@manufosela/before-after

Before/after image comparison slider web component

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Before After

Image comparison slider to reveal before/after views.

← Back to components GitHub Repo Playground npm

Basic Usage

Drag the divider to compare two images. Default position is 50%.

<before-after>
  <img slot="before" src="grayscale.jpg" alt="Before">
  <img slot="after" src="color.jpg" alt="After">
</before-after>

Different Image Sizes

Images with different dimensions. The container adapts to fit both without gaps.

<before-after>
  <img slot="before" src="photo-800x500.jpg" alt="Before">
  <img slot="after" src="photo-800x600.jpg" alt="After">
</before-after>

Custom Initial Position

Start with the divider at 25%.

<before-after position="25">
  <img slot="before" src="grayscale.jpg" alt="Before">
  <img slot="after" src="color.jpg" alt="After">
</before-after>

Custom Labels

Customize the before and after labels.

<before-after before-label="Original" after-label="Edited">
  <img slot="before" src="original.jpg" alt="Original">
  <img slot="after" src="edited.jpg" alt="Edited">
</before-after>

Hover Mode

The divider follows the mouse without clicking.

<before-after hover-mode hide-labels>
  ...
</before-after>

Custom Styles

Customize divider color, handle size, and label appearance via CSS custom properties.

<before-after style="
  --before-after-divider-color: #ff6600;
  --before-after-divider-width: 4px;
  --before-after-handle-size: 48px;
  --before-after-handle-color: #ff6600;
  --before-after-label-bg: rgba(255, 102, 0, 0.8);
">
  ...
</before-after>

Disabled State

The slider is disabled and cannot be interacted with.

<before-after disabled position="35">
  ...
</before-after>

Programmatic Control

Control the position programmatically and listen for events.

Events will appear here...

const el = document.querySelector('before-after');
el.position = 75;

el.addEventListener('before-after-change', (e) => {
  console.log('Position:', e.detail.position);
});

Keyboard Navigation

Focus the slider and use the keyboard to control it:

Arrow Left / Arrow Right — move 1%
Page Up / Page Down — move 10%
Home — go to 0%
End — go to 100%

Demo code (CodePen-ready HTML, CSS, JS)

HTML (html)

<h1>Before After</h1>
  <p class="subtitle">Image comparison slider to reveal before/after views.</p>
  <div class="demo-links">
    <a href="https://manufosela.dev/ui-components/">&larr; Back to components</a>
    <a href="https://github.com/manufosela/ui-components/tree/main/packages/before-after" target="_blank" rel="noopener">GitHub Repo</a>
    <a href="playground.html">Playground</a>
    <a href="https://www.npmjs.com/package/@manufosela/before-after" target="_blank" rel="noopener">npm</a>
  </div>
  <div class="demo-theme-toggle">
    <theme-toggle theme="dark"></theme-toggle>
  </div>

  <div class="demo-section">
    <h2>Basic Usage</h2>
    <p>Drag the divider to compare two images. Default position is 50%.</p>
    <before-after>
      <img slot="before" src="https://picsum.photos/id/10/800/500?grayscale" alt="Grayscale landscape">
      <img slot="after" src="https://picsum.photos/id/10/800/500" alt="Color landscape">
    </before-after>
    <div class="code-block">&lt;before-after&gt;
  &lt;img slot="before" src="grayscale.jpg" alt="Before"&gt;
  &lt;img slot="after" src="color.jpg" alt="After"&gt;
&lt;/before-after&gt;</div>
  </div>

  <div class="demo-section">
    <h2>Different Image Sizes</h2>
    <p>Images with different dimensions. The container adapts to fit both without gaps.</p>
    <before-after before-label="800x500" after-label="800x600">
      <img slot="before" src="https://picsum.photos/id/11/800/500?grayscale" alt="800x500 grayscale">
      <img slot="after" src="https://picsum.photos/id/11/800/600" alt="800x600 color">
    </before-after>
    <div class="code-block">&lt;before-after&gt;
  &lt;img slot="before" src="photo-800x500.jpg" alt="Before"&gt;
  &lt;img slot="after" src="photo-800x600.jpg" alt="After"&gt;
&lt;/before-after&gt;</div>
  </div>

