useColorArea
Provides the behavior and accessibility implementation for a color area component. Color area allows users to adjust two channels of an RGB, HSL or HSB color value against a two-dimensional gradient background.
install | yarn add @react-aria/color |
---|---|
version | 3.0.0-beta.33 |
usage | import {useColorArea} from '@react-aria/color' |
API#
useColorArea(
(props: AriaColorAreaOptions,
, state: ColorAreaState
)): ColorAreaAria
Features#
The <input type="color"> HTML element
can be used to build a color picker, however it is very inconsistent across browsers and operating systems and consists
of a complete color picker rather than a color area. useColorArea
helps achieve accessible and
touch-friendly color areas that can be styled as needed.
- Support for adjusting two-channel values of an HSL, HSB or RGB color value
- Support for mouse, touch, and keyboard via the useMove hook
- Multi-touch support
- Pressing on the color area background moves the thumb to that position
- Supports using the arrow keys, for changing value by step, as well as shift + arrow key, page up/down, home, and end keys, for changing the value by page step.
- Support for disabling the color area
- Prevents text selection while dragging
- Exposed to assistive technology as a
2D slider
element via ARIA - Uses two hidden native input elements within a group to support touch screen readers
- Automatic ARIA labeling using the localized channel names by default
- Support for mirroring in RTL locales
Anatomy#
A color area consists of a rectangular background area that provides, using a two-dimensional gradient,
a visual representation of the range of color values from which a user can select, and a thumb that the user can drag
to change the selected color value. Two visually hidden <input>
elements are used to represent the color channel
values to assistive technologies.
useColorArea
returns five sets of props that you should spread onto the appropriate elements:
Name | Type | Description |
colorAreaProps | DOMAttributes | Props for the color area container element. |
thumbProps | DOMAttributes | Props for the thumb element. |
xInputProps | InputHTMLAttributes<HTMLInputElement> | Props for the visually hidden horizontal range input element. |
yInputProps | InputHTMLAttributes<HTMLInputElement> | Props for the visually hidden vertical range input element. |
State is managed by the useColorAreaState
hook from @react-stately/color
. The state object should be passed as an option to useColorArea
.
By default, useColorArea
provides an aria-label
for the localized string "Color Picker",
which labels the visually hidden <input>
elements for the two color channels, or on mobile devices,
the group containing them. If you wish to override this with a more specific label, an aria-label
or
aria-labelledby
prop may be passed to further to identify the element to assistive technologies.
The aria-valuetext
for each <input>
will include the localized color channel name and current value for each
channel.
Example#
This example shows how to build a color area with a draggable thumb to adjust two color channel values of a color. Styling for
the background gradient and positioning of the thumb are provided by useColorArea
in the returned props for each element.
The two <input>
elements inside the thumb represent the color channel values to assistive technologies, and are hidden
from view. The thumb also uses the
useFocusRing hook to grow in size when it is keyboard focused (try tabbing to it).
import {useColorArea} from '@react-aria/color';
import {useColorAreaState} from '@react-stately/color';
import {useFocusRing} from '@react-aria/focus';
const SIZE = 192;
const FOCUSED_THUMB_SIZE = 28;
const THUMB_SIZE = 20;
const BORDER_RADIUS = 4;
function ColorArea(props) {
let inputXRef = React.useRef(null);
let inputYRef = React.useRef(null);
let containerRef = React.useRef(null);
let state = useColorAreaState(props);
let { isDisabled } = props;
let {
colorAreaProps,
xInputProps,
yInputProps,
thumbProps
} = useColorArea({ ...props, inputXRef, inputYRef, containerRef }, state);
let { focusProps, isFocusVisible } = useFocusRing();
return (
<div
ref={containerRef}
{...colorAreaProps}
style={{
...colorAreaProps.style,
width: SIZE,
height: SIZE,
borderRadius: BORDER_RADIUS,
background: isDisabled
? 'rgb(142, 142, 142)'
: colorAreaProps.style.background,
opacity: isDisabled ? 0.3 : undefined
}}
>
<div
{...thumbProps}
style={{
...thumbProps.style,
background: isDisabled
? 'rgb(142, 142, 142)'
: state.getDisplayColor().toString('css'),
border: `2px solid `,
borderRadius: '50%',
boxShadow: '0 0 0 1px black, inset 0 0 0 1px black',
boxSizing: 'border-box',
height: isFocusVisible ? FOCUSED_THUMB_SIZE + 4 : THUMB_SIZE,
width: isFocusVisible ? FOCUSED_THUMB_SIZE + 4 : THUMB_SIZE
}}
>
