Method and apparatus for recording characters

DETAILED DESCRIPTION It is an object of the present invention to specify a method and an apparatus for picture-element-by-picture-element and image-line-by-image-line recording of characters, particularly print characters, with which characters are contour-coded and with which the contour-coded character data can be precisely and quickly converted into control instructions for the picture-element-by-picture-element and image-line-by-image-line recording in the recording raster.
With respect to the method of the invention, this object is achieved in that before the recording every closed contour of a character proceeding from a starting point on every contour is described by contour segments following one another in one circumferential direction around the contour.
Coordinate values x, y of the contour segments in a coding raster of a first XY coordinate system referenced to an em-quad (also known as em-square) associated with the character.
These values are stored as coded character data.
During recording, the coded character data of every character to be recorded is called up by the text data and coordinate values x.
sub.
0, y.
sub.
0 of starting points on every contour and the coordinate values x, y of the contour segments are modified by a dimensional or scaling factor derived from a recording size of the characters and from a relationship of the recording raster to the coding raster.
Picture element coordinates x*, y* of those picture elements of the recording raster which optimally approximate a corresponding contour segment are determined for every successive contour segment of the character by respective interpolation steps x.
sub.
i, y.
sub.
i between intersections of the recording raster executed from a starting point to an end point of a contour segment.
Interpolation steps x.
sub.
i, y.
sub.
i are checked for a change of direction.
Every identified picture element between two successive interpolation steps x.
sub.
i, y.
sub.
i is respectively marked by a market signal as a switch point for the recording element when a fixed directional change of the corresponding interpolation steps x