3. Post­Script out­lines and PS hinting

3.1. PS hint­ing UI elements

Pref­er­ences

The Preferences dia­log box con­trols some vital aspects of how PostScript-flavored fonts (Type 1 and Open­Type PS) are gen­er­ated. In Preferences / Generating Type 1, the option Autohint unhinted glyphs allows you to auto­mat­i­cally auto­hint the font when it is gen­er­ated even if you did not per­form any spe­cific auto­hint­ing tasks. If a glyph does not con­tain any PS hints and this option is enabled, FLS will auto­mat­i­cally gen­er­ate hints for that glyph.

If you wish to con­trol your hint­ing man­u­ally and there are good rea­sons why you did not hint some glyphs, dis­able this option. (This will also allow you to gen­er­ate PostScript-flavored fonts with­out hint­ing if you remove the PS hints from all the glyphs).

Note that if the Autohint unhinted glyphs option is enabled, the ras­ter­ized pre­views in the Type 1 Hinting mode (and in its Pre­view panel) for glyphs with no PS hints present will be gen­er­ated after the glyphs have been auto­hinted in the back­ground, so you will see no hints but a PS-hinted pre­view. So if you want to reli­ably pre­view the ras­ter­i­za­tion of your actual PS hints, you should dis­able this option.

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On the Generating Type 1 / Type 1 autohinting page, dis­able the option Remove all existing hints before autohinting if you wish FLS to add auto­mat­i­cally gen­er­ated hints to exist­ing PS hints.

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Appli­ca­tion windows

The most com­monly used design source for fonts are fonts (or .vfb doc­u­ments) with Post­Script out­lines. An exam­ple of such font is Myr­iad Roman:

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When a PostScript-flavored font is open, small green “H” marks in the lower-left cor­ner of the Font Window’s glyph cell will indi­cate glyphs in which PS replace­ment hints are present. Glyphs that have PS hints but have no replace­ments hints are not indi­cated in any par­tic­u­lar way.

Double-clicking on a glyph cell will open the Glyph Win­dow. To view the PS hints present in the glyph, enable View / Show Layers / Hints. To view the PS align­ment zones (blue zones), enable View / Show Layers / Alignment Zones.

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For a more detailed view of the PS hint­ing for a glyph, choose Tools / Hints & Guides / Type 1 Hinting.

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The Type 1 Hinting tool allows you to ras­ter­ized a pre­view of how the glyph will be ren­dered in a vari­ety of ras­ter­iz­ers. Click on the Preview panel but­ton in the Type 1 Hinting tool­bar to open the Type 1 Hinting Preview panel. A click on the lit­tle rec­tan­gle in the top-right cor­ner of the panel allows you to select the rasterizer.

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Note that Font­Lab Stu­dio 5.0.4 on Mac OS X has a bug in how it inte­grates with the built-in Adobe ras­ter­iz­ers, so FLS may crash or dis­play the wrong ras­ter­ized images when any of the Adobe ras­ter­iz­ers is selected. This bug does not affect the qual­ity of hint­ing writ­ten into the font. The Win­dows ver­sion of FLS is more stable.

Also keep in mind that if the option Autohint unhinted glyphs is enabled in Preferences, then the Type 1 Preview ras­ter­i­za­tion will be auto­hinted even if the glyph win­dow does not show any PS hints.

Font Info

While the hints are con­trolled on the glyph level, there is a num­ber of rel­e­vant font-wide hint­ing set­tings. To view and edit them, open File / Font Info and open the Hinting Settings subsection.

The first page, Type 1 and TrueType hinting: alignment zones, con­trols the pri­mary PS align­ments zones (that are typ­i­cally located above the base­line) as well as the sec­ondary PS align­ments zones (typ­i­cally located below the baseline).

The PS align­ment zones will be used in PS hint­ing, and they will also be con­verted into TT align­ment zones.

By click­ing on Auto zones, FLS will auto­mat­i­cally rebuild the PS align­ment zones for the font. It will do so by ana­lyz­ing the bound­ing boxes of a hard­coded list of upper­case and low­er­case Eng­lish let­ters. If your font con­tains mul­ti­ple alpha­bets (scripts), or if it con­tains numer­als or small caps that are of obvi­ously dif­fer­ent height than upper­case or low­er­case let­ters, you should add more PS align­ment zones that will con­trol the over­shoot suppression.