<input ref={inputXRef} {...xInputProps} {...focusProps} />
<input ref={inputYRef} {...yInputProps} {...focusProps} />
</div>
</div>
);
}
<ColorArea />
import {useColorArea} from '@react-aria/color';
import {useColorAreaState} from '@react-stately/color';
import {useFocusRing} from '@react-aria/focus';
const SIZE = 192;
const FOCUSED_THUMB_SIZE = 28;
const THUMB_SIZE = 20;
const BORDER_RADIUS = 4;
function ColorArea(props) {
let inputXRef = React.useRef(null);
let inputYRef = React.useRef(null);
let containerRef = React.useRef(null);
let state = useColorAreaState(props);
let { isDisabled } = props;
let {
colorAreaProps,
xInputProps,
yInputProps,
thumbProps
} = useColorArea({
...props,
inputXRef,
inputYRef,
containerRef
}, state);
let { focusProps, isFocusVisible } = useFocusRing();
return (
<div
ref={containerRef}
{...colorAreaProps}
style={{
...colorAreaProps.style,
width: SIZE,
height: SIZE,
borderRadius: BORDER_RADIUS,
background: isDisabled
? 'rgb(142, 142, 142)'
: colorAreaProps.style.background,
opacity: isDisabled ? 0.3 : undefined
}}
>
<div
{...thumbProps}
style={{
...thumbProps.style,
background: isDisabled
? 'rgb(142, 142, 142)'
: state.getDisplayColor().toString('css'),
border: `2px solid `,
borderRadius: '50%',
boxShadow:
'0 0 0 1px black, inset 0 0 0 1px black',
boxSizing: 'border-box',
height: isFocusVisible
? FOCUSED_THUMB_SIZE + 4
: THUMB_SIZE,
width: isFocusVisible
? FOCUSED_THUMB_SIZE + 4
: THUMB_SIZE
}}
>
<input
ref={inputXRef}
{...xInputProps}
{...focusProps}
/>
<input
ref={inputYRef}
{...yInputProps}
{...focusProps}
/>
</div>
</div>
);
}
<ColorArea />
import {useColorArea} from '@react-aria/color';
import {useColorAreaState} from '@react-stately/color';
import {useFocusRing} from '@react-aria/focus';
const SIZE = 192;
const FOCUSED_THUMB_SIZE =
28;
const THUMB_SIZE = 20;
const BORDER_RADIUS = 4;
function ColorArea(
props
) {
let inputXRef = React
.useRef(null);
let inputYRef = React
.useRef(null);
let containerRef =
React.useRef(null);
let state =
useColorAreaState(
props
);
let { isDisabled } =
props;
let {
colorAreaProps,
xInputProps,
yInputProps,
thumbProps
} = useColorArea({
...props,
inputXRef,
inputYRef,
containerRef
}, state);
let {
focusProps,
isFocusVisible
} = useFocusRing();
return (
<div
ref={containerRef}
{...colorAreaProps}
style={{
...colorAreaProps
.style,
width: SIZE,
height: SIZE,
borderRadius:
BORDER_RADIUS,
background:
isDisabled
? 'rgb(142, 142, 142)'
: colorAreaProps
.style
.background,
opacity:
isDisabled
? 0.3
: undefined
}}
>
<div
{...thumbProps}
style={{
...thumbProps
.style,
background:
isDisabled
? 'rgb(142, 142, 142)'
: state
.getDisplayColor()
.toString(
'css'
),
border:
`2px solid `,
borderRadius:
'50%',
boxShadow:
'0 0 0 1px black, inset 0 0 0 1px black',
boxSizing:
'border-box',
height:
isFocusVisible
? FOCUSED_THUMB_SIZE +
4
: THUMB_SIZE,
width:
isFocusVisible
? FOCUSED_THUMB_SIZE +
4
: THUMB_SIZE
}}
>
<input
ref={inputXRef}
{...xInputProps}
{...focusProps}
/>
<input
ref={inputYRef}
{...yInputProps}
{...focusProps}
/>
</div>
</div>
);
}
<ColorArea />
Usage#
The following examples show how to use the ColorArea
component created in the above example.
Uncontrolled#
By default, color area is uncontrolled, with a default value of white using the RGB color space (rgb(255, 255, 255)
).
You can change the default value using the defaultValue
prop, and the color area will use the color space of the provided value.
If no xChannel
or yChannel
is provided, for the RGB color space, the red
color channel maps to the horizontal axis or xChannel
,
and the green
color channel maps to the vertical axis or yChannel
. Similarly, for the HSL and HSB color spaces, the hue
color
channel maps to the horizontal axis or xChannel
, and the saturation
color channel maps to the vertical axis or yChannel
.
<label id="hsb-label-id">x: Hue, y: Saturation</label>
<ColorArea
aria-labelledby="hsb-label-id"
defaultValue="hsb(219, 58%, 93%)" />
<label id="hsb-label-id">x: Hue, y: Saturation</label>
<ColorArea
aria-labelledby="hsb-label-id"
defaultValue="hsb(219, 58%, 93%)" />
<label id="hsb-label-id">
x: Hue, y: Saturation
</label>
<ColorArea
aria-labelledby="hsb-label-id"
defaultValue="hsb(219, 58%, 93%)"
/>
Controlled#
A color area can be made controlled using the value
prop.
The parseColor
function is used to parse the initial color from an RGB, HSL or HSB string, stored in state.
The onChange
prop is used to update the value in the state when the user drags the thumb.
This is the more common usage because it allows to adjust the third color channel using a separate control,
like a color slider using the useColorSlider hook or a color wheel using the
useColorWheel hook, or to display the color value stored in a state using a preview swatch.
The onChangeEnd
prop can be used to handle when a user stops dragging the color area.
