Overpaint Function for Color Printer
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
In graphic presentations it is not uncommon for two objects of different colors to overlap, that is, to occupy the same area. For example, it may be desired to show a green box in the background, partially hidden behind a red circle. In a color printer the print head makes a separate pass for each ribbon color, and normally considers only the print tasks of that color in building the dot image for that pass. Therefore, in the above example, if the green box is printed first, on the subsequent red pass the printer overstrikes the area where the green box and the red circle overlap. Since the inks are not opaque, the overlap area is seen as a mixture of the two colors and the desired effect is not achieved. The present implementation permits "overpainting" without mixing colors.