NSShadow inside text NSBezierPath

- (void)drawInteriorWithFrame:(NSRect)cellFrame
                       inView:(NSView *)controlView
{
    NSBezierPath *stringPath = [self bezierPathWithString:self.stringValue
                                                   inFont:self.font];

    [NSGraphicsContext saveGraphicsState];

    _innerShadow = [[NSShadow alloc] init];
    _innerShadow.shadowColor = [NSColor blackColor];
    _innerShadow.shadowBlurRadius = 3.0;
    _innerShadow.shadowOffset = NSMakeSize(10, 0);

    NSSize offset = _innerShadow.shadowOffset;
    NSSize originalOffset = offset;
    CGFloat radius = _innerShadow.shadowBlurRadius;
    NSRect bounds = NSInsetRect(stringPath.bounds, -(ABS(offset.width) + radius), -(ABS(offset.height) + radius));
    offset.height += bounds.size.height;
    _innerShadow.shadowOffset = offset;

    NSBezierPath *drawingPath = [NSBezierPath bezierPathWithRect:bounds];
    [drawingPath setWindingRule:NSEvenOddWindingRule];
    [drawingPath appendBezierPath:stringPath];

    [stringPath addClip];
    [_innerShadow set];
    [[NSColor blackColor] set];
    [drawingPath fill];

    _innerShadow.shadowOffset = originalOffset;

    [NSGraphicsContext restoreGraphicsState];
}

- (NSBezierPath *)bezierPathWithString:(NSString *)text
                                inFont:(NSFont *)font
{
    // This has some weird alphabet shifting problem
    // Don't use in production until fixed

    NSBezierPath *aPath = [NSBezierPath bezierPath];
    [aPath moveToPoint:NSZeroPoint];

    NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString:text];
    CTLineRef line = CTLineCreateWithAttributedString((CFAttributedStringRef)CFBridgingRetain(attributedString));

    CFArrayRef glyphRuns = CTLineGetGlyphRuns(line);
    CFIndex count = CFArrayGetCount(glyphRuns);

    for (CFIndex index = 0; index < count; index++) {
        CTRunRef currentRun = CFArrayGetValueAtIndex(glyphRuns, index);

        CFIndex glyphCount = CTRunGetGlyphCount(currentRun);

        CGGlyph glyphs[glyphCount];
        CTRunGetGlyphs(currentRun, CTRunGetStringRange(currentRun), glyphs);

        NSGlyph bezierPathGlyphs[glyphCount];
        for (CFIndex glyphIndex = 0; glyphIndex < glyphCount; glyphIndex++) {
            bezierPathGlyphs[glyphIndex] = glyphs[glyphIndex];
        }

        [aPath appendBezierPathWithGlyphs:bezierPathGlyphs
                                    count:glyphCount
                                   inFont:font];
    }

    CFRelease(line);

    [aPath transformUsingAffineTransform:[self verticallyFlippedAffineTransformForRect:aPath.bounds]];

    return aPath;
}

- (NSAffineTransform *)verticallyFlippedAffineTransformForRect:(NSRect)rect
{
    NSAffineTransform *affineTransform = [NSAffineTransform transform];

    NSAffineTransformStruct transformStruct;
    transformStruct.m11 = 1.0;
    transformStruct.m12 = 0.0;
    transformStruct.tX  = 0;
    transformStruct.m21 = 0.0;
    transformStruct.m22 = -1.0;
    transformStruct.tY  = rect.size.height;
    [affineTransform setTransformStruct:transformStruct];

    return affineTransform;
}