From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.0 required=5.0 tests=BAYES_00,FORGED_HOTMAIL_RCVD2,
	FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: a07f3367d7,96b1bf0c24ced968
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII
Received: by 10.224.181.75 with SMTP id bx11mr6236171qab.7.1346447579442;
        Fri, 31 Aug 2012 14:12:59 -0700 (PDT)
Received: by 10.52.38.99 with SMTP id f3mr1749184vdk.5.1346447579408; Fri, 31
 Aug 2012 14:12:59 -0700 (PDT)
Path: 
 da15ni7637554qab.0!nntp.google.com!b19no129641qas.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail
Newsgroups: comp.lang.ada
Date: Fri, 31 Aug 2012 14:12:59 -0700 (PDT)
In-Reply-To: <50406532$0$10734$5b6aafb4@news.zen.co.uk>
Complaints-To: groups-abuse@google.com
Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=62.202.72.93;
 posting-account=gRqrnQkAAAAC_02ynnhqGk1VRQlve6ZG
NNTP-Posting-Host: 62.202.72.93
References: <7bd3df18-178b-4735-ac43-c6bb6df9e999@googlegroups.com>
 <50406532$0$10734$5b6aafb4@news.zen.co.uk>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <61c38064-4eef-425d-8936-c68f68ca6dbd@googlegroups.com>
Subject: Re: Question: re Image Files.
From: gautier_niouzes@hotmail.com
Injection-Date: Fri, 31 Aug 2012 21:12:59 +0000
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
Date: 2012-08-31T14:12:59-07:00
List-Id: <comp.lang.ada>


Le vendredi 31 ao=FBt 2012 09:18:11 UTC+2, Mark Murray a =E9crit=A0:

> Yes, but you have to handle each individual image format (GIF, JPEG,
> BMP etc) separately. This is a LOT of work to write a general program.

Sure. The good news is that it is already done :-)
Download or check-out GID: http://gen-img-dec.sf.net/=20
Then all the work is to define a container, say a flat byte buffer or a two=
-dimensional array, then define 2 procedures, e.g. here for a flat buffer:

    procedure Set_X_Y (x, y: Natural) is
    begin
      idx:=3D 3 * (x + image_width * (image_height - 1 - y));
    end Set_X_Y;
    --
    procedure Put_Pixel (
      red, green, blue : Primary_color_range;
      alpha            : Primary_color_range
    )
    is
    begin
      buffer(idx..idx+2):=3D (red, green, blue);
      idx:=3D idx + 3;
    end Put_Pixel;

plus a feedback procedure that can be null (just there for showing progess)=
, then instanciate a procedure:

    procedure Load_image is
      new GID.Load_image_contents(
        Primary_color_range,=20
        Set_X_Y,
        Put_Pixel,=20
        Feedback,=20
        GID.fast
      );

An that's it! PNG, BMP, GIF, JPEG, TGA are auto-detected.
You don't need to tell GID under what format the image is encoded.
I guess Austin is trying to do steganography.
The simplest way it to take test\mini.adb and customize it for that purpose=
.
Have fun!
_________________________=20
Gautier's Ada programming=20
http://freecode.com/users/gdemont