A system for driving a display comprising: an array (710; 810) of pixel circuits that includes a plurality of subsections, each subsection including a plurality of pixel circuits, and each of said pixel circuits comprising a light emitting device and a driving transistor for conveying a driving current through the light emitting device; a plurality of supply lines (701, 702; 802, 812) configured to provide driving currents to the pixel circuits in said subsections, each subsection being connected to a respective supply line of the plurality of supply lines (701, 702; 802, 812), all the pixel circuits of each subsection being coupled to the respective supply line connected to the subsection; an adjustable voltage supply configured to provide an adjustable supply voltage to each respective supply line of the plurality of supply lines (701, 702, 802, 812), wherein the adjustable supply voltage is separately adjustable for each of said subsections; and a controller configured to determine, based on digital data indicative of amounts of luminance to be emitted from the pixel circuits in each of said subsections, a respective output level of the supply voltage to apply to each respective supply line, and to control the adjustable voltage supply to supply said supply voltage to the respective supply line coupled to the subsection, each respective output level being sufficient to enable the pixel circuits in each of said subsections to emit light according to the digital data, wherein the system is configured to display a graphical user interface on the array of pixel circuits and each subsection of the plurality of subsections is dimensioned to coincide with a respective distinct portion of the array of pixel circuits on which a feature of the graphical user interface is displayed, and the system being configured to selectively brighten, by providing a respective output level of the supply voltage, one or more of said subsections to indicate that the corresponding feature of the graphical user interface is selected by the user and dim, by providing a respective output level of the supply voltage, one or more of said subsections to indicate that the corresponding feature of the graphical user interface is not selected by the user. an array (710; 810) of pixel circuits that includes a plurality of subsections, each subsection including a plurality of pixel circuits, and each of said pixel circuits comprising a light emitting device and a driving transistor for conveying a driving current through the light emitting device; a plurality of supply lines (701, 702; 802, 812) configured to provide driving currents to the pixel circuits in said subsections, each subsection being connected to a respective supply line of the plurality of supply lines (701, 702; 802, 812), all the pixel circuits of each subsection being coupled to the respective supply line connected to the subsection; an adjustable voltage supply configured to provide an adjustable supply voltage to each respective supply line of the plurality of supply lines (701, 702, 802, 812), wherein the adjustable supply voltage is separately adjustable for each of said subsections; and a controller configured to determine, based on digital data indicative of amounts of luminance to be emitted from the pixel circuits in each of said subsections, a respective output level of the supply voltage to apply to each respective supply line, and to control the adjustable voltage supply to supply said supply voltage to the respective supply line coupled to the subsection, each respective output level being sufficient to enable the pixel circuits in each of said subsections to emit light according to the digital data, wherein the system is configured to display a graphical user interface on the array of pixel circuits and each subsection of the plurality of subsections is dimensioned to coincide with a respective distinct portion of the array of pixel circuits on which a feature of the graphical user interface is displayed, and the system being configured to selectively brighten, by providing a respective output level of the supply voltage, one or more of said subsections to indicate that the corresponding feature of the graphical user interface is selected by the user and dim, by providing a respective output level of the supply voltage, one or more of said subsections to indicate that the corresponding feature of the graphical user interface is not selected by the user.