Calculating Comp Size (Top Right Anchor)

Layer had a pan on it.  Final keyframes for 1920,1080 layer:
     anchor = 1531.5, 387.7
     pos = 53, 653.5
     scale = 156.3, 156.3

To calculate comp size:

a=transform.anchorPoint; s=transform.scale; p=transform.position;
x= a[0]*s[0]/100 - p[0] + 1920;
y=((1080-a[1])*s[1]/100)+p[1];
[x,y]

Compsize = [4260.4, 1735.4]