Sophie: gtkmm2.4-documentation-2.17.4-1mdv2010.0 noarch

gtkmm2.4-documentation-2.17.4-1mdv2010.0.noarch.rpm

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<a accesskey="p" href="sec-clipboard-paste.html"><img src="icons/prev.png" alt="Prev"></a> </td>
<th width="60%" align="center">Chapter 17. The Clipboard</th>
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<div class="sect1" title="Examples">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="sec-clipboard-examples"></a>Examples</h2></div></div></div>
<div class="sect2" title="Simple">
<div class="titlepage"><div><div><h3 class="title">
<a name="sec-clipboard-example-simple"></a>Simple</h3></div></div></div>
<p>
This example allows copy and pasting of application-specific data, using the
standard text target. Although this is simple, it's not ideal because it does
not identify the <code class="classname">Clipboard</code> data as being of a particular
type.
</p>
<div class="figure">
<a name="figure-clipboard-simple"></a><p class="title"><b>Figure 17.1. Clipboard - Simple</b></p>
<div class="figure-contents"><div class="screenshot"><div><img src="figures/clipboard_simple.png" alt="Clipboard - Simple"></div></div></div>
</div>
<br class="figure-break"><p><a class="ulink" href="http://git.gnome.org/cgit/gtkmm-documentation/tree/examples/book/clipboard/simple/" target="_top">Source Code</a></p>
<p>File: <code class="filename">examplewindow.h</code>
</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:
  void on_button_copy();
  void on_button_paste();
  void on_clipboard_text_received(const Glib::ustring&amp; text);

  //Child widgets:
  Gtk::VBox m_VBox;

  Gtk::Label m_Label;
  
  Gtk::Table m_Table;
  Gtk::ToggleButton m_ButtonA1, m_ButtonA2, m_ButtonB1, m_ButtonB2;

  Gtk::HButtonBox m_ButtonBox;
  Gtk::Button m_Button_Copy, m_Button_Paste;
};

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

ExampleWindow::ExampleWindow()
: m_Label("Select cells in the table, click Copy, then open a second "
        "instance of this example to try pasting the copied data."),
  m_Table(2, 2, true),
  m_ButtonA1("A1"), m_ButtonA2("A2"), m_ButtonB1("B1"), m_ButtonB2("B2"),
  m_Button_Copy(Gtk::Stock::COPY), m_Button_Paste(Gtk::Stock::PASTE)
{
  set_title("Gtk::Clipboard example");
  set_border_width(12);

  add(m_VBox);

  m_VBox.pack_start(m_Label, Gtk::PACK_SHRINK);

  //Fill Table:
  m_VBox.pack_start(m_Table);
  m_Table.attach(m_ButtonA1, 0, 1, 0, 1);
  m_Table.attach(m_ButtonA2, 1, 2, 0, 1);
  m_Table.attach(m_ButtonB1, 0, 1, 1, 2);
  m_Table.attach(m_ButtonB2, 1, 2, 1, 2);

  //Add ButtonBox to bottom:
  m_VBox.pack_start(m_ButtonBox, Gtk::PACK_SHRINK);
  m_VBox.set_spacing(6);

  //Fill ButtonBox:
  m_ButtonBox.set_layout(Gtk::BUTTONBOX_END);
  m_ButtonBox.pack_start(m_Button_Copy, Gtk::PACK_SHRINK);
  m_Button_Copy.signal_clicked().connect(sigc::mem_fun(*this,
              &amp;ExampleWindow::on_button_copy) );
  m_ButtonBox.pack_start(m_Button_Paste, Gtk::PACK_SHRINK);
  m_Button_Paste.signal_clicked().connect(sigc::mem_fun(*this,
              &amp;ExampleWindow::on_button_paste) );

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_button_copy()
{
  //Build a string representation of the stuff to be copied:
  //Ideally you would use XML, with an XML parser here:
  Glib::ustring strData;
  strData += m_ButtonA1.get_active() ? "1" : "0";
  strData += m_ButtonA2.get_active() ? "1" : "0";
  strData += m_ButtonB1.get_active() ? "1" : "0";
  strData += m_ButtonB2.get_active() ? "1" : "0";

