daniel@mirsa.inria.fr (Daniel Dardailler) (02/27/89)
Here are the first comments we received about the PAX format, with our answers. |> From: Kent Landfield, kent%ssbell.uucp@uunet.uu.net |> I suggest that you rename it to something other than PAX. |> Pax is an archiving utility that reads and writes tar and cpio formats, OK. We will propose: PDF (Pixmap Distribution Format) -- our favorite XPM (X PixMap) -- with XBM for X bitmap format APX (Ascii PiXmap) So for all following postings, use "PDF" in the subject line, and no longer "PAX" (we will soon post a new version with the right diminutive). |> From: bzs@Encore.COM (Barry Shein) |> |> Good thing to bring up. |> |> Although I see the desires of the design, which are good, it seems |> like tying the colormap to, essentially, the ASCII printable character |> set (probably less without contortions) is an artificial and probably |> ultimately problematic limitation. You obviously missed the "_char_per_pixel" field. Re-read our posting. |> From: janssen@titan.sw.mcc.com (Bill Janssen) |> |> This is a nice idea, but hard to read from Lisp. I would prefer something |> closer to the BDF format, with fewer formatting characters that are |> language dependent. But you are able to read a X11 bitmap file, aren't you? You may also have used XReadBitmapFile or its Lisp alter-ego. We thought it was better to be compatible with C rather than imcompatible with everybody. |> From: markc@hpcvlx.HP.COM (Mark Cook) |> What's wrong the I/O file format already in use by xwd and xwud? I |> realize that they don't constitute a 'standard' format, but they are |> already in wide use (via the MIT distribution). The XImage they use |> also provides a very tight format for datafile storage of a Pixmap |> of arbitrary depth, allows for This format stores an image with some given depth, and must decode it to another depth, etc... Moreover, it is not an Ascii format and is machine dependent. |> From: raveling@vaxb.isi.edu (Paul Raveling) |> We've learned a fair bit about requirements for simple |> image formats after more than a year of using our own format |> under X. Some of the discussion at the image processing BOF at |> the X Conference backed up much of what we learned. The |> bottom line is that none of the current file formats are |> entirely satisfactory; some are close, but still no cigar. |> |> I think we should open the floor for nominations for a |> "simple image" format and matching support software. That's why we designed PDF: to be a "simple image" format for the X programmer, for small images, icons, tiles, logos... easily editable even without a color image editor, not a general image format. We are open to any constructive comments. |> From: Kerry Kimbrough, Texas Instruments, Kimbrough@dsg.csc.ti.com |> I strongly suggest you examine the ISO |> Computer Graphics Metafile standard for examples of graphics Nobody claims that the X11 bitmap format is a general one. Our screen images here are stored in a compressed format, yet we use the X11 bitmap format for all small images. The PDF (ex- PAX) format want to be what the x11 bitmap format is for monochrome images for color images -- a portable simplified format. ================== Daniel Dardailler daniel@mirsa.inria.fr Colas Nahaboo colas@mirsa.inria.fr BULL Research FRANCE -- Koala Project INRIA - Sophia Antipolis, 2004, route des Lucioles, 06565 Valbonne Cedex FRANCE Voice phone: (33) 93.65.77.71, Fax: (33) 93 65 77 66, Telex: 97 00 50 F
Kimbrough@dsg.csc.ti.COM (Kerry Kimbrough) (03/01/89)
> The PDF (ex- PAX) format want to be what the x11 bitmap > format is for monochrome images for color images -- a portable simplified > format. Fine, but for me this goal is too weak to be truly interesting. Certainly I would not support an X Consortium project to standardize an data interchange format for images unless: * image file interpreters can be effectively implemented in any programming language * an image file can be interpreted at runtime to create a pixmap or image structure * the interchange format is not gratuitously incompatible with existing ANSI/ISO standards