PREVIEW);
  }
}

static void sequencer_preview_clear(void)
{
  float col[3];

  UI_GetThemeColor3fv(TH_SEQ_PREVIEW, col);
  GPU_clear_color(col[0], col[1], col[2], 0.0);
  GPU_clear(GPU_COLOR_BIT);
}

static void sequencer_preview_get_rect(rctf *preview,
                                       Scene *scene,
                                       ARegion *region,
                                       SpaceSeq *sseq,
                                       bool draw_overlay,
                                       bool draw_backdrop)
{
  struct View2D *v2d = &region->v2d;
  float viewrect[2];

  sequencer_display_size(scene, viewrect);
  BLI_rctf_init(preview, -1.0f, 1.0f, -1.0f, 1.0f);

  if (draw_overlay && sseq->overlay_type == SEQ_DRAW_OVERLAY_RECT) {
    preview->xmax = v2d->tot.xmin +
                    (fabsf(BLI_rctf_size_x(&v2d->tot)) * scene->ed->over_border.xmax);
    preview->xmin = v2d->tot.xmin +
                    (fabsf(BLI_rctf_size_x(&v2d->tot)) * scene->ed->over_border.xmin);
    preview->ymax = v2d->tot.ymin +
                    (fabsf(BLI_rctf_size_y(&v2d->tot)) * scene->ed->over_border.ymax);
    preview->ymin = v2d->tot.ymin +
                    (fabsf(BLI_rctf_size_y(&v2d->tot)) * scene->ed->over_border.ymin);
  }
  else if (draw_backdrop) {
    float aspect = BLI_rcti_size_x(&region->winrct) / (float)BLI_rcti_size_y(&region->winrct);
    float image_aspect = viewrect[0] / viewrect[1];

    if (aspect >= image_aspect) {
      preview->xmax = image_aspect / aspect;
      preview->xmin = -preview->xmax;
    }
    else {
      preview->ymax = aspect / image_aspect;
      preview->ymin = -preview->ymax;
    }
  }
  else {
    *preview = v2d->tot;
  }
}

static void sequencer_draw_display_buffer(const bContext *C,
                                          Scene *scene,
                                          ARegion *region,
                                          SpaceSeq *sseq,
                                          ImBuf *ibuf,
                                          ImBuf *scope,
                                          bool draw_overlay,
                                          bool draw_backdrop)
{
  void *display_buffer;

  if (sseq->mainb == SEQ_DRAW_IMG_IMBUF && sseq->flag & SEQ_USE_ALPHA) {
    GPU_blend(true);
    GPU_blend_set_func_separate(
        GPU_SRC_ALPHA, GPU_ONE_MINUS_SRC_ALPHA, GPU_ONE, GPU_ONE_MINUS_SRC_ALPHA);
  }

  /* Format needs to be created prior to any immBindProgram call.
   * Do it here because OCIO binds it's own shader.
   */
  int format, type;
  bool glsl_used = false;
  GLuint texid;
  GPUVertFormat *imm_format = immVertexFormat();
  uint pos = GPU_vertformat_attr_add(imm_format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
  uint texCoord = GPU_vertformat_attr_add(
      imm_format, "texCoord", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

  if (scope) {
    ibuf = scope;

    if (ibuf->rect_float && ibuf->rect == NULL) {
      IMB_rect_from_float(ibuf);
    }

    display_buffer = (unsigned char *)ibuf->rect;
    format = GL_RGBA;
    type = GL_UNSIGNED_BYTE;
  }
  else {
    display_buffer = sequencer_OCIO_transform_ibuf(C, ibuf, &glsl_used, &format, &type);
  }

  if (draw_backdrop) {
    GPU_matrix_push();
    GPU_matrix_identity_set();
    GPU_matrix_push_projection();
    GPU_matrix_identity_projection_set();
  }

  glGenTextures(1, (GLuint *)&texid);
  glActiveTexture(GL_TEXTURE0);
  glBindTexture(GL_TEXTURE_2D, texid);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

