#03715: Importing font metrics into Fontographer
Font loses leading, spacing or kerning.
When Fontographer opens a font file, it reads all the pertinent information in that file. It does not search for related files. When opening a TrueType font, Fontographer gets all the relevant metrics data.
However, when opening a PostScript font, there is some useful data missing. It is missing from the file which Fontographer opened, but can be found in related files, such as the .afm and .pfm, or the Macintosh bitmap file. Since certain metrics information is found only in the related files, it is important to know how to get that into your font.
In order to make sure that your font will behave correctly it is wise to use Fontographer's File > Import Metrics feature immediately after opening a font. The valid input files are .afm, .pfm, .ttf, .bmap, and .met.
This will allow you to have accurate leading by importing the exact ascender/descender values for the font. This is more of an issue on the Mac than in Windows due to the peculiar ascender and descender values in the bitmap file. However, importing ascent and descent from a pfm may result in different values than what was interpreted in your PostScript font.
Import Spacing and Kerning
Since kerning information is not in the PostScript font, you'll want to extract whatever pairs were set in your original font. This will save you from having to make your own kern pairs and keep you from needing to adjust the letter and word spacing for your font in applications which support kerning.
Importing TrueType metrics
TrueType fonts have complete metrics and kerning data which will give you the ascender/descender in em units. Fontographer should automatically import these values when opening a TrueType but
sometimes changes to the font will change your metrics. If you suspect something is wrong with the metrics you should manually import them.
Importing metrics from the bitmap (Macintosh only)
On the Macintosh, if you want your modified font to have the exact metrics information as the original, you must import the metrics from the FOND in the Macintosh bitmap font. Apple has decreed that the FOND's ascender/descender should add up to a total of 4096. This is not a value in em units but an
Apple determined value. Quark for the Mac sets the baseline for the first line in a text block from the values in the FOND. This would be no problem, except that some font manufacturers do not adhere to the Apple guidelines for the ascender + descender = 4096.
Importing hand-edited bitmaps
It's also a good idea to import the bitmaps which come with a commercial PostScript font. These hand edited bitmaps are often of fairly high quality and are to be preferred over ATM rendered bitmaps. You will find the bitmaps in the screen font suitcase.
You can Select All or just import one of the point sizes.
After having imported the bitmaps, it is important then to recalculate the bitmaps on the characters you have modified. For instance, let's say you flipped all the vowels backwards. If you don't recalculate the bitmaps (set to retain shape) on the vowels, they won't come up on screen reading correctly, i.e., not
backwards, when you use them at the heights specified by the bitmap.
Fontographer's automatic bitmap generator will give you more than adequate results, but not PERFECT results (after all it is a machine, not a highly trained lettering artist or type designer skilled in the painting of bitmaps).
So you may wish to go into the bitmap editing window and "clean up" the bitmaps that Fontographer provides you, for optimal results.
When you are generating the font you would enter the size(s) of these bitmaps in the Bitmap Font to Output field. When this font is us ed in an application you will get the bitmaps at the size(s) you imported but all other sizes will be rendered by Adobe Type Manager or the TrueType rasterizer.