VSE: Update first thumbnail when moving handle

When handles are moved, job is created only for strips that need to
update first thumbnail.

ref T91618

3 files changed, 68 insertions, 52 deletions

diff --git a/source/blender/editors/space_sequencer/sequencer_thumbnails.c b/source/blender/editors/space_sequencer/sequencer_thumbnails.c
index f5c5c7af4b6..43c5e004040 100644
--- a/source/blender/editors/space_sequencer/sequencer_thumbnails.c
+++ b/source/blender/editors/space_sequencer/sequencer_thumbnails.c
@@ -86,6 +86,11 @@ static bool check_seq_need_thumbnails(Sequence *seq, rctf *view_area)
     return false;
   }
 
+  /* Handle is moved, but not for this strip. */
+  if ((G.moving & G_TRANSFORM_SEQ) != 0 && (seq->flag & (SEQ_LEFTSEL | SEQ_RIGHTSEL)) == 0) {
+    return false;
+  }
+
   return true;
 }
 
@@ -123,26 +128,13 @@ static void seq_get_thumb_image_dimensions(Sequence *seq,
   }
 }
 
-static float seq_thumbnail_get_start_frame(Sequence *seq, float frame_step, rctf *view_area)
-{
-  if (seq->start > view_area->xmin && seq->start < view_area->xmax) {
-    return seq->start;
-  }
-
-  /* Drawing and caching both check to see if strip is in view area or not before calling this
-   * function so assuming strip/part of strip in view. */
-
-  int no_invisible_thumbs = (view_area->xmin - seq->start) / frame_step;
-  return ((no_invisible_thumbs - 1) * frame_step) + seq->start;
-}
-
 static void thumbnail_start_job(void *data,
                                 short *stop,
                                 short *UNUSED(do_update),
                                 float *UNUSED(progress))
 {
   ThumbnailDrawJob *tj = data;
-  float start_frame, frame_step;
+  float frame_step;
 
   GHashIterator gh_iter;
 
@@ -155,9 +147,8 @@ static void thumbnail_start_job(void *data,
     if (check_seq_need_thumbnails(seq_orig, tj->view_area)) {
       seq_get_thumb_image_dimensions(
           val->seq_dupli, tj->pixelx, tj->pixely, &frame_step, tj->thumb_height, NULL, NULL);
-      start_frame = seq_thumbnail_get_start_frame(seq_orig, frame_step, tj->view_area);
       SEQ_render_thumbnails(
-          &tj->context, val->seq_dupli, seq_orig, start_frame, frame_step, tj->view_area, stop);
+          &tj->context, val->seq_dupli, seq_orig, frame_step, tj->view_area, stop);
       SEQ_relations_sequence_free_anim(val->seq_dupli);
     }
     BLI_ghashIterator_step(&gh_iter);
@@ -172,7 +163,6 @@ static void thumbnail_start_job(void *data,
     if (check_seq_need_thumbnails(seq_orig, tj->view_area)) {
       seq_get_thumb_image_dimensions(
           val->seq_dupli, tj->pixelx, tj->pixely, &frame_step, tj->thumb_height, NULL, NULL);
-      start_frame = seq_thumbnail_get_start_frame(seq_orig, frame_step, tj->view_area);
       SEQ_render_thumbnails_base_set(&tj->context, val->seq_dupli, seq_orig, tj->view_area, stop);
       SEQ_relations_sequence_free_anim(val->seq_dupli);
     }
@@ -458,40 +448,31 @@ void draw_seq_strip_thumbnail(View2D *v2d,
     upper_thumb_bound = seq->enddisp;
   }
 
-  float thumb_x_start = seq_thumbnail_get_start_frame(seq, thumb_width, &v2d->cur);
+  float timeline_frame = SEQ_render_thumbnail_first_frame_get(seq, thumb_width, &v2d->cur);
   float thumb_x_end;
 
-  while (thumb_x_start + thumb_width < v2d->cur.xmin) {
-    thumb_x_start += thumb_width;
-  }
-
-  /* Ignore thumbs to the left of strip. */
-  while (thumb_x_start + thumb_width < seq->startdisp) {
-    thumb_x_start += thumb_width;
-  }
-
   GSet *last_displayed_thumbnails = last_displayed_thumbnails_list_ensure(C, seq);
   /* Cleanup thumbnail list outside of rendered range, which is cleaned up one by one to prevent
    * flickering after zooming. */
   if (!sequencer_thumbnail_v2d_is_navigating(C)) {
-    last_displayed_thumbnails_list_cleanup(last_displayed_thumbnails, -FLT_MAX, thumb_x_start);
+    last_displayed_thumbnails_list_cleanup(last_displayed_thumbnails, -FLT_MAX, timeline_frame);
   }
 
   /* Start drawing. */
-  while (thumb_x_start < upper_thumb_bound) {
-    thumb_x_end = thumb_x_start + thumb_width;
+  while (timeline_frame < upper_thumb_bound) {
+    thumb_x_end = timeline_frame + thumb_width;
     clipped = false;
 
