GTK+ dialogs
In this part of the GTK+ programming tutorial, we will introduce dialogs.Dialog windows or dialogs are an indispensable part of most modern GUI applications. A dialog is defined as a conversation between two or more persons. In a computer application a dialog is a window which is used to "talk" to the application. A dialog is used to input data, modify data, change the application settings etc. Dialogs are important means of communication between a user and a computer program.
Message dialogs
Message dialogs are convenient dialogs that provide messages to the user of the application. The message consists of textual and image data.#include <gtk/gtk.h>In our example, we will show four kinds of message dialogs. Information, Warning, Question and Error message dialogs.
void show_info(GtkWidget *widget, gpointer window)
{
GtkWidget *dialog;
dialog = gtk_message_dialog_new(GTK_WINDOW(window),
GTK_DIALOG_DESTROY_WITH_PARENT,
GTK_MESSAGE_INFO,
GTK_BUTTONS_OK,
"Download Completed", "title");
gtk_window_set_title(GTK_WINDOW(dialog), "Information");
gtk_dialog_run(GTK_DIALOG(dialog));
gtk_widget_destroy(dialog);
}
void show_error(GtkWidget *widget, gpointer window)
{
GtkWidget *dialog;
dialog = gtk_message_dialog_new(GTK_WINDOW(window),
GTK_DIALOG_DESTROY_WITH_PARENT,
GTK_MESSAGE_ERROR,
GTK_BUTTONS_OK,
"Error loading file");
gtk_window_set_title(GTK_WINDOW(dialog), "Error");
gtk_dialog_run(GTK_DIALOG(dialog));
gtk_widget_destroy(dialog);
}
void show_question(GtkWidget *widget, gpointer window)
{
GtkWidget *dialog;
dialog = gtk_message_dialog_new(GTK_WINDOW(window),
GTK_DIALOG_DESTROY_WITH_PARENT,
GTK_MESSAGE_QUESTION,
GTK_BUTTONS_YES_NO,
"Are you sure to quit?");
gtk_window_set_title(GTK_WINDOW(dialog), "Question");
gtk_dialog_run(GTK_DIALOG(dialog));
gtk_widget_destroy(dialog);
}
void show_warning(GtkWidget *widget, gpointer window)
{
GtkWidget *dialog;
dialog = gtk_message_dialog_new(GTK_WINDOW(window),
GTK_DIALOG_DESTROY_WITH_PARENT,
GTK_MESSAGE_WARNING,
GTK_BUTTONS_OK,
"Unallowed operation");
gtk_window_set_title(GTK_WINDOW(dialog), "Warning");
gtk_dialog_run(GTK_DIALOG(dialog));
gtk_widget_destroy(dialog);
}
int main( int argc, char *argv[])
{
GtkWidget *window;
GtkWidget *table;
GtkWidget *info;
GtkWidget *warn;
GtkWidget *que;
GtkWidget *err;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
gtk_window_set_default_size(GTK_WINDOW(window), 220, 150);
gtk_window_set_title(GTK_WINDOW(window), "Message dialogs");
table = gtk_table_new(2, 2, TRUE);
gtk_table_set_row_spacings(GTK_TABLE(table), 2);
gtk_table_set_col_spacings(GTK_TABLE(table), 2);
info = gtk_button_new_with_label("Info");
warn = gtk_button_new_with_label("Warning");
que = gtk_button_new_with_label("Question");
err = gtk_button_new_with_label("Error");
gtk_table_attach(GTK_TABLE(table), info, 0, 1, 0, 1, GTK_FILL, GTK_FILL, 3, 3);
gtk_table_attach(GTK_TABLE(table), warn, 1, 2, 0, 1, GTK_FILL, GTK_FILL, 3, 3);
gtk_table_attach(GTK_TABLE(table), que, 0, 1, 1, 2, GTK_FILL, GTK_FILL, 3, 3);
gtk_table_attach(GTK_TABLE(table), err, 1, 2, 1, 2, GTK_FILL, GTK_FILL, 3, 3);
gtk_container_add(GTK_CONTAINER(window), table);
gtk_container_set_border_width(GTK_CONTAINER(window), 15);
g_signal_connect(G_OBJECT(info), "clicked",
G_CALLBACK(show_info), (gpointer) window);
g_signal_connect(G_OBJECT(warn), "clicked",
G_CALLBACK(show_warning), (gpointer) window);
g_signal_connect(G_OBJECT(que), "clicked",
G_CALLBACK(show_question), (gpointer) window);
g_signal_connect(G_OBJECT(err), "clicked",
G_CALLBACK(show_error), (gpointer) window);
g_signal_connect_swapped(G_OBJECT(window), "destroy",
G_CALLBACK(gtk_main_quit), G_OBJECT(window));
gtk_widget_show_all(window);
gtk_main();
return 0;
}
void show_question(GtkWidget *widget, gpointer window)In the show_question() function, we pop up the message dialog. The message dialog is created using the gtk_message_dialog_new() call. The parameters of the function specify, what kind of message dialog we create. The GTK_MESSAGE_QUESTION constant creates a question type dialog. GTK_BUTTONS_YES_NO constant will No and Yes buttons in the dialog. The last parameter is the text that we display in the dialog.
