Font detection in Codepoints

font-detection-codepoints.m

NSMutableAttributedString *displayedUnicodeString = [[NSMutableAttributedString alloc] initWithString:unicodeCharacter attributes:fontattributes];

[glyphView.character.textStorage setAttributedString:displayedUnicodeString];

// determine which font will actually be used by the character textview during rendering
NSFont *actualFont = [glyphView.character.textStorage attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL];

// if it matches the users selected font, that font has a glyph for this character
BOOL characterFoundInFont = [selectedFont.fontName isEqualToString:actualFont.fontName];

if (characterFoundInFont || useFallbackBehavior) {
    // never allow the lastresort font to display glyphs, they aren't what the user wants
    if ([actualFont.displayName isEqualToString:@"LastResort"]) {
        glyphView.type = RowTypeGlyphInvalid;
        glyphView.character.string = @"";
        [glyphView.character setToolTip:@"This character was only found in the LastResort font, no accurate glyph is available"];		
    }
    // character has no glyph at all because it is a control character, like backspace or carriage return
    else if (controlCharacter) {
        glyphView.type = RowTypeInvisible;
        [glyphView.character setToolTip:@"This is a control or invisible character with no glyph"];
    }
    // font glyph available
    else {
        glyphView.type = RowTypeGlyphFound;
        [glyphView.character setToolTip:[NSString stringWithFormat:@"This character is being rendered with the font: %@", actualFont.displayName]];
    }
}
// fallback behavior is disabled and the users selected font can't render the glyph, so display nothing
else {	
    glyphView.type = RowTypeGlyphNotFound;
    glyphView.character.string = @"";
    [glyphView.character setToolTip:@"This character was not found in the selected font"];
}