  if (type == GL_FLOAT) {
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, ibuf->x, ibuf->y, 0, format, type, display_buffer);
  }
  else {
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, ibuf->x, ibuf->y, 0, format, type, display_buffer);
  }

  if (!glsl_used) {
    immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_COLOR);
    immUniformColor3f(1.0f, 1.0f, 1.0f);
    immUniform1i("image", 0);
  }

  immBegin(GPU_PRIM_TRI_FAN, 4);

  rctf preview;
  rctf canvas;
  sequencer_preview_get_rect(&preview, scene, region, sseq, draw_overlay, draw_backdrop);

  if (draw_overlay && sseq->overlay_type == SEQ_DRAW_OVERLAY_RECT) {
    canvas = scene->ed->over_border;
  }
  else {
    BLI_rctf_init(&canvas, 0.0f, 1.0f, 0.0f, 1.0f);
  }

  immAttr2f(texCoord, canvas.xmin, canvas.ymin);
  immVertex2f(pos, preview.xmin, preview.ymin);

  immAttr2f(texCoord, canvas.xmin, canvas.ymax);
  immVertex2f(pos, preview.xmin, preview.ymax);

  immAttr2f(texCoord, canvas.xmax, canvas.ymax);
  immVertex2f(pos, preview.xmax, preview.ymax);

  immAttr2f(texCoord, canvas.xmax, canvas.ymin);
  immVertex2f(pos, preview.xmax, preview.ymin);

  immEnd();
  glBindTexture(GL_TEXTURE_2D, 0);
  glDeleteTextures(1, &texid);

  if (!glsl_used) {
    immUnbindProgram();
  }
  else {
    IMB_colormanagement_finish_glsl_draw();
  }

  if (sseq->mainb == SEQ_DRAW_IMG_IMBUF && sseq->flag & SEQ_USE_ALPHA) {
    GPU_blend(false);
  }

  if (draw_backdrop) {
    GPU_matrix_pop();
    GPU_matrix_pop_projection();
  }
}

static ImBuf *sequencer_get_scope(Scene *scene, SpaceSeq *sseq, ImBuf *ibuf, bool draw_backdrop)
{
  struct ImBuf *scope = NULL;
  SequencerScopes *scopes = &sseq->scopes;

  if (!draw_backdrop && (sseq->mainb != SEQ_DRAW_IMG_IMBUF || sseq->zebra != 0)) {
    sequencer_check_scopes(scopes, ibuf);

    switch (sseq->mainb) {
      case SEQ_DRAW_IMG_IMBUF:
        if (!scopes->zebra_ibuf) {
          ImBuf *display_ibuf = IMB_dupImBuf(ibuf);

          if (display_ibuf->rect_float) {
            IMB_colormanagement_imbuf_make_display_space(
                display_ibuf, &scene->view_settings, &scene->display_settings);
          }
          scopes->zebra_ibuf = make_zebra_view_from_ibuf(display_ibuf, sseq->zebra);
          IMB_freeImBuf(display_ibuf);
        }
        scope = scopes->zebra_ibuf;
        break;
      case SEQ_DRAW_IMG_WAVEFORM:
        if ((sseq->flag & SEQ_DRAW_COLOR_SEPARATED) != 0) {
          if (!scopes->sep_waveform_ibuf) {
            scopes->sep_waveform_ibuf = sequencer_make_scope(
                scene, ibuf, make_sep_waveform_view_from_ibuf);
          }
          scope = scopes->sep_waveform_ibuf;
        }
        else {
          if (!scopes->waveform_ibuf) {
            scopes->waveform_ibuf = sequencer_make_scope(
                scene, ibuf, make_waveform_view_from_ibuf);
          }
          scope = scopes->waveform_ibuf;
        }
        break;
      case SEQ_DRAW_IMG_VECTORSCOPE:
        if (!scopes->vector_ibuf) {
          scopes->vector_ibuf = sequencer_make_scope(scene, ibuf, make_vectorscope_view_from_ibuf);
        }
        scope = scopes->vector_ibuf;
        break;
      case SEQ_DRAW_IMG_HISTOGRAM:
        if (!scopes->histogram_ibuf) {
          scopes->histogram_ibuf = sequencer_make_scope(
              scene, ibuf, make_histogram_view_from_ibuf);
        }
        scope = scopes->histogram_ibuf;
        break;
    }

