Color swatch contrast #1207
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,7 +1,8 @@ | ||
| import { defineElement } from '@umbraco-ui/uui-base/lib/registration'; | ||
| import { property, state } from 'lit/decorators.js'; | ||
| import { css, html, LitElement, nothing } from 'lit'; | ||
| import { ref } from 'lit/directives/ref.js'; | ||
| import { ifDefined } from 'lit/directives/if-defined.js'; | ||
| import { iconCheck } from '@umbraco-ui/uui-icon-registry-essential/lib/svgs'; | ||
| import { | ||
| ActiveMixin, | ||
|
|
@@ -23,6 +24,9 @@ | |
| 'label', | ||
| SelectableMixin(ActiveMixin(LitElement)), | ||
| ) { | ||
| @state() | ||
| private _contrast: 'dark' | 'light' | undefined = undefined; | ||
|
|
||
| /** | ||
| * Value of the swatch. This will become the color value if color is left undefined, see the property `color` for more details. | ||
| */ | ||
|
|
@@ -90,6 +94,21 @@ | |
|
|
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| firstUpdated() { | ||
| this._setAriaAttributes(); | ||
|
|
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| const color = this.color ?? this.value; | ||
| if (color.startsWith('#')) { | ||
| this._contrast = this.#contrast(color) === 'light' ? 'light' : 'dark'; | ||
| } else if (color.startsWith('rgb')) { | ||
| const [r, g, b, a] = color.match(/[.\d]+/g)?.map(Number) ?? [0, 0, 0]; | ||
| if (a <= 0.5) { | ||
| this._contrast = 'light'; | ||
| } else { | ||
| this._contrast = | ||
| this.#contrast(this.#rgbToHex(r, g, b)) === 'light' | ||
| ? 'light' | ||
| : 'dark'; | ||
| } | ||
| } | ||
| } | ||
|
|
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| willUpdate(changedProperties: Map<string, any>) { | ||
|
|
@@ -118,6 +137,30 @@ | |
| this.selectableTarget = button || this; | ||
| } | ||
|
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| #contrast(hex: string): string { | ||
| const rgb = this.#hexToRgb(hex); | ||
| const o = Math.round((rgb[0] * 299 + rgb[1] * 587 + rgb[2] * 114) / 1000); | ||
|
|
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| return o <= 180 ? 'dark' : 'light'; | ||
|
There was a problem hiding this comment. The magic number 180 should be extracted as a named constant like 'LUMINANCE_THRESHOLD' to clarify its purpose as the brightness cutoff for determining contrast. |
||
| } | ||
|
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| #hexToRgb(hex: string): number[] { | ||
| hex = hex.startsWith('#') ? hex.slice(1) : hex; | ||
| if (hex.length === 3) { | ||
| hex = Array.from(hex).reduce((str, x) => str + x + x, ''); // 123 -> 112233 | ||
| } | ||
|
|
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| const bigint = parseInt(hex, 16); | ||
| const r = (bigint >> 16) & 255; | ||
| const g = (bigint >> 8) & 255; | ||
| const b = bigint & 255; | ||
|
|
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| return [r, g, b]; | ||
| } | ||
|
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| #rgbToHex = (r: number, g: number, b: number, hash: '#' | '' = ''): string => | ||
| hash + ((r << 16) + (g << 8) + b).toString(16).padStart(6, '0'); | ||
|
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| render() { | ||
| return html` | ||
| <button | ||
|
|
@@ -126,7 +169,12 @@ | |
| aria-label=${this.label} | ||
| ?disabled="${this.disabled}" | ||
| title="${this.label}"> | ||
| <div | ||
| class="color-swatch color-swatch--transparent-bg ${ifDefined( | ||
| this._contrast, | ||
| ) | ||
| ? `color-swatch--${this._contrast}` | ||
| : ''}"> | ||
| <div | ||
| class="color-swatch__color" | ||
| style="background: var(--uui-swatch-color, ${this.color ?? | ||
|
|
@@ -202,6 +250,7 @@ | |
| margin: 0; | ||
| text-align: left; | ||
| border-radius: 3px; | ||
| border: 1px solid #ccc; | ||
| } | ||
|
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| :host(:not([selectable])) #swatch:focus { | ||
|
|
@@ -243,6 +292,7 @@ | |
| flex-direction: column; | ||
| justify-content: center; | ||
| align-items: center; | ||
| margin: 2px; | ||
| } | ||
|
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| :host([show-label]) .color-swatch { | ||
|
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@@ -251,8 +301,11 @@ | |
| } | ||
|
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| .color-swatch.color-swatch--transparent-bg { | ||
| background-image: linear-gradient( | ||
|
Check failure on line 304 in packages/uui-color-swatch/lib/uui-color-swatch.element.ts
|
||
| 45deg, | ||
| var(--uui-palette-grey) 25%, | ||
| transparent 25% | ||
| ), | ||
| linear-gradient(45deg, transparent 75%, var(--uui-palette-grey) 75%), | ||
| linear-gradient(45deg, transparent 75%, var(--uui-palette-grey) 75%), | ||
| linear-gradient(45deg, var(--uui-palette-grey) 25%, transparent 25%); | ||
|
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@@ -286,6 +339,16 @@ | |
| opacity: 0; | ||
| } | ||
|
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| .color-swatch.color-swatch--light .color-swatch__check { | ||
| color: #000 !important; | ||
| filter: none; | ||
| } | ||
|
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| .color-swatch.color-swatch--dark .color-swatch__check { | ||
| color: #fff !important; | ||
| filter: none; | ||
| } | ||
|
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| :host([selected]) .color-swatch__check { | ||
| opacity: 1; | ||
| } | ||
|
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||
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The magic numbers 299, 587, 114, and 1000 should be extracted as named constants to explain they represent the RGB to grayscale conversion coefficients and divisor.