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<th width="60%" align="center">Chapter 8. Miscellaneous Widgets</th>
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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="sec-spinbutton"></a>SpinButton</h2></div></div></div>


<p>
A <code class="classname">SpinButton</code> allows the user to select a value from a
range of numeric values. It has an <code class="classname">Entry</code> widget with increment and decrement buttons
at the side. Clicking the buttons causes the value to 'spin' up and down across
the range of possible values. The <code class="classname">Entry</code> widget may also
be used to enter a value directly.
</p>

<p>
The value can have an adjustable number of decimal places, and the step size is
configurable. <code class="classname">SpinButton</code>s have an 'auto-repeat' feature
as well: holding down the increment or decrement button can optionally cause the value to
change more quickly the longer the button is held down.
</p>

<p>
<code class="classname">SpinButton</code>s use an <a class="link" href="chapter-adjustment.html" title="Chapter 16. Adjustments">Adjustment</a> object to hold information about
the range of values. These Adjustment attributes are used by the Spin Button
like so:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">

<p>
 <code class="literal">value</code>: value for the Spin Button
</p>
</li>
<li class="listitem">

<p>
 <code class="literal">lower</code>: lower range value
</p>
</li>
<li class="listitem">

<p>
 <code class="literal">upper</code>: upper range value
</p>
</li>
<li class="listitem">
<p>
 <code class="literal">step_increment</code>: value to increment/decrement when pressing
mouse button 1
</p>
</li>
<li class="listitem">

<p>
 <code class="literal">page_increment</code>: value to increment/decrement when pressing
mouse button 2
</p>
</li>
<li class="listitem">

<p>
 <code class="literal">page_size</code>: unused
</p>
</li>
</ul></div>
<p>
</p>

<p>
Additionally, mouse button 3 can be used to jump directly to the
<code class="literal">upper</code> or <code class="literal">lower</code> values.
</p>

<p>
The <code class="classname">SpinButton</code> can create a default
<code class="classname">Adjustment</code>, which you can access via the
<code class="methodname">get_adjustment()</code> method, or you can specify an existing
<code class="classname">Adjustment</code> in the constructor.
</p>


<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="spinbutton-methods"></a>Methods</h3></div></div></div>


<p>
The number of decimal places can be altered using the
<code class="methodname">set_digits()</code> method.
</p>

<p>
You can set the spinbutton's value using the <code class="methodname">set_value()</code>
method, and retrieve it with <code class="methodname">get_value()</code>.
</p>

<p>
The <code class="methodname">spin()</code> method 'spins' the
<code class="classname">SpinButton</code>, as if its increment or decrement button had been clicked.
You need to specify a <code class="classname">Gtk::SpinType</code> to specify the
direction or new position.
</p>

<p>
To prevent the user from typing non-numeric characters into the entry box, pass
<code class="literal">true</code> to the <code class="methodname">set_numeric()</code> method.
</p>

<p>
To make the <code class="classname">SpinButton</code> 'wrap' between its upper and
lower bounds, use the <code class="methodname">set_wrap()</code> method.
</p>

<p>
To force it to snap to the nearest <code class="literal">step_increment</code>,
use <code class="methodname">set_snap_to_ticks()</code>.
</p>

<p><a class="ulink" href="https://gnome.pages.gitlab.gnome.org/gtkmm/classGtk_1_1SpinButton.html" target="_top">Reference</a></p>

</div>

<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="spinbutton-example"></a>Example</h3></div></div></div>


<p>
Here's an example of a <code class="classname">SpinButton</code> in action:
</p>

<div class="figure">
<a name="figure-spinbutton"></a><p class="title"><b>Figure 8.6. SpinButton</b></p>
<div class="figure-contents">
  
  <div class="screenshot">
    <div class="mediaobject"><img src="figures/spinbutton.png" alt="SpinButton"></div>
  </div>
</div>
</div>
<br class="figure-break">

<p><a class="ulink" href="https://gitlab.gnome.org/GNOME/gtkmm-documentation/tree/master/examples/book/spinbutton" target="_top">Source Code</a></p>

<p>File: <code class="filename">examplewindow.h</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include &lt;gtkmm.h&gt;

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

protected:
  //Signal handlers:
  void on_checkbutton_snap();
  void on_checkbutton_numeric();
  void on_spinbutton_digits_changed();
  void on_button_close();

  enum enumValueFormats
  {
    VALUE_FORMAT_INT,
    VALUE_FORMAT_FLOAT
  };
  void on_button_getvalue(enumValueFormats display);

