Performance: Draw play head as an overlay

When playing back animations a playhead is updated in all the animation editors.
The drawing of the playhead is part of the drawing of the main region
`RGN_TYPE_WINDOW` that redraws the whole region.

This change will draw the play head and window scrollers when updating the
screen. This affects the Action editor, Timeline, Graph editor, NLA editor and
Sequence editor. There is noticeable speedup when using complex animation files.

Spring 02_020_A.anim.blend fps went from 11.8 to 12.5 when showing a timeline
and a action editor on a Ryzen 1700.

* When playing back animation the markers don't jump up/down when near the
  frame. This could be added back.

Reviewed By: Brecht van Lommel

Differential Revision: https://developer.blender.org/D8066

1 files changed, 41 insertions, 18 deletions

diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index 37a8880e7a1..4b4287722ba 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -4273,6 +4273,13 @@ static void SCREEN_OT_region_context_menu(wmOperatorType *ot)
  *
  * Animation Step.
  * \{ */
+static bool screen_animation_region_supports_time_follow(eSpace_Type spacetype,
+                                                         eRegionType regiontype)
+{
+  return (regiontype == RGN_TYPE_WINDOW &&
+          ELEM(spacetype, SPACE_SEQ, SPACE_GRAPH, SPACE_ACTION, SPACE_NLA)) ||
+         (spacetype == SPACE_CLIP && regiontype == RGN_TYPE_PREVIEW);
+}
 
 static bool match_region_with_redraws(eSpace_Type spacetype,
                                       eRegionType regiontype,
@@ -4364,6 +4371,37 @@ static bool match_region_with_redraws(eSpace_Type spacetype,
   return false;
 }
 
+static void screen_animation_region_tag_redraw(ScrArea *area,
+                                               ARegion *region,
+                                               const Scene *scene,
+                                               eScreen_Redraws_Flag redraws)
+{
+  /* Do follow time here if editor type supports it */
+  if ((redraws & TIME_FOLLOW) &&
+      (screen_animation_region_supports_time_follow(area->spacetype, region->regiontype))) {
+    float w = BLI_rctf_size_x(&region->v2d.cur);
+    if (scene->r.cfra < region->v2d.cur.xmin) {
+      region->v2d.cur.xmax = scene->r.cfra;
+      region->v2d.cur.xmin = region->v2d.cur.xmax - w;
+      ED_region_tag_redraw(region);
+      return;
+    }
+    else if (scene->r.cfra > region->v2d.cur.xmax) {
+      region->v2d.cur.xmin = scene->r.cfra;
+      region->v2d.cur.xmax = region->v2d.cur.xmin + w;
+      ED_region_tag_redraw (region);
+      return;
+    }
+  }
+
+  if ((region->regiontype == RGN_TYPE_WINDOW) &&
+      (ELEM(area->spacetype, SPACE_GRAPH, SPACE_NLA, SPACE_ACTION, SPACE_SEQ))) {
+    /* No need to do a full redraw as the playhead is only updated. */
+    return;
+  }
+  ED_region_tag_redraw(region);
+}
+
 //#define PROFILE_AUDIO_SYNCH
 
 static int screen_animation_step(bContext *C, wmOperator *UNUSED(op), const wmEvent *event)
@@ -4402,7 +4440,8 @@ static int screen_animation_step(bContext *C, wmOperator *UNUSED(op), const wmEv
     }
 
     if (scene_eval == NULL) {
-      /* Happens when undo/redo system is used during playback, nothing meaningful we can do here.
+      /* Happens when undo/redo system is used during playback, nothing meaningful we can do
+       * here.
        */
     }
     else if (scene_eval->id.recalc & ID_RECALC_AUDIO_SEEK) {
@@ -4547,23 +4586,7 @@ static int screen_animation_step(bContext *C, wmOperator *UNUSED(op), const wmEv
           }
 
           if (redraw) {
-            ED_region_tag_redraw(region);
-            /* do follow here if editor type supports it */
-            if ((sad->redraws & TIME_FOLLOW)) {
-              if ((region->regiontype == RGN_TYPE_WINDOW &&
-                   ELEM(area->spacetype, SPACE_SEQ, SPACE_GRAPH, SPACE_ACTION, SPACE_NLA)) ||
-                  (area->spacetype == SPACE_CLIP && region->regiontype == RGN_TYPE_PREVIEW)) {
-                float w = BLI_rctf_size_x(&region->v2d.cur);
-                if (scene->r.cfra < region->v2d.cur.xmin) {
-                  region->v2d.cur.xmax = scene->r.cfra;
-                  region->v2d.cur.xmin = region->v2d.cur.xmax - w;
-                }
-                else if (scene->r.cfra > region->v2d.cur.xmax) {
-                  region->v2d.cur.xmin = scene->r.cfra;
-                  region->v2d.cur.xmax = region->v2d.cur.xmin + w;
-                }
-              }
-            }
+            screen_animation_region_tag_redraw(area, region, scene, sad->redraws);
           }
         }
       }