Get Viewer's Coordinates: get3_xy

Calling Sequence

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get3_xy(xyz [, 1])

Description

Given 3-by-anything coordinates XYZ, return X and Y in viewer's coordinate system (set by rot3, mov3, orient3, etc.; see ``Functions For Setting Viewing Parameters'' on page ). If the second argument is present and non-zero, also return Z (for use in sort3d or get3_light, for example; see ``Sort z Coordinates: sort3d'' on page  and ``Find 3D Lighting: get3_light'' on page .). If the camera position has been set to a finite distance with setz3 (see ``Physical orientation'' on page ), the returned coordinates will be tangents of angles for a perspective drawing (and Z will be scaled by 1/zc). x, y, and z can be either 1D or 2D, so this routine is written in two cases.