1. A method of generating an image of a scalable graphical object for reproduction on a display device, said method comprising the steps of: providing a pixel map and a scaling factor, the pixel map being a representation of at least of portion of the image having a plurality of pixels; storing a plurality of pixel coverage representations, each associated with at least one of the plurality of pixels and each defining a correspondence between a pixel coverage value for each pixel and the scaling factor, at least one of the plurality of pixel coverage representations being shared between a plurality of pixels in the pixel map; for at least one pixel in the map: receiving a scaling factor of the scalable graphical object; identifying the pixel coverage representation associated with the pixel, and determining a pixel coverage value for the pixel using the pixel coverage representation in accordance with the received scaling factor; and rendering the scalable graphical object using the determined pixel coverage value for the pixel on the display device.