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README  view on Meta::CPAN

    it only moves along the x-axis (left to right and back). In the same
    fashion the second (Y) only moves up and down. When both are connected
    to a pen, we get a combination of both movements. As long as X and Y
    swing at the same speed (frequency), the result is a diagonal line.
    Because when X goes right Y goes up and vice versa. But if we start one
    pendulum at the center and the other at the upmost position we get a
    circle. In other words: we added an offset of 90 degrees to Y (or X).
    Our third pendulum W moves (wobbles) the paper in circulating manner
    around its center (but not rotating, so a dot in the left corner will
    always left). If both circular movements (of X, Y and the one of W) are
    concurrent - the pen just stays at one point over the paper and paints
    only a dot. If both are countercurrent - we get a circle. Interesting
    things start to happen, if we alter the speed of of X, Y and W. Than
    famous harmonic pattern appear. And for even more complex drawings I
    added R, which is not really a pendulum and not part of the original
    Harmonograph, but an additional rotary movement of the paper around its
    center. I added even 2 more pendula (E and F which are also lateral like
    X and Y), which draw an epicycle around the point where the dot would be
    normally drawn.

    The pendula out of metal do of course fizzle out over time, which you
    can see in the drawing as a spiraling movement toward the center. We
    emulate this with two damping factors: one for amplitude/radius and one
    for the frequency (speed). The radius or ampitude of Pendulum R is
    special and allows you to zoom in or out in case you wish to do so.
    Normally this is not necessary, since the program autoadjusts to the
    settings, so that the picture is always fully visible and as big as
    possible.

GUI
    The general layout of the program has three parts:

    1   In the left upper corner is the drawing board - showing the result
        of the Harmonograph.

    2   The whole right half of the window contains the settings, which
        guide the drawing operation. These are divided into six tabs, which
        will be explained in detail below.

    3   In the lower left corner are two rows of buttons. The first row
        contains only the progress bar and the *Draw* button for drawing a
        full picture. The progress bar remains white whily previe sketches
        are shown. But when a full picture is drawn, then it gets filled
        with colors that reflect the color flow used while drawing.

        The second row of buttons allow the mass production of graphic files
        without using the menu. That is explained in detail under
        "Commands".

    Please mind the tool tips - short help texts which appear if the mouse
    stands still over a widgets. Also helpful are messages in the status bar
    at the bottom - on bottom left regarding current state of the image and
    bottom right about state of the settings. Settings are all the
    parameters that guide the drawing. You change them via widgets controls
    on the right side. They can be saved and loaded from a file via the
    settings menu. Configuration are the general settings of this program,
    which are mostly saved colors and paths were to store images and
    settings.

    When browsing the main menu, help texts about the highlighted item also
    appears in the status bar. The Menu can be completely navigated with the
    keyboard. Just hold Alt and use the direction keys (up, down, left and
    right) or the highlighted letters. When holding the Alt key you can also
    see which Alt + letter combinations trigger which button.

  Pendulum
    Each of the first three tabs contains the settings of two pendula. The
    first tab holds the lateral or linear pendula: X (left right movement)
    and Y (up and down). The second tab shows settings of the epicycle
    pendula E (left right) and F (up down). They also just move in x or y
    direction, but they swing not around the center of the image but around
    the point, where the pencil would have been. The third tab allows you to
    tweak the pendula W (wobble) and R (rotation). W moves the center of the
    paper beneath the pencil in a rotating manner whereas R rotates the
    paper around its center. Each of these 6 pendula have the exact same
    settings which behave all the same, except radius of R, which works as a
    zoom.

    In the left upper corner of each pendulum settings is a checkbox to
    activate or deactivate the pendulum - good to see the pendulums part in
    the pen movement. The rest is organized in 8 rows, which can be divided
    into 3 parts. Row 1 - 4 are about the pendulum frequency in Hertz. Row
    five allows you set the starting point (offset) and the last 3 rows are
    about the radius or amplitude of the pendulum mirroring the rows 1, 3
    and 4 because the work exactly the same way just not for the frequency
    but the radius parameter.

    Row one sets the whole number part of the frequency. This is the part
    you need to generate to generate the famous images which are based on
    integer rations. You can either use the slider the + an - buttons or
    insert a number into the text field (which is true off all slider combo
    widgets). Behind the slider combo in row one is a drop down menu which
    lets you choose a natural constant like Pi or Phi. It gets multiplied
    with the frequency. This allows you to explore the nature of these
    famous constants. Among the constants are also the natural numbers 1, 2
    and 3 in case you need to crank up the frequency up to 300.

    The second row enables you to set values with three decimals. If you for
    instance choose a base frequency of 5 and dial in 15 in the second row,
    the actual frequency will be 5.015 times the natural constant. Behind
    the slider are two checkboxes. One to additionally invert (1/x) the
    frequency value and one to flip the pendulum direction (f = -f).

