User Guide

Multiple Master Fonts
589
Design Coordinates and Weight Vectors
You know that all axes have ranges. These ranges can vary from 0 to 9999,
but a more practical range of 0 to 1000 is usually used. Somehow we have to
define a way to designate the position of an intermediate MM design in the
design axis space.
A very natural way to define the position of the intermediate font is to use
its position on each design axis. These coordinates are called design
coordinates:
Width axis
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Intermediate design
Design
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There is also another type of coordinate called blend coordinates. Blend
coordinates are normalized to the given dynamic range of the axis. If an
axis has a (50-400) dynamic range then the design coordinate (50) equals
the blend coordinate 0.0. The design coordinate (400) equals the 1.0 blend
coordinate. Intermediate design coordinates are converted to the blend
coordinates using linear calculation (by default) or a non-linear axis graph
(described in the next section).
When we know the design coordinates we can calculate what proportion of
each master font we need to build the intermediate font. This process is
called blending.