User Guide

FontLab 4
556
Autohinting Process
When you select the Convert Hints to Instructions command in the popup
menu or apply the same action in the Transform or Transform All dialog
box, FontLab:
1. Converts all hints to links to find what points are linked by the hint.
2. For every horizontal link:
2.1 If one of the linked points is in the top or bottom alignment zone: adds
an AlignTop or AlignBottom command and connects another point to
it by the SingleLink command. Automatically links the SingleLink
command with one of the standard stems.
2.2. If none of points is in the alignment zone: links them by a DoubleLink
command or by a single link command if one point is linked to another
outline point.
2.3 Checks all outline points and if one of them is on the same horizontal
line as one of the linked points: links it by the SingleLink command. It
doesn’t do this if the point is adjacent to an already connected point.
3. For every vertical link:
3.1 Connects two points by the DoubleLink command or by the single link
command if one of the points is linked to another outline point.
3.2 Checks all outline points and if one of them is on the same horizontal
line as one of the linked points: links it by the SingleLink command. It
doesn’t do this if the point is close to an already connected point.
4. FontLab optionally detects “cusp” points and links them to one of the
single and double link commands.
5. For single and double link commands that connect round points, like
on the left and right sides of the ‘O’ FontLab may optionally add
middle delta commands that correct the rasterization of the curve.