[Bf-blender-cvs] [09c28f9b162] soc-2021-vse-strip-thumbnails: VSE strip thumbnail improvements

[Aditya Y Jeppu]

Commit: 09c28f9b1624b6b13103e55c977b2af97b9fd05f
Author: Aditya Y Jeppu
Date:   Wed Jun 16 23:43:30 2021 +0530
Branches: soc-2021-vse-strip-thumbnails
https://developer.blender.org/rB09c28f9b1624b6b13103e55c977b2af97b9fd05f

VSE strip thumbnail improvements

The left handle now slides over the thumbs when moving and updates the thumb
under the left handle to represent seq->startdisp. Strip slip offset has fixed
thumbs and they don't update images as they move but rather move along with the
strip itself. Helps to make the strip feel like it is a container for the movie
and the handle areas cut the movie to the strip size. Better UX.

===================================================================

M	source/blender/editors/space_sequencer/sequencer_draw.c

===================================================================

diff --git a/source/blender/editors/space_sequencer/sequencer_draw.c b/source/blender/editors/space_sequencer/sequencer_draw.c
index 3633cb578d5..35ddb1bf364 100644
--- a/source/blender/editors/space_sequencer/sequencer_draw.c
+++ b/source/blender/editors/space_sequencer/sequencer_draw.c
@@ -1142,10 +1142,12 @@ static void draw_seq_strip_thumbnail(View2D *v2d,
   float zoom_y = thumb_h / scene->r.ysch;
 
   y2 = y1 + thumb_h - pixely;
-  x1 = x1 + handsize_clamped;
+  x1 = seq->start;
 
-  int frame_factor = 0;
+  // TODO(AYJ) : add x1 = x1 + handsize_clamped
 
+  int frame_factor = 0;
+  float cut_off = 0;
   float upper_thumb_bound = strip_x2 - handsize_clamped;
 
   while (x1 < upper_thumb_bound - 1) {
@@ -1161,6 +1163,17 @@ static void draw_seq_strip_thumbnail(View2D *v2d,
       continue;
     }
 
+    /* set the clipping bound to show the left handle moving over thumbs and not shift thumbs */
+    if (IN_RANGE_INCL(seq->startdisp, x1, x2)) {
+      cut_off = seq->startdisp - x1;
+    }
+
+    /* ignore thumbs to the left of strip */
+    if (x2 < seq->startdisp) {
+      x1 = x2;
+      continue;
+    }
+
     /* clip if full thumbnail cannot be displayed */
     if (x2 >= (upper_thumb_bound - 1)) {
       x2 = (upper_thumb_bound - 1);
@@ -1169,14 +1182,14 @@ static void draw_seq_strip_thumbnail(View2D *v2d,
     }
 
     /* Get the image */
-    ibuf = SEQ_render_give_ibuf_direct(
-        &context, seq->start + seq->startofs + frame_factor * roundf(thumb_w), seq);
+    ibuf = SEQ_render_give_ibuf_direct(&context, x1 + cut_off, seq);
 
     if (ibuf) {
-      ED_draw_imbuf_ctx_clipping(C, ibuf, x1, y1, false, x1, y1, x2, y2, zoom_x, zoom_y);
+      ED_draw_imbuf_ctx_clipping(C, ibuf, x1, y1, true, x1 + cut_off, y1, x2, y2, zoom_x, zoom_y);
       IMB_freeImBuf(ibuf);
     }
 
+    cut_off = 0;
     frame_factor++;
     x1 = x2;
   }