#include <gtk/gtk.h>
GtkWidget *hscale, *vscale;
void cb_pos_menu_select( GtkWidget *item, GtkPositionType pos )
{
/* 设置两个比例构件的比例值的显示位置 */
   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, GtkUpdateType policy )
{
/* 设置两个比例构件的更新方式 */
   gtk_range_set_update_policy (GTK_RANGE (hscale), policy);
   gtk_range_set_update_policy (GTK_RANGE (vscale), policy);
}
void cb_digits_scale( GtkAdjustment *adj )
{
/* 设置 adj->value 圆整的小数位数 */
   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 )
{
/* 将示例调整对象的 page size 和 page increment size 设置
* 为"Page Size"比例构件指定的值 */
   set->page_size = get->value;
   set->page_increment = get->value;
/* 设置调整对象的值并使它引发一个 "changed" 信号,以重新配置所有
* 已经连接到这个调整对象的构件。 */
   gtk_adjustment_set_value (set, CLAMP (set->value,
             set->lower, (set->upper - set->page_size)));
}
void cb_draw_value( GtkToggleButton *button )
{
/* 根据复选按钮的状态设置在比例构件上是否显示比例值 */
   gtk_scale_set_draw_value (GTK_SCALE (hscale), button->active);
   gtk_scale_set_draw_value (GTK_SCALE (vscale), button->active);
}
/* 方便的函数 */
GtkWidget *make_menu_item (gchar *name, GCallback callback, gpointer data)
{
   GtkWidget *item;
   item = gtk_menu_item_new_with_label (name);
   g_signal_connect (G_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);
}
/* 创建示例窗口 */
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;
/* 标准的创建窗口代码 */
   window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
   g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK (gtk_main_quit), NULL);
   gtk_window_set_title (GTK_WINDOW (window), "RT's 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 */
/* 注意,page_size 值只对滚动条构件有区别,并且,你实际上能取得的最高值
* 是(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);
/* 重新使用同一个调整对象 */
   hscale = gtk_hscale_new (GTK_ADJUSTMENT (adj1));
   gtk_widget_set_size_request (GTK_WIDGET (hscale), 200, -1);
   scale_set_default_values (GTK_SCALE (hscale));
   gtk_box_pack_start (GTK_BOX (box3), hscale, TRUE, TRUE, 0);
   gtk_widget_show (hscale);
/* 再次重用同一个调整对象 */
   scrollbar = gtk_hscrollbar_new (GTK_ADJUSTMENT (adj1));
/* 注意,这导致当滚动条移动时,比例构件总是连续更新 */
   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);
/* 用一个复选按钮控制是否显示比例构件的值 */
   button = gtk_check_button_new_with_label("Display value on scale widgets");
   gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (button), TRUE);
   g_signal_connect (G_OBJECT (button), "toggled",
                     G_CALLBACK (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);
/* 用一个选项菜单以改变显示值的位置 */
   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", G_CALLBACK (cb_pos_menu_select),
                          GINT_TO_POINTER (GTK_POS_TOP));
   gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
   item = make_menu_item ("Bottom", G_CALLBACK (cb_pos_menu_select),
                          GINT_TO_POINTER (GTK_POS_BOTTOM));
   gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
   item = make_menu_item ("Left", G_CALLBACK (cb_pos_menu_select),
                           GINT_TO_POINTER (GTK_POS_LEFT));
   gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
   item = make_menu_item ("Right", G_CALLBACK (cb_pos_menu_select),
                           GINT_TO_POINTER (GTK_POS_RIGHT));
   gtk_menu_shell_append (GTK_MENU_SHELL (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);
/* 另一个选项菜单,这里是用于设置比例构件的更新方式 */
   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", G_CALLBACK (cb_update_menu_select),
                           GINT_TO_POINTER (GTK_UPDATE_CONTINUOUS));
   gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
   item = make_menu_item ("Discontinuous", G_CALLBACK (cb_update_menu_select),
                          GINT_TO_POINTER (GTK_UPDATE_DISCONTINUOUS));
   gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
   item = make_menu_item ("Delayed", G_CALLBACK (cb_update_menu_select),
                          GINT_TO_POINTER (GTK_UPDATE_DELAYED));
   gtk_menu_shell_append (GTK_MENU_SHELL (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);
/* 一个水平比例构件,用于调整示例比例构件的显示小数位数。 */
   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);
   g_signal_connect (G_OBJECT (adj2), "value_changed", 
                     G_CALLBACK (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);
/* 以及,最后一个水平比例构件用于调整滚动条的 page size。 */
   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);
   g_signal_connect (G_OBJECT (adj2), "value_changed",
                     G_CALLBACK (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");
   g_signal_connect_swapped (G_OBJECT (button), "clicked",
                             G_CALLBACK (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;
}