Crawly Crypt Collection 1/crawlyvol1.bin/graphics/printall/printall.doc

Text File | 1992-10-08 | 15KB | 260 lines

                PrintAll

1. Introduction

    The name may sound ambitious, but the author's intention is to support
    most major graphics formats available to the Atari computer/HP printer
    user.

    Version 1.0, the first public release, recognizes, reads and prints
    the following file extensions/formats in color or greyscale on the
    HP 500C Color DeskJet printer, and in greyscale on the HP 500:

        .GIF    Compuserve's Graphics Interchange Format
        .MTV    The MTV raytracer raw output file format (24 bit)
        .NEO    Neochrome low- and medium-res images
        .PC1    Degas Elite Compressed low-resolution format
        .PC2    Degas Elite Compressed medium-resolution format
        .PI1    Degas/Degas Elite low-resolution format
        .PI2    Degas/Degas Elite medium-resolution format
        .QRT    The QRT raytracer raw output file format (24 bit)
        .SPC    Spectrum 512 compressed images
        .SPU    Spectrum 512 uncompressed images

    Plans for future support include:

        .IMG    GEM bit image files
        .PC3    Degas Elite Compressed high-resolution format
        .PI3    Degas/Degas Elite high-resolution format
    .PNT    Prism Paint format
        .TN?    "Tiny" image format
        .RAS    Sun Microsystems "rasterfile" format
        .JPG    Joint Photographic Experts Group compressed images

    ...and more!

    Each type of image file is converted into an internal 24-bit representation.
    All subsequent processing, such as dithering, gamma correction and
    quantization for printing, is done in this 24-bit space.  This results in
    the truest possible representation of the original image on the printer.
    The price of this accuracy (there is always a price!) is memory usage.
    Users with less than 4 megabytes of RAM will find themselves limited in
    the maximum size of the images they can print.

2. Usage (The short form)

    This program is extremely simple to use.  Double-click on the file
    "printall.prg".  The resource file "printall.rsc" must either be in the
    same directory as printall.prg, or in the Desktop's search path.

    PrintAll will display its title box.  Select the "OK" button or press
    the return key to dismiss it.  You will then be presented with a file
    selector.  Select the file you wish to print.  A status bar will show
    the progress of reading and converting the file.

    Next, the Transmogrification (image processing) options dialog appears.
    Set the options to your liking, then select "OK" to continue.

    The Output options dialog appears next.  These options control how and
    where the image will print.  When you have set the options to your
    liking, select "OK" to continue.  If you have selected the "File"
    output destination, another file selector will appear.  Enter the file
    where you wish the printer commands to go.

    At this point, another status bar will appear.  The program will make
    one pass through the data, performing all the selected Transmogrifications
    and the quantization for output.  When this pass completes, the status
    bar will appear again for the final output pass.  At this point, the
    printer commands are generated and sent either to disk or to the printer.
    When complete, the process begins again at the file selection phase.

    Selecting "Cancel" in any dialog exits the program immediately.

3. Usage (The details)

    The file you select to be printed must have an extension that matches one
    of the supported types listed above.  This is because the extension of the
    file is used to determine its format.  If the extension is not recognized,
    an alert box will inform you of this.  After dismissing the alert, you
    will be presented with the file selector to make an alternate selection, or
    select the "Cancel" button to quit the program.

    If the file type is recognized, PrintAll opens the file and attempts to
    verify that the file is what it claims to be.  (This is not foolproof in
    all cases.)  If the verification succeeds, a status bar will appear and
    will indicate the progress of the file conversion.  Note that some file
    types, such as GIFs which are heavily compressed, will take a significant
    amount of time to read, decompress, and convert.  The dimensions of the
    image also have a direct relationship to the reading/conversion time.

    After the file has been successfully read, the Transmogrifications dialog
    appears.  Currently there are three choices: Inversion, Dithering and
    Gamma Correction.

