Easiest way for scanlines:
Use ditherbox, about 3x3, white background and draw a 3x1 white line on it. Fill the picture, and fade it to 25%. That makes nice and easy scan lines.
The same thing works for grids, but it's a little trickier.

"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram