It expands on the classic SDP (Scaled Density Pixels) standard by also introducing height-to-width (HDP) and width-to-width (WDP) scaling. (dimens, dimension, dimensions, dp, sp, dimen, responsive, adaptative, text unit, font scale, font size, resize, textunit, mm, cm, inch, device, physical, android, dpi, sdpi, auto, hdpi, ldpi, mdpi, precision)