=> R0 = font handle (0 for current)
R1 = character code (0 to start)
<= R0 corrupt
R1 = next character (-1 if this is the last)
R2 = internal character code of this character (-1 if unmapped)
This call can be used to determine which characters are present in a font, and which glyphs in the underlying font file characters map to. This call works only by looking at encoding files - it cannot guarantee that a given character is actually defined in a font file, but it can say which characters definitely aren't, by returning with R2 set to -1.
For example, for the font "\FHomerton.Medium\EUTF8", a call sequence might be:
On entry On exit
R1 = 0 R1 = &20 (space) R2 = -1
...
R1 = &10F (d-caron) R1 = &112 (E macron) R2 = &151
R1 = &112 (E-macron) R1 = &113 (e macron) R2 = &185
R1 = &113 (e-macron) R1 = &116 (E dot) R2 = &195
...
R1 = &FB02 (fl ligature) R1 = -1 R2 = &FF
So, in this example, we see that the fl ligature character (Unicode FB02) is character &FF within the Homerton.Medium font file.
This call may be of use in conjuction with Font_ReadFontMetrics' kerning data. Also, it would allow a character map program to scan through the UCS space to find defined characters.
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