HÀN THÊ THÀNH
Masaryk University, Brno, Czech Republic
thanh@informatics.muni.cz
Abstract: This paper describes the two typographic extensions that have been
implemented into pdfTEX: margin kerning and composing with font
expansion.
Margin kerning is the adjustments of the characters at the margins of a typeset text to make the margins appear smooth. Only mechanical justification of the margins often causes them look rather ragged, as certain characters can make a line appear shorter than others. Shifting such characters by an appropriate amount into the margins would greatly improve the appearance of a typeset text.
Composing with font expansion is the method to use a wider or narrower variant of a font to make interword spacing more even. A concept to stretch or shrink a font was introduced and integrated to the box/glue/penalty model of tex line breaking. The potentiality to adjust a line width by font expansion can be taken into consideration while a paragraph is being broken into lines, in order to choose better breakpoints.
These extensions turned out to noticeably improve the appearance of a typeset text. A number of `real-world' documents have been typeset using these typographic extensions.
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