[gtkada] Missing Gdk_Pixbuf_New_From_Data

[Dmitry A. Kazakov]

On Tue, 25 Sep 2007 22:06:38 +0800, you wrote:

> I am looking at GtkAda source (previous version and the latest 2.10.0  
> from Libre site). I found on the last line in gdk-pixbuf.ads that  
> gdk_pixbuf_new_from_data is missing or is not implemented. Why?

Because it requires flat arrays I guess.

You can use it directly using pragma Import. For example:

   X_Size : constant GInt := 16;
   Y_Size : constant GInt := 16;
   type Pixbuf_Image is array (Natural range 0..1023) of GUChar;
   pragma Convention (C, Pixbuf_Image);
   Pixels : constant Pixbuf_Image :=
   (  255,255,255,  0, 255,255,255,  0, 255,255,255,  0, 255,255,255,  0,
      255,255,255,  0, 255,255,255,  0, 255,255,255,  0, 255,255,255,  0,
      255,255,255,  0, 255,255,255,  0, 255,255,255,  0, 255,255,255,  0,
      255,255,255,  0, 255,255,255,  0, 255,255,255,  0, 255,255,255,  0,
     ...
   );
   function Get_Pixbuf
            (  Data       : Pixbuf_Image   := Pixels;
               Colorspace : Gdk_Colorspace := Colorspace_RGB;
               Has_Alpha  : GBoolean := 1;
               Bits       : Int := 8;
               Width      : Int := Int (X_Size);
               Height     : Int := Int (Y_Size);
               Rowstride  : Int := 64;
               Fn         : Address := Null_Address;
               Fn_Data    : Address := Null_Address
            )  return Gdk_Pixbuf;
   pragma Import (C, Get_Pixbuf, "gdk_pixbuf_new_from_data");

> Is there any method to read pixbuf from Ada.Streams? I believe the  
> missing function can do that with some implementation of conversion  
> and stuff. Has anyone done this before?

I did a slightly different thing, a generator of Ada packages from XPM
files. See

   http://www.dmitry-kazakov.de/ada/gtkada_contributions.htm#xpm2gtkada

With streams, you would first read the image pixels from the stream into
the memory and then call gdk_pixbuf_new_from_data. If you don't know the
image size in advance as in my example, you can use System.Address in the
first parameter of gdk_pixbuf_new_from_data instead.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de