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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter7.Container Widgets</title><meta name="generator" content="DocBook XSL Stylesheets V1.64.1"><link rel="home" href="index.html" title="Programming with gtkmm2"><link rel="up" href="index.html" title="Programming with gtkmm2"><link rel="previous" href="ch06s06.html" title="Tooltips"><link rel="next" href="ch07s02.html" title="Multiple-item widgets "></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter7.Container Widgets</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch06s06.html">Prev</a></td><th width="60%" align="center"></th><td width="20%" align="right"><a accesskey="n" href="ch07s02.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="sec-ContainerWidgets"></a>Chapter7.Container Widgets</h2></div></div><div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="ch07.html#sec-SingleItemWidgets">Single-item Containers</a></span></dt><dd><dl><dt><span class="sect2"><a href="ch07.html#sec-Frame">Frame</a></span></dt><dt><span class="sect2"><a href="ch07.html#id2506451">Paned</a></span></dt><dt><span class="sect2"><a href="ch07.html#sec-ScrolledWindows">ScrolledWindow</a></span></dt><dt><span class="sect2"><a href="ch07.html#sec-AspectFrames">AspectFrame</a></span></dt><dt><span class="sect2"><a href="ch07.html#sec-Alignment">Alignment</a></span></dt></dl></dd><dt><span class="sect1"><a href="ch07s02.html">Multiple-item widgets </a></span></dt><dd><dl><dt><span class="sect2"><a href="ch07s02.html#id2507422">Packing</a></span></dt><dt><span class="sect2"><a href="ch07s02.html#sec-helloworld2">An improved Hello World</a></span></dt><dt><span class="sect2"><a href="ch07s02.html#sec-stl-style">STL-style APIs</a></span></dt><dt><span class="sect2"><a href="ch07s02.html#sec-Boxes">Boxes</a></span></dt><dt><span class="sect2"><a href="ch07s02.html#sec-ButtonBoxes">ButtonBoxes </a></span></dt><dt><span class="sect2"><a href="ch07s02.html#id2509484">Table</a></span></dt><dt><span class="sect2"><a href="ch07s02.html#sec-Notebook">Notebook</a></span></dt></dl></dd></dl></div><p>All container widgets derive from <tt class="literal">Gtk::Container</tt>, not always directly. Some container widgets, such as <tt class="literal">Gtk::Table</tt> can hold many child widgets, so these typically have more complex interfaces. Others, such as <tt class="literal">Gtk::Frame</tt> contain only one child widget.
</p><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="sec-SingleItemWidgets"></a>Single-item Containers</h2></div></div><div></div></div><p>The single-item container widgets derive from <tt class="literal">Gtk::Bin</tt>, which provides the <tt class="literal">add()</tt> and <tt class="literal">remove()</tt> methods for the child widget. Note that <tt class="literal">Gtk::Button</tt> and <tt class="literal">Gtk::Window</tt> are technically single-item containers, but we have discussed them already elsewhere. 
</p><p>
We also discuss the <tt class="literal">Gtk::Paned</tt> widget, which allows you to divide
a window into two separate "panes".  This widget actually contains two
child widgets, but the number is fixed so it seems appropriate.
</p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sec-Frame"></a>Frame</h3></div></div><div></div></div><p>
Frames can enclose one or a group of widgets within a box, optionally with a title. For instance, you might place a group of <tt class="literal">RadioButton</tt>s or <tt class="literal">CheckButton</tt>s in a <tt class="literal">Frame</tt>.
</p><p><a href="../../reference/html/classGtk_1_1Frame.html" target="_top">Reference</a></p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2506338"></a>Example</h4></div></div><div></div></div><div class="figure"><a name="figure-frame"></a><p class="title"><b>Figure7.1.Frame</b></p><div class="screenshot"><div><img src="../figures/frame.png" alt="Frame"></div></div></div><p><a href="../../../examples/book/frame" target="_top">Source Code</a></p><p>File: examplewindow.h
</p><pre class="programlisting">
#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include &lt;gtkmm.h&gt;

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

protected:

  //Child widgets:
  Gtk::Frame m_Frame;
};

