Re: pixmap to pixbuf

ephrem boudonnet <[email protected]> writes:

> Hi Espen,
> 
> I would like to get a pixbuf from my offscreen drawable.
> I have written these bindings:
> 
> (defbinding colormap-get-system () colormap)
> 
> (defbinding pixbuf-get-from-drawable() (referenced pixbuf)
>   (drawable drawable)
>   (colormap colormap)
>   (srx int)
>   (sry int)
>   (destx int)
>   (desty int)
>   (width int)
>   (heigth int))
> 
> But when I call this function:
> 
> (defun pixmap-to-pixbuf ()
>   (let ((map (gdk::pixmap-new 10 10 1))
>      (cmap (gdk::colormap-get-system)))
>     (gdk::pixbuf-get-from-drawable map cmap 0 0 0 0 10 10)
>     ))
> 
> I have this error message:
> 
> Gdk: gdk_pixbuf_get_from_drawable: assertion `dest->colorspace == 
> GDK_COLORSPACE_RGB' failed
>    [Condition of type glib:critical-log-level]
> 
> In fact I don't know how to "specify" the destination pixbuf as the 
> documentation says:
> " If the specified destination pixbuf /dest/ is NULL, then this function 
> will create an RGB pixbuf with 8 bits per channel and no alpha".
> 
> Have you any idea?

Yes, a pixbuf could be given as the first argument to
GdkPixbufGetFromDrawable, which is missing in your definition.

This is how I would have done it:

(defbinding %pixbuf-get-from-drawable () (referenced pixbuf)
  (dest (or null pixbuf))
  (drawable drawable)
  (colormap (or null colormap))
  (src-x int)
  (src-y int)
  (dest-x int)
  (dest-y int)
  (width int)
  (height int))

(defun pixbuf-get-from-drawable (drawable &key (src-x 0) (src-y 0) (dest-x 0) (dest-y 0) width height colormap dest)
  (unless (or (and width height) (not (typep drawable 'window)))
    (error "Width and height must be specified for windows"))
  (or
   (%pixbuf-get-from-drawable dest drawable
    (cond
     (colormap)
     ((slot-boundp drawable 'colormap) nil)
     ((colormap-get-system)))
    src-x src-y dest-x dest-y (or width -1) (or height -1))
   (error "Couldn't get pixbuf from drawable")))

-- 
Espen