    /* future files may have new scopes we don't catch above */
    if (scope) {
      scopes->reference_ibuf = ibuf;
    }
  }
  return scope;
}

void sequencer_draw_preview(const bContext *C,
                            Scene *scene,
                            ARegion *region,
                            SpaceSeq *sseq,
                            int cfra,
                            int frame_ofs,
                            bool draw_overlay,
                            bool draw_backdrop)
{
  struct Main *bmain = CTX_data_main(C);
  struct Depsgraph *depsgraph = CTX_data_expect_evaluated_depsgraph(C);
  struct View2D *v2d = &region->v2d;
  struct ImBuf *ibuf = NULL;
  struct ImBuf *scope = NULL;
  float viewrect[2];
  const bool show_imbuf = ED_space_sequencer_check_show_imbuf(sseq);
  const bool draw_gpencil = ((sseq->flag & SEQ_SHOW_GPENCIL) && sseq->gpd);
  const char *names[2] = {STEREO_LEFT_NAME, STEREO_RIGHT_NAME};

  sequencer_stop_running_jobs(C, scene);
  if (G.is_rendering) {
    return;
  }

  if (sseq->render_size == SEQ_PROXY_RENDER_SIZE_NONE) {
    sequencer_preview_clear();
    return;
  }

  /* Setup view */
  sequencer_display_size(scene, viewrect);
  UI_view2d_totRect_set(v2d, viewrect[0] + 0.5f, viewrect[1] + 0.5f);
  UI_view2d_curRect_validate(v2d);
  UI_view2d_view_ortho(v2d);

  /* Draw background */
  if (!draw_backdrop && (!draw_overlay || sseq->overlay_type == SEQ_DRAW_OVERLAY_REFERENCE)) {
    sequencer_preview_clear();

    if (sseq->flag & SEQ_USE_ALPHA) {
      imm_draw_box_checker_2d(v2d->tot.xmin, v2d->tot.ymin, v2d->tot.xmax, v2d->tot.ymax);
    }
  }
  /* Get image */
  ibuf = sequencer_ibuf_get(
      bmain, depsgraph, scene, sseq, cfra, frame_ofs, names[sseq->multiview_eye]);

  if (ibuf) {
    scope = sequencer_get_scope(scene, sseq, ibuf, draw_backdrop);

    /* Draw image */
    sequencer_draw_display_buffer(
        C, scene, region, sseq, ibuf, scope, draw_overlay, draw_backdrop);

    /* Draw over image */
    if (sseq->flag & SEQ_SHOW_METADATA) {
      ED_region_image_metadata_draw(0.0, 0.0, ibuf, &v2d->tot, 1.0, 1.0);
    }
  }

  if (show_imbuf) {
    sequencer_draw_borders(sseq, v2d, scene);
  }

  if (draw_gpencil && show_imbuf) {
    sequencer_draw_gpencil(C);
  }

  /* TODO */
  /* sequencer_draw_maskedit(C, scene, region, sseq); */

  /* Scope is freed in sequencer_check_scopes when ibuf changes and
   * scope image is to be replaced. */
  if (ibuf) {
    IMB_freeImBuf(ibuf);
  }

  UI_view2d_view_restore(C);
  seq_prefetch_wm_notify(C, scene);
}

/* draw backdrop of the sequencer strips view */
static void draw_seq_backdrop(View2D *v2d)
{
  int i;

  uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
  immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

  /* darker gray overlay over the view backdrop */
  immUniformThemeColorShade(TH_BACK, -20);
  immRectf(pos, v2d->cur.xmin, -1.0, v2d->cur.xmax, 1.0);