#endif //GTKMM_EXAMPLEWINDOW_H
</pre><p>
</p><p>File: examplewindow.cc
</p><pre class="programlisting">
#include "examplewindow.h"

ExampleWindow::ExampleWindow()
{
 /* Set some window properties */
  set_title("Frame Example");
  set_size_request(300, 300);

  /* Sets the border width of the window. */
  set_border_width(10);

  add(m_Frame);

  /* Set the frames label */
  m_Frame.set_label("Gtk::Frame Widget");

  /* Align the label at the right of the frame */
  //m_Frame.set_label_align(Gtk::ALIGN_RIGHT, Gtk::ALIGN_TOP);

  /* Set the style of the frame */
  m_Frame.set_shadow_type(Gtk::SHADOW_ETCHED_OUT);

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}


</pre><p>
</p><p>File: main.cc
</p><pre class="programlisting">
#include &lt;gtkmm/main.h&gt;
#include "examplewindow.h"

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

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

  return 0;
}
</pre><p>
</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2506451"></a>Paned</h3></div></div><div></div></div><p>
Panes divide a widget into two halves, separated by a moveable
divider.  There are two such widgets: <tt class="literal">Gtk::HPaned</tt> adds a
horizontal divider, and <tt class="literal">Gtk::VPaned</tt> adds a vertical one.  Other
than the names and the orientations, there's no difference between the
two.
</p><p>
Unlike the other widgets in this chapter, pane widgets contain not
one but two child widgets, one in each pane. Therefore, you should use <tt class="literal">add1()</tt> and <tt class="literal">add2()</tt>
instead of the <tt class="literal">add()</tt> method.</p><p>
You can adjust the position of the divider using the <tt class="literal">set_position()</tt> method, and you will probably need to do so.
</p><p><a href="../../reference/html/classGtk_1_1Paned.html" target="_top">Reference</a></p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2506517"></a>Example</h4></div></div><div></div></div><div class="figure"><a name="figure-paned"></a><p class="title"><b>Figure7.2.Paned</b></p><div class="screenshot"><div><img src="../figures/paned.png" alt="Paned"></div></div></div><p><a href="../../../examples/book/paned" target="_top">Source Code</a></p><p>File: examplewindow.h
</p><pre class="programlisting">
#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include "messageslist.h"
#include "messagetext.h"
#include &lt;gtkmm.h&gt;

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

protected:

  //Child widgets:
  Gtk::VPaned m_VPaned;
  MessagesList m_MessagesList;
  MessageText m_MessageText;
};

#endif //GTKMM_EXAMPLEWINDOW_H
</pre><p>
</p><p>File: messageslist.h
</p><pre class="programlisting">
#ifndef GTKMM_EXAMPLE_MESSAGESLIST_H
#define GTKMM_EXAMPLE_MESSAGESLIST_H

#include &lt;gtkmm.h&gt;

class MessagesList: public Gtk::ScrolledWindow
{
public:
  MessagesList();
  virtual ~MessagesList();

  class ModelColumns : public Gtk::TreeModel::ColumnRecord
  {
  public:

    ModelColumns()
    { add(m_col_text); }

    Gtk::TreeModelColumn&lt;Glib::ustring&gt; m_col_text;
  };

  ModelColumns m_Columns;

protected:
  Glib::RefPtr&lt;Gtk::ListStore&gt; m_refListStore; //The Tree Model.
  Gtk::TreeView m_TreeView; //The Tree View.
};
#endif //GTKMM_EXAMPLE_MESSAGESLIST_H
</pre><p>
</p><p>File: messagetext.h
</p><pre class="programlisting">
#ifndef GTKMM_EXAMPLE_MESSAGETEXT_H
#define GTKMM_EXAMPLE_MESSAGETEXT_H

#include &lt;gtkmm.h&gt;

class MessageText : public Gtk::ScrolledWindow
{
public:
  MessageText();
  virtual ~MessageText();

  virtual void insert_text();

protected:
  Gtk::TextView m_TextView;
};

#endif //GTKMM_EXAMPLE_MESSAGETEXT_H
</pre><p>
</p><p>File: examplewindow.cc
</p><pre class="programlisting">
#include "examplewindow.h"

