Mask Set Threshold If a selection edge is feathered, this value defines the edge of the selection for tracing based on selection mask opacity. Enter a value from 1 (nearly transparent) to 255 (opaque). These values correspond to the lightness of pixels for a selection saved as a mask in a channel. Pixels in the selection mask that are more opaque (lighter) than the threshold value are treated as opaque and part of the selection. Pixels that are less opaque (darker) than the threshold value are treated as transparent and outside the selection. At a threshold of 1, the entire feathered edge will be part of the selection. At 255, only the com- pletely opaque part of the selection will be included. If a selection is not feathered, this value has no effect. Curves / Polygons Choose Curves to create paths with smooth anchor points and curve segments as appropriate. Choose Polygons to create paths with straight segments only. The Curves option can result in smoother paths with fewer anchor points when the selection border has curves. Loose /Tight Drag the slider to set the tolerance for tracing irregu- larities in the selection border. Loose follows the selection border less precisely (more smoothly) and creates fewer anchor points. Tight fol- lows the selection border more precisely (less smoothly) and creates more anchor points. Round /Sharp Drag the slider to set the tolerance for tracing cor- ners in the selection border. Round creates rounder corners, Sharp creates sharper corners.
Canvas 8 Help: Selections and channels (16 of 32)                                                   Page #666