  Glib::RefPtr&lt;Gtk::Clipboard&gt; refClipboard = Gtk::Clipboard::get();
  refClipboard-&gt;set_text(strData);
}

void ExampleWindow::on_button_paste()
{
  //Tell the clipboard to call our method when it is ready:
  Glib::RefPtr&lt;Gtk::Clipboard&gt; refClipboard = Gtk::Clipboard::get();
  refClipboard-&gt;request_text(sigc::mem_fun(*this,
              &amp;ExampleWindow::on_clipboard_text_received) );
}

void ExampleWindow::on_clipboard_text_received(const Glib::ustring&amp; text)
{
  //See comment in on_button_copy() about this silly clipboard format.
  if(text.size() &gt;= 4)
  {
    m_ButtonA1.set_active( text[0] == '1' );
    m_ButtonA2.set_active( text[1] == '1' );
    m_ButtonB1.set_active( text[2] == '1' );
    m_ButtonB2.set_active( text[3] == '1' );
  }
}
</pre>
<p>File: <code class="filename">main.cc</code>
</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;
  //Shows the window and returns when it is closed.
  Gtk::Main::run(window);

  return 0;
}
</pre>
</div>
<div class="sect2" title="Ideal">
<div class="titlepage"><div><div><h3 class="title">
<a name="sec-clipboard-example-ideal"></a>Ideal</h3></div></div></div>
<p>This is like the simple example, but it
</p>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">Defines a custom clipboard target, though the format of that target is still text.</li>
<li class="listitem">It supports pasting of 2 targets - both the custom one and a text one that creates an arbitrary text representation of the custom data.</li>
<li class="listitem">It uses <code class="methodname">request_targets()</code> and disables the Paste button if it can't use anything on the clipboard</li>
</ol></div>
<p>
</p>
<div class="figure">
<a name="figure-clipboard-ideal"></a><p class="title"><b>Figure 17.2. Clipboard - Ideal</b></p>
<div class="figure-contents"><div class="screenshot"><div><img src="figures/clipboard_ideal.png" alt="Clipboard - Ideal"></div></div></div>
</div>
<br class="figure-break"><p><a class="ulink" href="http://git.gnome.org/cgit/gtkmm-documentation/tree/examples/book/clipboard/ideal/" target="_top">Source Code</a></p>
<p>File: <code class="filename">examplewindow.h</code>
</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:
  void on_button_copy();
  void on_button_paste();

  void on_clipboard_get(Gtk::SelectionData&amp; selection_data, guint info);
  void on_clipboard_clear();

  void on_clipboard_received(const Gtk::SelectionData&amp; selection_data);
  void on_clipboard_received_targets(const Glib::StringArrayHandle&amp; targets_array);
   
  virtual void update_paste_status(); //Disable the paste button if there is nothing to paste.

  //Child widgets:
  Gtk::VBox m_VBox;

  Gtk::Label m_Label;
  
  Gtk::Table m_Table;
  Gtk::ToggleButton m_ButtonA1, m_ButtonA2, m_ButtonB1, m_ButtonB2;

  Gtk::HButtonBox m_ButtonBox;
  Gtk::Button m_Button_Copy, m_Button_Paste;

  Glib::ustring m_ClipboardStore; //Keep copied stuff here, until it is pasted. This could be a big complex data structure.
};

#endif //GTKMM_EXAMPLEWINDOW_H
</pre>
<p>File: <code class="filename">examplewindow.cc</code>
</p>
<pre class="programlisting">
#include "examplewindow.h"
#include &lt;algorithm&gt;

namespace
{

//These should usually be MIME types.
const char example_target_custom[] = "gtkmmclipboardexample";
const char example_target_text[]   = "UTF8_STRING";

} // anonymous namespace


ExampleWindow::ExampleWindow()
: m_Label("Select cells in the table, click Copy, then open a second instance "
          "of this example to try pasting the copied data.\nOr try pasting the "
          "text representation into gedit."),
  m_Table(2, 2, true),
  m_ButtonA1("A1"), m_ButtonA2("A2"), m_ButtonB1("B1"), m_ButtonB2("B2"),
  m_Button_Copy(Gtk::Stock::COPY), m_Button_Paste(Gtk::Stock::PASTE)
{
  set_title("Gtk::Clipboard example");
  set_border_width(12);

  add(m_VBox);

  m_VBox.pack_start(m_Label, Gtk::PACK_SHRINK);

  //Fill Table:
  m_VBox.pack_start(m_Table);
  m_Table.attach(m_ButtonA1, 0, 1, 0, 1);
  m_Table.attach(m_ButtonA2, 1, 2, 0, 1);
  m_Table.attach(m_ButtonB1, 0, 1, 1, 2);
  m_Table.attach(m_ButtonB2, 1, 2, 1, 2);

  //Add ButtonBox to bottom:
  m_VBox.pack_start(m_ButtonBox, Gtk::PACK_SHRINK);
  m_VBox.set_spacing(6);

