Code to generate a table of character widths for a particular font. Note that this does not account for things like kerning. Use the generated table to get a good estimate of a string size without having to invoke UIKit.

gistfile1.m

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
UIFont* font = [UIFont fontWithName:@"Baskerville-BoldItalic" size:26];

NSString* latinString = @"W";
CGSize latinSize = [latinString sizeWithFont:font];

NSString* kanjiString = @"儸";
CGSize kanjiSize = [kanjiString sizeWithFont:font];

printf("static const int kCharacterHeight = %.0f;\n", MAX(latinSize.height, kanjiSize.height));
printf("static const int kCharacterDefaultWidth = %.0f;\n", MAX(latinSize.width, kanjiSize.width));
printf("static const int kCharacterWidths[256] = {\n");

for (unichar c = 0; c < 256; c+= 1) {
    NSString* s = [NSString stringWithCharacters:&c length:1];
    printf("%2.0f, ", [s sizeWithFont:font].width);
    if ((c + 1) % 16 == 0)
        printf("\n");
}
printf("};\n");
#pragma GCC diagnostic pop