Patent ID: 6201550
Filing Date: 2001-03-13
Classification: G06T

Abstract:
An image forming apparatus that obtains an output image by executing image drawing commands, comprising:a drawing unit that draws a gradation pattern based on image drawing commands and gradation information; anda gradation generation unit that generates gradation information, wherein:said drawing unit accesses said gradation information when inputted data is image drawing commands that define a gradation pattern on a drawing plane and said gradation information includes a vector defined by coordinate values of a vector start point and a vector end point and color values of said vector start point and said vector end point,said gradation generation unit generates a gradation pattern whose color value changes along said vector in a plurality of adjacent bands that are of uniform color and that are perpendicular to said vector, and further generates gradation information for successive scan lines by successively identifying portions of the successive scan lines included in each band in a scan line direction in a drawing region for those successive scan lines showing said gradation pattern, andsaid gradation generation unit determines a distance on a scan line by multiplying a length between two arbitrary points on said vector by a reciprocal number of a cosine of an angle formed by said vector and said scan line.