Example
| Chapter 5. Range Widgets |

## Example

This example displays a window with three range widgets all connected to the same adjustment, along with a couple of controls for adjusting some of the parameters mentioned above and in the section on adjustments, so you can see how they affect the way these widgets work for the user.

Figure 5.1. Range Widgets

Source Code

File: `labeledoptionmenu.h`

    #ifndef GTKMM_EXAMPLE_RANGEWIDGETS_LABELEDOPTIONMENU_H
    #define GTKMM_EXAMPLE_RANGEWIDGETS_LABELEDOPTIONMENU_H

    #include <gtkmm.h>

    class LabeledOptionMenu : public Gtk::HBox
    {
    public:
      LabeledOptionMenu(const Glib::ustring& menu_title, Gtk::Menu& menu,
        bool homogeneous = false, int spacing = 10);

    protected:
        Gtk::Label m_label;

        #ifndef GTKMM_DISABLE_DEPRECATED
        Gtk::OptionMenu m_OptionMenu;
        #endif //GTKMM_DISABLE_DEPRECATED

        Gtk::Menu* m_pMenu;
    };
    #endif //GTKMM_EXAMPLE_RANGEWIDGETS_LABELEDOPTIONMENU_H

File: `examplewindow.h`

    #ifndef GTKMM_EXAMPLE_RANGEWIDGETS_H
    #define GTKMM_EXAMPLE_RANGEWIDGETS_H

    #include <gtkmm.h>

    class ExampleWindow : public Gtk::Window
    {
    public:
      ExampleWindow();
      virtual ~ExampleWindow();

    protected:
      //Signal handlers:
      virtual void on_checkbutton_toggled();
      virtual void on_menu_position(Gtk::PositionType type);
      virtual void on_menu_policy(Gtk::UpdateType type);
      virtual void on_adjustment1_value_changed();
      virtual void on_adjustment2_value_changed();
      virtual void on_button_quit();

      //Child widgets:
      Gtk::VBox m_VBox_Top, m_VBox2, m_VBox_HScale;
      Gtk::HBox m_HBox_Scales, m_HBox_Digits, m_HBox_PageSize;

      Gtk::Adjustment m_adjustment, m_adjustment_digits, m_adjustment_pagesize;

      Gtk::VScale m_VScale;
      Gtk::HScale m_HScale, m_Scale_Digits, m_Scale_PageSize;

      Gtk::HSeparator m_Separator;

      Gtk::CheckButton m_CheckButton;

      Gtk::HScrollbar m_Scrollbar;

      Gtk::Menu m_Menu_Position, m_Menu_Policy;

      Gtk::Button m_Button_Quit;
    };

    #endif //GTKMM_EXAMPLE_RANGEWIDGETS_H

File: `examplewindow.cc`

    #include "examplewindow.h"
    #include "labeledoptionmenu.h"
    #include <iostream>

    ExampleWindow::ExampleWindow()
    :
      m_VBox2(false, 20),
      m_VBox_HScale(false, 10),
      m_HBox_Scales(false, 10),
      m_HBox_Digits(false, 10),
      m_HBox_PageSize(false, 10),

      // value, lower, upper, step_increment, page_increment, page_size
      // note that the page_size value only makes a difference for
      // scrollbar widgets, and the highest value you'll get is actually
      // (upper - page_size).
      m_adjustment(0.0, 0.0, 101.0, 0.1, 1.0, 1.0),
      m_adjustment_digits(1.0, 0.0, 5.0),
      m_adjustment_pagesize(1.0, 1.0, 101.0),

      m_VScale(m_adjustment),
      m_HScale(m_adjustment),
      m_Scale_Digits(m_adjustment_digits),
      m_Scale_PageSize(m_adjustment_pagesize),

      // a checkbutton to control whether the value is displayed or not
      m_CheckButton("Display value on scale widgets", 0),

      // reuse the same adjustment again
      m_Scrollbar(m_adjustment),
      // notice how this causes the scales to always be update
      // continuously when the scrollbar is moved

      m_Button_Quit("Quit")
    {
      set_title("range controls");

      //VScale:
      m_VScale.set_update_policy(Gtk::UPDATE_CONTINUOUS);
      m_VScale.set_digits(1);
      m_VScale.set_value_pos(Gtk::POS_TOP);
      m_VScale.set_draw_value();

      //HScale:
      m_HScale.set_update_policy(Gtk::UPDATE_CONTINUOUS);
      m_HScale.set_digits(1);
      m_HScale.set_value_pos(Gtk::POS_TOP);
      m_HScale.set_draw_value();
      m_HScale.set_size_request(200, 30);

      add(m_VBox_Top);
      m_VBox_Top.pack_start(m_VBox2);
      m_VBox2.set_border_width(10);
      m_VBox2.pack_start(m_HBox_Scales);

      //Put VScale and HScale (above scrollbar) side-by-side.
      m_HBox_Scales.pack_start(m_VScale);
      m_HBox_Scales.pack_start(m_VBox_HScale);

      m_VBox_HScale.pack_start(m_HScale);

      //Scrollbar:
      m_Scrollbar.set_update_policy(Gtk::UPDATE_CONTINUOUS);
      m_VBox_HScale.pack_start(m_Scrollbar);

      //CheckButton:
      m_CheckButton.set_active();
      m_CheckButton.signal_toggled().connect( sigc::mem_fun(*this,
                  &ExampleWindow::on_checkbutton_toggled) );
      m_VBox2.pack_start(m_CheckButton);

      //OptionMenus:
      {
          using namespace Gtk::Menu_Helpers;

