GPAUP - Set Annotation Up Vector

Purpose

Use GPAUP to insert a Set Annotation Up Vector structure element into the open structure following the element pointer or to replace the element pointed at by the element pointer with a Set Annotation Up Vector structure element depending on the current edit mode.

At structure traversal time, this structure element specifies the y-axis direction for characters in a text string that the graPHIGS API uses to render all subsequent annotation text primitives. When rendering annotation text primitives, the graPHIGS API uses the annotation up vector along with a default annotation base vector set at right angles in the clockwise direction to the annotation up vector.

The traversal default value for annotation up vector is 0.0, 1.0, and for annotation base vector the traversal default is 1.0, 0.0.

If the annotation up vector is invalid, then a vector value defaults to a value of 0.0, 1.0, and a base vector value of 1.0, 0.0.

The graPHIGS API normalizes the specified vectors. If the application later inquires the content of this structure element, then the graPHIGS API returns the normalized vector, not the original vector specified by this subroutine.

For more information concerning annotation text and annotation text attributes, see The graPHIGS Programming Interface: Understanding Concepts

Parameters