@implementation MMTouchSlider

-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self];

    self.value = self.minimumValue + (self.maximumValue - self.minimumValue) * (touchLocation.x / self.frame.size.width);

    [super touchesBegan:touches withEvent:event];
}

- (CGRect)thumbRectForBounds:(CGRect)bounds trackRect:(CGRect)rect value:(float)value {

    CGRect thumbRect = [super thumbRectForBounds:bounds trackRect:rect value:value];
    return thumbRect;
}

@end

UISlider *slider = [[UISlider alloc] initWithFrame:CGRectMake(100, 100, 200, 10)];
float angleInDegrees = 270;
float angleInRadians = angleInDegrees * (M_PI/180);
slider.transform = CGAffineTransformMakeRotation(angleInRadians);
[self.view addSubView:slider];