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(parseColor('hsba(219, 58%, 93%, 0.75)'));
let [
endColor,
setEndColor
] = React.useState(color);
let [
xChannel,
yChannel,
zChannel
] = color.getColorChannels();
return (
<>
<label id="hsb-label-id-1">
x: {color.getChannelName(xChannel, 'en-US')}, y:{' '}
{color.getChannelName(yChannel, 'en-US')}
</label>
<div
style={{
display: 'flex',
flexWrap: 'wrap',
gap: '1rem'
}}
>
<div
style={{
display: 'flex',
flexDirection: 'column',
gap: '1rem'
}}
>
<ColorArea
aria-labelledby="hsb-label-id-1"
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
xChannel={xChannel}
yChannel={yChannel}
/>
<ColorSlider
channel={zChannel}
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
/>
<ColorSlider
channel="alpha"
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
/>
</div>
<div
style={{
display: 'flex',
flexDirection: 'column',
gap: '1rem'
}}
>
<div
style={{
display: 'flex',
gap: '6px'
}}
>
<ColorSwatch
color={color.withChannelValue('alpha', 1)}
aria-label={`current color swatch: `}
/>
<ColorSwatch
color={color}
aria-label={`current color swatch with alpha channel: `}
/>
</div>
<div
style={{
display: 'flex',
gap: '6px'
}}
>
<ColorSwatch
color={endColor.withChannelValue('alpha', 1)}
aria-label={`end color swatch: `}
/>
<ColorSwatch
color={endColor}
aria-label={`end color swatch with alpha channel: `}
/>
</div>
</div>
</div>
<p>Current color value: {color.toString('hsba')}</p>
<p>End color value: {endColor.toString('hsba')}</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(
parseColor('hsba(219, 58%, 93%, 0.75)')
);
let [
endColor,
setEndColor
] = React.useState(color);
let [
xChannel,
yChannel,
zChannel
] = color.getColorChannels();
return (
<>
<label id="hsb-label-id-1">
x: {color.getChannelName(xChannel, 'en-US')}, y:
{' '}
{color.getChannelName(yChannel, 'en-US')}
</label>
<div
style={{
display: 'flex',
flexWrap: 'wrap',
gap: '1rem'
}}
>
<div
style={{
display: 'flex',
flexDirection: 'column',
gap: '1rem'
}}
>
<ColorArea
aria-labelledby="hsb-label-id-1"
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
xChannel={xChannel}
yChannel={yChannel}
/>
<ColorSlider
channel={zChannel}
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
/>
<ColorSlider
channel="alpha"
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
/>
</div>
<div
style={{
display: 'flex',
flexDirection: 'column',
gap: '1rem'
}}
>
<div
style={{
display: 'flex',
gap: '6px'
}}
>
<ColorSwatch
color={color.withChannelValue('alpha', 1)}
aria-label={`current color swatch: `}
/>
<ColorSwatch
color={color}
aria-label={`current color swatch with alpha channel: `}
/>
</div>
<div
style={{
display: 'flex',
gap: '6px'
}}
>
<ColorSwatch
color={endColor.withChannelValue('alpha', 1)}
aria-label={`end color swatch: `}
/>
<ColorSwatch
color={endColor}
aria-label={`end color swatch with alpha channel: `}
/>
</div>
</div>
</div>
<p>Current color value: {color.toString('hsba')}</p>
<p>End color value: {endColor.toString('hsba')}</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(
parseColor(
'hsba(219, 58%, 93%, 0.75)'
)
);
let [
endColor,
setEndColor
] = React.useState(
color
);
let [
xChannel,
yChannel,
zChannel
] = color
.getColorChannels();
return (
<>
<label id="hsb-label-id-1">
x:{' '}
{color
.getChannelName(
xChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
yChannel,
'en-US'
)}
</label>
<div
style={{
display:
'flex',
flexWrap:
'wrap',
gap: '1rem'
}}
>
<div
style={{
display:
'flex',
flexDirection:
'column',
gap: '1rem'
}}
>
<ColorArea
aria-labelledby="hsb-label-id-1"
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
xChannel={xChannel}
yChannel={yChannel}
/>
<ColorSlider
channel={zChannel}
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
/>
<ColorSlider
channel="alpha"
value={color}
onChange={setColor}
onChangeEnd={setEndColor}
/>
</div>
<div
style={{
display:
'flex',
flexDirection:
'column',
gap: '1rem'
}}
>
<div
style={{
display:
'flex',
gap: '6px'
}}
>
<ColorSwatch
color={color
.withChannelValue(
'alpha',
1
)}
aria-label={`current color swatch: `}
/>
<ColorSwatch
color={color}
aria-label={`current color swatch with alpha channel: `}
/>
</div>
<div
style={{
display:
'flex',
gap: '6px'
}}
>
<ColorSwatch
color={endColor
.withChannelValue(
'alpha',
1
)}
aria-label={`end color swatch: `}
/>
<ColorSwatch
color={endColor}
aria-label={`end color swatch with alpha channel: `}
/>
</div>
</div>
</div>
<p>
Current color
value:{' '}
{color.toString(
'hsba'
)}
</p>
<p>
End color value:
{' '}
{endColor
.toString(
'hsba'
)}
</p>
</>
);
}
ColorSlider#
The ColorSlider
component used in the example above controls the channel value not controlled by the ColorArea
, in this case, the brightness
channel, or the alpha
channel.
It is built using the useColorSlider hook, and can be shared with other color components.
