/*

     File: Rotater.h

 Abstract: Rotater simulates an arm which rotates about the specified origin.

 It knows how much of an angle to rotate per frame, but doesn't know

 anything about real time -- you have to send -animate at the correct

 time to advance each frame.

  Version: 1.1

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 */

#import <Foundation/Foundation.h>

@interface Rotater : NSObject

{

    float   angle;                      // current angle in radians

    NSPoint origin;                     // origin about which we rotate

    float   radiansPerFrame;            // amount by which angle changes for each frame animation

    float   armLength;                  // length of arm (default: 100 units)

    NSPoint mostRecentPoint;            // most recent point set OR returned

    float   syncFraction;               // used to sync up (drifts from 1.0 down to 0.0 after a 'set')

}

#pragma mark PUBLIC INSTANCE METHODS

- (void) animate;                       // move to the next angle

//  Move the endpoint (not the origin) of the arm. Over the coming frames,

//  the rotater will move back to its original circle.

- (void) setXY:(NSSize)point;

//  Get the endpoint of the arm. This may include leftover displacement

//  from a previous -setX:andY:

- (NSSize) getXY;

#pragma mark PUBLIC INSTANCE METHODS -- ACCESS METHODS

@property (readwrite) NSPoint origin;

@property (readwrite) float radiansPerFrame;

@property (readwrite) float armLength;

@end