<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Widgets</title> <link rel="stylesheet" type="text/css" href="style.css"> <meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> <link rel="home" href="index.html" title="Programming with gtkmm 3"> <link rel="up" href="chapter-basics.html" title="Chapter 3. Basics"> <link rel="prev" href="sec-headers-and-linking.html" title="Headers and Linking"> <link rel="next" href="sec-signals-overview.html" title="Signals"> </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">Widgets</th></tr> <tr> <td width="20%" align="left"> <a accesskey="p" href="sec-headers-and-linking.html"><img src="icons/prev.png" alt="Prev"></a> </td> <th width="60%" align="center">Chapter 3. Basics</th> <td width="20%" align="right"> <a accesskey="n" href="sec-signals-overview.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> </table> <hr> </div> <div class="sect1"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="sec-widgets-overview"></a>Widgets</h2></div></div></div> <p><span class="application">gtkmm</span> applications consist of windows containing widgets, such as buttons and text boxes. In some other systems, widgets are called "controls". For each widget in your application's windows, there is a C++ object in your application's code. So you just need to call a method of the widget's class to affect the visible widget.</p> <p>Widgets are arranged inside container widgets such as frames and notebooks, in a hierarchy of widgets within widgets. Some of these container widgets, such as <code class="classname">Gtk::Grid</code>, are not visible - they exist only to arrange other widgets. Here is some example code that adds 2 <code class="classname">Gtk::Button</code> widgets to a <code class="classname">Gtk::Box</code> container widget: </p> <pre class="programlisting">m_box.pack_start(m_Button1); m_box.pack_start(m_Button2);</pre> <p> and here is how to add the <code class="classname">Gtk::Box</code>, containing those buttons, to a <code class="classname">Gtk::Frame</code>, which has a visible frame and title: </p> <pre class="programlisting">m_frame.add(m_box);</pre> <p> </p> <p> Most of the chapters in this book deal with specific widgets. See the <a class="link" href="chapter-container-widgets.html" title="Chapter 8. Container Widgets">Container Widgets</a> section for more details about adding widgets to container widgets. </p> <p>Although you can specify the layout and appearance of windows and widgets with C++ code, you will probably find it more convenient to design your user interfaces with <code class="literal">Glade</code> and load them at runtime with <code class="literal">Gtk::Builder</code>. See the <a class="link" href="chapter-builder.html" title="Chapter 26. Glade and Gtk::Builder">Glade and Gtk::Builder</a> chapter. </p> <p>Although <span class="application">gtkmm</span> widget instances have lifetimes and scopes just like those of other C++ classes, <span class="application">gtkmm</span> has an optional time-saving feature that you will see in some of the examples. <code class="function">Gtk::manage()</code> allows you to say that a child widget is owned by the container into which you place it. This allows you to <code class="function">new</code> the widget, add it to the container and forget about deleting it. You can learn more about <span class="application">gtkmm</span> memory management techniques in the <a class="link" href="chapter-memory.html" title="Chapter 25. Memory management">Memory Management chapter</a>. </p> </div> <div class="navfooter"> <hr> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"> <a accesskey="p" href="sec-headers-and-linking.html"><img src="icons/prev.png" alt="Prev"></a> </td> <td width="20%" align="center"><a accesskey="u" href="chapter-basics.html"><img src="icons/up.png" alt="Up"></a></td> <td width="40%" align="right"> <a accesskey="n" href="sec-signals-overview.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> <tr> <td width="40%" align="left" valign="top">Headers and Linking </td> <td width="20%" align="center"><a accesskey="h" href="index.html"><img src="icons/home.png" alt="Home"></a></td> <td width="40%" align="right" valign="top"> Signals</td> </tr> </table> </div> </body> </html>