Show code
import {useColorSlider} from '@react-aria/color';
import {useColorSliderState} from '@react-stately/color';
import {VisuallyHidden} from '@react-aria/visually-hidden';
import {useLocale} from '@react-aria/i18n';
import {useFocusRing} from '@react-aria/focus';
function ColorSlider(props) {
let { locale } = useLocale();
let state = useColorSliderState({ ...props, locale });
let trackRef = React.useRef(null);
let inputRef = React.useRef(null);
// Default label to the channel name in the current locale
let label = props.label || state.value.getChannelName(props.channel, locale);
let { trackProps, thumbProps, inputProps, labelProps, outputProps } =
useColorSlider({
...props,
label,
trackRef,
inputRef
}, state);
let { focusProps, isFocusVisible } = useFocusRing();
return (
<div
style={{
display: 'flex',
flexDirection: 'column',
alignItems: 'center',
width: SIZE
}}
>
{/* Create a flex container for the label and output element. */}
<div style={{ display: 'flex', alignSelf: 'stretch' }}>
<label {...labelProps}>{label}</label>
<output {...outputProps} style={{ flex: '1 0 auto', textAlign: 'end' }}>
{state.value.formatChannelValue(props.channel, locale)}
</output>
</div>
{/* The track element holds the visible track line and the thumb. */}
<div
className="color-slider-track"
{...trackProps}
ref={trackRef}
style={{
height: FOCUSED_THUMB_SIZE
}}
>
<div className="color-slider-track-background"></div>
<div
className="color-slider-track-color"
style={{
...trackProps.style
}}
>
</div>
<div
className={`color-slider-thumb `}
{...thumbProps}
style={{
...thumbProps.style
}}
>
<div className="color-slider-thumb-background"></div>
<div
className="color-slider-thumb-color"
style={{
background: state.getDisplayColor().toString('css')
}}
>
</div>
<VisuallyHidden>
<input ref={inputRef} {...inputProps} {...focusProps} />
</VisuallyHidden>
</div>
</div>
</div>
);
}
import {useColorSlider} from '@react-aria/color';
import {useColorSliderState} from '@react-stately/color';
import {VisuallyHidden} from '@react-aria/visually-hidden';
import {useLocale} from '@react-aria/i18n';
import {useFocusRing} from '@react-aria/focus';
function ColorSlider(props) {
let { locale } = useLocale();
let state = useColorSliderState({ ...props, locale });
let trackRef = React.useRef(null);
let inputRef = React.useRef(null);
// Default label to the channel name in the current locale
let label = props.label ||
state.value.getChannelName(props.channel, locale);
let {
trackProps,
thumbProps,
inputProps,
labelProps,
outputProps
} = useColorSlider({
...props,
label,
trackRef,
inputRef
}, state);
let { focusProps, isFocusVisible } = useFocusRing();
return (
<div
style={{
display: 'flex',
flexDirection: 'column',
alignItems: 'center',
width: SIZE
}}
>
{/* Create a flex container for the label and output element. */}
<div
style={{ display: 'flex', alignSelf: 'stretch' }}
>
<label {...labelProps}>{label}</label>
<output
{...outputProps}
style={{ flex: '1 0 auto', textAlign: 'end' }}
>
{state.value.formatChannelValue(
props.channel,
locale
)}
</output>
</div>
{/* The track element holds the visible track line and the thumb. */}
<div
className="color-slider-track"
{...trackProps}
ref={trackRef}
style={{
height: FOCUSED_THUMB_SIZE
}}
>
<div className="color-slider-track-background">
</div>
<div
className="color-slider-track-color"
style={{
...trackProps.style
}}
>
</div>
<div
className={`color-slider-thumb `}
{...thumbProps}
style={{
...thumbProps.style
}}
>
<div className="color-slider-thumb-background">
</div>
<div
className="color-slider-thumb-color"
style={{
background: state.getDisplayColor().toString(
'css'
)
}}
>
</div>
<VisuallyHidden>
<input
ref={inputRef}
{...inputProps}
{...focusProps}
/>
</VisuallyHidden>
</div>
</div>
</div>
);
}
import {useColorSlider} from '@react-aria/color';
import {useColorSliderState} from '@react-stately/color';
import {VisuallyHidden} from '@react-aria/visually-hidden';
import {useLocale} from '@react-aria/i18n';
import {useFocusRing} from '@react-aria/focus';
function ColorSlider(
props
) {
let { locale } =
useLocale();
let state =
useColorSliderState({
...props,
locale
});
let trackRef = React
.useRef(null);
let inputRef = React
.useRef(null);
// Default label to the channel name in the current locale
let label =
props.label ||
state.value
.getChannelName(
props.channel,
locale
);
let {
trackProps,
thumbProps,
inputProps,
labelProps,
outputProps
} = useColorSlider({
...props,
label,
trackRef,
inputRef
}, state);
let {
focusProps,
isFocusVisible
} = useFocusRing();
return (
<div
style={{
display: 'flex',
flexDirection:
'column',
