Display hidden characters in NSTextView

Question

I am writing a text editor for Mac OS X. I need to display hidden characters in an NSTextView (such as spaces, tabs, and special characters). I have spent a lot of time se

Answer 1

I solved the problem of converting between NSGlyphs and the corresponding unichar in the NSTextView. The code below works beautifully and replaces spaces with bullets for visible text:

- (void)drawGlyphsForGlyphRange:(NSRange)range atPoint:(NSPoint)origin
{
    NSFont *font = [[CURRENT_TEXT_VIEW typingAttributes]
                       objectForKey:NSFontAttributeName];

    NSGlyph bullet = [font glyphWithName:@"bullet"];

    for (int i = range.location; i != range.location + range.length; i++)
    {
        unsigned charIndex = [self characterIndexForGlyphAtIndex:i];

        unichar c =[[[self textStorage] string] characterAtIndex:charIndex];

        if (c == ' ')
            [self replaceGlyphAtIndex:charIndex withGlyph:bullet];
    }

    [super drawGlyphsForGlyphRange:range atPoint:origin];
}