PtToAngle

PtToAngle Obtain angle between point and rectangle center

#include <Quickdraw.h> Quickdraw

void PtToAngle( theRect, thePt, angle );

Rect *theRect ; rectangle of interest

Point thePt ; point, inside or outside of the rectangle

short *angle ; receives angle measurement; 0-359

PtToAngle determines an angular measure between the vertical center of a

rectangle and a specified point.

theRect is the address of an 8-byte Rect structure.

thePt is a point, in the same coordinate system as theRect .

angle is the address of an integer. Upon return, it will contain an angle

measured from a line extending from the center of theRect to the

middle of its top line. See the diagram, below.

Notes: This can be used to obtain an angle value for use in any of the arc paint and

fill functions that require an angle parameter.

The angle is not a true mathematical angle in circular degrees; as with arc

and wedge functions, all angles are based on the corners of a rectangle as

shown:

Thus, the angles are distorted to match the shape of the rectangle. For

instance:

In the figures, both "angles" are 45°, even though the one on the right is

obviously less acute.

Referenced by (5):