Fix slide out (#795)

Author: knezi

moviepy/video/compositing/transitions.py

@@ -59,7 +59,8 @@ def slide_in(clip, duration, side):
 
     >>> from moviepy.editor import *
     >>> clips = [... make a list of clips]
-    >>> slided_clips = [clip.fx( transfx.slide_in, 1, 'left')
+    >>> slided_clips = [CompositeVideoClip([
+                            clip.fx(transfx.slide_in, duration=1, side='left')])
                         for clip in clips]
     >>> final_clip = concatenate( slided_clips, padding=-1)
 
@@ -98,18 +99,19 @@ def slide_out(clip, duration, side):
 
     >>> from moviepy.editor import *
     >>> clips = [... make a list of clips]
-    >>> slided_clips = [clip.fx( transfx.slide_out, 1, 'bottom')
+    >>> slided_clips = [CompositeVideoClip([
+                            clip.fx(transfx.slide_out, duration=1, side='left')])
                         for clip in clips]
     >>> final_clip = concatenate( slided_clips, padding=-1)
 
     """
 
-    w, h = clip.size
-    ts = clip.duration - duration  # start time of the effect.
-    pos_dict = {'left': lambda t: (min(0, w*(1-(t-ts)/duration)), 'center'),
-                'right': lambda t: (max(0, w*((t-ts)/duration-1)), 'center'),
-                'top': lambda t: ('center', min(0, h*(1-(t-ts)/duration))),
-                'bottom': lambda t: ('center', max(0, h*((t-ts)/duration-1)))}
+    w,h = clip.size
+    ts = clip.duration - duration # start time of the effect.
+    pos_dict = {'left' : lambda t: (min(0,w*(-(t-ts)/duration)),'center'),
+                'right' : lambda t: (max(0,w*((t-ts)/duration)),'center'),
+                'top' : lambda t: ('center',min(0,h*(-(t-ts)/duration))),
+                'bottom': lambda t: ('center',max(0,h*((t-ts)/duration))) }
 
     return clip.set_position(pos_dict[side])