Blur/Glow/Blossom effect


I was trying to draw a glow effect by using a round brush with a radial gradient and drawing around my "edges" (underneath). However, the gradient doesn't seem to be relative to the brush itself, but to the component being drawn upon. Is there a way to make a brush like this?

I took a look at the JUCE glow effect, but it only works on components, and the effect doesn't seem to have the effect I want. In this picture ( there is some glow along the passageways, that I'm trying to replicate in JUCE.

Any suggestions appreciated.