Conversion of a sub-pixel format data to another sub-pixel data format

A method of producing a plurality of filter kernels for use in a sub-pixel rendering operation, said sub-pixel rendering operation converting input image data specified in a first sub-pixel format and indicating an input image to output image data specified in a second sub-pixel format, the method comprising:

• calculating a plurality of filter coefficients for each filter kernel by dividing a spatial area of said input image that is overlapped by a portion of a spatial rendering area by a total area of the spatial rendering area using floating point arithmetic;
• each of said filter coefficients being an element of the filter kernel;
• multiplying each said filter coefficient by a divisor to produce a filter kernel element product such that a sum of all filter kernel element products produces a filter sum that equals the divisor;
• performing a binary search operation to find a round off point for said filter sum such that when each filter coefficient is converted to an integer, a sum of the filter coefficients equals said divisor;
• and
• converting said filter coefficients to integers using said round off point.