  /* Alternating horizontal stripes */
  i = max_ii(1, ((int)v2d->cur.ymin) - 1);

  while (i < v2d->cur.ymax) {
    if (i & 1) {
      immUniformThemeColorShade(TH_BACK, -15);
    }
    else {
      immUniformThemeColorShade(TH_BACK, -25);
    }

    immRectf(pos, v2d->cur.xmin, i, v2d->cur.xmax, i + 1);

    i++;
  }

  /* Darker lines separating the horizontal bands */
  i = max_ii(1, ((int)v2d->cur.ymin) - 1);
  int line_len = (int)v2d->cur.ymax - i + 1;
  immUniformThemeColor(TH_GRID);
  immBegin(GPU_PRIM_LINES, line_len * 2);
  while (line_len--) {
    immVertex2f(pos, v2d->cur.xmax, i);
    immVertex2f(pos, v2d->cur.xmin, i);
  }
  immEnd();

  immUnbindProgram();
}

/* draw the contents of the sequencer strips view */
static void draw_seq_strips(const bContext *C, Editing *ed, ARegion *region)
{
  Scene *scene = CTX_data_scene(C);
  View2D *v2d = &region->v2d;
  SpaceSeq *sseq = CTX_wm_space_seq(C);
  Sequence *last_seq = BKE_sequencer_active_get(scene);
  int sel = 0, j;
  float pixelx = BLI_rctf_size_x(&v2d->cur) / BLI_rcti_size_x(&v2d->mask);

  /* loop through twice, first unselected, then selected */
  for (j = 0; j < 2; j++) {
    Sequence *seq;
    /* highlighting around strip edges indicating selection */
    int outline_tint = (j) ? -60 : -150;

    /* loop through strips, checking for those that are visible */
    for (seq = ed->seqbasep->first; seq; seq = seq->next) {
      /* boundbox and selection tests for NOT drawing the strip... */
      if ((seq->flag & SELECT) != sel) {
        continue;
      }
      else if (seq == last_seq) {
        continue;
      }
      else if (min_ii(seq->startdisp, seq->start) > v2d->cur.xmax) {
        continue;
      }
      else if (max_ii(seq->enddisp, seq->start + seq->len) < v2d->cur.xmin) {
        continue;
      }
      else if (seq->machine + 1.0f < v2d->cur.ymin) {
        continue;
      }
      else if (seq->machine > v2d->cur.ymax) {
        continue;
      }

      /* strip passed all tests unscathed... so draw it now */
      draw_seq_strip(C, sseq, scene, region, seq, outline_tint, pixelx);
    }

    /* draw selected next time round */
    sel = SELECT;
  }

  /* draw the last selected last (i.e. 'active' in other parts of Blender),
   * removes some overlapping error */
  if (last_seq) {
    draw_seq_strip(C, sseq, scene, region, last_seq, 120, pixelx);
  }

  /* draw highlight when previewing a single strip */
  if (special_seq_update) {
    const Sequence *seq = special_seq_update;
    GPU_blend(true);

    uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
    immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

    immUniformColor4ub(255, 255, 255, 48);
    immRectf(pos,
             seq->startdisp,
             seq->machine + SEQ_STRIP_OFSBOTTOM,
             seq->enddisp,
             seq->machine + SEQ_STRIP_OFSTOP);

    immUnbindProgram();

    GPU_blend(false);
  }
}

static void seq_draw_sfra_efra(Scene *scene, View2D *v2d)
{
  const Editing *ed = BKE_sequencer_editing_get(scene, false);
  const int frame_sta = scene->r.sfra;
  const int frame_end = scene->r.efra + 1;

  GPU_blend(true);

  uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
  immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

  /* draw darkened area outside of active timeline
   * frame range used is preview range or scene range */
  immUniformThemeColorShadeAlpha(TH_BACK, -25, -100);

  if (frame_sta < frame_end) {
    immRectf(pos, v2d->cur.xmin, v2d->cur.ymin, (float)frame_sta, v2d->cur.ymax);
    immRectf(pos, (float)frame_end, v2d->cur.ymin, v2d->cur.xmax, v2d->cur.ymax);
  }
  else {
    immRectf(pos, v2d->cur.xmin, v2d->cur.ymin, v2d->cur.xmax, v2d->cur.ymax);
  }

  immUniformThemeColorShade(TH_BACK, -60);

