Support variation selectors
Submitted by Behdad Esfahbod
Assigned to fon..@..op.org
I think can support this internally by including a unicode,selector pair as (selector<<21)|unicode value in the charset, but provide new API to the charset for querying. Or maybe expose that convention all the way to the API. Here's some code to that extent:
unsigned int var_num = 0; if (variation_selector - 0xFE00u < 16) var_num = variation_selector - 0xFE00 + 1; else if (variation_selector - 0xE0100u < (256 - 16)) var_num = variation_selector - 0xE0100 + 17; unicode = (var_num << 21) | unicode;
Note that currently FcCharSetPutLeaf has:
ucs4 >>= 8; if (ucs4 >= 0x10000) return FcFalse;
so the top byte of the ucs4 has been unused. Unfortunately the top byte is not enough as there are 256 values to fit, not 255 :(.