    The third row lets you dial in a damping value which makes the pendulum
    each round slower (bigger value -> more damping). Behind it is a
    selector. If its on minus the damping will be same each round but set on
    "*" the damping will be proportional to the frequency. Still behind it
    is a checkbox. When selected the frequency is allowed to become negative
    by damping.

    The fourth row is about daming acceleration or with other words, how
    much the damping changes from dot to dot. Beside the c value you have
    this time four types of acceleration. Minus and times work as before and
    plus and divided by are just their opposite.

    The fifth row has a slider that sets the starting position of the
    pendulum along its expected track. If the slider is on max you move the
    pendulum a quater rotation ahead. To add another quarter check the box
    left beside it. The last box adds another half rotation. This allows you
    to flip or mirror the image in meaningful ways.

README  view on Meta::CPAN

    move the currently selected color around.

    The third section below that displays the colors than can be used to
    draw the picture. They are ten colors, numbered from left to right.
    Below each color field there is a second rectangle showing the status of
    the color. If this rectangle is empty, the status is normal (used). If
    it's crossed out, them the color is inactive because in the visual
    settings you choose to use less than ten colors. The third option is
    selected color. To select a color, just click on the rectangle
    displaying that color or the status rectangle below. Then the status
    will show an arrow down.

    This means the section below displays the values of this color. And the
    values can also be changed there. First your have the *red* (R), *green*
    (G) and *blue* (B) values of the RGB color space. below that are ones of
    HSB: *hue*, *saturation* and *lightness*. These are more meaningful to
    the human mind. At the right end of each row that shows amd changes one
    color value is a button with a question mark. Push that to randomize
    this one value.

    The last and fifth section is analogous to the first one. It is a store
    for your favorite single colors. Just load and safe the currently
    selected color via the buttons. Be again cautious with the "Del" button.

  Commands
    In the lower left corner are two rows of command buttons. All other
    commands are in the menu.

    The lower left part of the window contains buttons in two rows. The
    upper row is just for drawing the complete image. It has a progress bar
    and the draw button. If the progress bar is white, you see just a sketch
    drawing - a preview of the full image that can be computed fast enought
    to react to all setting changes. If you push the draw button (or
    <Ctrl>+<S>), you will get a full image and the progress bar has the
    color of the drawing and also can show you the color progression over
    time, so you can see, which are the early and the later parts of the
    drawing.

    The second button row is for easy mass production of drawings. The three
    text fields are combined the parts of the file path. The first text
    field is naturally the directory where the files get saved. You can
    change it by pushing the *Dir* in front (left) of the text button and
    use the then opening Dir-Dialog to select another directory. The second
    text field holds the base file name, which has to be inserted by
    clicking on in and typing. The third text field is the file number and
    is readonly. That counter increments automatically when a file is
    generated. The complete file path is <dir>+<base
    name>+'_'+<counter>+<file ending>. The file ending is *.ini* for setting
    files and *.jpg* or *.png* or *.svg* for image files. The exact ending
    depends on what is the current configuration set in the image > format
    menu. Lets say your directory is "/home/user/images/h" and the base file
    name is beauty. If there is already a file
    "/home/user/images/h/beauty_4.png" - the program will detect that and
    set the counter to 5. You can play with the settings and than (no matter
    if there is currently a complete drawing or not) push the *Save* button
    to produce a complete drawing into "/home/user/images/h/beauty_5.png".
    If you push the *INI* button you safe the current settings into
    "/home/user/images/h/beauty_5.ini". This file can later be loaded via
    settings menu to restore the current state of all buttons in the tabs.

  Menu
    The upmost menu bar has only three very simple menus. Please not that
    each menu shows which key combination triggers the same command and
    while hovering over an menu item you see a short help text the left
    status bar field.

    The first menu is for loading and storing setting files with arbitrary
    names. I recommend giving them the file ending ".ini" for transparency
    reasons. A submenu allows a quick load of the recently used files. The
    first entry lets you reset the whole program to the starting state and
    the last is just to exit (safely with saving the configs).

    The second menu has only two commands for drawing an complete image and
    saving it in an arbitrary named PNG, JPG or SVG file (the file ending
    decides). The submenu above only sets the preferred format, which is the
    format of the serially save images by the command buttons in the left
    lower corner. The preferred file format is also the first wild card in
    the save dialog. Above that is another submenu for setting the image
    size.

    The third menu has only one item to oben the *about* - dialog, where you
    can see which perl, Wx and other versions you are currently using.

SEE ALSO
    App::GUI::Cellgraph

    App::GUI::Juliagraph

    App::GUI::Sierpingraph

    App::GUI::Spirograph

AUTHOR
    Herbert Breunung (lichtkind@cpan.org)

COPYRIGHT & LICENSE
    Copyright(c) 2022-25 by Herbert Breunung

    All rights reserved. This program is free software and can be used,
    changed and distributed under the GPL 3 licence.