WebGraphics gradient?

I am working on converting my desktop app to a web app and am noticing some differences among the graphics vs. webgraphics

Is there no gradient in WebGraphics? If not, is there a workaround to this?

Also, I noticed there was no ShadowBrush, but rather Shadow. All is fine with this, but how do you clear the shadow? In desktop graphics, you can call g.brush = nil. As a workaround in WebGraphics, I am doing the following

g.Shadow(0, color.White, 0, 0)

Is this correct, or is there a better way to reset the shadow? I am using this to make a slight shadow on a canvas for the background, but I want to clear it so the other elements are not shadowed (i.e. the text that is drawn)