  <div class="demo-section">
    <h2>Custom Initial Position</h2>
    <p>Start with the divider at 25%.</p>
    <before-after position="25">
      <img slot="before" src="https://picsum.photos/id/15/800/500?grayscale" alt="Grayscale">
      <img slot="after" src="https://picsum.photos/id/15/800/500" alt="Color">
    </before-after>
    <div class="code-block">&lt;before-after position="25"&gt;
  &lt;img slot="before" src="grayscale.jpg" alt="Before"&gt;
  &lt;img slot="after" src="color.jpg" alt="After"&gt;
&lt;/before-after&gt;</div>
  </div>

  <div class="demo-section">
    <h2>Custom Labels</h2>
    <p>Customize the before and after labels.</p>
    <before-after before-label="Original" after-label="Edited">
      <img slot="before" src="https://picsum.photos/id/20/800/500?grayscale" alt="Original">
      <img slot="after" src="https://picsum.photos/id/20/800/500" alt="Edited">
    </before-after>
    <div class="code-block">&lt;before-after before-label="Original" after-label="Edited"&gt;
  &lt;img slot="before" src="original.jpg" alt="Original"&gt;
  &lt;img slot="after" src="edited.jpg" alt="Edited"&gt;
&lt;/before-after&gt;</div>
  </div>

  <div class="demo-section">
    <h2>Hover Mode</h2>
    <p>The divider follows the mouse without clicking.</p>
    <before-after hover-mode hide-labels>
      <img slot="before" src="https://picsum.photos/id/25/800/500?grayscale" alt="Grayscale">
      <img slot="after" src="https://picsum.photos/id/25/800/500" alt="Color">
    </before-after>
    <div class="code-block">&lt;before-after hover-mode hide-labels&gt;
  ...
&lt;/before-after&gt;</div>
  </div>

  <div class="demo-section">
    <h2>Custom Styles</h2>
    <p>Customize divider color, handle size, and label appearance via CSS custom properties.</p>
    <before-after style="
      --before-after-divider-color: #ff6600;
      --before-after-divider-width: 4px;
      --before-after-handle-size: 48px;
      --before-after-handle-color: #ff6600;
      --before-after-label-bg: rgba(255, 102, 0, 0.8);
    ">
      <img slot="before" src="https://picsum.photos/id/30/800/500?grayscale" alt="Grayscale">
      <img slot="after" src="https://picsum.photos/id/30/800/500" alt="Color">
    </before-after>
    <div class="code-block">&lt;before-after style="
  --before-after-divider-color: #ff6600;
  --before-after-divider-width: 4px;
  --before-after-handle-size: 48px;
  --before-after-handle-color: #ff6600;
  --before-after-label-bg: rgba(255, 102, 0, 0.8);
"&gt;
  ...
&lt;/before-after&gt;</div>
  </div>

  <div class="demo-section">
    <h2>Disabled State</h2>
    <p>The slider is disabled and cannot be interacted with.</p>
    <before-after disabled position="35">
      <img slot="before" src="https://picsum.photos/id/35/800/500?grayscale" alt="Grayscale">
      <img slot="after" src="https://picsum.photos/id/35/800/500" alt="Color">
    </before-after>
    <div class="code-block">&lt;before-after disabled position="35"&gt;
  ...
&lt;/before-after&gt;</div>
  </div>

  <div class="demo-section">
    <h2>Programmatic Control</h2>
    <p>Control the position programmatically and listen for events.</p>
    <before-after id="controlled">
      <img slot="before" src="https://picsum.photos/id/40/800/500?grayscale" alt="Grayscale">
      <img slot="after" src="https://picsum.photos/id/40/800/500" alt="Color">
    </before-after>
    <div class="controls">
      <button onclick="document.getElementById('controlled').position = 0">0%</button>
      <button onclick="document.getElementById('controlled').position = 25">25%</button>
      <button onclick="document.getElementById('controlled').position = 50">50%</button>
      <button onclick="document.getElementById('controlled').position = 75">75%</button>
      <button onclick="document.getElementById('controlled').position = 100">100%</button>
    </div>
    <div id="event-log" class="output">Events will appear here...</div>
    <div class="code-block">const el = document.querySelector('before-after');
el.position = 75;

el.addEventListener('before-after-change', (e) =&gt; {
  console.log('Position:', e.detail.position);
});</div>
  </div>