ExampleWindow::ExampleWindow()
{
  set_title ("Paned Windows");
  set_border_width(10);
  set_default_size(450, 400);

  /* Add a vpaned widget to our toplevel window */
  add(m_VPaned);

  /* Now add the contents of the two halves of the window */
  m_VPaned.add1(m_MessagesList);
  m_VPaned.add2(m_MessageText);

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}


</pre><p>
</p><p>File: messageslist.cc
</p><pre class="programlisting">
#include "messageslist.h"
#include &lt;sstream&gt;

MessagesList::MessagesList()
{
  /* Create a new scrolled window, with scrollbars only if needed */
  set_policy(Gtk::POLICY_AUTOMATIC, Gtk::POLICY_AUTOMATIC);

  add(m_TreeView);

  /* create list store */
  m_refListStore = Gtk::ListStore::create(m_Columns);

  m_TreeView.set_model(m_refListStore);

  /* Add some messages to the window */
  for(int i = 0; i &lt; 10; ++i)
  {
    std::ostringstream text;
    text &lt;&lt; "message #" &lt;&lt; i;

    Gtk::TreeModel::Row row = *(m_refListStore-&gt;append());
    row[m_Columns.m_col_text] = text.str();
  }

  //Add the Model's column to the View's columns:
  m_TreeView.append_column("Messages", m_Columns.m_col_text);

  show_all_children();
}

MessagesList::~MessagesList()
{
}
</pre><p>
</p><p>File: messagetext.cc
</p><pre class="programlisting">
#include "messagetext.h"

MessageText::MessageText()
{
  set_policy(Gtk::POLICY_AUTOMATIC, Gtk::POLICY_AUTOMATIC);

  add(m_TextView);
  insert_text();

  show_all_children();
}

MessageText::~MessageText()
{
}

void MessageText::insert_text()
{
  Glib::RefPtr&lt;Gtk::TextBuffer&gt; refTextBuffer = m_TextView.get_buffer();

  Gtk::TextBuffer::iterator iter = refTextBuffer-&gt;get_iter_at_offset(0);
  refTextBuffer-&gt;insert(iter,
    "From: pathfinder@nasa.gov\n"
    "To: mom@nasa.gov\n"
    "Subject: Made it!\n"
    "\n"
    "We just got in this morning. The weather has been\n"
    "great - clear but cold, and there are lots of fun sights.\n"
    "Sojourner says hi. See you soon.\n"
    " -Path\n");
}
</pre><p>
</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sec-ScrolledWindows"></a>ScrolledWindow</h3></div></div><div></div></div><p>
<tt class="literal">ScrolledWindow</tt> widgets are used to create a scrollable area.  You can insert any type of widget into a <tt class="literal">ScrolledWindow</tt> window, and
it will be accessible regardless of its size by using the scrollbars. Note that <tt class="literal">ScrolledWindow</tt> is not a <tt class="literal">Gtk::Window</tt> despite the slightly misleading name.
</p><p>
Scrolled windows have <span class="emphasis"><em>scrollbar policies</em></span> which determine whether
the <tt class="literal">Scrollbar</tt>s will be displayed. The policies can be set with the <tt class="literal">set_policy()</tt> method. The policy may be one of <tt class="literal">Gtk::POLICY_AUTOMATIC</tt> or <tt class="literal">Gtk::POLICY_ALWAYS</tt>.
<tt class="literal">Gtk::POLICY_AUTOMATIC</tt> will cause the scrolled window to display
the scrollbar only if the contained widget is larger than the visible area. 
<tt class="literal">Gtk::POLICY_ALWAYS</tt> will cause the scrollbar to be displayed always.
</p><p><a href="../../reference/html/classGtk_1_1ScrolledWindow.html" target="_top">Reference</a></p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2506828"></a>Example</h4></div></div><div></div></div><p>
Here is a simple example that packs 100 toggle buttons into a ScrolledWindow. Try resizing the window to see the scrollbars react.
</p><div class="figure"><a name="figure-scrolledwindow"></a><p class="title"><b>Figure7.3.ScrolledWindow</b></p><div class="screenshot"><div><img src="../figures/scrolledwindow.png" alt="ScrolledWindow"></div></div></div><p><a href="../../../examples/book/scrolledwindow" target="_top">Source Code</a></p><p>File: examplewindow.h
</p><pre class="programlisting">
#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include &lt;gtkmm.h&gt;