          MenuList& list_vpos = m_Menu_Position.items();
          list_vpos.push_back(
                  MenuElem("Top", sigc::bind(sigc::mem_fun(*this,
                              &ExampleWindow::on_menu_position), Gtk::POS_TOP)));
          list_vpos.push_back(
                  MenuElem("Bottom", sigc::bind(sigc::mem_fun(*this,
                              &ExampleWindow::on_menu_position), Gtk::POS_BOTTOM)));
          list_vpos.push_back(
                  MenuElem("Left", sigc::bind(sigc::mem_fun(*this,
                              &ExampleWindow::on_menu_position), Gtk::POS_LEFT)));
          list_vpos.push_back(
                  MenuElem("Right", sigc::bind(sigc::mem_fun(*this,
                              &ExampleWindow::on_menu_position), Gtk::POS_RIGHT)));

          m_VBox2.pack_start(
                  *Gtk::manage(new LabeledOptionMenu("Scale Value Position:",
                          m_Menu_Position)));

          MenuList& list_upd = m_Menu_Policy.items();
          list_upd.push_back(
                  MenuElem("Continuous", sigc::bind(sigc::mem_fun(*this,
                              &ExampleWindow::on_menu_policy),
                          Gtk::UPDATE_CONTINUOUS)));
          list_upd.push_back(
                  MenuElem("Discontinuous", sigc::bind(sigc::mem_fun(*this,
                              &ExampleWindow::on_menu_policy),
                          Gtk::UPDATE_DISCONTINUOUS)));
          list_upd.push_back(
                  MenuElem("Delayed", sigc::bind(sigc::mem_fun(*this,
                              &ExampleWindow::on_menu_policy),
                          Gtk::UPDATE_DELAYED)));

          m_VBox2.pack_start(
                  *Gtk::manage(new LabeledOptionMenu("Scale Update Policy:",
                          m_Menu_Policy)));
      }

      //Digits:
      m_HBox_Digits.pack_start(
              *Gtk::manage(new Gtk::Label("Scale Digits:", 0)), Gtk::PACK_SHRINK);
      m_Scale_Digits.set_digits(0);
      m_adjustment_digits.signal_value_changed().connect(sigc::mem_fun(*this,
                  &ExampleWindow::on_adjustment1_value_changed));
      m_HBox_Digits.pack_start(m_Scale_Digits);

      //Page Size:
      m_HBox_PageSize.pack_start(
              *Gtk::manage(new Gtk::Label("Scrollbar Page Size:", 0)),
              Gtk::PACK_SHRINK);
      m_Scale_PageSize.set_digits(0);
      m_adjustment_pagesize.signal_value_changed().connect(sigc::mem_fun(*this,
                  &ExampleWindow::on_adjustment2_value_changed));
      m_HBox_PageSize.pack_start(m_Scale_PageSize);

      m_VBox2.pack_start(m_HBox_Digits);
      m_VBox2.pack_start(m_HBox_PageSize);
      m_VBox_Top.pack_start(m_Separator, Gtk::PACK_SHRINK);
      m_VBox_Top.pack_start(m_Button_Quit, Gtk::PACK_SHRINK);

      m_Button_Quit.set_flags(Gtk::CAN_DEFAULT);
      m_Button_Quit.grab_default();
      m_Button_Quit.signal_clicked().connect(sigc::mem_fun(*this,
                  &ExampleWindow::on_button_quit));
      m_Button_Quit.set_border_width(10);

      show_all_children();
    }

    ExampleWindow::~ExampleWindow()
    {
    }

    void ExampleWindow::on_checkbutton_toggled()
    {
        m_VScale.set_draw_value(m_CheckButton.get_active());
        m_HScale.set_draw_value(m_CheckButton.get_active());
    }

    void ExampleWindow::on_menu_position(Gtk::PositionType postype)
    {
        m_VScale.set_value_pos(postype);
        m_HScale.set_value_pos(postype);
    }

    void ExampleWindow::on_menu_policy(Gtk::UpdateType type)
    {
        m_VScale.set_update_policy(type);
        m_HScale.set_update_policy(type);
    }

    void ExampleWindow::on_adjustment1_value_changed()
    {
        double val = m_adjustment_digits.get_value();
        m_VScale.set_digits((int)val);
        m_HScale.set_digits((int)val);
    }

    void ExampleWindow::on_adjustment2_value_changed()
    {
        double val = m_adjustment_pagesize.get_value();
        m_adjustment.set_page_size((int)val);
        m_adjustment.set_page_increment((int)val);

        // note that we don't have to emit the "changed" signal;
        // gtkmm does this for us
    }

    void ExampleWindow::on_button_quit()
    {
        hide();
    }

File: `labeledoptionmenu.cc`

    #include "labeledoptionmenu.h"

    LabeledOptionMenu::LabeledOptionMenu(const Glib::ustring& menu_title,
            Gtk::Menu& menu, bool homogeneous, int spacing) :
        Gtk::HBox(homogeneous, spacing),
        m_label(menu_title),
        m_pMenu(&menu)
    {
      pack_start(m_label, Gtk::PACK_SHRINK);

      #ifndef GTKMM_DISABLE_DEPRECATED
      m_OptionMenu.set_menu(*m_pMenu);
      pack_start(m_OptionMenu);
      #endif //GTKMM_DISABLE_DEPRECATED
    }

File: `main.cc`

    #include <gtkmm/main.h>
    #include "examplewindow.h"

    int main(int argc, char *argv[])
    {
      Gtk::Main kit(argc, argv);

      ExampleWindow window;
      //Shows the window and returns when it is closed.
      Gtk::Main::run(window);

      return 0;
    }

Update Policies |  | Chapter 6. Miscellaneous Widgets