The MetaFont dialog (obviously the name is a rip-off of Knuth's work) will try to find important features of a font and a character and allow you to modify them. It does not read TeX .mf files. The features searched for are:
The results will probably always need to be examined and fixed up by the human eye, but they may provide a help in changing a font's attributes. At the moment the command is pretty primitive.
It "works" best on sans serif, non-Oblique fonts.
Bold fonts have thicker stems and are slightly more extended than normal fonts. In Knuth's Computers & Typesetting, the bold fonts have a stem width that is approximately 1.6 (1.68(at 12pt)-1.5(at 5pt)) times the stem width of the normal font. This is very similar to the 1.75 suggested by Microsoft's ratio of 700/400 (700 being the numeric weight of a bold font, and 400 being the numeric weight of a normal font).
In Knuth's Computer Modern Bold Extended Roman, the "m" character is extended to 1.15 times the width of the "m" in Computer Modern Roman, and the x-height is 1.03 times higher.
|Font||Ratio of Bold/Regular Stems||Ratio of DemiBold/Regular||Expansion||Bold serif height/Regular serif||Bold serif width/regular|
|Times New Roman||1.7||1||.98|
|Computer Modern Roman||1.68(at 12pt) - 1.5(at 5pt)||1.15|
At first glance this does not seem like much of a transformation, after all postscript and truetype fonts can be drawn at any pointsize. But traditionally, as the point-size decreases the boldness (thickness of the stems) increases slightly, the counters and side bearings also change. For metal type there were generally three drawings for a character in a given font, one for pointsizes less than 10, one for pointsizes 10,11 and 12, and one for display sizes (above 12). Most computer vector fonts do not show this change, while Knuth's Computer Modern fonts have a continuum:
|17pt||12pt||10pt||9pt||8pt||7pt||6pt||5pt||(12pt compared to cmr 12pt)|
|cmr||83%||100%||109%||116%||120%||124%||130%||139%||Computer Modern Roman||100%|
|cmti||100%||106%||112%||115%||122%||Computer Modern Text Italic||94%|
|cmbx||100%||105%||108%||112%||117%||120%||123%||Computer Modern Bold Extended||170%|
|cmtt||100%||109%||116%||120%||Computer Modern Typewriter||100%|
|cmss||99%||100%||102%||109%||113%||Computer Modern Sans Serif||120%|
To the left is an example of the same word (taken from a font specimine sheet) printed at 3 different point sizes (8,12 and 24) and then scaled up to the same size. The most obvious difference is that the characters are proportionally wider at the smaller pointsizes. It is less apparent that the stems of the letters are different:
|stem of the "n" (compared to 12pt)||89%||100%||117%|
|counter of the "n" (compared to 12pt)||104%||100%||89%|
|width of "originality" (compared to 12pt)||93%||100%||104%|
A SmallCaps font is made by scaling the capital letters to the x-height (so that they are the same height as lower case letters without ascendors) and then adjusting the stem widths so that they too will match stem widths of the lower case.
The Italic transformation contains at least four parts: A change in the letterforms of the lowercase letters, a skew, and a condensation and a narrowing of the vertical stems..
|Italic Angle||Condensation||Stem width change|
|Computer Modern Text Italic||14º||91%||94%|
|Times New Roman||16º||100%||91%|
Letterform changes in Galliard:
Letterform changes in
(These glyphs have been deskewed to display the shape transformation better.)
(These glyphs are also deskewed.)
This is not a complete list, but it shows most of the salient features of such a transformation.
The Oblique transformation is a simple skew,
|Computer Modern Slanted Sans Serif||9.5º|
|Arial Italic (actually an oblique)||12º|
|Adobe Helvetica Oblique||12º|
In these two transformations the stem width is held constant but the horizontal counter sizes and side bearings are increased (or decreased for condensed).