Distortion on RZA1H

I am working on distortion on RZA1H board.

I have gone through data sheets of IMR-LSD and we are assuming we can draw triangles whose source coordinates Y direction point maximum is 4. For e.g (0,0)(0,4),(16,0)(32,4),(100,0)(100,4).

I had  tried to draw triangles(distort image) whose source coordinates X &Y direction points are user defined e.g (0,0),(0,42),(100,0)(100,42),......but out distorted image is not as expected.

So, Is there any way to distort the source image as per User defined  source coordinates.

Or else ,we can distort the image properly only when whose source coordinates Y direction point lies in between (2,3,4) as  mentioned in IMR-LSD data sheet. 

Please revert back as soon as possible.