NSBezierPath圆角矩形具有错误的边角

NSBezierPath

 NSBezierPath *path = [NSBezierPath bezierPath];
    [path appendBezierPathWithRoundedRect:NSMakeRect(0, 0, [self bounds].size.width, [self bounds].size.height) xRadius:5 yRadius:5];

    NSGradient *fill = [[NSGradient alloc] initWithColorsAndLocations:[NSColor colorWithCalibratedRed:0.247 green:0.251 blue:0.267 alpha:0.6],0.0,[NSColor colorWithCalibratedRed:0.227 green:0.227 blue:0.239 alpha:0.6],0.5,[NSColor colorWithCalibratedRed:0.180 green:0.188 blue:0.196 alpha:0.6],0.5,[NSColor colorWithCalibratedRed:0.137 green:0.137 blue:0.157 alpha:0.6],1.0, nil];
    [fill drawInBezierPath:path angle:-90.0];

    [[NSColor lightGrayColor] set];
    [path stroke];