  /* thin lines where the actual frames are */
  immBegin(GPU_PRIM_LINES, 4);

  immVertex2f(pos, frame_sta, v2d->cur.ymin);
  immVertex2f(pos, frame_sta, v2d->cur.ymax);

  immVertex2f(pos, frame_end, v2d->cur.ymin);
  immVertex2f(pos, frame_end, v2d->cur.ymax);

  immEnd();

  if (ed && !BLI_listbase_is_empty(&ed->metastack)) {
    MetaStack *ms = ed->metastack.last;

    immUniformColor4ub(255, 255, 255, 8);
    immRectf(pos, ms->disp_range[0], v2d->cur.ymin, ms->disp_range[1], v2d->cur.ymax);

    immUniformThemeColorShade(TH_BACK, -40);

    immBegin(GPU_PRIM_LINES, 4);

    immVertex2f(pos, ms->disp_range[0], v2d->cur.ymin);
    immVertex2f(pos, ms->disp_range[0], v2d->cur.ymax);

    immVertex2f(pos, ms->disp_range[1], v2d->cur.ymin);
    immVertex2f(pos, ms->disp_range[1], v2d->cur.ymax);

    immEnd();
  }

  immUnbindProgram();

  GPU_blend(false);
}

typedef struct CacheDrawData {
  struct View2D *v2d;
  float stripe_offs;
  float stripe_ht;
  GPUVertBuf *raw_vbo;
  GPUVertBuf *preprocessed_vbo;
  GPUVertBuf *composite_vbo;
  GPUVertBuf *final_out_vbo;
  size_t raw_vert_count;
  size_t preprocessed_vert_count;
  size_t composite_vert_count;
  size_t final_out_vert_count;
} CacheDrawData;

/* Called as a callback */
static bool draw_cache_view_cb(
    void *userdata, struct Sequence *seq, int nfra, int cache_type, float UNUSED(cost))
{
  CacheDrawData *drawdata = userdata;
  struct View2D *v2d = drawdata->v2d;
  float stripe_bot, stripe_top, stripe_offs, stripe_ht;
  GPUVertBuf *vbo;
  size_t *vert_count;
  switch (cache_type) {
    case SEQ_CACHE_STORE_FINAL_OUT:
      stripe_ht = UI_view2d_region_to_view_y(v2d, 4.0f * UI_DPI_FAC * U.pixelsize) - v2d->cur.ymin;
      stripe_bot = UI_view2d_region_to_view_y(v2d, V2D_SCROLL_HANDLE_HEIGHT);
      stripe_top = stripe_bot + stripe_ht;
      vbo = drawdata->final_out_vbo;
      vert_count = &drawdata->final_out_vert_count;
      break;

    case SEQ_CACHE_STORE_RAW:
      stripe_offs = drawdata->stripe_offs;
      stripe_ht = drawdata->stripe_ht;
      stripe_bot = seq->machine + SEQ_STRIP_OFSBOTTOM + stripe_offs;
      stripe_top = stripe_bot + stripe_ht;
      vbo = drawdata->raw_vbo;
      vert_count = &drawdata->raw_vert_count;
      break;

    case SEQ_CACHE_STORE_PREPROCESSED:
      stripe_offs = drawdata->stripe_offs;
      stripe_ht = drawdata->stripe_ht;
      stripe_bot = seq->machine + SEQ_STRIP_OFSBOTTOM + (stripe_offs + stripe_ht) + stripe_offs;
      stripe_top = stripe_bot + stripe_ht;
      vbo = drawdata->preprocessed_vbo;
      vert_count = &drawdata->preprocessed_vert_count;
      break;

