PHIGURE C REFERENCE MANUAL - SET STEP ANGLE OF A CIRCLE OR ARC

SET STEP ANGLE OF A CIRCLE OR ARC

tset_step_angle

CALL SEQUENCE

void tset_step_angle (alpha, regul)

INPUT PARAMETERS

Pfloat	alpha;
Tangle_regularity	regul;

ARGUMENTS

alpha: Basic angle, in radians, between two consecutive points of the arc or circle.
regul: Flag indicating whether basic angle is regular or not:

TNOT_REGULAR_ANGLE: The angle is not regular.
TREGULAR_ANGLE: The angle is regular (default value).

EFFECT

This function is used to configure the geometrical appearance of circles and arcs which are built after the function tset_step_angle is called. A circle or arc built by a PHIGURE function is approximated by a polygon, that is, a sequence of straight line segments. alpha is the angle formed by two consecutive points of the polygon and the center of the circle. This angle is therefore used to control the number of points making up a circle or arc (if alpha = 2[pi]/360, the circle will be made up of 360 points.

The regul flag indicates whether an arc is perfectly symmetrical in relation to the bisecting axis of the angle it forms with the center of the circle. If regul = TREGULAR_ANGLE , the arc is made up of identical straight line segments with a basic angle approximately equal to alpha. If REGUL = TNOT_REGULAR_ANGLE, the arc is made up of identical straight line segments except at its two ends, where they are half the length of the others. In this case, the basic angle is exactly equal to alpha, except for the two ends, where it is equal to alpha/2, and the arc is perfectly symmetrical in relation to the bisecting axis.

For circles, if regul = TREGULAR_ANGLE , the circle is approximated by a regular polygon.

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