gistfile1.m

- (void) rotateHandleWithTouch:(UITouch*)touch {
    CGPoint previousLocation = [touch previousLocationInView:[touch view]];
    CGPoint newLocation = [touch locationInView:[touch view]];
    
    //preform all the same basic rig on both the current touch and previous touch
    CGPoint previousGlLocation = [[CCDirector sharedDirector] convertToGL:previousLocation];
    CGPoint newGlLocation = [[CCDirector sharedDirector] convertToGL:newLocation];
    
    CCSprite *handle = (CCSprite*)[_spriteManager getChildByTag:HANDLE_TAG];
    
    CGPoint previousVector = ccpSub(previousGlLocation, handle.position);
    CGFloat firstRotateAngle = -ccpToAngle(previousVector);
    CGFloat previousTouch = CC_RADIANS_TO_DEGREES(firstRotateAngle);
    
    CGPoint currentVector = ccpSub(newGlLocation, handle.position);
    CGFloat rotateAngle = -ccpToAngle(currentVector);
    CGFloat currentTouch = CC_RADIANS_TO_DEGREES(rotateAngle);
    handle.rotation += (currentTouch - previousTouch);
}