A picture that lets you know the radial gradient of a canvas

I believe that in a radial gradient, if a circle contains another circle, there is no way to know what the gradient looks like, but what if the two circles intersect or are separated? After reading this picture, you'll understand.

The gradients are all from red to blue ,

Createradialgradient (X1,Y1,R1, X2,Y2,R2)

The left image is a small circle to the large circle gradient, the middle of the courtyard to the small circle gradient, the right image is a gradient of two circles, you can clearly see the way the circle is absent or intersecting, the gradient always starts from the starting circle (including the inside of the starting circle), toward ending the circle direction until the end circle (excluding the inside of the

A picture that lets you know the radial gradient of a canvas