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Scaling Matrix Patterns

IP.com Disclosure Number: IPCOM000073954D
Original Publication Date: 1971-Feb-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 40K

IBM

Related People

Paris, DP: AUTHOR

Abstract

In generating matrix patterns for cathode-ray tube phototypesetters or for cathode-ray tube character generators, it is often desirable to vary the size of the character. To perform this scaling operation, the size of the matrix pattern for each character must be reduced by the scale factor; however, the size of the matrix elements must remain the same.

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Scaling Matrix Patterns

In generating matrix patterns for cathode-ray tube phototypesetters or for cathode-ray tube character generators, it is often desirable to vary the size of the character. To perform this scaling operation, the size of the matrix pattern for each character must be reduced by the scale factor; however, the size of the matrix elements must remain the same.

The method for accomplishing the scaling is based upon the projection geometry illustrated. Point P is the projection center. Line P-P(1)-P(2) connects the projection center with the centers of the two matrix planes. These planes are oriented perpendicularly to the line P-P(1)-P(2). Note that the size of the matrix elements is the same in both planes. Since the plane containing the original matrix pattern is further away from P than the plane containing the scaled matrix pattern, the scaling is a reduction. The scale factor is given by the ratio of the distance: P-P(1) to P-P(2).

With P as a projection center, the method for scaling effectively projects all element centers from the original plane into the scaled plane. Each element from the original plane is projected as if located at the center of that element into elements of the scaled plane. As shown, more than one element in the original plane will be projected into one element of the scaled plane.

If there are more white than black original elements mapped into one scaled clement, the scaled element is set to white. If there are more...