Creating a slider

In this recipe we will learn how to create a slider UI element by extending the InteractiveObject class mentioned in the Creating an interactive object that responds to the mouse recipe of this chapter.

Getting ready

Please refer to the Creating an interactive object that responds to the mouse recipe to find the InteractiveObject class headers and source code.

How to do it…

We will create a Slider class and show you how to use it.

1. Add a new header file named Slider.h to your project:

   #pragma once
   
   #include "cinder/gl/gl.h"
   #include "cinder/Color.h"
   
   #include "InteractiveObject.h"
   
   using namespace std;
   using namespace ci;
   using namespace ci::app;
   
   class Slider : publicInteractiveObject {
   public:
   Slider( ) : InteractiveObject( Rectf(0,0, 100,10) ) {
    mValue = 0.f;
   }
   Vec2f   getPosition() { return rect.getUpperLeft(); }
   void    setPosition(Vec2f position) { rect.offset(position); }
   void    setPosition(float x, float y) { setPosition(Vec2f(x,y)); }
   float   getWidth() { return getSize...