如何将GtkWindow的背景设置为图像？

Question

我有一个简单的C GTKLinux应用程序,需要将主窗口的背景设置为GIF文件中的图像.我做了一些阅读,似乎我应该能够做到以下几点:

1-将背景图像填充到GdkPixbuf使用gdk_pixbuf_new_from_file()
2-用于gdk_pixbuf_render_pixmap_and_mask()渲染GdkPixbuf到GdkPixMap
3集的背景中GtkWindow使用gdk_window_set_back_pixmap()

呼叫gdk_window_set_back_pixmap()似乎需要一个GdKWindow而不是一个GtkWindow.我的代码不起作用,下面是我的具体问题.

/*
 * Compile me with:
 *   gcc -o reels reels.c $(pkg-config --cflags --libs gtk+-2.0 gmodule-2.0)
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>

/* GTK */
#include <gdk/gdkx.h>
#include <gtk/gtk.h>

/**** prototypes ****/
static void destroy (GtkWidget*, gpointer);
GdkPixbuf *create_pixbuf(const gchar * filename);
/********************/

GtkWidget   *images[3][5];

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


GdkPixbuf *create_pixbuf(const gchar * filename)
{
   GdkPixbuf *pixbuf;
   GError *error = NULL;
   pixbuf = gdk_pixbuf_new_from_file(filename, &error);
   if(!pixbuf) {
      fprintf(stderr, "%s\n", error->message);
      g_error_free(error);
   }

   return pixbuf;
}


int main (int argc, char *argv[])
{
  GtkWidget *window, *table;
    GdkPixbufAnimation *animation;
    GtkWidget *image;
    int x,y;    
    GdkPixbuf *pixBuf;
    GdkPixmap *pixMap;

    gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_default_size (GTK_WINDOW (window), 628, 530);
  gtk_window_set_title (GTK_WINDOW (window), "Demo");
  gtk_container_set_border_width (GTK_CONTAINER (window), 10);
    //gtk_window_set_decorated( GTK_WINDOW(window), FALSE );

    pixBuf = create_pixbuf("background.gif");
    gdk_pixbuf_render_pixmap_and_mask(pixBuf, &pixMap, NULL, 255);
    gdk_window_set_back_pixmap( GDK_WINDOW (window), pixMap, (gboolean) TRUE);



#if 0
    /*  some code I found that is supposed to create a background image..
        Can't seem to get it converted correctly into 'C'
    */    

area=gtk.Drawingarea()

pixbuf=gtk.gdk.pixbuf_new_from_file('background.png')
pixmap, mask=pixbuf.render_pixmap_and_mask()

area.window.set_back_pixmap(pixmap, False)
#endif     

  g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK (destroy), NULL);
  table = gtk_table_new (3, 5, TRUE);

    /* setup animated gifs */
    for( y = 0; y < 3; y++ )
    {
        for( x = 0; x < 5; x++ )
        {
            /* set each Image widget to spin GIF */
            images[y][x] = gtk_image_new_from_file("spinning.gif");;
            gtk_table_attach (GTK_TABLE (table), images[y][x], x, x+1, y, y+1,    GTK_EXPAND, GTK_SHRINK, 0, 0);            
        }
    }

  /* Add five pixels of spacing between every row and every column. */
  gtk_table_set_row_spacings (GTK_TABLE (table), 5);
  gtk_table_set_col_spacings (GTK_TABLE (table), 5);

  gtk_container_add (GTK_CONTAINER (window), table);
  gtk_widget_show_all (window);

  gtk_main ();

  return 0;
}

代码编译并运行但我得到以下运行时错误(我预期,因为我不知道如何GdkWindow从a 派生GtkWindow:

(卷轴:10951):GLib-GObject-WARNING**:来自GtkWindow' toGdkWindow的无效演员'

(卷轴:10951):Gdk-CRITICAL**:gdk_window_set_back_pixmap:断言`GDK_IS_WINDOW(窗口)'失败

我的问题是:

1-如何GdkWindow从代码主窗口(GtkWindow)中派生出一个？
2-我是否需要使用绘图区？
3-我需要做什么才能将background.gif图像显示为主窗口的背景？

任何帮助将不胜感激.我已经看过许多代码片段,但是我很难将它们整合在一起,而且我Gtk还是很新的.

Answer 1

我的问题是:

1-如何从代码主窗口(GtkWindow)派生GdkWindow？
2-我是否需要使用绘图区？
3-我需要做什么才能将background.gif图像显示为主>窗口的背景？

如果要在gtk窗口中设置像背景一样的图像,则应该:
1 - 将图像加载到GdkPixbuf或变体.(gdk_pixbuf_new_from_file)
2 - 创建像素图和掩码位图.(gdk_pixbuf_render_pixmap_and_mask())
3 - 创建一个包含小部件样式信息的GtkStyle.
4 - 将渲染像素图加载到样式中.
5 - 将GtkStyle设置为主窗口.

一个例子:

#include <gtk/gtk.h>
#include <stdio.h>
#include <stdlib.h>

GdkPixbuf *load_pixbuf_from_file (const char *filename)
{
    GError *error = NULL;
    GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file (filename, &error);

    if (pixbuf == NULL)
    {
        g_print ("Error loading file: %d : %s\n", error->code, error->message);
        g_error_free (error);
        exit (1);
    }
    return pixbuf;
}

GdkPixbufAnimation *load_pixbuf_animation_from_file (const char *filename)
{
    GError *error = NULL;
    GdkPixbufAnimation *pixbuf = gdk_pixbuf_animation_new_from_file (filename, &error);

    if (pixbuf == NULL)
    {
        g_print ("Error loading file: %d : %s\n", error->code, error->message);
        g_error_free (error);
        exit (1);   
    }
    return pixbuf;
}

int main (int argc, char **argv)
{
    GtkWidget *window = NULL;
    GdkPixbuf *image = NULL;
    GdkPixbufAnimation * anim = NULL;
    GtkWidget *widget = NULL;
    GdkPixmap *background = NULL;
    GtkStyle *style = NULL;

    gtk_init (&argc, &argv);
    /* Load a non animated gif */
    image = load_pixbuf_from_file ("/home/midnigther/Desktop/pict.gif");
    //  widget = gtk_image_new_from_pixbuf (image);
    gdk_pixbuf_render_pixmap_and_mask (image, &background, NULL, 0);
    style = gtk_style_new ();
    style->bg_pixmap [0] = background;
    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title (GTK_WINDOW(window), "Load Image");
    gtk_window_set_default_size (GTK_WINDOW (window), 400, 300);
    gtk_widget_set_style (GTK_WIDGET(window), GTK_STYLE (style));
    gtk_window_set_transient_for (GTK_WINDOW (window), NULL);

    GtkWidget *hbox = NULL;
    hbox = gtk_hbox_new (0, FALSE);
    gtk_container_add (GTK_CONTAINER(window), hbox);

    GtkWidget *button = NULL;
    button = gtk_button_new_with_label ("Sonic");
    gtk_box_pack_start (GTK_BOX (hbox), button, FALSE, FALSE, 0);

    gtk_widget_show_all (window);
    gtk_main ();
    return 0;
}