     /* Checks to make sure that thumbs are loaded only when in view and within the confines of the
      * strip. Some may not be required but better to have conditions for safety as x1 here is
      * point to start caching from and not drawing. */
-    if (thumb_x_start > v2d->cur.xmax) {
+    if (timeline_frame > v2d->cur.xmax) {
       break;
     }
 
     /* Set the clipping bound to show the left handle moving over thumbs and not shift thumbs. */
-    if (IN_RANGE_INCL(seq->startdisp, thumb_x_start, thumb_x_end)) {
-      cut_off = seq->startdisp - thumb_x_start;
+    if (IN_RANGE_INCL(seq->startdisp, timeline_frame, thumb_x_end)) {
+      cut_off = seq->startdisp - timeline_frame;
       clipped = true;
     }
 
@@ -499,7 +480,7 @@ void draw_seq_strip_thumbnail(View2D *v2d,
     if (thumb_x_end > (upper_thumb_bound)) {
       thumb_x_end = upper_thumb_bound;
       clipped = true;
-      if (thumb_x_end - thumb_x_start < 1) {
+      if (thumb_x_end - timeline_frame < 1) {
         break;
       }
     }
@@ -508,14 +489,12 @@ void draw_seq_strip_thumbnail(View2D *v2d,
     float zoom_y = thumb_height / image_height;
 
     float cropx_min = (cut_off / pixelx) / (zoom_y / pixely);
-    float cropx_max = ((thumb_x_end - thumb_x_start) / pixelx) / (zoom_y / pixely);
-    if (cropx_max == (thumb_x_end - thumb_x_start)) {
+    float cropx_max = ((thumb_x_end - timeline_frame) / pixelx) / (zoom_y / pixely);
+    if (cropx_max == (thumb_x_end - timeline_frame)) {
       cropx_max = cropx_max + 1;
     }
     BLI_rcti_init(&crop, (int)(cropx_min), (int)cropx_max, 0, (int)(image_height)-1);
 
-    int timeline_frame = round_fl_to_int(thumb_x_start);
-
     /* Get the image. */
     ImBuf *ibuf = SEQ_get_thumbnail(&context, seq, timeline_frame, &crop, clipped);
 
@@ -529,7 +508,7 @@ void draw_seq_strip_thumbnail(View2D *v2d,
     else if (!sequencer_thumbnail_v2d_is_navigating(C)) {
       /* Clear images in frame range occupied by new thumbnail. */
       last_displayed_thumbnails_list_cleanup(
-          last_displayed_thumbnails, thumb_x_start, thumb_x_end);
+          last_displayed_thumbnails, timeline_frame, thumb_x_end);
       /* Insert new thumbnail frame to list. */
       BLI_gset_add(last_displayed_thumbnails, POINTER_FROM_INT(timeline_frame));
     }
@@ -558,10 +537,10 @@ void draw_seq_strip_thumbnail(View2D *v2d,
 
     ED_draw_imbuf_ctx_clipping(C,
                                ibuf,
-                               thumb_x_start + cut_off,
+                               timeline_frame + cut_off,
                                y1,
                                true,
-                               thumb_x_start + cut_off,
+                               timeline_frame + cut_off,
                                y1,
                                thumb_x_end,
                                thumb_y_end,
@@ -570,7 +549,7 @@ void draw_seq_strip_thumbnail(View2D *v2d,
     IMB_freeImBuf(ibuf);
     GPU_blend(GPU_BLEND_NONE);
     cut_off = 0;
-    thumb_x_start += thumb_width;
+    timeline_frame = SEQ_render_thumbnail_next_frame_get(seq, timeline_frame, thumb_width);
   }
-  last_displayed_thumbnails_list_cleanup(last_displayed_thumbnails, thumb_x_start, FLT_MAX);
+  last_displayed_thumbnails_list_cleanup(last_displayed_thumbnails, timeline_frame, FLT_MAX);
 }
diff --git a/source/blender/sequencer/SEQ_render.h b/source/blender/sequencer/SEQ_render.h
index bfe10d3eae9..a74eba5fc6f 100644
--- a/source/blender/sequencer/SEQ_render.h
+++ b/source/blender/sequencer/SEQ_render.h
@@ -17,6 +17,7 @@ struct ListBase;
 struct Main;
 struct Scene;
 struct Sequence;
+struct rctf;
 
