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GTK v1.2 Tutorial(英文)

来源:Linux-cn.com 作者:Webmaster 时间:2007-05-05 点击: [收藏] [投稿]

  The user can also move the slider all the way to one end or the other of the trough using the keyboard. With the VScale widget, this is done with the Home and End keys, whereas with the VScrollbar widget, this is done by typing Control-Page Up and Control-Page Down.

Horizontal Range Widgets

  The left and right arrow keys work as you might expect in these widgets, moving the slider back and forth by step_increment. The Home and End keys move the slider to the ends of the trough. For the HScale widget, moving the slider by page_increment is accomplished with Control-Left and Control-Right, while for HScrollbar, it's done with Control-Home and Control-End.

8.5 Example

  This example is a somewhat modified version of the "range controls" test from testgtk.c. It basically puts up a window with three range widgets all connected to the same adjustment, and a couple of controls for adjusting some of the parameters mentioned above and in the section on adjustments, so you can see how they affect the way these widgets work for the user.


/* example-start rangewidgets rangewidgets.c */
#include <gtk/gtk.h>
GtkWidget *hscale, *vscale;
void cb_pos_menu_select( GtkWidget *item,GtkPositionTypepos )
{
/* Set the value position on both scale widgets */
gtk_scale_set_value_pos (GTK_SCALE (hscale), pos);
gtk_scale_set_value_pos (GTK_SCALE (vscale), pos);
}
void cb_update_menu_select( GtkWidget *item,GtkUpdateTypepolicy )
{
/* Set the update policy for both scale widgets */
gtk_range_set_update_policy (GTK_RANGE (hscale), policy);
gtk_range_set_update_policy (GTK_RANGE (vscale), policy);
}
void cb_digits_scale( GtkAdjustment *adj )
{
/* Set the number of decimal places to which adj->value is rounded */
gtk_scale_set_digits (GTK_SCALE (hscale), (gint) adj->value);
gtk_scale_set_digits (GTK_SCALE (vscale), (gint) adj->value);
}
void cb_page_size( GtkAdjustment *get,GtkAdjustment *set )
{
/* Set the page size and page increment size of the sample
 * adjustment to the value specified by the "Page Size" scale */
set->page_size = get->value;
set->page_increment = get->value;
/* Now emit the "changed" signal to reconfigure all the widgets that
 * are attached to this adjustment */
gtk_signal_emit_by_name (GTK_OBJECT (set), "changed");
}
void cb_draw_value( GtkToggleButton *button )
{
/* Turn the value display on the scale widgets off or on depending
 *on the state of the checkbutton */
gtk_scale_set_draw_value (GTK_SCALE (hscale), button->active);
gtk_scale_set_draw_value (GTK_SCALE (vscale), button->active);
}
/* Convenience functions */
GtkWidget *make_menu_item(gchar *name,GtkSignalFunccallback,gpointer data )
{
GtkWidget *item;
item = gtk_menu_item_new_with_label (name);
gtk_signal_connect (GTK_OBJECT (item), "activate",
callback, data);
gtk_widget_show (item);
return(item);
}
void scale_set_default_values( GtkScale *scale )
{
gtk_range_set_update_policy (GTK_RANGE (scale),GTK_UPDATE_CONTINUOUS);
gtk_scale_set_digits (scale, 1);
gtk_scale_set_value_pos (scale, GTK_POS_TOP);
gtk_scale_set_draw_value (scale, TRUE);
}
/* makes the sample window */
void create_range_controls( void )
{
GtkWidget *window;
GtkWidget *box1, *box2, *box3;
GtkWidget *button;
GtkWidget *scrollbar;
GtkWidget *separator;
GtkWidget *opt, *menu, *item;
GtkWidget *label;
GtkWidget *scale;
GtkObject *adj1, *adj2;
/* Standard window-creating stuff */
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_signal_connect (GTK_OBJECT (window), "destroy",
GTK_SIGNAL_FUNC(gtk_main_quit),
NULL);
gtk_window_set_title (GTK_WINDOW (window), "range controls");
box1 = gtk_vbox_new (FALSE, 0);
gtk_container_add (GTK_CONTAINER (window), box1);
gtk_widget_show (box1);
box2 = gtk_hbox_new (FALSE, 10);
gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
gtk_widget_show (box2);
/* value, lower, upper, step_increment, page_increment, page_size */
/* Note that the page_size value only makes a difference for
 * scrollbar widgets, and the highest value you'll get is actually
 * (upper - page_size). */
adj1 = gtk_adjustment_new (0.0, 0.0, 101.0, 0.1, 1.0, 1.0);
vscale = gtk_vscale_new (GTK_ADJUSTMENT (adj1));
scale_set_default_values (GTK_SCALE (vscale));
gtk_box_pack_start (GTK_BOX (box2), vscale, TRUE, TRUE, 0);
gtk_widget_show (vscale);
box3 = gtk_vbox_new (FALSE, 10);
gtk_box_pack_start (GTK_BOX (box2), box3, TRUE, TRUE, 0);
gtk_widget_show (box3);
/* Reuse the same adjustment */
hscale = gtk_hscale_new (GTK_ADJUSTMENT (adj1));
gtk_widget_set_usize (GTK_WIDGET (hscale), 200, 30);
scale_set_default_values (GTK_SCALE (hscale));
gtk_box_pack_start (GTK_BOX (box3), hscale, TRUE, TRUE, 0);
gtk_widget_show (hscale);
/* Reuse the same adjustment again */
scrollbar = gtk_hscrollbar_new (GTK_ADJUSTMENT (adj1));
/* Notice how this causes the scales to always be updated
 * continuously when the scrollbar is moved */
gtk_range_set_update_policy (GTK_RANGE (scrollbar),GTK_UPDATE_CONTINUOUS);
