compose: font APIs do not handle .ttc files correctly #715
Description
TrueType Collection (.ttc) files are a collection of .ttf (maybe also .otf?) files mushed together into one file. These files are common with CJK fonts.
Currently the compose font APIs only get the information from the first font contained within the collection.
Instead, they should iterate over the index within the file to get the information from all fonts.
Example C code
#include <fontconfig/fontconfig.h>
#include <stdio.h>
int main(int argc, char **argv) {
if (argc != 2) {
fprintf(stderr, "Usage: %s <font-file>\n", argv[0]);
return 1;
}
const char *file = argv[1];
FcConfig *config = FcInitLoadConfigAndFonts();
int index = 0;
FcPattern *pat = NULL;
while ((pat = FcFreeTypeQuery((const FcChar8 *)file, index, NULL, NULL))) {
FcChar8 *fullname;
if (FcPatternGetString(pat, FC_FULLNAME, 0, &fullname) == FcResultMatch) {
printf("Index %d: %s\n", index, fullname);
} else {
printf("Index %d: [no name found]\n", index);
}
FcPatternDestroy(pat);
index++;
}
FcFini();
return 0;
}This then works with both normal font files as well ttc files
$ ./ttc-fontconfig-test tests/samples/compose/NotoSansCJK-Regular.ttc
Index 0: Noto Sans CJK JP
Index 1: Noto Sans CJK KR
Index 2: Noto Sans CJK SC
Index 3: Noto Sans CJK TC
Index 4: Noto Sans CJK HK
Index 5: Noto Sans Mono CJK JP
Index 6: Noto Sans Mono CJK KR
Index 7: Noto Sans Mono CJK SC
Index 8: Noto Sans Mono CJK TC
Index 9: Noto Sans Mono CJK HK
$ ./ttc-fontconfig-test tests/samples/compose/Raleway-Regular.ttf
Index 0: Raleway Regular
But of course, the API usage will need to adjusted throughout the codebase to handle getting multiple results from one file.