{
GtkWidget *dialog;
dialog = gtk_message_dialog_new(GTK_WINDOW(window),
GTK_DIALOG_DESTROY_WITH_PARENT,
GTK_MESSAGE_QUESTION,
GTK_BUTTONS_YES_NO,
"Are you sure to quit?");
gtk_window_set_title(GTK_WINDOW(dialog), "Question");
gtk_dialog_run(GTK_DIALOG(dialog));
gtk_widget_destroy(dialog);
}
gtk_window_set_title(GTK_WINDOW(dialog), "Warning");Here we set a title for the message dialogs. And finally run the dialogs. The dialogs must be destroyed manually.
gtk_dialog_run(GTK_DIALOG(dialog));
gtk_widget_destroy(dialog);
GtkAboutDialog
The GtkAboutDialog displays information about the application. GtkAboutDialog can display a logo, the name of the application, version, copyright, website or licence information. It is also possible to give credits to the authors, documenters, translators and artists#include <gtk/gtk.h>The code example uses a GtkAboutDialog with some of its features. To pop up the about dialog, we click on the client area of the window.
void show_about(GtkWidget *widget, gpointer data)
{
GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file("battery.png", NULL);
GtkWidget *dialog = gtk_about_dialog_new();
gtk_about_dialog_set_name(GTK_ABOUT_DIALOG(dialog), "Battery");
gtk_about_dialog_set_version(GTK_ABOUT_DIALOG(dialog), "0.9");
gtk_about_dialog_set_copyright(GTK_ABOUT_DIALOG(dialog),
"(c) Jan Bodnar");
gtk_about_dialog_set_comments(GTK_ABOUT_DIALOG(dialog),
"Battery is a simple tool for battery checking.");
gtk_about_dialog_set_website(GTK_ABOUT_DIALOG(dialog),
"http://www.batteryhq.net");
gtk_about_dialog_set_logo(GTK_ABOUT_DIALOG(dialog), pixbuf);
g_object_unref(pixbuf), pixbuf = NULL;
gtk_dialog_run(GTK_DIALOG (dialog));
gtk_widget_destroy(dialog);
}
int main( int argc, char *argv[])
{
GtkWidget *window;
GtkWidget *about;
GdkPixbuf *battery;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
gtk_window_set_default_size(GTK_WINDOW(window), 220, 150);
gtk_window_set_title(GTK_WINDOW(window), "Battery");
gtk_container_set_border_width(GTK_CONTAINER(window), 15);
gtk_widget_add_events(window, GDK_BUTTON_PRESS_MASK);
battery = gtk_image_get_pixbuf(GTK_IMAGE(
gtk_image_new_from_file("battery.png")));
g_signal_connect(G_OBJECT(window), "button-press-event",
G_CALLBACK(show_about), (gpointer) window);
g_signal_connect_swapped(G_OBJECT(window), "destroy",
G_CALLBACK(gtk_main_quit), G_OBJECT(window));
gtk_widget_show_all(window);
gtk_main();
return 0;
}
GtkWidget *dialog = gtk_about_dialog_new();We create a new GtkAboutDialog.
gtk_about_dialog_set_name(GTK_ABOUT_DIALOG(dialog), "Battery");These function calls set a name, version and the copyright.
gtk_about_dialog_set_version(GTK_ABOUT_DIALOG(dialog), "0.9");
gtk_about_dialog_set_copyright(GTK_ABOUT_DIALOG(dialog),
"(c) Jan Bodnar");
GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file("battery.png", NULL);
...
gtk_about_dialog_set_logo(GTK_ABOUT_DIALOG(dialog), pixbuf);
g_object_unref(pixbuf), pixbuf = NULL;
This code creates a logo. 
Figure: GtkAboutDialog
GtkFontSelectionDialog
The GtkFontSelectionDialog is a dialog for selecting fonts. It is typically used in applications, that do some text editing or formatting.#include <gtk/gtk.h>In the code example, we put a simple label into the center of the window. We show a font selecting dialog by clicking on the toolbar button.
