OpenType Designer - Pair Adjustment

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OpenType Designer - Pair Adjustment

Pair adjustments are most commonly used to create kerning pairs.

You can use the automatic kerning wizard to generate kerning pairs for all Latin characters.


Note: Even though you can set values for the second glyph, it is recommended that you keep those values all at zero. If you do set any of those values to non-zero, the text layout engine will skip the next possible pair for adjustment, which is usually not what a font designer intends, or expects to happen.

On the right pane you can change the properties for each glyph separately, or when you create a class of glyphs, modify the properties of each glyph in the class simultaneously.

When you select a pair containing a class, the droplist on the top of the right pane allows you to select a single glyph from the class, please note however that when you edit a value, it will be for all glyphs in the class at once.

To easily identify positive and negative kern values (XAdvance for the first glyph), the listbox will show negative kerning pairs in green, positive in blue, and zero in red.

Tip: Use the edit box above the kern pair listbox to filter the list.

Tip: Select the pair adjustment lookup in the tree (left pane) and right-click to select Trim if you wish to remove kerning pairs that have a low absolute XAdvance.


To modify the values, you can either type in the values manually, or use your mouse and keyboard to drag the glyph into the right position.

The left and right mouse buttons allow you to change the XAdvance of the glyph you click on

While holding down the shift button, you can change the XPlacement and YPlacement of the glyph you click on.


Note: For a description of the XAdvance, YAdvance, XPlacement and YPlacement fields, please see the Pos Syntax


Add a new Pair Adjustment


Delete the selected Pair Adjustment


Reset the values to their previous values


Set all fields to zero

On exporting a font, all subtables containing class-based kerning will be saved in a compact class-based format, unless the subtable contains overlapping classes. Then such subtable will be saved in a flat format. To check whether subtables contain overlapping classes, open the table in the OpenType Layout Feature Code Editor and compile the code.