Run the project to see how it works.

Create slider:
CCSlider *_slider = [CCSlider sliderWithTrackImage:@"slider_track.png" knobImage:@"slider_knob.png" target:self selector:@selector(scaleChanged:)];
_slider.position = ccp(240,160);
_slider.rotation = -30;
_slider.height = 100;
_slider.horizontalPadding = 50;
_slider.trackTouchOutsideContent = YES;
_slider.evaluateFirstTouch = NO;
_slider.minValue = .5;
_slider.maxValue = 1;
_slider.value = .5;
[self addChild:_slider];

Slider value changed callback:
- (void) scaleChanged:(CCSlider *) slider{
	bg.scale = slider.value;
}