【求助】gtk不能更新绘图区域，不知道错在哪里

qiankun11516 · 发表于 2014-11-14 21:20:53

我想在窗口化两个正方形，然后点一下BUTTON这两个正方形变化一下。程序大体都写好了。但是点了BUTTON之后不会更新，必须最小化一下窗口在还原才会更新，不知道问什么~~~
源代码：
#include <gtk/gtk.h>
#include <math.h>
#define DRAWING_AREA_WIDTH 400
#define DRAWING_AREA_HEIGHT 400
#define WINDOW_BORDER_WIDTH 5  //有谁能告诉我gtk_container_set_border_width（）这个函数有什么意义么？
GtkWidget *drawing_area;
GtkWidget *window;
GtkWidget *box1;
GtkWidget *button;
int w = 10;
int h = 10;
gboolean
expose_event_callback (
GtkWidget *widget,
GdkEventExpose *event,
gpointer data)
{
int x1, y1, x2, y2;
GdkColor color;
GdkDrawable *canvas;
GdkGC *gc;
canvas = widget->window;  //不知道在主函数调用这个函数的时候，widget是怎么传递的，看来有时间又要好好看看g_signal_connect的实现机制了
gc = widget->style->fg_gc[GTK_WIDGET_STATE(widget)];
//w = 100;
//h = 100;
gdk_draw_rectangle (canvas, gc, FALSE, 50, 50, w, h); //画方
gdk_draw_rectangle (canvas, gc, FALSE, 100, 100, w, h); //画方
w=w+10;
h=h+10;
return TRUE;
}
gboolean
release ( GtkWidget *widget,
               GdkEvent  *event,
         gpointer data )
{
      //printf("thks");
int x1, y1, x2, y2;
GdkColor color;
GdkDrawable *canvas;
GdkGC *gc;
canvas = widget->window;  //不知道在主函数调用这个函数的时候，widget是怎么传递的，看来有时间又要好好看看g_signal_connect的实现机制了
gc = widget->style->fg_gc[GTK_WIDGET_STATE(widget)];
//w = 100;
//h = 100;
gdk_draw_rectangle (canvas, gc, FALSE, 50, 50, w, h); //画方
gdk_draw_rectangle (canvas, gc, FALSE, 100, 100, w, h); //画方
w=w+10;
h=h+10;
return TRUE;
}
gint delete_event( GtkWidget *widget,
               GdkEvent  *event,
         gpointer data )
{
/* If you return FALSE in the "delete_event" signal handler,
* * GTK will emit the "destroy" signal. Returning TRUE means
* * you don't want the window to be destroyed.
* * This is useful for popping up 'are you sure you want to quit?'
* * type dialogs. */

g_print ("delete event occurred/n");

/* Change TRUE to FALSE and the main window will be destroyed with
* * a "delete_event". */

return FALSE;
}

void destroy( GtkWidget *widget,
            gpointer data )
{
gtk_main_quit ();
}

int main( int argc,
      char *argv[] )
{
/* GtkWidget is the storage type for widgets */

/* This is called in all GTK applications. Arguments are parsed
   * from the command line and are returned to the application. */
gtk_init (&argc, &argv);
box1 = gtk_hbox_new(FALSE, 0);
/* create a new window */
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
button = gtk_button_new_with_label ("Button 1");
gtk_signal_connect (GTK_OBJECT (button), "clicked",
GTK_SIGNAL_FUNC (release), (gpointer) "button 1");
/* When the window is given the "delete_event" signal (this is given
* * by the window manager, usually by the "close" option, or on the
* * titlebar), we ask it to call the delete_event () function
* * as defined above. The data passed to the callback
* * function is NULL and is ignored in the callback function. */
g_signal_connect (G_OBJECT (window), "delete_event",
            G_CALLBACK (delete_event), NULL);

/* Here we connect the "destroy" event to a signal handler.
* * This event occurs when we call gtk_widget_destroy() on the window,
* * or if we return FALSE in the "delete_event" callback. */
g_signal_connect (G_OBJECT (window), "destroy",
            G_CALLBACK (destroy), NULL);

/* Sets the border width of the window. */
gtk_container_set_border_width (GTK_CONTAINER (window), WINDOW_BORDER_WIDTH);
/* Set window title  */
gtk_window_set_title (GTK_WINDOW(window), "Drawing Area");

drawing_area = gtk_drawing_area_new ();
gtk_widget_set_size_request (drawing_area, DRAWING_AREA_WIDTH, DRAWING_AREA_HEIGHT);
g_signal_connect (G_OBJECT(drawing_area), "expose_event", G_CALLBACK(expose_event_callback), NULL);
                                    //expose_event是什么东东，传递给expose_event的参数又是如何进行的？
gtk_box_pack_start(GTK_BOX(box1), drawing_area, TRUE, TRUE, 0);
gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0);
gtk_container_add (GTK_CONTAINER (window), box1);
//gtk_container_add (GTK_CONTAINER(window), drawing_area);
gtk_widget_show_all(window);

gtk_main ();

return 0;
}

谢谢~~

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