Image processing method and apparatus

Abstract

In image processing adapted to a display apparatus using a plurality of line buffers for storing data regarding dots aligned on scanning lines on the screen, when a line having a prescribed width and a prescribed length is drawn on the screen, a line drawing range is calculated with reference to start-point coordinates and end-point coordinates as well as the width of line, thus selecting dots on the screen with reference to coordinates of intersections between the scanning lines and the boundaries of the line drawing range, wherein data regarding the selected dots are written into at least one of the line buffers. In line terminating processing, a virtual circle whose diameter matches the width of the line is imaginarily drawn at one end of the line, so that data regarding dots belonging to the virtual circle are written into at least one of the line buffers.

1 . An image processing method adapted to a display apparatus using a plurality of line buffers for storing data regarding dots aligned on scanning lines displayed on a screen, said image processing method comprising the steps of:
 when drawing a line having a predetermined width and a predetermined length on the screen, detecting dots belonging to a virtual circle, which is drawn at one end of the line and whose diameter matches the width of the line; and   writing data regarding the detected dots into at least one of the line buffers.   
   
   
       2 . An image processing method adapted to a display apparatus using a plurality of line buffers for storing data regarding dots aligned on scanning lines displayed on a screen, said image processing method comprising the steps of:
 reading line attribute data representing attributes of a line, having a prescribed width and a prescribed length, to be drawn on the screen from a storage device;   making a decision as to whether or not the line attribute data designate line terminating processing to be performed on at least one end of the line;   in the line terminating processing, detecting dots belonging to a virtual circle, which is drawn at one end of the line and whose diameter matches the width of the line; and   writing data regarding the detected dots into at least one of the line buffers.   
   
   
       3 . An image processing method according to  claim 2 , wherein the dots are detected based on the line attribute data designating the line terminating processing with reference to start-point coordinates or end-point coordinates of the line. 
   
   
       4 . An image processing method according to  claim 3 , wherein the dots are detected based on area ratios, each of which is calculated with reference to a boundary of the virtual circle drawn at one end of the line. 
   
   
       5 . An image processing apparatus adapted to a display apparatus using a plurality of line buffers for storing data regarding dots aligned on scanning lines displayed on a screen, said image processing apparatus comprising:
 a detection section for when a line having a prescribed width and a prescribed length is drawn on the screen, detecting dots belonging to a virtual circle, which is drawn at one end of the line and whose diameter matches the width of the line; and   a write section for writing data regarding the detected dots into at least one of the plurality of line buffers.   
   
   
       6 . An image processing apparatus adapted to a display apparatus using a plurality of line buffers for storing data regarding dots aligned on scanning lines displayed on a screen, said image processing apparatus comprising:
 a read section for reading line attribute data regarding a line, having a prescribed width and a prescribed length, to be drawn on the screen, from a storage device;   a decision section for making a decision as to whether or not the line attribute data designate line terminating processing;   a detection section for in the line terminating processing, detecting dots belonging to a virtual circle, which is drawn at one end of the line and whose diameter matches the width of the line; and   a write section for writing data regarding the detected dots into at least one of the line buffers.   
   
   
       7 . An image processing apparatus according to  claim 6 , wherein the dots are detected based on the line attribute data designating the line terminating processing with reference to start-point coordinates or end-point coordinates of the line. 
   
   
       8 . An image processing apparatus according to  claim 7 , wherein the dots are detected based on area ratios, each of which is calculated with reference to a boundary of the virtual circle drawn at one end of the line.