    Setting Inversion to "Yes" causes PrintAll to invert the color values of
    the image.  If printing in color, the image will resemble a color negative;
    if printing in black, the image will be black-white reversed.  The default
    state of Inversion is "No", which will produce a "normal" image.

    Setting Dithering to "Yes" causes PrintAll to use an error-distribution
    algorithm when quantizing the 24-bit internal format down to the number
    of shades available for printing.  If dithering is enabled and a pixel
    cannot be represented exactly on the printer, the magnitude and direction
    of the error is distributed to the right, lower-right, and lower neighbor
    pixels.  This is results in a more accurate rendition of the color or grey
    values in the image than does quantization alone.  In particular, dithering
    can significantly reduce or eliminate "false contouring", the appearance
    of artificial lines at color value changes where no lines should appear.

    There is, again, a price.  In some images with very large areas of a
    constant pixel value, the error distribution may cause diagonal lines to
    appear in these areas.  You will have to decide if the false contouring
    is more acceptable than the dithering noise.  The default setting for
    Dithering is "Yes", because the process is effective far more often than
    not.

    Gamma Correction is used to compensate for the different intensity curves
    of a CRT screen and the printer's inks.  Higher gamma values (up to a
    maximum of 9) lighten the image; lower values (down to a minimum of .1)
    darken it.  The extremes are arbitrary values and are not necessarily
    useful values for any particular purpose.

    A gamma value of 1.0 produces a direct mapping between a pixel's value in
    memory and its value when quantized for printing.  However, because of the
    differences in the relative perceived intensity of a CRT compared to that
    of the inks used in the printer, this setting will not necessarily result
    in a printed image that matches the image seen on the CRT.

    The default gamma value of 2.5 is appropriate for color printing on the
    500C; gamma values smaller than this produce an image which tends to be
    too dark.  For black ink printing, the gamma value should be set around 1.
    Of course you should experiment with different values with different
    images, and for different effects.  Different media will also affect the
    appropriate gamma setting, as will the setting of the "Quality" option.

    When you have selected the desired Transmogrification options, click on
    the "OK" button to continue.  The "Cancel" button quits the program.

3. Output Options

    The output options determine how and where the image is printed.  The first
    choice is that of the color (CMY) or black ink cartridge.  If you do not
    have an HP 500C color printer, the only appropriate choice here is "Black".
    I cannot vouch for what the result will be if the "Color" option is used
    with a non-color printer.  The program itself has no means of verifying
    your printer type.  Caveat user.

    The Orientation option determines the direction in which the image will be
    printed on the page.  The "Portrait" orientation causes the image to be
    printed in the same direction as you see it on the screen, whereas the
    Landscape orientation causes the image to be rotated 90 degrees, so that
    the horizontal axis of the screen maps to the longer axis of an 8.5 by 11
    sheet of paper.

    Vertical Justification selects where on the length of the page the image
    will be placed, regardless of orientation.  "Top" places the edge of the
    image approximately one-half inch from the top edge of the page.  "Center"
    causes the image to be center-justified along the length of the page.
    "Bottom" places the image so that its trailing edge is approximately one-
    half inch from the bottom edge of the page.

    Horizontal Justification is just like Vertical Justification, but for the
    other axis of the paper (surprise!).

    Power-user note: Careful choice of resolution, matrix, position and
    orientation options combined with repeated loading of the same sheet of
    paper can produce an interesting collage effect with smaller images.

    Output Destination selects whether the printer commands go to the printer
    port, as set up in the Control Panel dialog, or to a file.  If you select
    output to file, you may choose via a file selector where to put the result.
    Output to file is somewhat faster than output to printer, and provides the
    option of making additional copies of the image without going through all of
    the processing steps again.  However, depending on the size and complexity
    of the image, the output can be quite large.  Output direct to the printer
    requires no additional disk storage.

