What additional tool do I need to add to my pixel-editing program?

What additional tool do I need to add to my pixel-editing program?

Joe Strout's picture

I'm working on a pixel paint program for Mini Micro. Currently I have 15 tools defined, but I have room for 16!

First column: pencil, brush, fill, eyedropper.
Second column: eraser, draw line, draw rectangle, fill rectangle.
Third column: shift content, ???, draw ellipse, fill ellipse.
Last column: select, blur, lighten, darken.

Pixel artists: what one additional tool would you really love to see in a pixel paint program?