Arc2PolyBezier procedure

Declaration

procedure Arc2PolyBezier(X: Integer; Y: Integer; Width: Integer; 
 Height: Integer; Angle1: Integer; 
 Angle2: Integer; Rotation: Integer; 
 var Points: TBezierPointArray)

Description

The arc is defined by a rectangle which bounds the full ellipse. The rectangle has the specified Width and Height, its top/left corner is at the point X,Y. Start of the arc is given by the eccentric angle Angle1, and its length is given by Angle2. Both angles are expressed in 1/16th of a degree. A full circle, for example, is equal to 5760 (16*360). A positive value of Angle2 means counter-clockwise while a negative value means clockwise direction. Zero degrees is at the 3 o'clock position.

The Rotation parameter accepts a angle for a rotated ellipse - for a non-rotated ellipse this value would be 0, or 360*16.

The arc is approximated by one or more Bezier curves. If the angle length is greater than 45*16 (45 degrees), it breaks the arc into arcs of 45 degrees.

The points with indices 0, 3, 6, etc are Bezier curve points (points on the arc), the points with indices 1, 4, 7 are the right-sided control points, those with indices 2, 5, ... the left-sided controls points of the curve points at indices 0, 3, 6, ...

The points are arranged such that they can be immediately passed to the TCanvas.PolyBezier with parameter Continuous = True.