VSE UX: Make Speed Effect strips more user friendly.

**Drawing Changes:**
- F-curve drawing for Stretch, Multiply, Length and Frame Number.
- Value drawing when no keyframes for Stretch, Length and Frame Numbers.

General view of the new drawing for each speed effect mode:
{F9796642, size=full}

Detail of the horizontal zero (blue) line in the new `Multiply` mode:
{F9798520, size=full}

Nice to have (but I don't know how):
- Auto adjusting of endframe when using Multiply or Boost.

Differential Revision: https://developer.blender.org/D6110

2 files changed, 2 insertions, 1 deletions

diff --git a/source/blender/sequencer/intern/effects.c b/source/blender/sequencer/intern/effects.c
index 7757271a2e5..316eceb6b73 100644
--- a/source/blender/sequencer/intern/effects.c
+++ b/source/blender/sequencer/intern/effects.c
@@ -3136,7 +3136,7 @@ static int early_out_speed(Sequence *UNUSED(seq), float UNUSED(facf0), float UNU
  * useful to use speed effect on these strips because they can be animated. This can be done by
  * using their length as is on timeline as content length. See T82698.
  */
-static int seq_effect_speed_get_strip_content_length(const Sequence *seq)
+int seq_effect_speed_get_strip_content_length(const Sequence *seq)
 {
   if ((seq->type & SEQ_TYPE_EFFECT) != 0 && SEQ_effect_get_num_inputs(seq->type) == 0) {
     return seq->enddisp - seq->startdisp;
diff --git a/source/blender/sequencer/intern/effects.h b/source/blender/sequencer/intern/effects.h
index 1bce4f324c3..de9c886aa57 100644
--- a/source/blender/sequencer/intern/effects.h
+++ b/source/blender/sequencer/intern/effects.h
@@ -39,6 +39,7 @@ struct Sequence;
  */
 
 struct SeqEffectHandle seq_effect_get_sequence_blend(struct Sequence *seq);
+int seq_effect_speed_get_strip_content_length(const struct Sequence *seq);
 void seq_effect_speed_rebuild_map(struct Scene *scene, struct Sequence *seq, bool force);
 float seq_speed_effect_target_frame_get(const struct SeqRenderData *context,
                                         struct Sequence *seq,