Some simple functions to help with graphics and positioning on retina devices.

MDGraphicsFunctions.h

static __inline__ CGFloat MDRound(CGFloat value)
{
    static CGFloat scale = 0;
    if (scale <= 0) {
        scale = [[UIScreen mainScreen] scale];
    }
    
    return roundf(value*scale)/scale;
}

static __inline__ CGFloat MDPixel()
{
    static CGFloat scale = 0;
    if (scale <= 0) {
        scale = [[UIScreen mainScreen] scale];
    }
    
    return 1./scale;
}