gtk_box_pack_start (GTK_BOX (box3), scrollbar, TRUE, TRUE, 0);
gtk_widget_show (scrollbar);
box2 = gtk_hbox_new (FALSE, 10);
gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
gtk_widget_show (box2);
/* A checkbutton to control whether the value is displayed or not */
button = gtk_check_button_new_with_label("Display value on scale widgets");
gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (button), TRUE);
gtk_signal_connect (GTK_OBJECT (button), "toggled",
GTK_SIGNAL_FUNC(cb_draw_value), NULL);
gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
gtk_widget_show (button);
box2 = gtk_hbox_new (FALSE, 10);
gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
/* An option menu to change the position of the value */
label = gtk_label_new ("Scale Value Position:");
gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
gtk_widget_show (label);
opt = gtk_option_menu_new();
menu = gtk_menu_new();
item = make_menu_item ("Top",
GTK_SIGNAL_FUNC(cb_pos_menu_select),
GINT_TO_POINTER (GTK_POS_TOP));
gtk_menu_append (GTK_MENU (menu), item);
item = make_menu_item ("Bottom", GTK_SIGNAL_FUNC (cb_pos_menu_select), 
 GINT_TO_POINTER (GTK_POS_BOTTOM));
gtk_menu_append (GTK_MENU (menu), item);
item = make_menu_item ("Left", GTK_SIGNAL_FUNC (cb_pos_menu_select),
 GINT_TO_POINTER (GTK_POS_LEFT));
gtk_menu_append (GTK_MENU (menu), item);
item = make_menu_item ("Right", GTK_SIGNAL_FUNC (cb_pos_menu_select),
GINT_TO_POINTER (GTK_POS_RIGHT));
gtk_menu_append (GTK_MENU (menu), item);
gtk_option_menu_set_menu (GTK_OPTION_MENU (opt), menu);
gtk_box_pack_start (GTK_BOX (box2), opt, TRUE, TRUE, 0);
gtk_widget_show (opt);
gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
gtk_widget_show (box2);
box2 = gtk_hbox_new (FALSE, 10);
gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
/* Yet another option menu, this time for the update policy of the
 * scale widgets */
label = gtk_label_new ("Scale Update Policy:");
gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
gtk_widget_show (label);
opt = gtk_option_menu_new();
menu = gtk_menu_new();
item = make_menu_item ("Continuous",
GTK_SIGNAL_FUNC (cb_update_menu_select),
GINT_TO_POINTER (GTK_UPDATE_CONTINUOUS));
gtk_menu_append (GTK_MENU (menu), item);
item = make_menu_item ("Discontinuous",
GTK_SIGNAL_FUNC (cb_update_menu_select),
GINT_TO_POINTER (GTK_UPDATE_DISCONTINUOUS));
gtk_menu_append (GTK_MENU (menu), item);
item = make_menu_item ("Delayed",
 GTK_SIGNAL_FUNC (cb_update_menu_select),
 GINT_TO_POINTER (GTK_UPDATE_DELAYED));
gtk_menu_append (GTK_MENU (menu), item);
gtk_option_menu_set_menu (GTK_OPTION_MENU (opt), menu);
gtk_box_pack_start (GTK_BOX (box2), opt, TRUE, TRUE, 0);
gtk_widget_show (opt);
gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
gtk_widget_show (box2);
box2 = gtk_hbox_new (FALSE, 10);
gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
/* An HScale widget for adjusting the number of digits on the
 * sample scales. */
label = gtk_label_new ("Scale Digits:");
gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
gtk_widget_show (label);
adj2 = gtk_adjustment_new (1.0, 0.0, 5.0, 1.0, 1.0, 0.0);
gtk_signal_connect (GTK_OBJECT (adj2), "value_changed",
GTK_SIGNAL_FUNC (cb_digits_scale), NULL);
scale = gtk_hscale_new (GTK_ADJUSTMENT (adj2));
gtk_scale_set_digits (GTK_SCALE (scale), 0);
gtk_box_pack_start (GTK_BOX (box2), scale, TRUE, TRUE, 0);
gtk_widget_show (scale);
gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
gtk_widget_show (box2);
box2 = gtk_hbox_new (FALSE, 10);
gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
/* And, one last HScale widget for adjusting the page size of the
 * scrollbar. */
label = gtk_label_new ("Scrollbar Page Size:");
gtk_box_pack_start (GTK_BOX (box2), label, FALSE, FALSE, 0);
gtk_widget_show (label);
adj2 = gtk_adjustment_new (1.0, 1.0, 101.0, 1.0, 1.0, 0.0);
gtk_signal_connect (GTK_OBJECT (adj2), "value_changed",
GTK_SIGNAL_FUNC (cb_page_size), adj1);
scale = gtk_hscale_new (GTK_ADJUSTMENT (adj2));
gtk_scale_set_digits (GTK_SCALE (scale), 0);
gtk_box_pack_start (GTK_BOX (box2), scale, TRUE, TRUE, 0);
gtk_widget_show (scale);
gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0);
gtk_widget_show (box2);
separator = gtk_hseparator_new ();
gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 0);
gtk_widget_show (separator);
box2 = gtk_vbox_new (FALSE, 10);
gtk_container_set_border_width (GTK_CONTAINER (box2), 10);
gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, TRUE, 0);
gtk_widget_show (box2);
button = gtk_button_new_with_label ("Quit");
gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
 GTK_SIGNAL_FUNC(gtk_main_quit),
 NULL);
gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0);
GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
gtk_widget_grab_default (button);
gtk_widget_show (button);
gtk_widget_show (window);
}
int main( int argc,
char *argv[] )
{
gtk_init(&argc, &argv);
create_range_controls();
gtk_main();
return(0);
}
/* example-end */


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