Patent ID: 8368713

Claim:
A figure drawing device which draws a figure by painting pixels on a scanning line, comprising: at least one processor to perform: painted pixel increase/decrease control to increase or decrease a number of painting pixels up to a final painting pixel on the scanning line by one pixel; scanning line increase/decrease control to increase or decrease a number of scanning lines to draw a figure by one scanning line; and pixel data output to output pixel data to draw a figure on a basis of control of the painted pixel increase/decrease control and the scanning line increase/decrease control; a stencil buffer to hold pixel data of a figure in an intermediate stage of sequential drawing for a finally drawn figure; the at least one processor to further perform: consecutive pixel data holding to temporarily hold pixel data of a plurality of pixels consecutive on one scanning line and read from the stencil buffer; pixel data transit state detection to detect a transit state between a painted state and unpainted state of a pixel held in the consecutive pixel data holding; and pixel data write to perform a logical operation of pixel data output by the drawing data output to draw a new figure in the sequential drawing process and pixel data held in the consecutive pixel data holding, and to perform inversion or non-inversion on the logical operation result depending on data transit state detected by the pixel data transit state detection, thereby to write back data to the stencil buffer.