  //Fill ButtonBox:
  m_ButtonBox.set_layout(Gtk::BUTTONBOX_END);
  m_ButtonBox.pack_start(m_Button_Copy, Gtk::PACK_SHRINK);
  m_Button_Copy.signal_clicked().connect(sigc::mem_fun(*this,
              &amp;ExampleWindow::on_button_copy) );
  m_ButtonBox.pack_start(m_Button_Paste, Gtk::PACK_SHRINK);
  m_Button_Paste.signal_clicked().connect(sigc::mem_fun(*this,
              &amp;ExampleWindow::on_button_paste) );

  show_all_children();

  update_paste_status();
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_button_copy()
{
  //Build a string representation of the stuff to be copied:
  //Ideally you would use XML, with an XML parser here:
  Glib::ustring strData;
  strData += m_ButtonA1.get_active() ? "1" : "0";
  strData += m_ButtonA2.get_active() ? "1" : "0";
  strData += m_ButtonB1.get_active() ? "1" : "0";
  strData += m_ButtonB2.get_active() ? "1" : "0";

  //Store the copied data until it is pasted:
  m_ClipboardStore = strData;

  Glib::RefPtr&lt;Gtk::Clipboard&gt; refClipboard = Gtk::Clipboard::get();

  //Targets:
  std::list&lt;Gtk::TargetEntry&gt; listTargets;

  listTargets.push_back( Gtk::TargetEntry(example_target_custom) );
  listTargets.push_back( Gtk::TargetEntry(example_target_text) );

  refClipboard-&gt;set(listTargets, sigc::mem_fun(*this,
              &amp;ExampleWindow::on_clipboard_get), sigc::mem_fun(*this,
                  &amp;ExampleWindow::on_clipboard_clear) );

  update_paste_status();
}

void ExampleWindow::on_button_paste()
{
  //Tell the clipboard to call our method when it is ready:
  Glib::RefPtr&lt;Gtk::Clipboard&gt; refClipboard = Gtk::Clipboard::get();

  refClipboard-&gt;request_contents(example_target_custom, 
    sigc::mem_fun(*this, &amp;ExampleWindow::on_clipboard_received) );

  update_paste_status();
}

void ExampleWindow::on_clipboard_get(Gtk::SelectionData&amp; selection_data, guint)
{
  //info is meant to indicate the target, but it seems to be always 0,
  //so we use the selection_data's target instead.

  const std::string target = selection_data.get_target();

  if(target == example_target_custom)
  {
    // This set() override uses an 8-bit text format for the data.
    selection_data.set(example_target_custom, m_ClipboardStore);
  }
  else if(target == example_target_text)
  {
    //Build some arbitrary text representation of the data,
    //so that people see something when they paste into a text editor:
    Glib::ustring text_representation;

    text_representation += m_ButtonA1.get_active() ? "A1, " : "";
    text_representation += m_ButtonA2.get_active() ? "A2, " : "";
    text_representation += m_ButtonB1.get_active() ? "B1, " : "";
    text_representation += m_ButtonB2.get_active() ? "B2, " : "";

    selection_data.set_text(text_representation);
  }
  else
  {
    g_warning("ExampleWindow::on_clipboard_get(): "
            "Unexpected clipboard target format.");
  }
}

void ExampleWindow::on_clipboard_clear()
{
  //This isn't really necessary. I guess it might save memory.
  m_ClipboardStore.clear();
}

void ExampleWindow::on_clipboard_received(
        const Gtk::SelectionData&amp; selection_data)
{
  const std::string target = selection_data.get_target();

  //It should always be this, because that' what we asked for when calling
  //request_contents().
  if(target == example_target_custom)
  {
    Glib::ustring clipboard_data = selection_data.get_data_as_string();

    //See comment in on_button_copy() about this silly clipboard format.
    if(clipboard_data.size() &gt;= 4)
    {
      m_ButtonA1.set_active( clipboard_data[0] == '1' );
      m_ButtonA2.set_active( clipboard_data[1] == '1' );
      m_ButtonB1.set_active( clipboard_data[2] == '1' );
      m_ButtonB2.set_active( clipboard_data[3] == '1' );
    }
  }
}

void ExampleWindow::update_paste_status()
{
  //Disable the paste button if there is nothing to paste.

  Glib::RefPtr&lt;Gtk::Clipboard&gt; refClipboard = Gtk::Clipboard::get();

  //Discover what targets are available:
  refClipboard-&gt;request_targets(sigc::mem_fun(*this,
              &amp;ExampleWindow::on_clipboard_received_targets) );
}

void ExampleWindow::on_clipboard_received_targets(
  const Glib::StringArrayHandle&amp; targets_array)
{
  // Get the list of available clipboard targets:
  std::list&lt;std::string&gt; targets = targets_array;

  const bool bPasteIsPossible =
    std::find(targets.begin(), targets.end(),
      example_target_custom) != targets.end();

  // Enable/Disable the Paste button appropriately:
  m_Button_Paste.set_sensitive(bPasteIsPossible);
}

</pre>
<p>File: <code class="filename">main.cc</code>
</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;
  //Shows the window and returns when it is closed.
  Gtk::Main::run(window);

  return 0;
}
</pre>
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