Apparatus for converting image outline data into dot data representative of image dots

A data converting apparatus for converting a set of original outline data representative of an outline of a desired image such as a letter, a symbol or a graphical representation, into a set of dot data which is indicative of whether an image dot is to be formed in each of a plurality of picture elements positioned in a coordinate system to form a dot representation of the desired image, said apparatus comprising:

• memory means for storing a plurality of sets of original outline data each indicative of an outline of an image;
• selection means for selecting one set of original outline data indicative of an outline of one desired image;
• coordinate defining means for converting the original outline data for the desired image into original data of coordinate values indicative of a position of at least one point on the outline of the desired image relative to a coordinate system where picture elements are defined to be arranged, the original data of coordinate values including coordinate values of opposite end points of each of at least one straight line segment if the outline of the desired image includes at least one straight line segment;
• straight line segment determining means for determining whether the outline selected by said selecting means includes at least one straight line segment;
• angle determining means for determining whether an angle defined between each of the at least one straight line segment determined by said straight line segment determining means and a predetermined reference direction defined in the coordinate system falls within a predetermined threshold angle;
• offset error determining means for determining whether an offset error, which may occur as a result of offsetting of coordinate values of opposite end points of the straight line segment determined by said angle determining means to fall within the predetermined threshold angle, calculated as a ratio of the offsetting and a distance obtained from projecting the opposite end points on a line tangent to one end point and perpendicular to the predetermined reference line, exceeds a predetermined tolerance range;
• correction means for correcting the straight line segment determined by said offset error determining means into a corrected straight line segment whose opposite end points do not exceed the predetermined tolerance range, said correcting means changing the original data of coordinate values for the outline including the corrected straight line segment into corrected data of coordinate values;
• and
• filling-in means for offsetting one of the original data of coordinate values and the corrected data of coordinate values for the outline of the desired image so as to determine picture elements on the coordinate system where image dots should be located for producing a dot image substantially reproducing the desired image and for producing a set of dot data indicative of the dot image.

A character output device for outputting a character image, comprising:

• memory means for storing one set of outline data representative of an outline for each of a plurality of characters, which set may include at least one straight line segment;
• direction determining means for comparing at least one straight line segment of a set of selected outline data with a predetermined reference direction and for determining whether an angle defined between a direction of each straight line segment and the predetermined reference direction falls within a predetermined range of angles;
• offset error determining means for determining whether an offset error produced when a straight line segment determined by the direction determining means as falling within the predetermined range of angles is converted to a dot image exceeds a predetermined tolerance range, the predetermined tolerance range being a ratio of maximum offset to actual offset;
• correction means for correcting the straight line segment determined by the offset error determining means so that the offset error of the straight line segment does not exceed the predetermined tolerance range;
• and
• filling-in means for converting the outline data including the straight line segment corrected by the correction means to a dot image and outputting dot data representative of the dot image.