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Subpictures with Variable Dimensions

IP.com Disclosure Number: IPCOM000052661D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 4 page(s) / 51K

Publishing Venue

IBM

Related People

Bantz, DF: AUTHOR [+3]

Abstract

A method is described for selectively stretching and rotating a master subpicture to produce a large class of images in a computer graphics system. A subpicture is a collection of lines, circles, arcs, dimensions, etc., which can be added to a drawing as a group. Any image created on the graphics system can be used as the master for a subpicture. At the time it is filed, the designer can indicate which elements of the subpicture, if any, are to be variable. These variable declarations are filed as part of the subpicture and are referenced when an instance is requested.

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Subpictures with Variable Dimensions

A method is described for selectively stretching and rotating a master subpicture to produce a large class of images in a computer graphics system. A subpicture is a collection of lines, circles, arcs, dimensions, etc., which can be added to a drawing as a group. Any image created on the graphics system can be used as the master for a subpicture. At the time it is filed, the designer can indicate which elements of the subpicture, if any, are to be variable. These variable declarations are filed as part of the subpicture and are referenced when an instance is requested.

Points can be declared to be variable. A "positioning point" can be specified for the subpicture. When an instance is requested on a drawing, this point of the instance will coincide with the requested location. If defaulted, the (0,0) point of the subpicture is used. A "rotation point" can be specified for the subpicture. When an instance is requested on a drawing, two points can be entered by the user. The instance is rotated so that a line between the positioning and rotation points of the instance coincides with a line between the two points entered. If the rotation point is defaulted, no rotation is performed.

Any number of "stretch points" can be specified for the subpicture. When an instance is requested on a drawing, input stretch points can be entered by the user. The subpicture stretch points are replaced, in the instance, by the points entered by the user. The rotation point is regarded as a stretch point as well. If only rotation is desired, the rotation point should be entered at the end of a construction line at the proper angle. Then, only the construction line will be "stretched', leaving the instance rotated but otherwise unaltered. Similarly, if a point on the subpicture is to be stretched along only one axis of the subpicture, a construction line parallel to the other axis can be used between that point and the stretch point.

Dimensions can be declared to be variable. When an instance is requested on a drawing, parameters must be entered by the user to substitute for the variable dimensions. If defaulted, the dimension values in the subpicture are used.

A subpicture to be instanced can be designated by the user by name, or it can be temporarily assigned to a function key, or it can be permanently assigned to a fixed key.

When an instance of a subpicture is requested, the points input by the user are rotated, if necessary, to the orientation specified in the subpicture. All variable point and dimension substitutions are made, and the Proportioning Algorithm [*] is invoked to produce a correct instance. The substituted points are fixed in the instance prior to invocation of proportioning, to prevent coordinate adjustment by the algorithm. Subsequent to proportioning, the instance is rotated, if necessary, to produce its final orientation.

There are two general methods for generating instances, and these will be r...