    Matrix selects the size of the halftoning matrix used to output each pixel.
    The 3 by 3 matrix produces 10 greyscale values or 1,000 possible colors (10
    intensities of cyan times 10 of magenta times 10 of yellow), per pixel.
    The 4 by 4 matrix provides 17 greyscale values or 4,913 possible colors per
    pixel (do the math yourself).  When dithering is used, the effective output
    is even higher, due to the pixel averaging that takes place in the eye.

    Resolution selects the size of the output pixels.  At 300 dots per inch
    (dpi) resolution, one output pixel is one dot, times the matrix size.  At
    150 dpi, one output pixel is two dots wide and two dots high, times the
    matrix size, and so on.  Obviously, the higher the output resolution, the
    better looking the image.  However, with image formats like Degas low-
    resolution, a 300 dpi image with a 3 by 3 matrix will only be about 3.2
    inches wide!  On the other hand, resolutions below 150 are not very
    useful, in the author's opinion, except perhaps for special effects.

    A side effect of changing the matrix size is that the output image size is
    also changed.  The Dimension display at the bottom of the dialog is
    provided to help you select the appropriate combination of matrix and
    resolution.  Remember that the width of the output is restricted to a
    maximum of 8 inches by the printer, and length is restricted to 10.5
    inches.  When Landscape orientation is chosen, the width of the image is
    mapped to the length of the page, and vice versa.

4. General hints

    This program uses tons of memory.  It should be graceful about reporting
    insufficient memory conditions, and allow you to continue without bombs.
    However, the author uses it on a 4 megabyte machine and has never
    encountered this condition, so be warned.  Until such time as Atari comes
    out with a virtual memory operating system, serious image processing will
    require lots of RAM.

    From the author's own experience, the HP JetSeries CutSheet Paper (HP
    part number 51630Y) is highly recommended for color printing.  This
    specially-coated paper produces blacker blacks and brighter brights than
    any other paper that was tried.  If you've been less than impressed with
    the quality of the color output and have not used the HP paper, give it
    a try.

    For printing with black ink, use a good-quality ink jet paper.  I usually
    use the printer's "Draft Quality" setting and a gamma of 1.0.

    The most spectacular images I have printed have been 24-bit raytraces from
    the DKB raytracer, in QRT format.  If you have access to this software, I
    highly recommend it.

    The second most spectacular images I have printed have been 256-color GIFs
    of size 640 by 480 or larger.  But note: all GIFs are not created equal!
    Since by definition the format requires a color look-up table, the software
    which generates the look-up table from the original image is crucial.  Many
    GIF images end up using only a fraction of the total 256 colors available,
    and the result is a less-than-perfect reproduction of the original image.
    The GIF files that have the optimally-chosen set of 256 colors and that use
    all of them are quite stunning.

    Spectrum 512 images also look good if you do not enlarge them too much.
    Try printing them two to a page (V-just "Top" for the first and V-just
    "Bottom" for the second; remember to reload the page image-side down), at
    150 dpi resolution with the 3 by 3 matrix (6.4 inches by 4.0 inches).

5. The legal department: No warranty

    The author believes that this software will do a reasonable job of printing
    the supported file formats on an HP DeskJet 500 or 500C printer.  However:

    This software is freeware.  As such, it is provided on an as-is basis,
    with absolutely no warantees, either express or implied, including, but not
    limited to performance, usefulness, reliability, fitness for a particular
    purpose or merchantability.  The user assumes any and all risk involved in
    the use of this software.  In no event will the author be liable for
    direct, indirect, incidental, or consequential damages resulting from the
    use of, or inability to use, this software.

6. Support

    I am on Compuserve, in the ATARIPRO and ATARIARTS forums, fairly regularly.
    I would enjoy hearing favorable comments, and also welcome suggestions, bug
    reports and entreaties for future format support.  I won't promise any
    particular action except to say that I am a user of this program as well
    as its author.  See you on-line.

    Greg Wageman 74016,352