Mini editor de texto

Para la compresión de los temas tratados con anterioridad se presenta un ejemplo de un mini editor de etxto que tendrá las funciones de limpiar, cortar, copiar, pegar, negrita, subrayado, tachado y coloreado, el cual tendrá el siguiente aspecto:
Figura 1. Mini editor de texto
Ahora veamos el código de esta aplicación:
#include <gtk/gtk.h>

GtkWidget *create_window ();
void create_tags (GtkTextBuffer * buffer);
void on_button_clear_clicked (GtkButton * button, gpointer user_data);
void on_button_cut_clicked (GtkButton * button, gpointer user_data);
void on_button_copy_clicked (GtkButton * button, gpointer user_data);
void on_button_paste_clicked (GtkButton * button, gpointer user_data);
void on_button_bold_clicked (GtkButton * button, gpointer user_data);
void on_button_underline_clicked (GtkButton * button, gpointer user_data);
void on_button_strike_clicked (GtkButton * button, gpointer user_data);
void on_button_color_clicked (GtkButton * button, gpointer user_data);

int
main (int argc, char *argv[])
{
    GtkWidget *window;

    gtk_init (&argc, &argv);

    window = create_window ();
    gtk_widget_show_all (window);

    gtk_main ();
    return 0;
}

GtkWidget *
create_window ()
{
    GtkWidget *window;
    GtkWidget *vbox_main;
    GtkWidget *handlebox;
    GtkWidget *toolbar;
    GtkWidget *button_clear;
    GtkWidget *button_cut;
    GtkWidget *button_copy;
    GtkWidget *button_paste;
    GtkWidget *button_bold;
    GtkWidget *button_underline;
    GtkWidget *button_strike;
    GtkWidget *button_color;
    GtkWidget *scrolledwindow;
    GtkWidget *textview;
    GtkTextBuffer *buffer;

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title (GTK_WINDOW (window), "Mini editor de texto");
    gtk_window_set_default_size (GTK_WINDOW (window), 400, 500);

    vbox_main = gtk_vbox_new (FALSE, 0);
    gtk_container_add (GTK_CONTAINER (window), vbox_main);

    handlebox = gtk_handle_box_new ();
    gtk_box_pack_start (GTK_BOX (vbox_main), handlebox, FALSE, FALSE,
                0);

    toolbar = gtk_toolbar_new ();
    gtk_container_add (GTK_CONTAINER (handlebox), toolbar);

    button_clear = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                         "gtk-clear",
                         NULL,
                         NULL, NULL, NULL, -1);
    button_cut = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                           "gtk-cut",
                           NULL, NULL, NULL, NULL, -1);
    button_copy = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                        "gtk-copy",
                        NULL,
                        NULL, NULL, NULL, -1);
    button_paste = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                         "gtk-paste",
                         NULL,
                         NULL, NULL, NULL, -1);

    gtk_toolbar_append_space (GTK_TOOLBAR (toolbar));

    button_bold = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                        "gtk-bold",
                        NULL,
                        NULL, NULL, NULL, -1);
    button_underline = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                             "gtk-underline",
                             NULL,
                             NULL, NULL, NULL, -1);
    button_strike = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                          "gtk-strikethrough",
                          NULL,
                          NULL, NULL, NULL, -1);
    button_color = gtk_toolbar_insert_stock (GTK_TOOLBAR (toolbar),
                         "gtk-select-color",
                         NULL,
                         NULL, NULL, NULL, -1);
    scrolledwindow = gtk_scrolled_window_new (NULL, NULL);
    gtk_box_pack_start (GTK_BOX (vbox_main), scrolledwindow, TRUE,
                TRUE, 0);

    textview = gtk_text_view_new ();
    gtk_container_add (GTK_CONTAINER (scrolledwindow), textview);

    buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (textview));
    create_tags (buffer);

    g_signal_connect ((gpointer) window, "delete_event",
              G_CALLBACK (gtk_main_quit), NULL);
    g_signal_connect ((gpointer) button_clear, "clicked",
              G_CALLBACK (on_button_clear_clicked),
              (gpointer) textview);
    g_signal_connect ((gpointer) button_cut, "clicked",
              G_CALLBACK (on_button_cut_clicked),
              (gpointer) textview);
    g_signal_connect ((gpointer) button_copy, "clicked",
              G_CALLBACK (on_button_copy_clicked),
              (gpointer) textview);
    g_signal_connect ((gpointer) button_paste, "clicked",
              G_CALLBACK (on_button_paste_clicked),
              (gpointer) textview);
    g_signal_connect ((gpointer) button_bold, "clicked",
              G_CALLBACK (on_button_bold_clicked),
              (gpointer) textview);
    g_signal_connect ((gpointer) button_underline, "clicked",
              G_CALLBACK (on_button_underline_clicked),
              (gpointer) textview);
    g_signal_connect ((gpointer) button_strike, "clicked",
              G_CALLBACK (on_button_strike_clicked),
              (gpointer) textview);
    g_signal_connect ((gpointer) button_color, "clicked",
              G_CALLBACK (on_button_color_clicked),
              (gpointer) textview);
    return window;
}

void
on_button_clear_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_delete_selection (textbuffer, TRUE, TRUE);
}

void
on_button_cut_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_cut_clipboard (textbuffer,
                       gtk_clipboard_get (GDK_NONE), TRUE);
}


void
on_button_copy_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_copy_clipboard (textbuffer,
                    gtk_clipboard_get (GDK_NONE));
}

void
on_button_paste_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_paste_clipboard (textbuffer,
                     gtk_clipboard_get (GDK_NONE),
                     NULL, TRUE);
}

void
on_button_bold_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;
    GtkTextIter start, end;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_get_selection_bounds (textbuffer, &start, &end);

    gtk_text_buffer_apply_tag_by_name (textbuffer, "bold", &start,
                       &end);
}

void
on_button_underline_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;
    GtkTextIter start, end;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_get_selection_bounds (textbuffer, &start, &end);

    gtk_text_buffer_apply_tag_by_name (textbuffer, "underline", &start,
                       &end);
}


void
on_button_strike_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;
    GtkTextIter start, end;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_get_selection_bounds (textbuffer, &start, &end);

    gtk_text_buffer_apply_tag_by_name (textbuffer, "strike", &start,
                       &end);
}

void
on_button_color_clicked (GtkButton * button, gpointer user_data)
{
    GtkTextBuffer *textbuffer = NULL;
    GtkTextIter start, end;

    g_assert (GTK_IS_TEXT_VIEW (user_data));

    textbuffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (user_data));

    gtk_text_buffer_get_selection_bounds (textbuffer, &start, &end);

    gtk_text_buffer_apply_tag_by_name (textbuffer, "color", &start,
                       &end);
}

void
create_tags (GtkTextBuffer * buffer)
{
    g_assert (GTK_IS_TEXT_BUFFER (buffer));

    gtk_text_buffer_create_tag (buffer, "bold",
                    "weight", PANGO_WEIGHT_BOLD, NULL);
    gtk_text_buffer_create_tag (buffer, "underline",
                    "underline", PANGO_UNDERLINE_SINGLE,
                    NULL);
    gtk_text_buffer_create_tag (buffer, "strike", "strikethrough",
                    TRUE, NULL);
    gtk_text_buffer_create_tag (buffer, "color", "foreground", "blue",
                    NULL);
}