goocanvas vs crcanvas,which better?

[chen zhixin <thexin1985 gmail com>]

Program need to draw realtime lines on per frame,first time i use
cairo_surface_create_similar  and draw surface on the frame.
(frame draw on GtkDrawingArea),this make fast on my pc and the
Machine(use slitaz system),but when i use ubuntu on the machine,the
Xorg process take 100% cpu,this make me craze,i still don't kown why.

I want to use canvas to change this,there are some cairo
canvas,goocanvas can be found in lib.gnome.org,it will be a part of
gnome?
goocanvas vs crcanvas ,which should i use? or somebody have a good
method to do these.

software do these:
1. capture frame from TV card by V4L2,and then change fmt from yuyv to gray.
2. draw gray frame to GtkDrawingarea by gdk_draw_gray to a GdkPixmap.
3. do some other things on the GdkPixmap,such as draw pixbuf and
text,and then gdk_draw_drawable.
4. measure on the drawingarea.such as
line,circle,ellipse,polygon,arrow,draw results on the frame.
5. do other things ,such as zoom,save as image,video.

there are some problems:
1. can create cairo surface on GRAY picture,then i can draw something on it ?