User Guide

Hinting
509
Visual TrueType Hints
In FontLab we use a small set of high-level hinting instructions that are
automatically compiled to TrueType instructions during font export.
Because these instructions can be set and edited visually we call them
visual TrueType hints or just visual hints.
Visual hints are enough to define TrueType hints even in very complex
situations and they are compiled in very compact and effective TrueType
instruction code.
The visual hint set includes the following commands:
Align Aligns (moves) the position of the outline point to the designated
position on the grid or to the edge of the alignment zone.
Single Link
Sets the position of the point relative to the position of another
point. Distance can be linked with one of the stem widths.
Distances also may be rounded or not.
Double Link Sets the distance between two points to an integer value that may
be linked with a stem width
Interpolate
Interpolates the position of a point between two other points
Middle Delta Slightly shifts a point at a specific PPM. This command works
before the final interpolation of untouched points.
Final Delta
Slightly shifts a point at a specific PPM. This command works after
the final interpolation of untouched points. This command is used
for the final outline correction.
All commands are available in horizontal and vertical directions. There are
no “diagonal” visual instructions.
Sequence of commands
Visual commands may be set in any sequence, but they are interpreted in a very specific order.
FontLab automatically detects the logic of the hinting program and does intelligent sorting.
1.
Align commands are always interpreted first.
2.
Double links are interpreted first also, except that middle delta instructions may set points that
are linked by double links.
3.
Single links and interpolate commands are interpreted in logical sequence.
4.
Middle delta commands are interpreted after commands that set positions of the points for
which they are set, but before commands that are based on these points.
5.
Final delta commands are interpreted after final interpolation of the untouched points.