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

protected:
  //Signal handlers:
  virtual void on_button_close();

  //Child widgets:
  Gtk::ScrolledWindow m_ScrolledWindow;
  Gtk::Table m_Table;
  Gtk::Button m_Button_Close;
};

#endif //GTKMM_EXAMPLEWINDOW_H
</pre><p>
</p><p>File: examplewindow.cc
</p><pre class="programlisting">
#include "examplewindow.h"
#include &lt;stdio.h&gt; //For sprintf()

ExampleWindow::ExampleWindow()
: m_Table(10, 10),
  m_Button_Close("Close")
{
  set_title("Gtk::ScrolledWindow example");
  set_border_width(0);
  set_size_request(300, 300);

  m_ScrolledWindow.set_border_width(10);

  /* the policy is one of Gtk::POLICY AUTOMATIC, or Gtk::POLICY_ALWAYS.
   * Gtk::POLICY_AUTOMATIC will automatically decide whether you need
   * scrollbars, whereas Gtk::POLICY_ALWAYS will always leave the scrollbars
   * there.  The first one is the horizontal scrollbar, the second,
   * the vertical. */
  m_ScrolledWindow.set_policy(Gtk::POLICY_AUTOMATIC, Gtk::POLICY_ALWAYS);

  get_vbox()-&gt;pack_start(m_ScrolledWindow);

  /* set the spacing to 10 on x and 10 on y */
  m_Table.set_row_spacings(10);
  m_Table.set_col_spacings(10);

  /* pack the table into the scrolled window */
  m_ScrolledWindow.add(m_Table);

  /* this simply creates a grid of toggle buttons on the table
   * to demonstrate the scrolled window. */
  for(int i = 0; i &lt; 10; i++)
  {
     for(int j = 0; j &lt; 10; j++)
     {
        char buffer[32];
        sprintf(buffer, "button (%d,%d)\n", i, j);
        Gtk::Button* pButton = Gtk::manage(new Gtk::ToggleButton(buffer));
        m_Table.attach(*pButton, i, i + 1, j, j + 1);
     }
  }

  /* Add a "close" button to the bottom of the dialog */
  m_Button_Close.signal_clicked().connect(slot(*this, &amp;ExampleWindow::on_button_close));

  /* this makes it so the button is the default. */
  m_Button_Close.set_flags(Gtk::CAN_DEFAULT);

  Gtk::Box* pBox = get_action_area();
  if(pBox)
    pBox-&gt;pack_start(m_Button_Close);

  /* This grabs this button to be the default button. Simply hitting
   * the "Enter" key will cause this button to activate. */
  m_Button_Close.grab_default();

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

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


</pre><p>
</p><p>File: main.cc
</p><pre class="programlisting">
#include &lt;gtkmm/main.h&gt;
#include "examplewindow.h"

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

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

  return 0;
}
</pre><p>
</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sec-AspectFrames"></a>AspectFrame</h3></div></div><div></div></div><p>
The <tt class="literal">AspectFrame</tt> widget looks like a <tt class="literal">Frame</tt> widget, but it also
enforces the <span class="emphasis"><em>aspect ratio</em></span> (the ratio of the width to the
height) of the child widget, adding extra
space if necessary. For instance, this would allow you to display a photograph without allowing the user to distort it horizontally or vertically while resizing.
</p><p><a href="../../reference/html/classGtk_1_1AspectFrame.html" target="_top">Reference</a></p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2507029"></a>Example</h4></div></div><div></div></div><p>
The following program uses a <tt class="literal">Gtk::AspectFrame</tt> to present a drawing area whose aspect ratio will always be 2:1, no matter how the user resizes the top-level window.</p><p>TODO: screenshot</p><p><a href="../../../examples/book/aspectframe" target="_top">Source Code</a></p><p>File: examplewindow.h
</p><pre class="programlisting">
#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include &lt;gtkmm.h&gt;

