| 摘要 |
PURPOSE:To increase a picture drawing speed by selecting two directions from eight directions in which one coordinate is set as the original point in accordance with a distance, etc. going along a coordinate axis between two coordinates designated on an orthogonal coordinate face, and deriving a straight line between the two coordinates by using said directions. CONSTITUTION:A coordinate designated by an input device 1 is supplied to a CPU2, and an arithmetic processing of picture drawing of a straight line is executed by this CPU2 and it is supplied to a picture forming V-RAM3. This V-RAM3 is read out by a scanning sequence and outputted to a CRT4. In case of drawing a straight line from two coordinates designated in this way, the following picture drawing is executed for one adjacent coordinate in eight direction of up and down, and right and left, and directions of 45 deg., respectively, with respect to an optional coordinate ''0'' which has been brought to picture drawing. That is to say, the horizontal right direction is set as ''1'', from which a direction 2 - a direction 8 are named counterclockwise. In this way, a line brought to picture drawing always becomes a connected line. Subsequently, two directions are selected by placing the start point on the original point, and a straight line between two coordinates is derived by using said directions, by which a picture drawing speed can be increased. |