alignItems:
'center',
width: SIZE
}}
>
{/* Create a flex container for the label and output element. */}
<div
style={{
display:
'flex',
alignSelf:
'stretch'
}}
>
<label
{...labelProps}
>
{label}
</label>
<output
{...outputProps}
style={{
flex:
'1 0 auto',
textAlign:
'end'
}}
>
{state.value
.formatChannelValue(
props
.channel,
locale
)}
</output>
</div>
{/* The track element holds the visible track line and the thumb. */}
<div
className="color-slider-track"
{...trackProps}
ref={trackRef}
style={{
height:
FOCUSED_THUMB_SIZE
}}
>
<div className="color-slider-track-background">
</div>
<div
className="color-slider-track-color"
style={{
...trackProps
.style
}}
>
</div>
<div
className={`color-slider-thumb `}
{...thumbProps}
style={{
...thumbProps
.style
}}
>
<div className="color-slider-thumb-background">
</div>
<div
className="color-slider-thumb-color"
style={{
background:
state
.getDisplayColor()
.toString(
'css'
)
}}
>
</div>
<VisuallyHidden>
<input
ref={inputRef}
{...inputProps}
{...focusProps}
/>
</VisuallyHidden>
</div>
</div>
</div>
);
}
Show CSS
.color-slider-track,
.color-slider-track-background,
.color-slider-track-color {
width: 100%;
border-radius: 4px;
forced-color-adjust: none;
position: relative;
}
.color-slider-track-background,
.color-slider-track-color {
position: absolute;
height: 100%;
}
.color-slider-thumb {
position: absolute;
top: 14px;
border: 2px solid white;
box-shadow:
0 0 0 1px black,
inset 0 0 0 1px black;
border-radius: 50%;
box-sizing: border-box;
width: 20px;
height: 20px;
}
.color-slider-thumb.is-focused {
width: 32px;
height: 32px;
}
.color-slider-track-background,
.color-slider-thumb-background {
background-size: 16px 16px;
background-position:
-2px -2px,
-2px 6px,
6px -10px,
-10px -2px;
background-color: white;
background-image:
linear-gradient(-45deg, transparent 75.5%, rgb(188, 188, 188) 75.5%),
linear-gradient(45deg, transparent 75.5%, rgb(188, 188, 188) 75.5%),
linear-gradient(-45deg, rgb(188, 188, 188) 25.5%, transparent 25.5%),
linear-gradient(45deg, rgb(188, 188, 188) 25.5%, transparent 25.5%);
}
.color-slider-thumb-background,
.color-slider-thumb-color {
position: absolute;
border-radius: 50%;
width: 100%;
height: 100%;
}
.color-slider-track,
.color-slider-track-background,
.color-slider-track-color {
width: 100%;
border-radius: 4px;
forced-color-adjust: none;
position: relative;
}
.color-slider-track-background,
.color-slider-track-color {
position: absolute;
height: 100%;
}
.color-slider-thumb {
position: absolute;
top: 14px;
border: 2px solid white;
box-shadow:
0 0 0 1px black,
inset 0 0 0 1px black;
border-radius: 50%;
box-sizing: border-box;
width: 20px;
height: 20px;
}
.color-slider-thumb.is-focused {
width: 32px;
height: 32px;
}
.color-slider-track-background,
.color-slider-thumb-background {
background-size: 16px 16px;
background-position:
-2px -2px,
-2px 6px,
6px -10px,
-10px -2px;
background-color: white;
background-image:
linear-gradient(-45deg, transparent 75.5%, rgb(188, 188, 188) 75.5%),
linear-gradient(45deg, transparent 75.5%, rgb(188, 188, 188) 75.5%),
linear-gradient(-45deg, rgb(188, 188, 188) 25.5%, transparent 25.5%),
linear-gradient(45deg, rgb(188, 188, 188) 25.5%, transparent 25.5%);
}
.color-slider-thumb-background,
.color-slider-thumb-color {
position: absolute;
border-radius: 50%;
width: 100%;
height: 100%;
}
.color-slider-track,
.color-slider-track-background,
.color-slider-track-color {
width: 100%;
border-radius: 4px;
forced-color-adjust: none;
position: relative;
}
.color-slider-track-background,
.color-slider-track-color {
position: absolute;
height: 100%;
}
.color-slider-thumb {
position: absolute;
top: 14px;
border: 2px solid white;
box-shadow:
0 0 0 1px black,
inset 0 0 0 1px black;
border-radius: 50%;
box-sizing: border-box;
width: 20px;
height: 20px;
}
.color-slider-thumb.is-focused {
width: 32px;
height: 32px;
}
.color-slider-track-background,
.color-slider-thumb-background {
background-size: 16px 16px;
background-position:
-2px -2px,
-2px 6px,
6px -10px,
-10px -2px;
background-color: white;
background-image:
linear-gradient(-45deg, transparent 75.5%, rgb(188, 188, 188) 75.5%),
linear-gradient(45deg, transparent 75.5%, rgb(188, 188, 188) 75.5%),
linear-gradient(-45deg, rgb(188, 188, 188) 25.5%, transparent 25.5%),
linear-gradient(45deg, rgb(188, 188, 188) 25.5%, transparent 25.5%);
}
.color-slider-thumb-background,
.color-slider-thumb-color {
position: absolute;
border-radius: 50%;
width: 100%;
height: 100%;
}
ColorSwatch#
The ColorSwatch
component used in the example above implements an image preview of the color with the useColorSwatch hook.
