Scanline Fill
The algorithm can be sped up by filling lines. Instead of pushing each potential future pixel coordinate on the stack, it inspects the neighbour lines (previous and next) to find adjacent segments that may be filled in a future pass; the coordinates (either the start or the end) of the line segment are pushed on the stack. In most cases this scanline algorithm is at least an order of magnitude faster than the per-pixel one.
Efficiency: each pixel is checked once.
Read more about this topic: Flood Fill
Famous quotes containing the word fill:
“Paper is cheap, and authors need not now erase one book before they write another. Instead of cultivating the earth for wheat and potatoes, they cultivate literature, and fill a place in the Republic of Letters. Or they would fain write for fame merely, as others actually raise crops of grain to be distilled into brandy.”
—Henry David Thoreau (1817–1862)