void select_font(GtkWidget *widget, gpointer label)
{
GtkResponseType result;
GtkWidget *dialog = gtk_font_selection_dialog_new("Select Font");
result = gtk_dialog_run(GTK_DIALOG(dialog));
if (result == GTK_RESPONSE_OK || result == GTK_RESPONSE_APPLY)
{
PangoFontDescription *font_desc;
gchar *fontname = gtk_font_selection_dialog_get_font_name(
GTK_FONT_SELECTION_DIALOG(dialog));
font_desc = pango_font_description_from_string(fontname);
gtk_widget_modify_font(GTK_WIDGET(label), font_desc);
g_free(fontname);
}
gtk_widget_destroy(dialog);
}
int main( int argc, char *argv[])
{
GtkWidget *window;
GtkWidget *label;
GtkWidget *vbox;
GtkWidget *toolbar;
GtkToolItem *font;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
gtk_window_set_default_size(GTK_WINDOW(window), 280, 200);
gtk_window_set_title(GTK_WINDOW(window), "Font Selection Dialog");
vbox = gtk_vbox_new(FALSE, 0);
gtk_container_add(GTK_CONTAINER(window), vbox);
toolbar = gtk_toolbar_new();
gtk_toolbar_set_style(GTK_TOOLBAR(toolbar), GTK_TOOLBAR_ICONS);
gtk_container_set_border_width(GTK_CONTAINER(toolbar), 2);
font = gtk_tool_button_new_from_stock(GTK_STOCK_SELECT_FONT);
gtk_toolbar_insert(GTK_TOOLBAR(toolbar), font, -1);
gtk_box_pack_start(GTK_BOX(vbox), toolbar, FALSE, FALSE, 5);
label = gtk_label_new("ZetCode");
gtk_label_set_justify(GTK_LABEL(label), GTK_JUSTIFY_CENTER);
gtk_box_pack_start(GTK_BOX(vbox), label, TRUE, FALSE, 5);
g_signal_connect(G_OBJECT(font), "clicked",
G_CALLBACK(select_font), label);
g_signal_connect_swapped(G_OBJECT(window), "destroy",
G_CALLBACK(gtk_main_quit), NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}
GtkWidget *dialog = gtk_font_selection_dialog_new("Select Font");
result = gtk_dialog_run(GTK_DIALOG(dialog));
We create and show the GtkFontSelectionDialog.if (result == GTK_RESPONSE_OK || result == GTK_RESPONSE_APPLY)If the user clicked on the OK or APPLY button, we proceed. We get the selected font name. Than we change the label's font to the selected font name.
{
PangoFontDescription *font_desc;
gchar *fontname = gtk_font_selection_dialog_get_font_name(
GTK_FONT_SELECTION_DIALOG(dialog));
font_desc = pango_font_description_from_string(fontname);
gtk_widget_modify_font(GTK_WIDGET(label), font_desc);
g_free(fontname);
}
Figure: GtkFontSelectionDialog
GtkColorSelectionDialog
GtkColorSelectionDialog is a dialog for selecting a color.#include <gtk/gtk.h>The example is very similar to the previous one. This time we change the color of the label.
void select_font(GtkWidget *widget, gpointer label)
{
GtkResponseType result;
GtkColorSelection *colorsel;
GtkWidget *dialog = gtk_color_selection_dialog_new("Font Color");
result = gtk_dialog_run(GTK_DIALOG(dialog));
if (result == GTK_RESPONSE_OK)
{
GdkColor color;
colorsel = GTK_COLOR_SELECTION(
GTK_COLOR_SELECTION_DIALOG(dialog)->colorsel);
gtk_color_selection_get_current_color(colorsel,
&color);
gtk_widget_modify_fg(GTK_WIDGET(label),
GTK_STATE_NORMAL,
&color);
}
gtk_widget_destroy(dialog);
}
int main( int argc, char *argv[])
{
GtkWidget *window;
GtkWidget *widget;
GtkWidget *label;
GtkWidget *vbox;
GtkWidget *toolbar;
GtkToolItem *font;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
gtk_window_set_default_size(GTK_WINDOW(window), 280, 200);
gtk_window_set_title(GTK_WINDOW(window), "Color Selection Dialog");
vbox = gtk_vbox_new(FALSE, 0);
gtk_container_add(GTK_CONTAINER(window), vbox);
toolbar = gtk_toolbar_new();
gtk_toolbar_set_style(GTK_TOOLBAR(toolbar), GTK_TOOLBAR_ICONS);
gtk_container_set_border_width(GTK_CONTAINER(toolbar), 2);
font = gtk_tool_button_new_from_stock(GTK_STOCK_SELECT_COLOR);
gtk_toolbar_insert(GTK_TOOLBAR(toolbar), font, -1);
gtk_box_pack_start(GTK_BOX(vbox), toolbar, FALSE, FALSE, 5);
label = gtk_label_new("ZetCode");
gtk_label_set_justify(GTK_LABEL(label), GTK_JUSTIFY_CENTER);
gtk_box_pack_start(GTK_BOX(vbox), label, TRUE, FALSE, 5);
g_signal_connect(G_OBJECT(font), "clicked",
G_CALLBACK(select_font), label);
g_signal_connect_swapped(G_OBJECT(window), "destroy",
G_CALLBACK(gtk_main_quit), NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}
GtkWidget *dialog = gtk_color_selection_dialog_new("Font Color");
result = gtk_dialog_run(GTK_DIALOG(dialog));
We create and show the GtkColorSelectionDialog. if (result == GTK_RESPONSE_OK)If the user pressed OK, we get the color and modify the label's color.
{
GdkColor color;
colorsel = GTK_COLOR_SELECTION(
GTK_COLOR_SELECTION_DIALOG(dialog)->colorsel);
gtk_color_selection_get_current_color(colorsel,
&color);
gtk_widget_modify_fg(GTK_WIDGET(label),
GTK_STATE_NORMAL,
&color);
}
Figure: GtkColorSelectionDialog
This chapter was about dialogs in GTK+.
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