  <div class="demo-section">
    <h2>Keyboard Navigation</h2>
    <p>Focus the slider and use the keyboard to control it:</p>
    <ul style="color: #1d1d1f; line-height: 2;">
      <li><span class="kbd">Arrow Left</span> / <span class="kbd">Arrow Right</span> &mdash; move 1%</li>
      <li><span class="kbd">Page Up</span> / <span class="kbd">Page Down</span> &mdash; move 10%</li>
      <li><span class="kbd">Home</span> &mdash; go to 0%</li>
      <li><span class="kbd">End</span> &mdash; go to 100%</li>
    </ul>
    <before-after>
      <img slot="before" src="https://picsum.photos/id/45/800/500?grayscale" alt="Grayscale">
      <img slot="after" src="https://picsum.photos/id/45/800/500" alt="Color">
    </before-after>
  </div>

CSS (css)

:root {
  --bg: #0c0f14;
  --bg-elevated: #141923;
  --bg-panel: #171d28;
  --border: #262f3f;
  --text: #f4f6fb;
  --text-muted: #a7b0c2;
  --text-dim: #7d879b;
  --accent: #ff8a3d;
  --accent-strong: #ff6a00;
  --accent-soft: rgba(255, 138, 61, 0.16);
  --shadow: 0 20px 50px rgba(5, 8, 14, 0.45);
  --radius-lg: 22px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --max-width: 1160px;
}

h1 { color: #1d1d1f; }
    .demo-section {
      background: white;
      padding: 2rem;
      border-radius: 12px;
      margin-bottom: 2rem;
      box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    }
    h2 { margin-top: 0; color: #1d1d1f; }
    p { color: #86868b; line-height: 1.6; }
    a { color: #3b82f6; }
    .code-block {
      background: #1d1d1f;
      color: #f5f5f7;
      padding: 1rem;
      border-radius: 8px;
      font-family: monospace;
      font-size: 0.8rem;
      margin-top: 1rem;
      overflow: auto;
      max-height: 300px;
      white-space: pre;
    }
    .output {
      margin-top: 1rem;
      padding: 1rem;
      background: #f5f5f7;
      border-radius: 8px;
      font-family: monospace;
    }
    before-after {
      max-width: 100%;
    }
    .controls {
      display: flex;
      gap: 0.5rem;
      margin-top: 1rem;
      flex-wrap: wrap;
    }
    .controls button {
      padding: 0.5rem 1rem;
      border: 1px solid #d2d2d7;
      border-radius: 6px;
      background: #fff;
      cursor: pointer;
      font-size: 0.85rem;
    }
    .controls button:hover {
      background: #f0f0f0;
    }
    footer {
      text-align: center;
      margin-top: 3rem;
      padding-top: 2rem;
      border-top: 1px solid #d2d2d7;
      color: #86868b;
      font-size: 0.9rem;
    }
    footer a { color: #1d1d1f; text-decoration: none; }
    footer a:hover { text-decoration: underline; }
    .kbd {
      display: inline-block;
      padding: 2px 6px;
      border: 1px solid #ccc;
      border-radius: 4px;
      background: #f9f9f9;
      font-family: monospace;
      font-size: 0.85rem;
    }
  


@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;600;700&display=swap');

