How to render/update a small rectangle of GdkImlibImage in a GnomeCanvasImage ?

[Percy Zahl <zahl fkp uni-hannover de>]

Hello Gnome developer ...

I need a fast update of small, rectangular region of a GdkImlibImage,
which is displayed via a GnomeCanvasImageItem.

I tryed the following calls:

[it is:
 GdkImlibImage *gimg; 
 GnomeCanvas *area;
 GnomeCanvasItem *gitem;
]

// change rgb data:
    gimg->rgb_data[...]=...;

// tell imlib that data has changed...
// Doese someone know how to tell Imlib which rectangle was changed ? (I
found no function)
    gdk_imlib_changed_image(gimg);

// this does not refresh "line i":
    gnome_canvas_request_redraw( GNOME_CANVAS(area), 0., i,
gimg->rgb_width, i);

// This works, but it is quite slow, because is repaints the whole
image:
    gnome_canvas_item_request_update(GNOME_CANVAS_ITEM(gitem));

Any Idea ?

-- 
with friendly regards / mit freundlichem Gruss,
                   Percy Zahl
Email: zahl@fkp.uni-hannover.de
Dipl.Phys. P.Zahl: http://www.fkp.uni-hannover.de/~zahl/main.html
Institut f"ur Festk"orperphysik, Appelstr. 2, D-30167 Hannover
Tel.Labor: +49 (0)511/762-4825, Fax: -4877