Abstract: The present invention relates to an outline font expanding method and an outline font expanding device each of which can reproduce faithfully the line width of an original outline font. The coordinate system for vector data is defined on the boundaries between dots to create an outline font on the boundaries. The number of dots in the main scanning direction is calculated as a unit change when the outline font is moved by one dot in the secondary scanning direction. A value obtained by dividing the unit change by 2 is added to the coordinate in the main scanning direction of the outline font. while the scanning line is moved dot by dot in the main scanning direction, the intersection of the scanning line and the outline font is obtained at each move position. Thus, the filling range over the scanning line is defined in the main scanning direction.

Abstract: A sampling point generating apparatus generates sampling points on an original curve even at gentle slope portions of the original curve and, according to the sampling points, provides a curve that closely approximates the original curve. To accomplish this function, the apparatus has a unit for drawing a straight line between the start and end points of the original curve; a unit for calculating errors between the coordinates of the original curve and the coordinates of the straight line; a unit for detecting extremal value points, where increase or decrease in the errors is reversed, according to the errors; and a unit for generating intermediate points among the extremal value points. The extremal value points and intermediate points are used as sampling points to provide a cubic curve that closely approximates the original curve.