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

protected:

  //Child widgets:
  Gtk::AspectFrame m_AspectFrame;
  Gtk::DrawingArea m_DrawingArea;
};

#endif //GTKMM_EXAMPLEWINDOW_H
</pre><p>
</p><p>File: examplewindow.cc
</p><pre class="programlisting">
#include "examplewindow.h"

ExampleWindow::ExampleWindow()
: m_AspectFrame("2x1", /* label */
    Gtk::ALIGN_CENTER, /* center x */
    Gtk::ALIGN_CENTER, /* center y */
    2.0, /* xsize/ysize = 2 */
    false /* ignore child's aspect */)
{
  set_title("Aspect Frame");
  set_border_width(10);

  // Add a child widget to the aspect frame */
  // Ask for a 200x200 window, but the AspectFrame will give us a 200x100
  // window since we are forcing a 2x1 aspect ratio */
  m_DrawingArea.set_size_request(200, 200);
  m_AspectFrame.add(m_DrawingArea);

  // Add the aspect frame to our toplevel window:
  add(m_AspectFrame);

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}


</pre><p>
</p><p>File: main.cc
</p><pre class="programlisting">
#include &lt;gtkmm/main.h&gt;
#include "examplewindow.h"

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

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

  return 0;
}
</pre><p>
</p></div></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="sec-Alignment"></a>Alignment</h3></div></div><div></div></div><p>
The <tt class="literal">Alignment</tt> widget allows you to place a widget at
a position and size relative to the size of the <tt class="literal">Alignment</tt> widget
itself.  For instance, it might be used to center a widget.
</p><p>
You need to specify the <tt class="literal">Alignment</tt>'s characteristics to the constructor, or to the <tt class="literal">set()</tt> method. In particular, you won't notice much effect unless you specify a number other than 1.0 for the <tt class="literal">xscale</tt> and <tt class="literal">yscale</tt> parameters, because 1.0 simply means that the child widget will expand to fill all available space.
</p><p><a href="../../reference/html/classGtk_1_1Alignment.html" target="_top">Reference</a></p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2507220"></a>Example</h4></div></div><div></div></div><p>
This example right-aligns a button in a window by using an <tt class="literal">Alignment</tt> widget.
</p><div class="figure"><a name="figure-alignment"></a><p class="title"><b>Figure7.4.Alignment</b></p><div class="screenshot"><div><img src="../figures/alignment.png" alt="Alignment"></div></div></div><p><a href="../../../examples/book/alignment" target="_top">Source Code</a></p><p>File: examplewindow.h
</p><pre class="programlisting">
#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:
  virtual void on_button_clicked();

  //Child widgets:
  Gtk::Alignment m_Alignment;
  Gtk::Button m_Button;
};

#endif //GTKMM_EXAMPLEWINDOW_H
</pre><p>
</p><p>File: examplewindow.cc
</p><pre class="programlisting">
#include "examplewindow.h"

ExampleWindow::ExampleWindow()
: m_Alignment(Gtk::ALIGN_RIGHT, Gtk::ALIGN_CENTER, 0.0, 0.0),
  m_Button("Close")
{
  set_title("Gtk::Alignement");
  set_border_width(10);
  set_default_size(200, 50);

  add(m_Alignment);

  m_Alignment.add(m_Button);

  m_Button.signal_clicked().connect( SigC::slot(*this, &amp;ExampleWindow::on_button_clicked) );

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

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


</pre><p>
</p><p>File: main.cc
</p><pre class="programlisting">
#include &lt;gtkmm/main.h&gt;
#include "examplewindow.h"

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

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

  return 0;
}
</pre><p>
</p><p>
See the <a href="ch06s05.html" title="ProgressBar">ProgressBar</a> section for another example that uses an <tt class="literal">Alignment</tt>.</p></div></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch06s06.html">Prev</a></td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"><a accesskey="n" href="ch07s02.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Tooltips</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">Multiple-item widgets </td></tr></table></div></body></html>