Patent ID: 8379047

Claim:
A method, comprising: using a computer to perform: receiving input representing a brush stroke made by a brush tool of an image editing program sweeping across a canvas, wherein the brush tool comprises a plurality of bristles; receiving input specifying a target opacity value for paint to be deposited on the canvas by the brush stroke; generating per-pixel data for each canvas pixel affected by the brush stroke reflecting the effects of the brush stroke on the canvas pixel, wherein the per-pixel data for each canvas pixel comprises a respective opacity value and one or more respective color values; and storing the per-pixel data in a representation of an image on the canvas, as modified by the brush stroke; wherein said generating comprises: computing a per-bristle opacity value dependent on the number of bristles in the brush tool and dependent on the target opacity value for the brush stroke; and determining an effect of each bristle of the brush tool on the color and opacity values of each canvas pixel affected by the brush stroke dependent on the per-bristle opacity.