示例
这个示例可以说是testgtk.c里的"范围控制"测试部分的修改版。它主要是在一个窗口上放置了三个范围构件，都连接到同一个调整对象，并使用上面以及调整对象部分提到的一些调整参数的控制方法，这样你可以看到它们怎样影响这些构件的使用效果。
#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), "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;
}
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可以注意到程序没有对 "delete_event" 事件调用 g_signal_connect()，仅仅对 "destroy" 信号调用了该函数。但是 "destroy" 函数一样会执行，因为未经处理的 "delete_event" 事件会引发一个 "destroy" 信号给窗口。