The Turnpolicy determines how to resolve ambiguities during decomposition of bitmaps into paths.
prefers to connect black (foreground) components
always take a left turn
prefers to connect the color (black or white) that occurs most frequently in a local neighborhood of the current position
prefers to connect the color (black or white) that occurs least frequently in a local neighborhood of the current position
choose pseudo-ramdomly
always take a right turn
prefers to connect white (background) components