    case SEQ_CACHE_STORE_COMPOSITE:
      stripe_offs = drawdata->stripe_offs;
      stripe_ht = drawdata->stripe_ht;
      stripe_top = seq->machine + SEQ_STRIP_OFSTOP - stripe_offs;
      stripe_bot = stripe_top - stripe_ht;
      vbo = drawdata->composite_vbo;
      vert_count = &drawdata->composite_vert_count;
      break;

    default:
      return true;
  }

  int cfra = seq->start + nfra;
  float vert_pos[6][2];
  copy_v2_fl2(vert_pos[0], cfra, stripe_bot);
  copy_v2_fl2(vert_pos[1], cfra, stripe_top);
  copy_v2_fl2(vert_pos[2], cfra + 1, stripe_top);
  copy_v2_v2(vert_pos[3], vert_pos[2]);
  copy_v2_v2(vert_pos[4], vert_pos[0]);
  copy_v2_fl2(vert_pos[5], cfra + 1, stripe_bot);

  for (int i = 0; i < 6; i++) {
    GPU_vertbuf_vert_set(vbo, *vert_count + i, vert_pos[i]);
  }

  *vert_count += 6;
  return false;
}

static void draw_cache_view_batch(
    GPUVertBuf *vbo, size_t vert_count, float col_r, float col_g, float col_b, float col_a)
{
  GPUBatch *batch = GPU_batch_create_ex(GPU_PRIM_TRIS, vbo, NULL, GPU_BATCH_OWNS_VBO);
  GPU_vertbuf_data_len_set(vbo, vert_count);
  GPU_batch_program_set_builtin(batch, GPU_SHADER_2D_UNIFORM_COLOR);
  GPU_batch_uniform_4f(batch, "color", col_r, col_g, col_b, col_a);
  if (vert_count > 0) {
    GPU_batch_draw(batch);
  }
  GPU_batch_discard(batch);
}

static void draw_cache_view(const bContext *C)
{
  Scene *scene = CTX_data_scene(C);
  ARegion *region = CTX_wm_region(C);
  struct View2D *v2d = &region->v2d;

  if ((scene->ed->cache_flag & SEQ_CACHE_VIEW_ENABLE) == 0) {
    return;
  }

  GPU_blend(true);
  uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
  immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);

  float stripe_bot, stripe_top;
  float stripe_offs = UI_view2d_region_to_view_y(v2d, 1.0f) - v2d->cur.ymin;
  float stripe_ht = UI_view2d_region_to_view_y(v2d, 4.0f * UI_DPI_FAC * U.pixelsize) -
                    v2d->cur.ymin;

  CLAMP_MAX(stripe_ht, 0.2f);
  CLAMP_MIN(stripe_offs, stripe_ht / 2);

  if (scene->ed->cache_flag & SEQ_CACHE_VIEW_FINAL_OUT) {
    stripe_bot = UI_view2d_region_to_view_y(v2d, V2D_SCROLL_HANDLE_HEIGHT);
    stripe_top = stripe_bot + stripe_ht;
    float bg_color[4] = {1.0f, 0.4f, 0.2f, 0.1f};

    immUniformColor4f(bg_color[0], bg_color[1], bg_color[2], bg_color[3]);
    immRectf(pos, scene->r.sfra, stripe_bot, scene->r.efra, stripe_top);
  }

  for (Sequence *seq = scene->ed->seqbasep->first; seq != NULL; seq = seq->next) {
    if (seq->type == SEQ_TYPE_SOUND_RAM) {
      continue;
    }

    if (seq->startdisp > v2d->cur.xmax || seq->enddisp < v2d->cur.xmin) {
      continue;
    }

    stripe_bot = seq->machine + SEQ_STRIP_OFSBOTTOM + stripe_offs;
    stripe_top = stripe_bot + stripe_ht;

    if (scene->ed->cache_flag & SEQ_CACHE_VIEW_RAW) {
      float bg_color[4] = {1.0f, 0.1f, 0.02f, 0.1f};
      immUniformColor4f(bg_color[0], bg_color[1], bg_color[2], bg_color[3]);
      immRectf(pos, seq->startdisp, stripe_bot, seq->enddisp, stripe_top);
    }