 typedef enum eSeqTaskId {
   SEQ_TASK_MAIN_RENDER,
@@ -64,7 +65,6 @@ struct ImBuf *SEQ_render_give_ibuf_direct(const SeqRenderData *context,
 void SEQ_render_thumbnails(const struct SeqRenderData *context,
                            struct Sequence *seq,
                            struct Sequence *seq_orig,
-                           float start_frame,
                            float frame_step,
                            rctf *view_area,
                            const short *stop);
@@ -77,6 +77,18 @@ struct ImBuf *SEQ_get_thumbnail(const struct SeqRenderData *context,
                                 rcti *crop,
                                 bool clipped);
 /**
+ * Get frame for first thumbnail.
+ */
+float SEQ_render_thumbnail_first_frame_get(struct Sequence *seq,
+                                           float frame_step,
+                                           struct rctf *view_area);
+/**
+ * Get frame for first thumbnail.
+ */
+float SEQ_render_thumbnail_next_frame_get(struct Sequence *seq,
+                                          float last_frame,
+                                          float frame_step);
+/**
  * Get frame step for equally spaced thumbnails. These thumbnails should always be present in
  * memory, so they can be used when zooming.
  */
diff --git a/source/blender/sequencer/intern/render.c b/source/blender/sequencer/intern/render.c
index 18b0794dc72..8d8a13be09e 100644
--- a/source/blender/sequencer/intern/render.c
+++ b/source/blender/sequencer/intern/render.c
@@ -1992,6 +1992,32 @@ ImBuf *SEQ_render_give_ibuf_direct(const SeqRenderData *context,
   return ibuf;
 }
 
+float SEQ_render_thumbnail_first_frame_get(Sequence *seq, float frame_step, rctf *view_area)
+{
+  int first_drawable_frame = max_iii(seq->startdisp, seq->start, view_area->xmin);
+
+  /* First frame should correspond to handle position. */
+  if (first_drawable_frame == seq->startdisp) {
+    return seq->startdisp;
+  }
+
+  float aligned_frame_offset = (int)((first_drawable_frame - seq->start) / frame_step) *
+                               frame_step;
+  return seq->start + aligned_frame_offset;
+}
+
+float SEQ_render_thumbnail_next_frame_get(Sequence *seq, float last_frame, float frame_step)
+{
+  float next_frame = last_frame + frame_step;
+
+  /* If handle position was displayed, align next frame with `seq->start`. */
+  if (last_frame == seq->startdisp) {
+    next_frame = seq->start + ((int)((last_frame - seq->start) / frame_step) + 1) * frame_step;
+  }
+
+  return next_frame;
+}
+
 /* Gets the direct image from source and scales to thumbnail size. */
 static ImBuf *seq_get_uncached_thumbnail(const SeqRenderData *context,
                                          SeqRenderState *state,
@@ -2053,7 +2079,6 @@ ImBuf *SEQ_get_thumbnail(
 void SEQ_render_thumbnails(const SeqRenderData *context,
                            Sequence *seq,
                            Sequence *seq_orig,
-                           float start_frame,
                            float frame_step,
                            rctf *view_area,
                            const short *stop)
@@ -2063,24 +2088,24 @@ void SEQ_render_thumbnails(const SeqRenderData *context,
 
   /* Adding the hold offset value (seq->anim_startofs) to the start frame. Position of image not
    * affected, but frame loaded affected. */
-  start_frame = start_frame - frame_step;
   float upper_thumb_bound = (seq->endstill) ? (seq->start + seq->len) : seq->enddisp;
   upper_thumb_bound = (upper_thumb_bound > view_area->xmax) ? view_area->xmax + frame_step :
                                                               upper_thumb_bound;
 
-  while ((start_frame < upper_thumb_bound) & !*stop) {
+  float timeline_frame = SEQ_render_thumbnail_first_frame_get(seq, frame_step, view_area);
+  while ((timeline_frame < upper_thumb_bound) & !*stop) {
     ImBuf *ibuf = seq_cache_get(
-        context, seq_orig, round_fl_to_int(start_frame), SEQ_CACHE_STORE_THUMBNAIL);
+        context, seq_orig, round_fl_to_int(timeline_frame), SEQ_CACHE_STORE_THUMBNAIL);
     if (ibuf) {
       IMB_freeImBuf(ibuf);
-      start_frame += frame_step;
+      timeline_frame = SEQ_render_thumbnail_next_frame_get(seq, timeline_frame, frame_step);
       continue;
     }
 
-    ibuf = seq_get_uncached_thumbnail(context, &state, seq, round_fl_to_int(start_frame));
+    ibuf = seq_get_uncached_thumbnail(context, &state, seq, round_fl_to_int(timeline_frame));
 
     if (ibuf) {
-      seq_cache_thumbnail_put(context, seq_orig, round_fl_to_int(start_frame), ibuf, view_area);
+      seq_cache_thumbnail_put(context, seq_orig, round_fl_to_int(timeline_frame), ibuf, view_area);
       IMB_freeImBuf(ibuf);
       seq_orig->flag &= ~SEQ_FLAG_SKIP_THUMBNAILS;
     }
@@ -2090,7 +2115,7 @@ void SEQ_render_thumbnails(const SeqRenderData *context,
       return;
     }
 
-    start_frame += frame_step;
+    timeline_frame = SEQ_render_thumbnail_next_frame_get(seq, timeline_frame, frame_step);
   }
 }