File format:

<sizeX>
<sizeY>
<x1> <y1>
<x2> <y2>
...
<xn> <yn>

Here, <xi> <yi> represent the coordinates of i-th points (out of <sizeX>*<sizeY>) after the grid is applied. Coordinates are integer values with values 0 and 10000 representing minimum and maximum (X or Y) coordinate of original data set. Currently, the <sizeX> parameter must be equal to <sizeY>. Points are numbered in top-down and left-right order as illustrated below on a 5x5 grid:

1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
21 22 23 24 25

Example 1: An identity grid that doesn't alter source data can be coded like this:

2
2
0 0
10000 0
0 10000
10000 10000

Example 2: A grid that works like a vertical mirror can be coded like this:

2
2
10000 0
0 0
10000 10000
0 10000

Example 3: A grid that shrinks data in the horizontal direction and extends data in the vertical direction can be coded like this:

2
2
3000 -3000
7000 -3000
3000 13000
7000 13000

A 4.50 bug  prevents the grid given in Example 3 from being properly drawn in the 4.50 distort grid preview dialog, however, it is applied exactly as it should be.