Preparing a font for hinting

Hinting controls points on the glyph outline. Some hinting is global, affecting the entire font or available to any glyph in the font. Visual TrueType stores these global values in three tables:

·       The control value table (‘cvt’) stores values you enter to control the regularity of features. Visual TrueType refers to these values when applying links, anchors, and strokes.

·       The pre-program table (‘prep’) stores values for certain conditions, such as the ppem size limits for hinting, that always apply to the font. Each time you change glyph size or resolution, Visual TrueType executes the table to scale the control values to fractional numbers representing the font size and resolution you’re hinting.

·       The font program table (‘fpgm’) stores functions that can be called from the prep table or from hints applied to the glyph. Re-using the same function for multiple glyphs eliminates repetitive code.

Other hinting is local, or particular to a glyph, and stored as part of its glyph table (‘glyf’). Visual TrueType applies all global hinting to the font before executing local hinting of a glyph.

Preparing the font for hinting creates an empty template for the ‘cvt’ table, a partially completed template for the ‘prep’ table, and a ready-to-use ‘fpgm table. You will learn more about these tables in conjunction with hinting tasks you can do with Visual TrueType. However, before doing any hinting, you must fill in the template for the ‘cvt’ table (see “Using the Control Value Table”). Completing the other two templates is optional for advanced users who know how to set these values to refine hinting for specific situations.

In addition, preparing a font can:

·       Remove previous hinting. Many font programs autohint the font. You should remove those instructions because Visual TrueType ignores them and they increase the disk space required for the font. Or you can clear hinting you’ve done, so Visual TrueType removes private tables that contain source data for VTT Talk and TrueType (glyph program).

·       Import character group data included in the font. Each glyph belongs to a character group, and Visual TrueType applies ‘cvt’ values for the group as you hint the glyph. You can change a glyph’s character group with the Change Char Group command on the Edit menu (see “Changing a Glyph’s Character Group”).

Visual TrueType assumes that you want to remove hinting, import character group data, and import the templates and tables it needs. If you’ve opened a font for the first time, you probably want to accept the default settings.

Prepare font dialog

If you’re preparing the font for the first time, use the default settings.

However, maybe you’ve been working on the font and need to “start over” on some aspect. Just clear the check boxes for those options you don’t want. For example, to start over with hinting, yet keep the character groups and table data, clear all options except Remove Existing Instructions.

Visual TrueType overwrites any existing information for the selected option. To keep you from accidentally overwriting work you wanted to keep, Visual TrueType gives you a chance to change your mind. A prompt, customized to the selected settings, will ask you to confirm. The default setting is No, so you must click Yes to proceed.

Prepare font confirmation dialog

Click Yes only if you want to proceed with the bulleted actions.

To prepare the open font for hinting

1.       On the Tools menu, click Prepare Font.

2.      Click OK.

3.      When prompted to confirm the selected options, click Yes.

To start over with an open font you’ve been hinting

1.       On the Tools menu, click Prepare Font.

2.      If you want to keep hinting you’ve already done to the font, click to clear the Remove Existing Instructions check box.
If you’ve assigned glyphs to new character groups and want to keep those assignments, click to clear Import Character Group Data.
If you want to keep data you’ve already entered in global tables, click to clear Import a ‘Cvt’ Template, a Standard ‘Fpgm,’ and a ‘Prep’ Template.

3.      Click OK.

4.     When prompted to confirm the selected options, click Yes.