Example-based hinting of true type fonts

ABSTRACT

Hinting in TrueType is a time-consuming manual process in which a typographer creates a sequence of instructions for better fitting the characters of a font to a grid of pixels. In this paper, we propose a new method for automatically hinting TrueType fonts by transferring hints of one font to another. Given a hinted source font and a target font without hints, our method matches the outlines of corresponding glyphs in each font, and then translates all of the individual hints for each glyph from the source to the target font. It also translates the control value table (CVT) entries, which are used to unify feature sizes across a font. The resulting hinted font already provides a great improvement over the unhinted version. More importantly, the translated hints, which preserve the sound, hand-designed hinting structure of the original font, provide a very good starting point for a professional typographer to complete and fine-tune, saving time and increasing productivity. We demonstrate our approach with examples of automatically hinted fonts at typical display sizes and screen resolutions. We also provide estimates of the time saved by a professional typographer in hinting new fonts using this semi-automatic approach.

REFERENCES

• 1: Adobe Systems, Inc. Adobe Type 1 Font Format, March 1990.
• 2: Sten E Andler. Automatic generation of gridfitting hints for rasterization of outline fonts or graphics. In Proceedings of the International Conference on Electronic Publishing, Document Manipulation, and Typography, pages 221-234, September 1990.
• 3: Apple Computer, Inc. The TrueType Font Format Specification, 1990. Version 1.0.
• 4: Claude B6trisey. G~n~ration Automatique de Contraintes pour CaractOres Typographiques ~ l'Aide d' un ModOle Topologique. PhD thesis, l~cole Polytechnique F6d6rale de Lausanne, 1993.
• 5: Roger D. Hersch, Character generation under grid constraints, Proceedings of the 14th annual conference on Computer graphics and interactive techniques, p.243-252, August 1987
• 6: Roger D. Hersch , Claude Betrisey, Model-based matching and hinting of fonts, Proceedings of the 18th annual conference on Computer graphics and interactive techniques, p.71-80, July 1991
• 7: Beat Stamm, Visual True Type: A Graphical Method for Authoring Font Intelligence, Proceedings of the 7th International Conference on Electronic Publishing, Held Jointly with the 4th International Conference on Raster Imaging and Digital Typography: Electronic Publishing, Artistic Imaging, and Digital Typography, p.77-92, March 30-April 03, 1998

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.7 DOCUMENT AND TEXT PROCESSING

Additional Classification:
  I. Computing Methodologies
  I.4 IMAGE PROCESSING AND COMPUTER VISION
      I.4.7 Feature Measurement
          Subjects: Size and shape
      I.4.8 Scene Analysis
          Subjects: Shape
  I.5 PATTERN RECOGNITION
      I.5.2 Design Methodology
          Subjects: Feature evaluation and selection
  I.7 DOCUMENT AND TEXT PROCESSING

General Terms:
Design, Documentation, Measurement, Performance, Theory

Keywords:
automatic hinting, digital typography, gridfitting, shape matching