  //Child widgets:
  Gtk::Frame m_Frame_NotAccelerated, m_Frame_Accelerated;
  Gtk::Box m_HBox_NotAccelerated, m_HBox_Accelerated,
    m_HBox_Buttons;
  Gtk::Box m_VBox_Main, m_VBox, m_VBox_Day, m_VBox_Month, m_VBox_Year,
    m_VBox_Accelerated, m_VBox_Value, m_VBox_Digits;
  Gtk::Label m_Label_Day, m_Label_Month, m_Label_Year,
    m_Label_Value, m_Label_Digits,
    m_Label_ShowValue;
  Glib::RefPtr&lt;Gtk::Adjustment&gt; m_adjustment_day, m_adjustment_month, m_adjustment_year,
    m_adjustment_value, m_adjustment_digits;
  Gtk::SpinButton m_SpinButton_Day, m_SpinButton_Month, m_SpinButton_Year,
    m_SpinButton_Value, m_SpinButton_Digits;
  Gtk::CheckButton m_CheckButton_Snap, m_CheckButton_Numeric;
  Gtk::Button m_Button_Int, m_Button_Float, m_Button_Close;
};

#endif //GTKMM_EXAMPLEWINDOW_H
</code></pre>
<p>File: <code class="filename">examplewindow.cc</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "examplewindow.h"
#include &lt;iostream&gt;
#include &lt;cstdio&gt;

ExampleWindow::ExampleWindow()
:
  m_Frame_NotAccelerated("Not accelerated"),
  m_Frame_Accelerated("Accelerated"),
  m_VBox_Main(Gtk::Orientation::VERTICAL, 5),
  m_VBox(Gtk::Orientation::VERTICAL),
  m_VBox_Day(Gtk::Orientation::VERTICAL),
  m_VBox_Month(Gtk::Orientation::VERTICAL),
  m_VBox_Year(Gtk::Orientation::VERTICAL),
  m_VBox_Accelerated(Gtk::Orientation::VERTICAL),
  m_VBox_Value(Gtk::Orientation::VERTICAL),
  m_VBox_Digits(Gtk::Orientation::VERTICAL),
  m_Label_Day("Day: ", Gtk::Align::START),
  m_Label_Month("Month: ", Gtk::Align::START),
  m_Label_Year("Year: ", Gtk::Align::START),
  m_Label_Value("Value: ", Gtk::Align::START),
  m_Label_Digits("Digits: ", Gtk::Align::START),
  m_adjustment_day( Gtk::Adjustment::create(1.0, 1.0, 31.0, 1.0, 5.0, 0.0) ),
  m_adjustment_month( Gtk::Adjustment::create(1.0, 1.0, 12.0, 1.0, 5.0, 0.0) ),
  m_adjustment_year( Gtk::Adjustment::create(2012.0, 1.0, 2200.0, 1.0, 100.0, 0.0) ),
  m_adjustment_value( Gtk::Adjustment::create(0.0, -10000.0, 10000.0, 0.5, 100.0, 0.0) ),
  m_adjustment_digits( Gtk::Adjustment::create(2.0, 1.0, 5.0, 1.0, 1.0, 0.0) ),
  m_SpinButton_Day(m_adjustment_day),
  m_SpinButton_Month(m_adjustment_month),
  m_SpinButton_Year(m_adjustment_year),
  m_SpinButton_Value(m_adjustment_value, 1.0, 2),
  m_SpinButton_Digits(m_adjustment_digits),
  m_CheckButton_Snap("Snap to 0.5-ticks"),
  m_CheckButton_Numeric("Numeric only input mode"),
  m_Button_Int("Value as Int"),
  m_Button_Float("Value as Float"),
  m_Button_Close("Close")
{
  set_title("SpinButton");

  m_VBox_Main.set_margin(10);
  set_child(m_VBox_Main);

  m_VBox_Main.append(m_Frame_NotAccelerated);

  m_VBox.set_margin(5);
  m_Frame_NotAccelerated.set_child(m_VBox);

  /* Day, month, year spinners */

  m_VBox.set_spacing(5);
  m_VBox.append(m_HBox_NotAccelerated);

  m_Label_Day.set_expand();
  m_VBox_Day.append(m_Label_Day);

  m_SpinButton_Day.set_wrap();
  m_SpinButton_Day.set_expand();
  m_VBox_Day.append(m_SpinButton_Day);

  m_HBox_NotAccelerated.set_spacing(5);
  m_HBox_NotAccelerated.append(m_VBox_Day);

  m_Label_Month.set_expand();
  m_VBox_Month.append(m_Label_Month);

  m_SpinButton_Month.set_wrap();
  m_SpinButton_Month.set_expand();
  m_VBox_Month.append(m_SpinButton_Month);

  m_HBox_NotAccelerated.append(m_VBox_Month);

  m_Label_Year.set_expand();
  m_VBox_Year.append(m_Label_Year);

  m_SpinButton_Year.set_wrap();
  m_SpinButton_Year.set_expand();
  m_SpinButton_Year.set_size_request(55, -1);
  m_VBox_Year.append(m_SpinButton_Year);

  m_HBox_NotAccelerated.append(m_VBox_Year);

