| 摘要 |
PURPOSE:To make line segment patterns coincident with each other completely by setting a value to be given to a cross point integer coordinate while supposing that an error and an offset of a line style register especially as the initial condition to a digital differentiation analyzer (DDA) are used to draw a line segment from a start point coordinate to an end point coordinate. CONSTITUTION:A line segment from a start point PS to an end point PE is clipped by a line through an optional midpoint of the line segment in parallel with the X or Y coordinate, and a line segment from a cross point integer coordinate PC nearest the cross point between the clipping line and the line segment (from the PS to the PE) to the point PE is drawn. As the initial condition given to the DDA, each axis difference and main axis designation are calculated from the coordinates of the points PS, PE and as the error and the offset of the line style register, values to be given at the point PC are set when a line segment is drawn from the point PS to the point PE as assumption, and as the main axis length, the main axis length from the point PC to the point PE is set to start the DDA. Thus, the line segment drawn completely and the clipping line segment generate a dot string of the equivalent line style. |
