Fonts in Focus No. 8

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03

existieren Möglichkeiten, der ‚wahren‘ Form der Zeichen nahe zu kommen. Zwar wird man nur schwer das exakte Design mit all seinen Details wiedergeben können, doch mit viel Aufwand und Zeit lassen sich gute Ergebnisse auch in sehr kleinen Schriftgraden erzielen. Wer diese QualitĂ€t einmal erlebt hat, weigert sich ebenfalls, wieder auf schlecht umgesetzte Schrift am Bildschirm zu ‚starren‘. Dass Hinting bald nicht mehr notwendig sei, wurde schon oft prophezeit – und hat sich genau so oft als Irrglaube erwiesen. Neue Technologien brauchen lange, bis sie flĂ€chendeckend Verbreitung finden. Es ist daher noch immer ratsam, die Darstellung von Fonts auf Bildschirmen mit den zur VerfĂŒgung stehenden Mitteln fĂŒr die Benutzer zu optimieren. Auch wenn in ein paar Jahren alles besser wird.

03 – Hinting Evolution 1. Zeile: ohne Hints 2. Zeile: Anker & Alignment Zones 3. Zeile: StĂ€mme 4. Zeile: fertiger Font inkl. Deltahints (Font = Arial)

In the Analogy of the Cave by the ancient philosopher Plato, humans cannot directly see ‘real’ things. Everything that happens around them occurs behind their backs, thus being projected by a light, which is even further behind them, onto a wall. The people are forced to interpret the truth in view the shadow only. Their ability to do that depends on the source of light, the sharpness of the shadow and – last but not least – the evenness of the cave’s wall.

An analogy between font ‘Hinting’ and Plato’s Analogy of the Cave

Useful Hints Atilla Korap

The English word ‘Hinting’ comes from ‘Hint’. The idea revolves around Hints giving the rasterizer ‘hints’ on how it should display the characters with low resolution. One differentiates between global Hints, which are applicable for all characters and several point sizes and Deltahints, which apply to a single character and an individual point size.

The presentation of displayed fonts can be thought of in a similar manner. So-called rasterizers evaluate the font data, thereby calculating how characters are displayed (see Fonts in Focus 7). That sounds much simpler than it is, unless you don’t have more than a few pixels per character to illustrate all the ascenders and descenders, in addition to all the excess protrusions, as is the case with small point sizes. The result: an irregular x-height, inconsistent stems, lumps where diagonals meet, curved stems that are too thin or even broken off, and counters that fill in – such as with ‘e’ or ‘o’. In order to prevent this, font producers optimize their fonts so they may be displayed in small point sizes on low-resolution devices such as monitors. We are talking about Hinting. Applying to the Analogy of the Cave, the monitor corresponds to the cave wall and the resolution to its evenness. The rasterizer is the source of light whilst the characters are the ‘real’ things. Hinting allows the ‘real’ things to be manipulated so that they are also recognisable even on an uneven wall. How does Hinting work? Both the PostScript and the TrueType formats make up Hinting’s specifications. PostScript outlines usually concern general Hints, whilst Hinting for TrueType fonts offers much more powerful tools to improve screen display. These tools exist in the form of an instruction set. TrueType Hints have also been named ‘instructions’ for this reason.

Fonts in Focus 8

38 Tech Talk


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