Font hinting
This article needs additional citations for verification. (August 2011) |
Font hinting (also known as instructing) is the use of mathematical instructions to adjust the display of an
liquid crystal displays) subpixel rendering
for further clarity.
Overview
Anti- alias- ing Hinting
|
Without |
With |
---|---|---|
Without |
||
With |
For the purpose of on-screen text display, font hinting designates which primary pixels are
Tom Rickner.[1]
Implementations
In the
grid-fitting, which modifies the height and width of font characters to line up to the set pixel grid of screen display. The open-source FreeType 2 font rendering engine uses an auto-hinter when such hinting data are not present or their use is restricted by a software patent.[2] As of 2011, the FreeType website states that the relevant font hinting patents have now all expired, and hinting is now enabled in FreeType by default.[2]
Guidelines
According to the TrueType Reference Manual,[3] font instructors (those performing font hinting) must balance the following two constraints when hinting a font:
- At small sizes, chance effects should not be allowed to magnify small differences in the original outline design of a glyph.
- At large sizes, the subtlety of the original design should emerge.[3]
The reference manual suggests that, for screen viewing, fonts should be readable at 9 pixels per
, so that the font retains its normal character while not producing exaggerated effects at small sizes.High-DPI displays
With the advent of
high-DPI displays (generally considered to be displays with more than 300 pixels per inch), font hinting has become less relevant, as aliasing effects become un-noticeable to the human eye. As a result Apple's Quartz text renderer, which is targeted for Apple's Retina displays, now ignores font hint information completely.[4][5]
See also
References
- ^ "Georgia & Verdana — Typefaces designed for the screen (finally)". Daniel Will-Harris. 2003. Archived from the original on 2013-08-28. Retrieved 2010-05-24.
- ^ a b "FREETYPE & PATENTS". the FreeType Project. 2009-06-09. Retrieved 2010-01-28.
- ^ a b "TrueType Reference Manual". developer.apple.com. Archived from the original on 2012-12-25.
- ^ Biľak, Peter (2010-05-17). "Typotheque: Font hinting article on Typotheque by Peter Biľak". www.typotheque.com. Retrieved 2023-09-15.
- ^ "A Closer Look At Font Rendering". Smashing Magazine. 2012-04-24. Retrieved 2023-09-15.
External links
- "TrueType Hinting". Microsoft Corporation. June 30, 1997. Retrieved November 6, 2007.
- An online font hinting tool
- The Raster Tragedy at Low-Resolution Revisited: Opportunities and Challenges beyond "Delta-Hinting". Beat Stamm. March 2011. A revised and extended version of the original 1998 article covering anti-aliasing including sub-pixel rendering, opportunities made possible by anti-aliasing, challenges in the rasterizer and elsewhere, and a discussion of font hinting in the context of these opportunities and challenges.
- FreeType and Patents
- Tutorial on the DejaVu font wiki Archived 2007-09-03 at the Wayback Machine
- Texts Rasterization Exposures Article from the Anti-Grain Geometry Project.