
<section id='WCF_ColorControl_id'>
    <title>
        Color Control
    </title>
    <para>
        A Color Control is used to select a color.
    </para>
    <exhibit>
        <img src='WCF_ColorControl_ScreenCap.png'/>
    </exhibit>
    <para>
        A sample of the current color is displayed in the box, followed
        by a name for that color. If the color is one of the standard
        ones recognized by &app_name;, its common name is displayed. Otherwise,
        the relative intensities of red, green, and blue are displayed,
        as in "RGB 10, 100, 255". The RGB values can range from 0 to 255.
    </para>
    <para>
        Press a letter key, <keytext>A</keytext> through <keytext>Z</keytext>,
        to cycle through all colors with names beginning with that letter.
    </para>
    <para>
        Press <keytext>Alt +</keytext> &downarrowkey;, the <keytext>Space
        Bar</keytext>, or the drop-down button <img
        src='WCF_DropdownButton_Figure.png'/> to display a drop-down list
        of named colors.
    </para>
    <exhibit>
        <img src='WCF_ColorControl_ScreenCap_Down.png'
        standard_colors='true'/>
    </exhibit>
    <para>
        Select Custom Color to display the Select Color dialog box, which
        allows you to pick from all possible colors.
    </para>
    <exhibit>
        <img src='WCF_ColorControl_ScreenCap_ColorDialogBox.png'/>
    </exhibit>
    <para>
        Colors can be specified using four color models: Red/Green/Blue
        (RGB), Lightness/Chroma/Hue, Hue/Saturation/Value (HSV), and CIELAB
        (L*a*b*). Values can be entered numerically or adjusted using
        the sliders.
    </para>
    <para>
        If you are making aesthetic adjustments to an existing color,
        consider using Lightness/Chroma/Hue. The conceptually-similar
        HSV model, while supported for historical reasons, is not recommended,
        as the color axes are highly non-orthogonal (for example, changing
        the saturation can cause large perceived changes in the value).
        The Lightness/Chroma/Hue model corrects many of HSV's flaws.
    </para>
    <para>
        The Hex representation of colors encodes RGB values as 3 two-digit
        hexadecimal numbers. It is a commonly-used method of representing
        color in the web development field.
    </para>
    <para>
        Left-click on the color swatch display to visually choose a color.
    </para>
    <exhibit>
        <img
        src='WCF_ColorControl_ScreenCap_ColorDialogBox_Swatches.png'/>
    </exhibit>
    <para>
        Use the dropdown to select how the color swatches are organized:
        Hue vs Chroma, Hue vs Lightness, or Chroma vs Lightness. Once
        the organizational axes are selected, the third value in the Lightness/Chroma/Hue
        triad becomes the independent variable, and is controlled by its
        slider. For example, if you organize the color swatches by Hue
        vs Lightness, then you can view all possible color swatches by
        dragging the Chroma slider.
    </para>
    <para>
        Use the LCH Model dropdown to select the mathematical method used
        to map Lightness/Chroma/Hue triplets to perceived colors. While
        the older CIELAB model is supported, unless you have special needs,
        it is recommended that you use the CIECAM02 model, as it exhibits
        greater perceptual uniformity.
    </para>
</section>