  //Accelerated:
  m_VBox_Main.append(m_Frame_Accelerated);

  m_VBox_Accelerated.set_margin(5);
  m_Frame_Accelerated.set_child(m_VBox_Accelerated);

  m_VBox_Accelerated.set_spacing(5);
  m_VBox_Accelerated.append(m_HBox_Accelerated);

  m_HBox_Accelerated.append(m_VBox_Value);

  m_Label_Value.set_expand();
  m_VBox_Value.append(m_Label_Value);

  m_SpinButton_Value.set_wrap();
  m_SpinButton_Value.set_expand();
  m_SpinButton_Value.set_size_request(100, -1);
  m_VBox_Value.append(m_SpinButton_Value);

  m_HBox_Accelerated.append(m_VBox_Digits);

  m_VBox_Digits.append(m_Label_Digits);
  m_Label_Digits.set_expand();

  m_SpinButton_Digits.set_wrap();
  m_adjustment_digits-&gt;signal_value_changed().connect( sigc::mem_fun(*this,
              &amp;ExampleWindow::on_spinbutton_digits_changed) );

  m_VBox_Digits.append(m_SpinButton_Digits);
  m_SpinButton_Digits.set_expand();

  //CheckButtons:
  m_VBox_Accelerated.append(m_CheckButton_Snap);
  m_CheckButton_Snap.set_expand();
  m_CheckButton_Snap.set_active();
  m_CheckButton_Snap.signal_toggled().connect( sigc::mem_fun(*this,
              &amp;ExampleWindow::on_checkbutton_snap) );

  m_VBox_Accelerated.append(m_CheckButton_Numeric);
  m_CheckButton_Numeric.set_expand();
  m_CheckButton_Numeric.set_active();
  m_CheckButton_Numeric.signal_toggled().connect( sigc::mem_fun(*this,
              &amp;ExampleWindow::on_checkbutton_numeric) );

  //Buttons:
  m_VBox_Accelerated.append(m_HBox_Buttons);

  m_Button_Int.signal_clicked().connect( sigc::bind( sigc::mem_fun(*this,
                  &amp;ExampleWindow::on_button_getvalue), VALUE_FORMAT_INT) );
  m_HBox_Buttons.set_spacing(5);
  m_HBox_Buttons.append(m_Button_Int);
  m_Button_Int.set_expand();

  m_Button_Float.signal_clicked().connect( sigc::bind( sigc::mem_fun(*this,
                  &amp;ExampleWindow::on_button_getvalue), VALUE_FORMAT_FLOAT) );
  m_HBox_Buttons.append(m_Button_Float);
  m_Button_Float.set_expand();

  m_VBox_Accelerated.append(m_Label_ShowValue);
  m_Label_ShowValue.set_expand();
  m_Label_ShowValue.set_text("0");

  //Close button:
  m_Button_Close.signal_clicked().connect( sigc::mem_fun(*this,
              &amp;ExampleWindow::on_button_close) );
  m_VBox_Main.append(m_Button_Close);
}

ExampleWindow::~ExampleWindow()
{
}


void ExampleWindow::on_button_close()
{
  set_visible(false);
}

void ExampleWindow::on_checkbutton_snap()
{
  m_SpinButton_Value.set_snap_to_ticks( m_CheckButton_Snap.get_active() );
}

void ExampleWindow::on_checkbutton_numeric()
{
  m_SpinButton_Value.set_numeric( m_CheckButton_Numeric.get_active() );
}

void ExampleWindow::on_spinbutton_digits_changed()
{
  m_SpinButton_Value.set_digits( m_SpinButton_Digits.get_value_as_int() );
}

void ExampleWindow::on_button_getvalue(enumValueFormats display)
{
  gchar buf[32];

  if (display == VALUE_FORMAT_INT)
    sprintf (buf, "%d", m_SpinButton_Value.get_value_as_int());
  else
    sprintf (buf, "%0.*f", m_SpinButton_Value.get_digits(),
            m_SpinButton_Value.get_value());

  m_Label_ShowValue.set_text(buf);
}
</code></pre>
<p>File: <code class="filename">main.cc</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "examplewindow.h"
#include &lt;gtkmm/application.h&gt;

int main(int argc, char *argv[])
{
  auto app = Gtk::Application::create("org.gtkmm.example");

  //Shows the window and returns when it is closed.
  return app-&gt;make_window_and_run&lt;ExampleWindow&gt;(argc, argv);
}
</code></pre>


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