Advanced random is useful for creating a texture. The new canvas plugin could be used to create a gradient. Probably by setting the colors of each pixel.
as a psuedo example suppose you have a 100x100 canvas and you want to make a horizontal gradient from red [255,0,0] to blue [0,255,0]. You could do something like this:
start of layout
for x=0 to 99
for y=0 to 99
-- set pixel at x,y to rgb(lerp(255, 0, x/99), lerp(0, 255, x/99), lerp(0, 0, x/99))
The actual use of the new canvas plugin seems to have a few other steps you have to consider, such as copying the pixels to the image, but that is just one action.