Show code
import {useColorSwatch} from '@react-aria/color';
function ColorSwatch(props) {
let {colorSwatchProps, color} = useColorSwatch(props);
return (
<span
{...colorSwatchProps}
style={{
...colorSwatchProps.style,
display: 'inline-block',
width: 32,
height: 32,
borderRadius: 4,
background: `linear-gradient( , ),
repeating-conic-gradient(#CCC 0% 25%, white 0% 50%) 50% / 16px 16px`,
...props.style
}} />
);
}
import {useColorSwatch} from '@react-aria/color';
function ColorSwatch(props) {
let { colorSwatchProps, color } = useColorSwatch(props);
return (
<span
{...colorSwatchProps}
style={{
...colorSwatchProps.style,
display: 'inline-block',
width: 32,
height: 32,
borderRadius: 4,
background: `linear-gradient( , ),
repeating-conic-gradient(#CCC 0% 25%, white 0% 50%) 50% / 16px 16px`,
...props.style
}}
/>
);
}
import {useColorSwatch} from '@react-aria/color';
function ColorSwatch(
props
) {
let {
colorSwatchProps,
color
} = useColorSwatch(
props
);
return (
<span
{...colorSwatchProps}
style={{
...colorSwatchProps
.style,
display:
'inline-block',
width: 32,
height: 32,
borderRadius: 4,
background:
`linear-gradient( , ),
repeating-conic-gradient(#CCC 0% 25%, white 0% 50%) 50% / 16px 16px`,
...props.style
}}
/>
);
}
xChannel and yChannel#
The color channel for each axis of a color area can be specified using the xChannel
and yChannel
props.
An array of channel names for a color can be returned using the color.getColorChannels
method.
To get a localized channel name to use as a label, you can use the color.getChannelName
method.
RGB#
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(parseColor('rgb(100, 149, 237)'));
let [
rChannel,
gChannel,
bChannel
] = color.getColorChannels();
return (
<>
<div style={{ display: 'inline-flex', flexWrap: 'wrap' }}>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="gbr-label-id-1">
x: {color.getChannelName(gChannel, 'en-US')}, y:{' '}
{color.getChannelName(bChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="gbr-label-id-1"
value={color}
onChange={setColor}
xChannel={gChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={rChannel}
value={color}
onChange={setColor}
/>
</div>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="brg-label-id-1">
x: {color.getChannelName(bChannel, 'en-US')}, y:{' '}
{color.getChannelName(rChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="brg-label-id-1"
value={color}
onChange={setColor}
xChannel={bChannel}
yChannel={rChannel}
/>
<ColorSlider
channel={gChannel}
value={color}
onChange={setColor}
/>
</div>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="rgb-label-id-1">
x: {color.getChannelName(rChannel, 'en-US')}, y:{' '}
{color.getChannelName(gChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="rgb-label-id-1"
value={color}
onChange={setColor}
xChannel={rChannel}
yChannel={gChannel}
/>
<ColorSlider
channel={bChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current RGB color value:{' '}
<ColorSwatch
color={color}
style={{
width: '16px',
height: '16px',
verticalAlign: 'text-bottom'
}}
/>{' '}
{color.toString('rgb')}
</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(parseColor('rgb(100, 149, 237)'));
let [
rChannel,
gChannel,
bChannel
] = color.getColorChannels();
return (
<>
<div
style={{ display: 'inline-flex', flexWrap: 'wrap' }}
>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="gbr-label-id-1">
x: {color.getChannelName(gChannel, 'en-US')}, y:
{' '}
{color.getChannelName(bChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="gbr-label-id-1"
value={color}
onChange={setColor}
xChannel={gChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={rChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="brg-label-id-1">
x: {color.getChannelName(bChannel, 'en-US')}, y:
{' '}
{color.getChannelName(rChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="brg-label-id-1"
value={color}
onChange={setColor}
xChannel={bChannel}
yChannel={rChannel}
/>
<ColorSlider
channel={gChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="rgb-label-id-1">
x: {color.getChannelName(rChannel, 'en-US')}, y:
{' '}
{color.getChannelName(gChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="rgb-label-id-1"
value={color}
onChange={setColor}
xChannel={rChannel}
yChannel={gChannel}
/>
<ColorSlider
channel={bChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current RGB color value:{' '}
<ColorSwatch
color={color}
style={{
width: '16px',
height: '16px',
verticalAlign: 'text-bottom'
}}
/>{' '}
{color.toString('rgb')}
</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(
parseColor(
'rgb(100, 149, 237)'
)
);
let [
rChannel,
gChannel,
bChannel
] = color
.getColorChannels();
return (
<>
<div
style={{
display:
'inline-flex',
flexWrap:
'wrap'
}}
>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="gbr-label-id-1">
x:{' '}
{color
.getChannelName(
gChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
bChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="gbr-label-id-1"
value={color}
onChange={setColor}
xChannel={gChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={rChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="brg-label-id-1">
x:{' '}
{color
.getChannelName(
bChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
rChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="brg-label-id-1"
value={color}
onChange={setColor}
xChannel={bChannel}
yChannel={rChannel}
/>
<ColorSlider
channel={gChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="rgb-label-id-1">
x:{' '}
{color
.getChannelName(
rChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
gChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="rgb-label-id-1"
value={color}
onChange={setColor}
xChannel={rChannel}
yChannel={gChannel}
/>
<ColorSlider
channel={bChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current RGB color
value:{' '}
