Simulating color diffusion in a graphical display

Abstract

As described herein, an electronic device with a display screen may simulate the color diffusion that occurs in a physical painting process. For instance, the user may perform one or more actions that simulate a brushstroke on the display screen such as swiping a touch-sensitive area or dragging a cursor across the screen. The electronic device then calculates a geodesic distance between a pixel inside a region defined by the brushstroke and a pixel located outside this region based on the physical distance between the two pixels and a weighting factor that varies depending on whether an image boundary is between the two pixels. Based on the geodesic distance, the electronic device uses a color diffusion relationship that defines the effect of the color of the brushstroke on the pixel and a time delay controlling when the color of the brushstroke reaches the pixel in order to simulate color diffusion.