title: Two dimensional color ramp (256x256 matrix) interpolated from 4 corner colors
body: <p>What I want to achieve is to programmatically create a two-dimensional color ramp represented by a 256x256 matrix of color values. The expected result can be seen in the attached image. What I have for a starting point are the 4 corner colors of the matrix from which the remaining 254 colors inbetween should be interpolated. While I had some success for interpolating the colors for one axis, the two-dimensional calculation provides me some bad headaches. While the image seems to have a non-linear color gradient, I would be happy with a linear one.</p>
  
  <p>If you could give me some hints how to do this with numpy or other tools I`ll be more than thankful.</p>
  
  <p><a href="https://i.stack.imgur.com/o1BUK.png" rel="noreferrer"><img src="https://i.stack.imgur.com/o1BUK.png" alt="enter image description here"></a></p>