Font hinting

Last updated
A font test without hinting (upper rows) and with hinting (lower rows) at both true size and 400% scaling. Note the increased edge contrast with the hinted text but more faithful character shape and more natural inter-character spacing in the unhinted text. Font-hinting-example.png
A font test without hinting (upper rows) and with hinting (lower rows) at both true size and 400% scaling. Note the increased edge contrast with the hinted text but more faithful character shape and more natural inter-character spacing in the unhinted text.

Font hinting, also known as instructing, is the use of mathematical instructions to adjust the display of an outline font so that it lines up with a rasterized grid. At low screen resolutions, hinting is critical for producing clear, legible text. It can be accompanied by antialiasing and (on liquid crystal displays) subpixel rendering for further clarity.

Contents

Overview

Anti-
alias-
ing
Hinting  

Without

With

Without
Hinting sample noaa nohint large.png
Hinting sample aa nohint large.png

With
Hinting sample noaa hint large.png
Hinting sample aa hint large.png

For the purpose of on-screen text display, font hinting designates which primary pixels are interpolated to more clearly render a font.[ citation needed ] Hints are usually created in a font editor during the typeface design process and embedded in the font. A font can be hinted either automatically (through processed algorithms based on the character outlines) or set manually. Most font editors are able to do automatic hinting, and this approach is suitable for many fonts. However, high-quality commercial fonts are often manually hinted to provide the sharpest appearance on computer displays. Verdana is one example of a font that contains a large amount of hinting data, much of which was accomplished manually by type engineer Tom Rickner. [1]

Implementations

In the TrueType font format, released in 1991 by Apple Inc, hinting invokes tables of font data used to render fonts properly on screen. One aspect of TrueType hinting is 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:

The reference manual suggests that, for screen viewing, fonts should be readable at 9 pixels per em at 72 pixels per inch. Particular attention should be paid to the cap height, x-height, and baseline, 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

Related Research Articles

ClearType is Microsoft's implementation of subpixel rendering technology in rendering text in a font system. ClearType attempts to improve the appearance of text on certain types of computer display screens by sacrificing color fidelity for additional intensity variation. This trade-off is asserted to work well on LCD flat panel monitors.

<span class="mw-page-title-main">PostScript</span> File format and programming language

PostScript is a page description language and dynamically typed, stack-based programming language. It is most commonly used in the electronic publishing and desktop publishing realm, but as a Turing complete programming language, it can be used for many other purposes as well. PostScript was created at Adobe Systems by John Warnock, Charles Geschke, Doug Brotz, Ed Taft and Bill Paxton from 1982 to 1984. The most recent version, PostScript 3, was released in 1997.

TrueType is an outline font standard developed by Apple in the late 1980s as a competitor to Adobe's Type 1 fonts used in PostScript. It has become the most common format for fonts on the classic Mac OS, macOS, and Microsoft Windows operating systems.

<span class="mw-page-title-main">Verdana</span> Humanist sans-serif font

Verdana is a humanist sans-serif typeface designed by Matthew Carter for Microsoft Corporation, with hand-hinting done by Thomas Rickner, then at Monotype. Demand for such a typeface was recognized by Virginia Howlett of Microsoft's typography group and commissioned by Steve Ballmer. The name "Verdana" is derived from "verdant" (green) and "Ana".

<span class="mw-page-title-main">Typeface</span> Set of characters that share common design features

A typeface is a design of letters, numbers and other symbols, to be used in printing or for electronic display. Most typefaces include variations in size, weight, slope, width, and so on. Each of these variations of the typeface is a font.

In digital signal processing, spatial anti-aliasing is a technique for minimizing the distortion artifacts (aliasing) when representing a high-resolution image at a lower resolution. Anti-aliasing is used in digital photography, computer graphics, digital audio, and many other applications.

<span class="mw-page-title-main">Tahoma (typeface)</span> Humanist sans-serif font

Tahoma is a humanist sans-serif typeface that Matthew Carter designed for Microsoft Corporation. Microsoft first distributed it, along with Carter's Verdana, as a computer font with Office 97.

<span class="mw-page-title-main">Subpixel rendering</span> Technique for increasing apparent display resolution

Subpixel rendering is a method used to increase the effective resolution of a color display device. It takes advantage of each pixel's composition of individually addressable red, green, and blue components adjacent on the display matrix, called subpixels, and uses them as rendering units instead of pixels.

