1.If you want a different splash image for GRUB, you are limited to a 14-color X Window pixmap (. xpm) file that must be gzipped.
如果您想对GRUB使用不同的启动图像，那么您只能使用14色XWindowpixmap（.xpm）文件，而且文件必须被gzip压缩。
2.A backing pixmap is allocated when the window is shown, and is deallocated when it becomes hidden.
一个背景象素映射是当window显示时分配，当隐藏的时候释放。
3.Next, we check if cache already contains the necessary pixmap.
下一步，检查缓存是否已经有了需要的位图。
4.pixmap. font_name - Sets the font to be used with the given widget. font_name
设置要使用的字体与给定的部件。
5.Produce pixmaps and pixmap masks of Images
产生图像的位图与位图掩码