Xfce Foundation Classes
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Scrolled Windows


Scrolled windows are used to create a scrollable area with another widget inside it. You may insert any type of widget into a scrolled window, and it will be accessible regardless of the size by using the scrollbars.

The following constructors can be used to create a new scrolled window.

ScrolledWindow();

ScrolledWindow(Gtk::Adjustment *hadjustment, Gtk::Adjustment *vadjustment);

The 'hadjustment' argument is the adjustment for the horizontal direction, and the 'vadjustment' argument the adjustment for the vertical direction. Unless you specifically need to create your own Adjustments you should use the first constructor which forces the scrolled window to create it's own Adjustments.

You can set and get the adjustments after the scrolled window has been created using the following four methods:

void set_hadjustment(Gtk::Adjustment *hadjustment);

void set_vadjustment(Gtk::Adjustment *vadjustment);

Gtk::Adjustment* get_hadjustment() const;

Gtk::Adjustment* get_vadjustment() const;

You can set the scrollbar policy with the following method:
void set_policy(Gtk::PolicyType hscrollbar_policy, Gtk::PolicyType vscrollbar_policy);

The first argument sets the policy for the horizontal scrollbar, and the second the policy for the vertical scrollbar. The policy may be one of values from the Gtk::PolicyType enum:
  • GTK_POLICY_AUTOMATIC - automatically decide whether you need the scrollbar.
  • GTK_POLICY_ALWAYS - always leave the scrollbar there.
  • GTK_POLICY_NEVER - the scrollbar is never present.
You place your widget into the scrolled window using the following method:

void add_with_viewport(Gtk::Widget& child);

ScrolledWindow Example

Here is a simple example that packs a table with 100 toggle buttons into a scrolled window. I've only commented the parts of source code that may be new to you.

The header file for the ScrolledWindow example <scrolledwindow.hh>:

#include <xfc/main.hh>
#include <xfc/gtk/dialog.hh>

using namespace Xfc;

class ScrolledWindow : public Gtk::Dialog
{
public:
    ScrolledWindow();
    virtual ~ScrolledWindow();
};

and the source file is scrolledwindow.cc:

#include "scrolledwindow.hh"
#include <xfc/gtk/buttonbox.hh>
#include <xfc/gtk/scrolledwindow.hh>
#include <xfc/gtk/table.hh>
#include <xfc/gtk/togglebutton.hh>

ScrolledWindow::ScrolledWindow()
{
    set_title("ScrolledWindow example");
    set_border_width(0);
    set_size_request(300, 300);
   
    // Create a new scrolled window.
    Gtk::ScrolledWindow *scrolled_window = new Gtk::ScrolledWindow;
    scrolled_window->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.
    scrolled_window->set_policy(Gtk::POLICY_AUTOMATIC, Gtk::POLICY_ALWAYS);
   
    // The dialog window is created with a vbox (client_area) packed into it.                               
    client_area()->pack_start(*scrolled_window);
    scrolled_window->show();
   
    // Create a table of 10 by 10 squares.
    Gtk::Table *table = new Gtk::Table(10, 10);
   
    // Set the spacing to 10 on x and 10 on y
    table->set_row_spacings(10);
    table->set_col_spacings(10);
   
    // Pack the table into the scrolled window
    scrolled_window->add_with_viewport(*table);
    table->show();
   
    // This simply creates a grid of toggle buttons on the table to demonstrate the scrolled window.
    for (int i = 0; i < 10; i++)
    {
        for (int j = 0; j < 10; j++)
        {
            String text = String::format("button (%d,%d)\n", i, j);
            Gtk::ToggleButton *button = new Gtk::ToggleButton(text);
            table->attach(*button, i, i + 1, j, j + 1);
            button->show();
        }
    }

    // Add a "close" button to the bottom of the dialog
    Gtk::Button *button = new Gtk::Button("close");
    button->signal_clicked().connect(sigc::mem_fun(this, &ScrolledWindow::dispose));

    // This makes it so the button is the default.
    button->set_flags(Gtk::CAN_DEFAULT);
    action_area()->pack_start(*button);

    // This grabs this button to be the default button. Simply hitting the "Enter" key will activate this button.
    button->grab_default();
    button->show();
}

ScrolledWindow::~ScrolledWindow()
{
}

int main (int argc, char *argv[])
{
    using namespace Main;

    init(&argc, &argv);

    ScrolledWindow window;
    window.signal_destroy().connect(sigc::ptr_fun(&Xfc::Main::quit));
    window.show();

    run();
    return 0;
}

Compiling ScrolledWindow

If you compiled and installed XFC yourself, you will find the source code for ScrolledWindow in the <examples/scrolledwindow> source directory along with a Makefile. If XFC came pre-installed, or you installed it from an RPM package, you will find the source code in the </usr/share/doc/xfcui-X.X/examples/scrolledwindow> subdirectory. In this case you will have to create the Makefile yourself (replace X.X with the version number of the libXFCui library you have installed).

To create a Makefile for ScrolledWindow, add the following lines to a new text file and save it using the name "Makefile":

CC = g++

CFLAGS = -Wall -O2

scrolledwindow: scrolledwindow.cc scrolledwindow.hh
    $(CC) scrolledwindow.cc -o scrolledwindow $(CFLAGS) `pkg-config xfcui-X.X --cflags --libs`

clean:
    rm -f *.o scrolledwindow

If you cut and paste these lines make sure the whitespace before $(CC) and rm is a tab character. When you compile and run this program you will see the following window appear:



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 XFC 4.4