Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!ncar!ico!attc!marbru
From: marbru@attc.UUCP (Martin Brunecky)
Newsgroups: comp.windows.x
Subject: Re: XImages
Message-ID: <936@attc.UUCP>
Date: 17 Dec 90 18:00:58 GMT
References: <927@attc.UUCP> <9012121928.AA08593@hansen.com> <935@attc.UUCP>
Reply-To: marbru@auto-trol.UUCP (Martin Brunecky)
Organization: Auto-trol Technology, Denver
Lines: 45

>In article <9012121928.AA08593@hansen.com> jim@ncd.COM (Jim Fulton) writes:
>
>       ImageByteOrder specifies whether the Most- or Least-Significant Byte
>	of each bitmap-unit will be returned first.

I replied:
   Than how do you explain that the Sun's Open Windows (2.0) server and
   DECwidnows(Ultrix or VMS) servers report oposite ImageByteOrder, but the 
   first *byte* in returned image (accessed as (char*))is my pixel[0,0] for 
   both servers ? (talking 8 bitplane systems on both sides, scanline unit
   32 on both sides).

Now, when I looked at the MIT code: XImUtil.c, I have found this code:

static unsigned long _XGetPixel8 (ximage, x, y)
    register XImage *ximage;
    int x;
    int y;
{
        unsigned char pixel;

        if ((ximage->format == ZPixmap) && (ximage->bits_per_pixel == 8)) {
            pixel = ((unsigned char *)ximage->data)
                        [y * ximage->bytes_per_line + x];
            if (ximage->depth != 8)       ^^^^^^^^^^^^^^^^^^^!!!!
                pixel &= low_bits_table[ximage->depth];
            return pixel;
        } else {
            _XInitImageFuncPtrs(ximage);
            return XGetPixel(ximage, x, y);
        }
}

   Note this code does NOT pay ANY attention to the ImageByteOrder, yet
   it will be used whenever the format (the first line) is matched.

   Is this a deviation from the protocol, or am I interpretting your
   statement incorrectly ?


-- 
=*= Opinions presented here are solely of my own and not those of Auto-trol =*=
Martin Brunecky                           {...}sunpeaks!auto-trol!marbru
(303) 252-2499                        (sometimes also:  marbru@auto-trol.COM )
Auto-trol Technology Corp. 12500 North Washington St., Denver, CO 80241-2404