<ColorSwatch
color={color}
style={{
width:
'16px',
height:
'16px',
verticalAlign:
'text-bottom'
}}
/>{' '}
{color.toString(
'rgb'
)}
</p>
</>
);
}
HSL#
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(parseColor('hsl(219, 79%, 66%)'));
let [
hChannel,
sChannel,
lChannel
] = color.getColorChannels();
return (
<>
<div style={{ display: 'inline-flex', flexWrap: 'wrap' }}>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="slh-label-id-1">
x: {color.getChannelName(sChannel, 'en-US')}, y:{' '}
{color.getChannelName(lChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="slh-label-id-1"
value={color}
onChange={setColor}
xChannel={sChannel}
yChannel={lChannel}
/>
<ColorSlider
channel={hChannel}
value={color}
onChange={setColor}
/>
</div>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="lhs-label-id-1">
x: {color.getChannelName(hChannel, 'en-US')}, y:{' '}
{color.getChannelName(lChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="lhs-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={lChannel}
/>
<ColorSlider
channel={sChannel}
value={color}
onChange={setColor}
/>
</div>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="hsl-label-id-1">
x: {color.getChannelName(hChannel, 'en-US')}, y:{' '}
{color.getChannelName(sChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="hsl-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={sChannel}
/>
<ColorSlider
channel={lChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current HSL color value:{' '}
<ColorSwatch
color={color}
aria-hidden="true"
style={{
width: '16px',
height: '16px',
verticalAlign: 'text-bottom'
}}
/>{' '}
{color.toString('hsl')}
</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(parseColor('hsl(219, 79%, 66%)'));
let [
hChannel,
sChannel,
lChannel
] = color.getColorChannels();
return (
<>
<div
style={{ display: 'inline-flex', flexWrap: 'wrap' }}
>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="slh-label-id-1">
x: {color.getChannelName(sChannel, 'en-US')}, y:
{' '}
{color.getChannelName(lChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="slh-label-id-1"
value={color}
onChange={setColor}
xChannel={sChannel}
yChannel={lChannel}
/>
<ColorSlider
channel={hChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="lhs-label-id-1">
x: {color.getChannelName(hChannel, 'en-US')}, y:
{' '}
{color.getChannelName(lChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="lhs-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={lChannel}
/>
<ColorSlider
channel={sChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="hsl-label-id-1">
x: {color.getChannelName(hChannel, 'en-US')}, y:
{' '}
{color.getChannelName(sChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="hsl-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={sChannel}
/>
<ColorSlider
channel={lChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current HSL color value:{' '}
<ColorSwatch
color={color}
aria-hidden="true"
style={{
width: '16px',
height: '16px',
verticalAlign: 'text-bottom'
}}
/>{' '}
{color.toString('hsl')}
</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(
parseColor(
'hsl(219, 79%, 66%)'
)
);
let [
hChannel,
sChannel,
lChannel
] = color
.getColorChannels();
return (
<>
<div
style={{
display:
'inline-flex',
flexWrap:
'wrap'
}}
>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="slh-label-id-1">
x:{' '}
{color
.getChannelName(
sChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
lChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="slh-label-id-1"
value={color}
onChange={setColor}
xChannel={sChannel}
yChannel={lChannel}
/>
<ColorSlider
channel={hChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="lhs-label-id-1">
x:{' '}
{color
.getChannelName(
hChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
lChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="lhs-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={lChannel}
/>
<ColorSlider
channel={sChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="hsl-label-id-1">
x:{' '}
{color
.getChannelName(
hChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
sChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="hsl-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={sChannel}
/>
<ColorSlider
channel={lChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current HSL color
value:{' '}
<ColorSwatch
color={color}
aria-hidden="true"
style={{
width:
'16px',
height:
'16px',
verticalAlign:
'text-bottom'
}}
/>{' '}
{color.toString(
'hsl'
)}
</p>
</>
);
}
HSB#
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(parseColor('hsb(219, 58%, 93%)'));
let [
hChannel,
sChannel,
bChannel
] = color.getColorChannels();
return (
<>
<div style={{ display: 'inline-flex', flexWrap: 'wrap' }}>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="sbh-label-id-1">
x: {color.getChannelName(sChannel, 'en-US')}, y:{' '}
{color.getChannelName(bChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="sbh-label-id-1"
value={color}
onChange={setColor}
xChannel={sChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={hChannel}
value={color}
onChange={setColor}
/>
</div>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="bhs-label-id-1">
x: {color.getChannelName(hChannel, 'en-US')}, y:{' '}
{color.getChannelName(bChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="bhs-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={sChannel}
value={color}
onChange={setColor}
/>
</div>
<div style={{ marginRight: '2rem', marginBottom: '2rem' }}>
<label id="hsb-label-id-2">
x: {color.getChannelName(hChannel, 'en-US')}, y:{' '}
{color.getChannelName(sChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="hsb-label-id-2"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={sChannel}
/>
<ColorSlider
channel={bChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current HSB color value:{' '}
