In order to work with gradients and straight lines successfully, a good understanding of coordinates and linear graphs is needed. The gradient close gradient A measure of the slope of a line. The ...

Any straight line graph has a constant gradient, which is calculated by the change in 𝑦 divided by the change in 𝑥, along any section of the graph.

This is more obvious if your gradient has a straight line of color in it. if you compare the images before and after the warp you will see that the straight line of color is the same in both.