    stripe_bot += stripe_ht + stripe_offs;
    stripe_top = stripe_bot + stripe_ht;

    if (scene->ed->cache_flag & SEQ_CACHE_VIEW_PREPROCESSED) {
      float bg_color[4] = {0.1f, 0.1f, 0.75f, 0.1f};
      immUniformColor4f(bg_color[0], bg_color[1], bg_color[2], bg_color[3]);
      immRectf(pos, seq->startdisp, stripe_bot, seq->enddisp, stripe_top);
    }

    stripe_top = seq->machine + SEQ_STRIP_OFSTOP - stripe_offs;
    stripe_bot = stripe_top - stripe_ht;

    if (scene->ed->cache_flag & SEQ_CACHE_VIEW_COMPOSITE) {
      float bg_color[4] = {1.0f, 0.6f, 0.0f, 0.1f};
      immUniformColor4f(bg_color[0], bg_color[1], bg_color[2], bg_color[3]);
      immRectf(pos, seq->startdisp, stripe_bot, seq->enddisp, stripe_top);
    }
  }

  immUnbindProgram();

  size_t cache_num_items = BKE_sequencer_cache_get_num_items(scene);

  if (cache_num_items > 0) {
    GPUVertFormat format = {0};
    GPU_vertformat_attr_add(&format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

    CacheDrawData userdata;
    userdata.v2d = v2d;
    userdata.stripe_offs = stripe_offs;
    userdata.stripe_ht = stripe_ht;
    userdata.raw_vert_count = 0;
    userdata.preprocessed_vert_count = 0;
    userdata.composite_vert_count = 0;
    userdata.final_out_vert_count = 0;
    userdata.raw_vbo = GPU_vertbuf_create_with_format(&format);
    userdata.preprocessed_vbo = GPU_vertbuf_create_with_format(&format);
    userdata.composite_vbo = GPU_vertbuf_create_with_format(&format);
    userdata.final_out_vbo = GPU_vertbuf_create_with_format(&format);

    /* We can not get item count per cache type, so using total item count is safe. */
    size_t max_vert_count = cache_num_items * 6;
    GPU_vertbuf_data_alloc(userdata.raw_vbo, max_vert_count);
    GPU_vertbuf_data_alloc(userdata.preprocessed_vbo, max_vert_count);
    GPU_vertbuf_data_alloc(userdata.composite_vbo, max_vert_count);
    GPU_vertbuf_data_alloc(userdata.final_out_vbo, max_vert_count);

    BKE_sequencer_cache_iterate(scene, &userdata, draw_cache_view_cb);

    draw_cache_view_batch(userdata.raw_vbo, userdata.raw_vert_count, 1.0f, 0.1f, 0.02f, 0.4f);
    draw_cache_view_batch(
        userdata.preprocessed_vbo, userdata.preprocessed_vert_count, 0.1f, 0.1f, 0.75f, 0.4f);
    draw_cache_view_batch(
        userdata.composite_vbo, userdata.composite_vert_count, 1.0f, 0.6f, 0.0f, 0.4f);
    draw_cache_view_batch(
        userdata.final_out_vbo, userdata.final_out_vert_count, 1.0f, 0.4f, 0.2f, 0.4f);
  }

  GPU_blend(false);
}

/* Draw Timeline/Strip Editor Mode for Sequencer */
void draw_timeline_seq(const bContext *C, ARegion *region)
{
  Scene *scene = CTX_data_scene(C);
  Editing *ed = BKE_sequencer_editing_get(scene, false);
  SpaceSeq *sseq = CTX_wm_space_seq(C);
  View2D *v2d = &region->v2d;
  View2DScrollers *scrollers;
  short cfra_flag = 0;
  float col[3];

  seq_prefetch_wm_notify(C, scene);

  /* clear and setup matrix */
  UI_GetThemeColor3fv(TH_BACK, col);
  if (ed && ed->metastack.first) {
    GPU_clear_color(col[0], col[1], col[2] - 0.1f, 0.0f);
  }
  else {
    GPU_clear_color(col[0], col[1], col[2], 0.0f);
  }
  GPU_clear(GPU_COLOR_BIT);