<span class="mw-page-title-main">FreeType</span> Software development library to render text onto bitmaps, and other font-related operations

FreeType is a software development library used to render text onto bitmaps, and which provides support for other font-related operations. The FreeType font rasterization engine is free and open-source software with the source code dual-licensed under a BSD-like license and the GPL. FreeType supports a number of font formats, including TrueType, Type 1, and OpenType.

Ikarus is a type design and production software developed by URW and Brendel Informatik foundries, for converting existing typefaces and logos into digital format for use on computer driven printing, plotting and sign cutting devices.

<span class="mw-page-title-main">Typography of Apple Inc.</span> Overview of typography of Apple Inc.

Apple Inc. uses a large variety of typefaces in its marketing, operating systems, and industrial design with each product cycle. These change throughout the years with Apple's change of style in their products. This is evident in the design and marketing of the company. The current logo is a white apple with a bite out of it, which was first utilized in 2013.

A computer font is implemented as a digital data file containing a set of graphically related glyphs. A computer font is designed and created using a font editor. A computer font specifically designed for the computer screen, and not for printing, is a screen font.

<span class="mw-page-title-main">Font rasterization</span> Process of converting text from vector to raster

Font rasterization is the process of converting text from a vector description to a raster or bitmap description. This often involves some anti-aliasing on screen text to make it smoother and easier to read. It may also involve hinting—information embedded in the font data that optimizes rendering details for particular character sizes.

The Saffron Type System is a system for rendering high-quality scalable type on digital displays. It was developed by Mitsubishi Electric Research Laboratories, and is built on a core of adaptively-sampled distance field (ADF) technology. Saffron has been licensed to Adobe and Monotype and is shipping in numerous products such as the Adobe Flash Player and Amazon Kindle. Saffron has been implemented in both software and hardware.

<span class="mw-page-title-main">Georgia (typeface)</span> 1996 typeface by Matthew Carter

Georgia is a serif typeface designed in 1993 by Matthew Carter and hinted by Tom Rickner for Microsoft. It was intended as a serif typeface that would appear elegant but legible when printed small or on low-resolution screens. The typeface is inspired by Scotch Roman designs of the 19th century and was based on designs for a print typeface on which Carter was working when contacted by Microsoft; this would be released under the name Miller the following year. The typeface's name referred to a tabloid headline, "Alien heads found in Georgia."

<span class="mw-page-title-main">X Rendering Extension</span>

The X Rendering Extension is an extension to the X11 core protocol to implement image compositing in the X server, to allow an efficient display of transparent images.

Meiryo is a Japanese sans-serif gothic typeface. Microsoft bundled Meiryo with Office Mac 2008 as part of the standard install, and it replaces MS Gothic as the default system font on Japanese systems beginning with Windows Vista.

Apple's Macintosh computer supports a wide variety of fonts. This support was one of the features that initially distinguished it from other systems.

Bitstream Font Fusion is a small, fast, object-oriented font engine written in ANSI C capable of rendering high-quality text on any platform, any device, and at any resolution. The entire source code is portable, optimized, and executes independent of operating system and processor. The font engine is capable of rendering 2,400-3,300 characters per second on a 100 MIPS CPU.

<span class="mw-page-title-main">Peter Karow</span> German entrepreneur

Peter Karow is a German entrepreneur, inventor and software developer. He holds several patents in the field of desktop publishing and is known for his work on computer fonts. He contributed with several books and patents to the development of operating systems for computers. He is recognized as the inventor of outline computer fonts.

References

  1. "Georgia & Verdana — Typefaces designed for the screen (finally)". Daniel Will-Harris. 2003. Archived from the original on 2013-08-28. Retrieved 2010-05-24.
  2. 1 2 "FREETYPE & PATENTS". the FreeType Project. 2009-06-09. Retrieved 2010-01-28.
  3. 1 2 "TrueType Reference Manual". developer.apple.com. Archived from the original on 2012-12-25.
  4. Biľak, Peter (2010-05-17). "Typotheque: Font hinting article on Typotheque by Peter Biľak". www.typotheque.com. Retrieved 2023-09-15.
  5. "A Closer Look At Font Rendering". Smashing Magazine. 2012-04-24. Retrieved 2023-09-15.