Re: Question-making positon and scaling expression

If you put your image in a precomp that is exactly the size of the image, you have several options for a scale expression. This expression will cause the image (and any replacement) to exactly fill the precomp (but will distort the image if the replacement has a different aspect ratio):

w = thisComp.width/width;
h = thisComp.height/height;
[value[0]*w,value[1]*h]

This one eliminates the distortion, and makes the best fit without cropping the image, but it may leave gaps at the top and bottom, or on the sides:

w = thisComp.width/width;
h = thisComp.height/height;
if (w < h) value*w else value*h

This one eliminates the distortion and fills the precomp, but may crop the top and bottom or the sides:

w = thisComp.width/width;
h = thisComp.height/height;
if (w > h) value*w else value*h


All of these assume that all the images are square pixels. If not, the expressions get somewhat more complicated.

Dan