Hagen - Pragma ADE

esult We thrive U+57:W [kern] U+65:e [glue] U+74:t
[kern] U+68:h U+72:r U+69:i U+76:v [kern] U+65:e
5.2.9 Pairwise positioning
This variant of positioning involved the first, second or both glyphs of a glyph pair. The
specification can influence the horizontal and vertical positions we well as the widths of
the positioned glyphs.
We need an example here.
5.2.10 Mark positioning
Marks are (often) small symbols that represent accents (in latin) or vowels (in arabic)
that get attached to base glyphs. In the input stream they come after the character
that they apply to. Many fonts come with precomposed latin characters which means
that an à in the input is mapped directly onto its corresponding shape. When the input
contains an a followed by a ̀ input normalization will normally turn this into an à.
But, when this doesn’t happen, the font machinery has to make sure that the mark gets
positioned right onto the base character. In traditional Type1 fonts that more or less
happened automatically by overlaying the shapes. In OpenType (single) positioning is
used to place the mark right.
\showotfcomposition{dejavu-serif*default at 24pt}{}{à a\utfchar{"0300} à}
\showotfcomposition{cambria*default at 24pt}{}{à a\utfchar{"0300} à}
\showotfcomposition{lmroman10regular*default at 24pt}{}{à a\utfchar{"0300} à}
\showotfcomposition{lucidabrightot*default at 24pt}{}{à a\utfchar{"0300} à}
\showotfcomposition{texgyrepagellaregular*default at 24pt}{}{à a\utfchar{"0300} à}
Of course a font can contain logic that replaces a sequence of base and mark into precomposed
characters with the right Unicode entry.
font 79: DejaVuSerif.ttf @ 24.0pt
features analyze=yes, curs=yes, devanagari=yes, extrafeatures=yes,
kern=yes, liga=yes, mark=yes, mkmk=yes, mode=node, script=dflt,
tlig=yes, trep=yes
step 1 à à à U+E0:à [glue] U+61:a U+300:̀ [glue] U+E0:à
feature 'mark', lookup 'mb_l_1_s', anchor Anchor-1, bound 1,
anchoring mark U+00300 (gravecomb) to basechar U+00061 (a) =>
(12.66797pt,0pt)
result à à à U+E0:à [glue] U+61:a U+300:̀ [glue] U+E0:à
71
Features