am making an app in which i have to control a smile of a face like graphics. For example if i slide the slider down(to a value less than middle) it should give the arc a sad face(like :-( ) effect and if i slide the slider up the arc should give the effect of smile(like :-) ).initially lips are like :-| . I need to control the lips which is an arc using a slider?

smileSliderViewController.h

#import <UIKit/UIKit.h>

@interface smileSliderViewController : UIViewController
{
    IBOutlet UISlider *slider;


}
-(IBAction)valueChange:(id)sender;

@end

smileSliderViewController.m

#import "smileSliderViewController.h"
//#import "smile.h"

@implementation smileSliderViewController


-(IBAction)valueChange:(id)sender
{
    int value = (int)(slider.value);

    if(value>0 && value<25)
    {
        //value--;

        CGContextRef context = UIGraphicsGetCurrentContext();
        CGContextSetLineWidth(context, 2.0);
        CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();  
        CGFloat components[] = {0.0,0.0,1.0,1.0};                      
        CGColorRef color = CGColorCreate(colorspace, components);
        CGContextSetStrokeColorWithColor(context, color);



        CGContextMoveToPoint(context, 120,180);
        CGContextAddArcToPoint(context, 190 , 170, 270, 200, 0 );
        CGContextStrokePath(context);

    }



}

smile.h

#import <UIKit/UIKit.h>
#import "smile.m"


@interface smile : UIView 
{
    IBOutlet UISlider *slider;
}

@end

smile.m

#import "smile.h"
#import "smileSliderViewController.h"


@implementation smile


- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        // Initialization code
    }
    return self;
}


- (void)drawRect:(CGRect)rect
{
      CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetLineWidth(context, 2.0);
    //CGContextSetStrokeColor(context, [UIColor redColor].CGColor);
    CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();  
    CGFloat components[] = {0.0,0.0,1.0,1.0};                      
    CGColorRef color = CGColorCreate(colorspace, components);  

    CGContextSetStrokeColorWithColor(context, color);
    CGRect rectangle = CGRectMake(60, 20, 200,200);
    CGContextAddEllipseInRect(context, rectangle);
    CGContextStrokePath(context);


    /*CGRect rectangle1 = CGRectMake(130,170,50,10);
    CGContextAddRect(context,rectangle1);
    CGContextStrokePath(context);*/


    /*CGContextMoveToPoint(context,100,200);
    CGContextAddArcToPoint(context,120,150,400,150,70 );
    CGContextStrokePath(context);*/

    /*CGContextMoveToPoint(context, 100,100);
    CGContextAddArcToPoint(context, -100,200, -400,200, 80);
    CGContextStrokePath(context);*/

    CGContextSetStrokeColorWithColor(context,color);
    CGRect rectangle2 = CGRectMake(80, 90, 50, 8);
    CGContextAddEllipseInRect(context, rectangle2);
    CGContextStrokePath(context);

    CGContextSetStrokeColorWithColor(context,color);
    CGRect rectangle3 = CGRectMake(180, 90, 50, 8);
    CGContextAddEllipseInRect(context, rectangle3);
    CGContextStrokePath(context);


    CGContextSetStrokeColorWithColor(context,color);
    CGContextMoveToPoint(context, 155,120);
    CGContextAddLineToPoint(context, 155,160);
    CGContextStrokePath(context);

    /*CGContextSetStrokeColorWithColor(context, color);
    CGRect rectangle4 = CGRectMake(130, 180, 50,8);
    CGContextAddEllipseInRect(context, rectangle4);
    CGContextStrokePath(context);*/

    /*CGContextSetStrokeColorWithColor(context,color);
    CGContextMoveToPoint(context, 120,180);
    CGContextAddLineToPoint(context, 190,180);
    CGContextStrokePath(context);*/
    int value = (int)(slider.value);

    if(value == 25)
    {

    CGContextMoveToPoint(context, 120,180);
    CGContextAddArcToPoint(context, 190 , 180, 250 , 180, 0 );
     CGContextStrokePath(context);
    }




}