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                                                  Chapter 9: Colors   69
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    CHAPTER NINE:  COLORS

    Some PADtalk properties and commands require that you specify a color.
    Traditionally on personal computers, colors are represented by a
    foreground color and a background color combination, or attribute. There
    are always 256 attributes available in character mode, but these are
    translated by some hardware systems to black and white. Colors 0 to 127
    are normal intensity combinations, and colors 128 to 255 are high
    intensity combinations.

    There are 16 possible colors, each corresponding to a number. Each color
    can be used as a background or foreground (16*16=256).

    0     black                  8     dark grey

    1     blue                   9     light blue

    2     green                  10    light green

    3     cyan                   11    light cyan

    4     red                    12    light red

    5     magenta                13    light magenta

    6     brown                  14    light brown

    7     grey                   15    white


    SPECIFYING COLORS

    The color names from this table can be used to specify a color in an
    English-like manner, as in the following example:

    set the fillColor of button 1 to red;

    set the acceleratorColor of pg btn "help" to light red;

    put yellow into myColor;

    You can combine the color keywords using the word on to form a
    foreground/background attribute specification. When no background is
    specified, black is assumed. The syntax for such a combination is as
    follows:

    <foreground color> on <background color>



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                                                  Chapter 9: Colors   70
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    For example, the following statement sets the fill color of button 1 to
    be light blue background with red lettering.

    set the fillColor of button 1 to red on light blue;


    COLOR NUMBERS

    The color constants are translated by HyperPAD to single numbers between
    0 and 255 using the following formula:

       color = (background * 16) + foreground

    For example, the color red on white translates to:

       color = (white * 16) + red
       color = (15 * 16) + 4c
       color = 244

    Thus, the following two statements are equivalent:

    set the fillColor of button 1 to red on white;
    set the fillColor of button 1 to 244;

    Representing colors as numbers allows you to algorithmically adjust the
    colors of objects, as in the following example:

    -- ask for the foreground color number
    ask "type in foreground color number";
    put it into fcolor;

    -- ask for the background color number
    ask "type in background color number";
    put in into bcolor;

    -- set the color
    set the color of page field 1 to (bcolor * 16) + fcolor;

    The colors available are determined by the graphics card and monitor
    used. The color constants 0 through 7 are low intensity, whereas colors
    8 through 15 are high intensity. On some monitors, you may need to
    finely adjust the contrast to see the high intensity colors.

    Using a high intensity color as a background is blinking on most
    hardware configurations. HyperPAD disables this blinking capability to
    provide you with the maximum number of color combinations (256). You can
    specify the higher intensity colors using the word blinking:

    set the color of button 1 to blinking grey on red;



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                                                  Chapter 9: Colors   71
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    When you design pads for monochrome systems, all of the 256 available
    colors are translated to black and white. In general, it is safe to use
    the following color combinations:

       color 7 (grey)              white on black
       color 112 (black on grey)   reverse video

    These are the default colors for all objects.

    On LCD systems, such as some laptops, the color combinations may be
    different.