  UI_view2d_view_ortho(v2d);

  /* calculate extents of sequencer strips/data
   * NOTE: needed for the scrollers later
   */
  boundbox_seq(scene, &v2d->tot);

  /* draw backdrop */
  draw_seq_backdrop(v2d);

  /* regular grid-pattern over the rest of the view (i.e. 1-second grid lines) */
  UI_view2d_constant_grid_draw(v2d, FPS);

  /* Only draw backdrop in pure sequence view. */
  if (sseq->view == SEQ_VIEW_SEQUENCE && sseq->draw_flag & SEQ_DRAW_BACKDROP) {
    sequencer_draw_preview(C, scene, region, sseq, scene->r.cfra, 0, false, true);
    UI_view2d_view_ortho(v2d);
  }

  ED_region_draw_cb_draw(C, region, REGION_DRAW_PRE_VIEW);

  seq_draw_sfra_efra(scene, v2d);

  /* sequence strips (if there is data available to be drawn) */
  if (ed) {
    /* draw the data */
    draw_seq_strips(C, ed, region);
    /* text draw cached (for sequence names), in pixelspace now */
    UI_view2d_text_cache_draw(region);
  }

  /* current frame */
  UI_view2d_view_ortho(v2d);
  if ((sseq->flag & SEQ_DRAWFRAMES) == 0) {
    cfra_flag |= DRAWCFRA_UNIT_SECONDS;
  }
  ANIM_draw_cfra(C, v2d, cfra_flag);

  /* markers */
  UI_view2d_view_orthoSpecial(region, v2d, 1);
  int marker_draw_flag = DRAW_MARKERS_MARGIN;
  if (sseq->flag & SEQ_SHOW_MARKERS) {
    ED_markers_draw(C, marker_draw_flag);
  }

  UI_view2d_view_ortho(v2d);
  /* draw cache on top of markers area */
  if (ed) {
    draw_cache_view(C);
  }
  /* preview range */
  ANIM_draw_previewrange(C, v2d, 1);

  /* overlap playhead */
  if (scene->ed && scene->ed->over_flag & SEQ_EDIT_OVERLAY_SHOW) {
    int cfra_over = (scene->ed->over_flag & SEQ_EDIT_OVERLAY_ABS) ?
                        scene->ed->over_cfra :
                        scene->r.cfra + scene->ed->over_ofs;

    uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
    immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_UNIFORM_COLOR);
    float viewport_size[4];
    GPU_viewport_size_get_f(viewport_size);
    immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
    immUniform1f("dash_width", 20.0f * U.pixelsize);
    immUniform1f("dash_factor", 0.5f);
    immUniformThemeColor(TH_CFRAME);

    immBegin(GPU_PRIM_LINES, 2);
    immVertex2f(pos, cfra_over, v2d->cur.ymin);
    immVertex2f(pos, cfra_over, v2d->cur.ymax);
    immEnd();

    immUnbindProgram();
  }

  /* callback */
  ED_region_draw_cb_draw(C, region, REGION_DRAW_POST_VIEW);

  /* reset view matrix */
  UI_view2d_view_restore(C);

  /* scrubbing region */
  ED_time_scrub_draw(region, scene, !(sseq->flag & SEQ_DRAWFRAMES), true);

  /* scrollers */
  scrollers = UI_view2d_scrollers_calc(v2d, NULL);
  UI_view2d_scrollers_draw(v2d, scrollers);
  UI_view2d_scrollers_free(scrollers);

  /* channel numbers */
  {
    rcti rect;
    BLI_rcti_init(
        &rect, 0, 15 * UI_DPI_FAC, 15 * UI_DPI_FAC, region->winy - UI_TIME_SCRUB_MARGIN_Y);
    UI_view2d_draw_scale_y__block(region, v2d, &rect, TH_SCROLL_TEXT);
  }
}