blender: Add a limitation hints to the panel

Hits show helpful scripting information like what the previous inserted
position was, if enough time has passed to send a new command and how
to get the slowest or fastest move possible.

Author: funjack

README.md

@@ -93,11 +93,38 @@ Shortcuts
 The following keyboard shortcuts are registered (focus must be on the Video
 Sequencer Editor):
 
-- `0-9`, `Numpad 0-9` : Insert postion at 0% - 90% at current frame.
+- `0-9`, `Numpad 0-9` : Insert position at 0% - 90% at current frame.
 - `-`, `Numpad period` : Insert position at 100% at current frame.
 - `` ` ``  : Insert a copy of the previous stroke at current frame.
 - `=`  : Fill up until the current frame with copies of the previous stroke.
 
+Hint label descriptions
+-----------------------
+
+In the funscripting panel there are a couple of hints displayed. These are just
+helpful hints, so feel free to ignore when you feel that's appropriate.
+
+- **Previous**: The position of the previous action.
+- **Interval**: Time in ms since the previous action, icons:
+   - *Warning triangle*: too soon, there is not enough time to technically send
+     the action.
+   - *Green check-mark*: sweet spot, the previous action will transition into
+     this one.
+   - *Clock*: there will be a 'pause' in the script, since the previous action
+     has already finished.
+- **Slowest**: The amount of distance to get the slowest move possible for the
+  current frame.
+- **Fastest**: The amount of distance to get the fastest move possible for the
+  current frame.
+
+The distance calculation for fastest and slowest is currently using
+Launchcontrol's 20-80 speed limits rules.
+
+### Example
+
+If previous position was 20, and the slowest hint gives 10. Inserting either 10
+or 30 will result in the slowest move in the specified direction.
+
 Tips
 ----
 

funscripting.py

@@ -57,9 +57,42 @@ def poll(cls, context):
         return context.selected_sequences is not None \
                 and len(context.selected_sequences) == 1
 
-    def draw(self, context):
+    def limitinfo(self, context):
+        """Labels with hints of the limitations"""
+        scene = context.scene
+        seq = context.selected_sequences[0]
+        keyframes = launch_keyframes(seq.name)
         layout = self.layout
+        row = layout.row(align=True)
+        col = row.column(align=True)
+        last = {"frame":0, "value":0}
+        if keyframes is not None:
+            for kf in reversed(keyframes):
+                frame = kf.co[0]
+                value = kf.co[1]
+                if frame > scene.frame_current:
+                    continue
+                if frame < scene.frame_current:
+                    last = {"frame":frame, "value":value}
+                    break
+        interval = frame_to_ms(scene.frame_current) - frame_to_ms(last["frame"])
+        icon = "FILE_TICK" if interval > 100 or last["frame"] == 0 else "ERROR"
+        if interval > 1000:
+            icon = "TIME"
+        mindist = launch_distance(20, interval)
+        maxdist = launch_distance(80, interval)
+        col.label(text="Previous: %d" % last["value"])
+        col = row.column(align=True)
+        col.label("Slowest: %d" % mindist)
+        row = layout.row(align=True)
+        col = row.column(align=True)
+        col.label(text="Interval: %d ms" % interval, icon=icon)
+        col = row.column(align=True)
+        col.label("Fastest: %d" % maxdist)
 
+    def draw(self, context):
+        self.limitinfo(context)
+        layout = self.layout
         for x in [0, 10, 40, 70, 100]:
             row = layout.row(align=True)
             row.alignment = 'EXPAND'
@@ -322,6 +355,14 @@ def ms_to_frame(time):
     fps_base = scene.render.fps_base
     return round(time/1000/fps_base*fps+1)
 
+def launch_distance(speed, duration):
+    """Returns the launch movement distance for given speed and time in ms."""  
+    if speed <= 0 or duration <= 0:
+        return 0
+    time = pow(speed/25000, -0.95)
+    diff = time - duration
+    return 90 - int(diff/time*90)
+
 def register():
     bpy.utils.register_class(FunscriptPositionButton)
     bpy.utils.register_class(FunscriptRepeatButton)