In the first post, in this series on Fine Tuning, I looked at editing the Autohinter code, where the Autohinter did not recognize certain features.
In this post I will look at second category.
2. Local adjustments to individual glyphs hints, to add Interpolate commands, to improve the typographic color and proportion of the glyph,
The Autohinter in VTT 6.10 does not currently add Interpolate commands. An Interpolation helps to control the proportions of a glyph, by maintaining the relative position of one or more ‘child’ points that fall between two other ‘parent’ points. The key word is between — the child point(s) cannot be further in the Y direction than either parent or on the same Y coordinate.
When a YInterpolate command is added, it moves the point or points that are Interpolated, along the Y-Axis, in the hinted outline, so that their relationship to a reference point 1 and a reference point 2, is kept the same as it was in the original un-hinted outline. This helps to preserve the original proportion and maintains a good typographic colour onscreen.
The following animation shows some examples of YInterpolations that are added to a typical font. The Animation shows adding YInterpolate commands to the following glyphs, Capital A, B, K, N, R, V, W, X, Y, and lowercase k, v, w, x, y. Note, once added and compiled, this instruction works to fix all sizes of the glyph. The animation is just under 3 minutes long. This is all the time it takes to add the Interpolation commands to the glyphs, I mentioned above.
Note: When using the Graphical hinting tools, make sure to have the following set up in the Tools > Options Window. This will ensure that when the hints are added via the graphical hinting tools, the code will be automatically compiled. When the code is written directly into the VTT Talk window, it needs to be compiled. (ctrl R)
I will take a closer look at the YInterpolate command in the next post in the series.