Small gaps in borders can be “filled” by setting the Close gaps to a value other than None. This prevents fills from leaking into undesired areas just because there is a small break in a line (as might happen in tracing a cartoon). Note that the gaps are defined in terms of screen pixels so different zoom levels will give different results. Also note, calculating the fill when there are gaps can take some time.

The Paint Bucket Tool was applied to the leftmost region in the three figures. The square areas are separated from this region by dashed lines with gaps of 1, 2, and 4 pixels from top to bottom. The Close gaps parameter was set, from left to right, to Small, Medium, Large. The filling was done at a zoom of 100%.