下面演示了如何在窗口中增加一个按钮，示例代码均有注释
#include <gtk/gtk.h>
static void print_hello (GtkWidget *widget,gpointer data)
{
//这是一个回调函数，这个data表示传给回调函数的参数。
g_print ("你好，世界\n");
}
static gboolean on_delete_event (GtkWidget *widget,GdkEvent *event,gpointer data)
{
//如果返回FALSE在delete_event信号处理中，GTK将发送destroy信号，否则不会，这样窗口就不会关闭。
g_print ("delete event occurred\n");
return TRUE;
}
int main (int argc,char *argv[])
{
GtkWidget *window;
GtkWidget *button;
//初始化gtk应用程序
gtk_init (&argc, &argv);
//创造新的窗口，设置它的标题
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window), "你好");
//将delete_event信号绑定在on_delte_devent回调函数上，传递的参数为NULL
g_signal_connect (window, "delete-event", G_CALLBACK (on_delete_event), NULL);
//将destroy信号绑定在gtk_main_quit回调函数上，传递的参数为NULL
g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit), NULL);
//设置窗口的边框宽度
gtk_container_set_border_width (GTK_CONTAINER (window), 10);
//创建一个新的标签
button = gtk_button_new_with_label ("Hello World");
//处理按钮的clicked信号
g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);
//g_signal_connect_swapped将clicked信号连接到window窗口的gtk_widget_destroy事件中。
g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_widget_destroy), window);
//将按钮加入到容器中
gtk_container_add (GTK_CONTAINER (window), button);
//显示这个按钮
gtk_widget_show (button);
//显示窗口
gtk_widget_show (window);
//开始GTK的主循环
gtk_main ();
return 0;
}
在XMANGER下用VIM编写好后，编译运行
#include <gtk/gtk.h>
/* Surface to store current scribbles */
static cairo_surface_t *surface = NULL;
static void
clear_surface (void)
{
cairo_t *cr;
cr = cairo_create (surface);
cairo_set_source_rgb (cr, 1, 1, 1);
cairo_paint (cr);
cairo_destroy (cr);
}
/* Create a new surface of the appropriate size to store our scribbles */
static gboolean
configure_event_cb (GtkWidget *widget,
GdkEventConfigure *event,
gpointer data)
{
if (surface)
cairo_surface_destroy (surface);
surface = gdk_window_create_similar_surface (gtk_widget_get_window (widget),
CAIRO_CONTENT_COLOR,
gtk_widget_get_allocated_width (widget),
gtk_widget_get_allocated_height (widget));
/* Initialize the surface to white */
clear_surface ();
/* We've handled the configure event, no need for further processing. */
return TRUE;
}
/* Redraw the screen from the surface. Note that the ::draw
* signal receives a ready-to-be-used cairo_t that is already
* clipped to only draw the exposed areas of the widget
*/
static gboolean
draw_cb (GtkWidget *widget,
cairo_t *cr,
gpointer data)
{
cairo_set_source_surface (cr, surface, 0, 0);
cairo_paint (cr);
return FALSE;
}
/* Draw a rectangle on the surface at the given position */
static void
draw_brush (GtkWidget *widget,
gdouble x,
gdouble y)
{
cairo_t *cr;
/* Paint to the surface, where we store our state */
cr = cairo_create (surface);
cairo_rectangle (cr, x - 3, y - 3, 6, 6);
cairo_fill (cr);
cairo_destroy (cr);
/* Now invalidate the affected region of the drawing area. */
gtk_widget_queue_draw_area (widget, x - 3, y - 3, 6, 6);
}
/* Handle button press events by either drawing a rectangle
* or clearing the surface, depending on which button was pressed.
* The ::button-press signal handler receives a GdkEventButton
* struct which contains this information.
*/
static gboolean
button_press_event_cb (GtkWidget *widget,
GdkEventButton *event,
gpointer data)
{
/* paranoia check, in case we haven't gotten a configure event */
if (surface == NULL)
return FALSE;
if (event->button == 1)
{
draw_brush (widget, event->x, event->y);
}
else if (event->button == 3)
{
clear_surface ();
gtk_widget_queue_draw (widget);
}
/* We've handled the event, stop processing */
return TRUE;
}
/* Handle motion events by continuing to draw if button 1 is
* still held down. The ::motion-notify signal handler receives
* a GdkEventMotion struct which contains this information.
*/
static gboolean
motion_notify_event_cb (GtkWidget *widget,
GdkEventMotion *event,
gpointer data)
{
int x, y;
GdkModifierType state;
/* paranoia check, in case we haven't gotten a configure event */
if (surface == NULL)
return FALSE;
/* This call is very important; it requests the next motion event.
* If you don't call gdk_window_get_pointer() you'll only get
* a single motion event. The reason is that we specified
* GDK_POINTER_MOTION_HINT_MASK to gtk_widget_set_events().
* If we hadn't specified that, we could just use event->x, event->y
* as the pointer location. But we'd also get deluged in events.
* By requesting the next event as we handle the current one,
* we avoid getting a huge number of events faster than we
* can cope.
*/
gdk_window_get_pointer (event->window, &x, &y, &state);
if (state & GDK_BUTTON1_MASK)
draw_brush (widget, x, y);
/* We've handled it, stop processing */
return TRUE;
}
static void
close_window (void)
{
if (surface)
cairo_surface_destroy (surface);
gtk_main_quit ();
}
int
main (int argc,
char *argv[])
{
GtkWidget *window;
GtkWidget *frame;
GtkWidget *da;
gtk_init (&argc, &argv);
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window), "Drawing Area");
g_signal_connect (window, "destroy", G_CALLBACK (close_window), NULL);
gtk_container_set_border_width (GTK_CONTAINER (window), 8);
frame = gtk_frame_new (NULL);
gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
gtk_container_add (GTK_CONTAINER (window), frame);
da = gtk_drawing_area_new ();
/* set a minimum size */
gtk_widget_set_size_request (da, 100, 100);
gtk_container_add (GTK_CONTAINER (frame), da);
/* Signals used to handle the backing surface */
g_signal_connect (da, "draw",
G_CALLBACK (draw_cb), NULL);
g_signal_connect (da,"configure-event",
G_CALLBACK (configure_event_cb), NULL);
/* Event signals */
g_signal_connect (da, "motion-notify-event",
G_CALLBACK (motion_notify_event_cb), NULL);
g_signal_connect (da, "button-press-event",
G_CALLBACK (button_press_event_cb), NULL);
/* Ask to receive events the drawing area doesn't normally
* subscribe to. In particular, we need to ask for the
* button press and motion notify events that want to handle.
*/
gtk_widget_set_events (da, gtk_widget_get_events (da)
| GDK_BUTTON_PRESS_MASK
| GDK_POINTER_MOTION_MASK
| GDK_POINTER_MOTION_HINT_MASK);
gtk_widget_show_all (window);
gtk_main ();
return 0;
}
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