<ColorSwatch
color={color}
style={{
width: '16px',
height: '16px',
verticalAlign: 'text-bottom'
}}
/>{' '}
{color.toString('hsb')}
</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(parseColor('hsb(219, 58%, 93%)'));
let [
hChannel,
sChannel,
bChannel
] = color.getColorChannels();
return (
<>
<div
style={{ display: 'inline-flex', flexWrap: 'wrap' }}
>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="sbh-label-id-1">
x: {color.getChannelName(sChannel, 'en-US')}, y:
{' '}
{color.getChannelName(bChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="sbh-label-id-1"
value={color}
onChange={setColor}
xChannel={sChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={hChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="bhs-label-id-1">
x: {color.getChannelName(hChannel, 'en-US')}, y:
{' '}
{color.getChannelName(bChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="bhs-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={sChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight: '2rem',
marginBottom: '2rem'
}}
>
<label id="hsb-label-id-2">
x: {color.getChannelName(hChannel, 'en-US')}, y:
{' '}
{color.getChannelName(sChannel, 'en-US')}
</label>
<ColorArea
aria-labelledby="hsb-label-id-2"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={sChannel}
/>
<ColorSlider
channel={bChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current HSB color value:{' '}
<ColorSwatch
color={color}
style={{
width: '16px',
height: '16px',
verticalAlign: 'text-bottom'
}}
/>{' '}
{color.toString('hsb')}
</p>
</>
);
}
import {parseColor} from '@react-stately/color';
function Example() {
let [
color,
setColor
] = React.useState(
parseColor(
'hsb(219, 58%, 93%)'
)
);
let [
hChannel,
sChannel,
bChannel
] = color
.getColorChannels();
return (
<>
<div
style={{
display:
'inline-flex',
flexWrap:
'wrap'
}}
>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="sbh-label-id-1">
x:{' '}
{color
.getChannelName(
sChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
bChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="sbh-label-id-1"
value={color}
onChange={setColor}
xChannel={sChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={hChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="bhs-label-id-1">
x:{' '}
{color
.getChannelName(
hChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
bChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="bhs-label-id-1"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={bChannel}
/>
<ColorSlider
channel={sChannel}
value={color}
onChange={setColor}
/>
</div>
<div
style={{
marginRight:
'2rem',
marginBottom:
'2rem'
}}
>
<label id="hsb-label-id-2">
x:{' '}
{color
.getChannelName(
hChannel,
'en-US'
)}, y:{' '}
{color
.getChannelName(
sChannel,
'en-US'
)}
</label>
<ColorArea
aria-labelledby="hsb-label-id-2"
value={color}
onChange={setColor}
xChannel={hChannel}
yChannel={sChannel}
/>
<ColorSlider
channel={bChannel}
value={color}
onChange={setColor}
/>
</div>
</div>
<p>
Current HSB color
value:{' '}
<ColorSwatch
color={color}
style={{
width:
'16px',
height:
'16px',
verticalAlign:
'text-bottom'
}}
/>{' '}
{color.toString(
'hsb'
)}
</p>
</>
);
}
Disabled#
A color area can be disabled using the isDisabled
prop. This prevents the thumb from being focused or dragged.
It's up to you to style your color area to appear disabled accordingly.
<ColorArea
defaultValue="hsl(0, 100%, 50%)"
xChannel="saturation"
yChannel="lightness"
isDisabled />
<ColorArea
defaultValue="hsl(0, 100%, 50%)"
xChannel="saturation"
yChannel="lightness"
isDisabled />
<ColorArea
defaultValue="hsl(0, 100%, 50%)"
xChannel="saturation"
yChannel="lightness"
isDisabled
/>
HTML forms#
ColorArea supports the xName
and yName
props for integration with HTML forms. The values will be submitted as numbers between the minimum and maximum value for the corresponding channel in the X and Y direction.
<ColorArea xName="red" yName="green" />
<ColorArea xName="red" yName="green" />
<ColorArea
xName="red"
yName="green"
/>
Internationalization#
Labeling#
By default, useColorArea
provides an aria-label
for the localized string "Color Picker",
which labels the visually hidden <input>
elements for the two color channels, or on mobile devices,
the group containing them. If you wish to override this with a more specific label, an aria-label
or
aria-labelledby
prop may be passed to further to identify the element to assistive technologies.
For example, for a color area that adjusts a text color you might pass the aria-label
prop,
"Text color", which useColorArea
will return as the aria-label
prop "Text color, Color picker". When a custom aria-label
is provided, it should be localized accordingly.
Role description#
In order to communicate to a screen reader user that the color area adjusts in two dimensions,
useColorArea
provides an aria-roledescription
, using the localized string "2D Slider", on each of the
visually hidden <input>
elements.
Value formatting#
The aria-valuetext
of each <input>
element is formatted according to the user's locale automatically.
It includes the localized color channel name and current value for each channel, with the channel name
and value that the <input>
element controls coming before the channel name and value for the adjacent
<input>
element. For example, for an RGB color area where the xChannel
is "blue", the yChannel
is "green", when the current selected color is yellow (rgb(255, 255, 0)
), the <input>
representing the
blue channel will have aria-valuetext
to announce as "Blue: 0, Green: 255", and the <input>
representing the green channel will have aria-valuetext
to announce as "Green: 255, Blue: 0".
RTL#
In right-to-left languages, color areas should be mirrored.
Orientation of the gradient background, positioning of the thumb,
and dragging behavior is automatically mirrored by useColorArea
.