Digit image processing.

[Nengming Zhang <znm china com>]

I'd like to do some digit image processing experiments. I'm now studying
GIMP, but cann't fully understand, although it's perfectly good. Many
problems arise:
    (1)    Read/Write image ( Does GIMP uses plug-ins?)
    (2)   The image in the memory.(Does it uses GdkPixmap data
structure?)
    The _GdkImage structure and _GdkVisual is somewhat complicate. Does
anyone please give me some explanations or send me some documention.
     (3)  Where can I add my code in GIMP so that  without much
alternation I can process the   GdkPixmap  in( 2).
    (4)   Does "display" is something copy   GdkPixmap to  GdkDrawable
or GdkWindow


struct _GdkVisual
                {
                  GdkVisualType type;
                  gint depth;
                  GdkByteOrder byte_order;
                  gint colormap_size;
                  gint bits_per_rgb;

                  guint32 red_mask;
                  gint red_shift;
                  gint red_prec;

                  guint32 green_mask;
                  gint green_shift;
                  gint green_prec;

                  guint32 blue_mask;
                  gint blue_shift;
                  gint blue_prec;
                };
struct _GdkImage
                {
                  GdkImageType  type;
                  GdkVisual    *visual;
                 GdkByteOrder  byte_order;
                  guint16       width;
                  guint16       height;
                  guint16       depth;
                  guint16       bpp;
                  guint16       bpl;
                  gpointer      mem;
                };