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The sec­ond page, Type 1 hinting: standard stems, con­trols the ver­ti­cal PS stan­dard stems that cor­re­spond to x-direction hint­ing, as well as the hor­i­zon­tal PS stan­dard stems that cor­re­spond to y-direction hinting.

The PS stan­dard stems will be used in PS hint­ing, and they will also be con­verted into TT stan­dard stems which are stored in the CVT table.

Click­ing on Auto stems will auto­mat­i­cally build a list of PS stan­dard stems found in the font. This will be done by ana­lyz­ing the PS hint val­ues found in the font — which means that the font needs to have hint­ing for Auto stems to work.

Also note that quite often, FLS will gen­er­ate more PS stan­dard stems than really nec­es­sary. For exam­ple, in Myr­iad Roman, the orig­i­nal V stem val­ues are 88 92, and the orig­i­nal H stem val­ues are 67 73. After Auto stems, V stem val­ues will be 88 70 97 and H stem val­ues will be 73 55 68. In some cases, stem val­ues will be quite close to each other, and you may want to unify them.

Note: When con­vert­ing PS hint­ing into TT hint­ing, you can con­trol the Single link attachment precision with which FLS will match each stem width with the TT stan­dard stems. If you cre­ate fewer stan­dard stems and increase the pre­ci­sion, the stems in the TT font will appear more uni­form. If you cre­ate more stan­dard stems and decrease the pre­ci­sion, the stems in the TT font will appear more varied.

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The Type 1 hinting: global hinting parameters page only affects PS hint­ing. It does not affect TT hint­ing. Please refer to the FLS man­ual and the Type 1 font for­mat spec­i­fi­ca­tion for more infor­ma­tion about those parameters.

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The Type 1 autohinting page defines the min­i­mal and max­i­mal dis­tances (in font units) between out­line for which PS hints will be auto­mat­i­cally gen­er­ated if glyphs are auto­hinted. For very thin fonts, low­er­ing the Min width val­ues may be a good idea. For very bold fonts, rais­ing the Max width val­ues may be useful.

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3.2. PS autohinting

If your font already has PS hints, PS stan­dard stems and align­ment zones defined, you can skip this step.

If your font does not have PS hints, you should per­form the fol­low­ing steps to obtain PS hint­ing automatically:

  1. Go to Font Info / Hinting Settings and click on Auto zones.
  2. Add and revise the align­ment zones as needed.
  3. For each font that has stems that are thin­ner than 20 units or thicker than 250 units (default val­ues), nav­i­gate to Font Info / Hinting Settings / T1 Autohinting and set the Min width or Max width val­ues to match the thick­ness of your thinnest/thickest stems. Click on OK.
  4. Choose Tools / Action Set.
  5. From the Hints and Guidelines sec­tion, add the action Autohint to your action set.
  6. If you’d like to only gen­er­ate y-direction hints (i.e. hor­i­zon­tal hints) because you plan to gen­er­ate a TrueType-flavored font that does not need to be hinted in the x-direction (for exam­ple because the font will only work in ClearType, or the font is italic and the ver­ti­cal hints to not make much sense), add the action Remove hints/guides to your action set, and in the action’s options check Remove vertical hints and uncheck all the other options.
  7. From the Hints and Guidelines sec­tion, add the action Autoreplace to your action set.
  8. [sin­glepic w=645 id=12]

  9. Choose Apply action to: All glyphs in the font or All opened fonts. Click on Run.
  10. Go to File / Font Info / Hinting Settings / Standard stems (T1 hinting) and click on Auto stems.
  11. Add, revise and merge the PS stan­dard stems as needed.
  12. Click on OK.
  13. If you wish to use the Adobe PS auto­hin­ter, from the Macros tool­bar choose the Outlines sub­group and pick the Auto-hint macro. Ctrl-click on the Run but­ton to view the macro UI, set the desired para­me­ters and run the auto­hint­ing process.

After com­plet­ing this process, you have a hinted PostScript-flavored font.

Note: the Adobe PS auto­hin­ter relies on the pres­ence of stan­dard stems in the font. The Font­Lab auto-stems algo­rithm relies on the pres­ence of PS hints in the font. The Font­Lab PS auto­hin­ter ana­lyzes the out­lines only. There­fore, the the rec­om­mended chain of actions to use Adobe PS auto­hint­ing is: auto-zones, Font­Lab auto­hint, auto-stems, Adobe autohint.

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