:root {
  --bg: #f5f5f7;
  --bg-2: #ffffff;
  --bg-spot-1: #f8e9d0;
  --bg-spot-2: #e8eef8;
  --card: #ffffff;
  --text: #1d1d1f;
  --muted: #6b7280;
  --line: #e5e7eb;
  --accent: #ffb000;
  --accent-2: #00a7d6;
  --accent-soft: rgba(255, 176, 0, 0.18);
  --surface-1: #f3f4f6;
  --surface-2: #eef2f7;
  --code-bg: #111827;
  --code-text: #f9fafb;
  --panel-bg: rgba(255, 255, 255, 0.85);
  --overlay-bg: rgba(255, 255, 255, 0.98);
}

:root.dark {
  --bg: #0f1117;
  --bg-2: #151a26;
  --bg-spot-1: #1a2136;
  --bg-spot-2: #1d1b34;
  --card: #1c2233;
  --text: #f3f6ff;
  --muted: #b8c0d9;
  --line: #2b3247;
  --accent: #ffb000;
  --accent-2: #00d0ff;
  --accent-soft: rgba(255, 176, 0, 0.25);
  --surface-1: #0b0f1a;
  --surface-2: #263046;
  --code-bg: #0b0f1a;
  --code-text: #d6d9e6;
  --panel-bg: rgba(28, 34, 51, 0.8);
  --overlay-bg: rgba(15, 17, 23, 0.98);
}

* {
  box-sizing: border-box;
}

a {
  color: var(--accent);
}

h1 {
  color: var(--accent);
}

.demo-links {
  margin-top: 12px;
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.demo-links a {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 12px;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.85rem;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.demo-links a:hover {
  color: var(--text);
  border-color: var(--accent-2);
}

.demo-theme-toggle {
  margin-top: 12px;
  display: flex;
  justify-content: center;
}

header {
  border-bottom: 1px solid var(--line);
}

.demo-card,
.section,
.demo-section,
.panel,
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  color: var(--text);
  box-shadow: 0 18px 36px rgba(6, 10, 24, 0.45);
}

.demo-card {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.demo-card .code-block {
  margin-top: auto;
}

.demo-grid,
.grid {
  align-items: stretch;
}

.demo-card h2,
.demo-card h3,
.section h2,
.demo-section h2,
.panel-header {
  color: var(--text);
}

.label,
.stat-label,
.category-title,
.subtitle,
.hint,
.note {
  color: var(--muted);
}

.info-item,
.capability,
.preference,
.option-group,
.output,
.current-url,
.event-log,
.result-card,
.log,
.stat {
  background: var(--surface-1);
  border: 1px solid var(--line);
  color: var(--text);
}

.info-item .label,
.capability .name {
  color: var(--muted);
}

.panel-header,
.options,
.topbar,
.top-links {
  background: var(--panel-bg);
  border-bottom: 1px solid var(--line);
  color: var(--text);
}

.subtitle,
.hint,
.note,
.demo-card p,
.section p,
.demo-section p {
  color: var(--muted);
}

.code-block,
pre,
code {
  background: var(--code-bg);
  color: var(--code-text);
  border-radius: 8px;
}

.value-display,
.output,
.result,
.demo-output {
  background: var(--surface-1);
  border: 1px solid var(--line);
  color: var(--text);
}

button {
  background: linear-gradient(120deg, var(--accent), #ff6a00);
  color: #111;
  border: none;
}

button:hover {
  filter: brightness(1.05);
}

input,
select,
textarea {
  background: var(--surface-1);
  color: var(--text);
  border: 1px solid var(--line);
}

footer {
  color: var(--muted);
}

footer a {
  color: var(--text);
}

arc-slider {
  --arc-slider-text-color: var(--text);
  --arc-slider-value-bg: var(--surface-1);
  --arc-slider-value-border: var(--line);
  --arc-slider-value-shadow: 0 6px 16px rgba(0, 0, 0, 0.35);
}

