This menu is not present in the Metrics View.
PfaEdit deals in pixel sizes, not point sizes. The conversion between pixels and points differs on different systems and indeed on different screens. A point is (approximately) 1/72 of an inch, a pixel is however big a pixel happens to be on your screen. Usually pixels range from about 1/72 of an inch to about 1/144 of an inch. Different systems support different screen resolutions as "standard", and PfaEdit tries to know about these standards.
Screen Resolution |
72dpi Mac |
75dpi X |
96dpi Win |
100dpi X |
120dpi Win |
---|---|---|---|---|---|
10pt | 10 | 10 | 13 | 14 | 17 |
12pt | 12 | 12~13 | 16 | 17 | 20 |
18pt | 18 | 19 | 24 | 25 | 30 |
24pt | 24 | 25 | 32 | 33 | 40 |
Sadly your screen will probably not match one of the standard screens precisely. On X the standard resolutions are 75 and 100dpi, on MS Windows 96 and 120dpi, and on the Mac 72dpi. This dialog provides the conversion between pixel size and point sizes at these resolutions.
Normally the new characters are created by rasterizing the outline font. If your system has the freetype2 library installed (and you checked the "Use FreeType" box) then PfaEdit will use the FreeType rasterizer to generate bitmaps, otherwise it will use PfaEdit's built-in rasterizer (which isn't as good, but involves a little less overhead).
Finally, if you have no outline font then the new characters will be created by scaling the (bitmap) font displayed in the font view.
In CID keyed fonts there will not be a set of bitmaps for each sub font, instead the entire complex of sub-fonts share bitmaps.
If the shift key is not depressed when selecting the menu item this will only build accented letters, if the shift key is depressed it will build general composite characters (fractions, ligatures, digits inside parens, roman numerals, etc.) as well. If invoked by short-cut (Ctl-Shft-A) or mnemonic it will only build accented letters.
If the current character is an accented character (and all the base characters
and accents have already been created) then this command will delete anything
that is currently in the foreground and put a reference to the base character
and another reference to the accent character into the foreground. So if
the current character were "À" then a reference to "A" would be added
to it, and a reference to "`" would be centered above the "A".
If Copy From is set to All Fonts then any
bitmaps will have a similar process done (even in the outline character view).
Choosing accents can be a slightly tricky process. Unicode says that accented letters should be built out of the accents in the range 0x300-0x340, but this does not work too well in postscript. A Type1 font works better if the accented character is in the Adobe Standard Encoding, which means either using accents around 0x2d0 or ascii characters. Pfaedit will first attempt to find an accent around 0x2d0, then in ascii and finally in the 0x300-0x340 range.
Not all accents should be centered above the base character, a cedilla is (usually) centered underneath the base, while other accents need to be placed to the left or right, or even overstruck. PfaEdit should know about proper placement of most accents (or at least a rough approximation thereto).
Some Unicode characters contain more than one accent. Additional accents will be treated similarly. This command can also be used to generate more general composite characters . Unicode 0x2163 is the roman numeral IV and this command may be used to build it. Greek capital Alpha looks exactly like Latin capital A and can be created. On the other hand the oe ligature will be replaced by an "o" followed by "e", so be a little careful. Some accents (for example cedilla) are treated unexpectedly on certain letters (different ways in different languages), so be careful of g-cedilla. Å often merges the ring into the top of the A, but here it will float above it. Be alert.
NOTE: My centering algorithms attempt to guess what will look centered to the human eye (centering it in the middle of the character will often not look centered). You should examine all built characters and be prepared to adjust the accent.
The algorithms take some account of the italicangle
You can configure how high the accent should float above the base character
with the AccentOffsetPercent preference item. This lets you specify the
percentage of the em to use as a separation. To avoid accents at slightly
different heights, all characters near the x-height are treated as being
at the x-height, and similarly for all characters near the cap height.