[comp.windows.x] ZPixmap, XPutImage question, X11R4

jason@tfs.UUCP (Jason Venner) (09/18/90)

In the PutImage code for ZPixmap's it specifically ignores the case
where the image data is in bytes, and the bits in the bytes need to be
reversed.

Why is this?

	if (((image->byte_order == dpy->byte_order) ||
		  (image->bits_per_pixel == 8)) &&
		 ((long)image->bytes_per_line == bytes_per_dest) &&
		 ((req_xoffset == 0) ||
		  ((req_yoffset + req->height) < image->height))) {
		Data(dpy, (char *)src, length);
		if (shifted_src)
		  Xfree((char *)shifted_src);
		return;
	}

rws@EXPO.LCS.MIT.EDU (Bob Scheifler) (09/19/90)

    In the PutImage code for ZPixmap's it specifically ignores the case
    where the image data is in bytes, and the bits in the bytes need to be
    reversed.

    Why is this?

Bits in a byte never need to be revered in Z format.  Z format always
contains "integer" values, with the usual bit order for an integer
representation.  Bit order only affects XY format.  Only byte order
can vary for Z format.