GTK＋里为什么不能显示透明背景？

发布于 2022-08-08 12:26:00 字数 4212 浏览 12 评论 8

这具是我的代码，基本上是照着网上找的资料来的，但是为什么不能显示透明背景呢？
这里的cheng.png是背景为透明的图片，效果如附件中所示

#include<gtk/gtk.h>
#include"pixmap.h"

int main(int argc, char * argv[])
{
      GtkWidget * window, * fixed, * image, * eventbox;
      GdkPixbuf * pixbuf;
      GdkPixmap * pixmap, * pixmap2;
      GdkBitmap * bitmap, bitmap2;

gtk_init(&argc, &argv);

      window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
      gtk_window_set_title(GTK_WINDOW(window), "bg";
      // Very important!!
      gtk_widget_set_app_paintable(window, TRUE);
      gtk_widget_realize(window);
//    gtk_window_fullscreen(GTK_WINDOW(window));
      gtk_widget_set_size_request(window, 412, 550);
      g_signal_connect(G_OBJECT(window), "delete_event",
                     G_CALLBACK(gtk_main_quit), NULL);

fixed = gtk_fixed_new();
gtk_container_add(GTK_CONTAINER(window), fixed);

//    set_widget_bg(fixed, "cheng.png";
      pixbuf = gdk_pixbuf_new_from_file("cheng.png", NULL);
//    gdk_pixbuf_render_pixmap_and_mask(pixbuf, &pixmap2, &bitmap2, 12;
      pixmap = gdk_pixmap_new(fixed->window, gdk_pixbuf_get_width(pixbuf),
                     gdk_pixbuf_get_height(pixbuf), -1);
      gdk_pixbuf_render_to_drawable(pixbuf, pixmap,
                     fixed->style->fg_gc[GTK_STATE_NORMAL],
                     0, 0, 0, 0,
                     gdk_pixbuf_get_width(pixbuf),
                     gdk_pixbuf_get_height(pixbuf),
                     GDK_RGB_DITHER_NORMAL, 0, 0);
      g_object_unref(pixbuf);
      gdk_window_set_back_pixmap(fixed->window, pixmap, FALSE);
//    gtk_widget_shape_combine_mask(fixed, bitmap2, 0, 0);
      gtk_widget_show(fixed);

      gtk_widget_show(window);
      gtk_main();