rich-select {
  --caller-background: var(--card);
  --caller-color: var(--text);
  --caller-border: 1px solid var(--line);
  --caller-hover-background: var(--surface-2);
  --caller-hover-color: var(--text);
  --caller-hover-border-color: var(--line);
  --caller-focus-border-color: var(--accent-2);
  --caller-focus-shadow: 0 0 0 3px rgba(0, 208, 255, 0.25);
  --caller-disabled-background: var(--surface-1);
  --caller-disabled-color: #6b7280;
  --caller-disabled-border-color: var(--line);
  --arrow-color: var(--muted);
  --selectOptions-background: var(--card);
  --selectOptions-border: 1px solid var(--line);
  --selectOptions-shadow: 0 10px 22px rgba(0, 0, 0, 0.45);
  --input-background: var(--surface-1);
  --input-border: 1px solid var(--line);
  --input-color: var(--text);
  --input-placeholder-color: #6b7280;
  --option-color: var(--text);
  --option-hover-background: var(--surface-2);
  --option-hover-color: var(--text);
  --option-active-background: var(--accent);
  --option-active-color: #111;
  --option-selected-background: var(--accent-soft);
  --option-selected-color: var(--text);
  --option-disabled-background: var(--surface-1);
  --option-disabled-color: #6b7280;
}

multi-select {
  --multi-select-bg: var(--card);
  --multi-select-border-color: var(--line);
  --multi-select-border-hover: var(--line);
  --multi-select-border-focus: var(--accent-2);
  --multi-select-text-color: var(--text);
  --multi-select-placeholder-color: #6b7280;
  --multi-select-arrow-color: var(--muted);
  --multi-select-dropdown-bg: var(--card);
  --multi-select-shadow: 0 10px 22px rgba(0, 0, 0, 0.45);
  --multi-select-option-hover-bg: var(--surface-2);
  --multi-select-option-selected-bg: var(--accent-soft);
}

tab-nav {
  --tab-bg: var(--card);
  --tab-border: var(--line);
  --tab-text: var(--muted);
  --tab-active-text: var(--text);
  --tab-hover-bg: var(--surface-2);
  --tab-active-border: var(--accent);
  --tab-disabled: #9ca3af;
}

slider-underline {
  --slider-track: var(--surface-2);
  --slider-fill: var(--accent);
  --slider-thumb: var(--accent);
  --slider-label-color: var(--text);
  --slider-tick-color: #9ca3af;
  --slider-tick-value-color: var(--muted);
}

header-nav {
  --header-bg: var(--card);
  --header-shadow: 0 12px 24px rgba(0, 0, 0, 0.2);
  --header-link-color: var(--text);
  --header-link-hover: var(--accent);
  --header-mobile-hover-bg: var(--surface-2);
}

calendar-inline {
  --calendar-bg: var(--card);
  --calendar-shadow: 0 12px 24px rgba(0, 0, 0, 0.2);
  --calendar-text: var(--text);
  --calendar-accent: var(--accent);
  --calendar-today: var(--accent-soft);
  --calendar-selected: var(--accent);
  --calendar-hover-bg: var(--surface-2);
  --calendar-muted: var(--muted);
  --calendar-muted-strong: #9ca3af;
  --calendar-other-month: #9ca3af;
  --calendar-disabled: #cbd5e1;
  --calendar-holiday: #ef4444;
  --calendar-holiday-selected: #111;
}

marked-calendar {
  --calendar-bg: var(--card);
  --calendar-border: var(--line);
  --calendar-title: var(--text);
  --calendar-muted: var(--muted);
  --calendar-surface: var(--surface-1);
  --calendar-accent: var(--accent);
  --calendar-accent-hover: #ff7a1a;
  --calendar-border-strong: var(--line);
  --calendar-contrast: #111;
  --calendar-nav-bg: var(--surface-1);
  --calendar-nav-hover: var(--surface-2);
}

radar-chart {
  --radar-bg: var(--card);
  --radar-grid-color: var(--line);
  --radar-axis-color: #94a3b8;
  --radar-label-color: var(--muted);
}

multi-carousel {
  --carousel-bg: var(--card);
  --carousel-arrow-bg: var(--surface-1);
  --carousel-arrow-color: var(--text);
  --carousel-arrow-hover-bg: var(--surface-2);
  --carousel-arrow-hover-color: var(--text);
  --carousel-nav-bg: var(--surface-1);
  --carousel-nav-color: var(--muted);
  --carousel-nav-hover: #9ca3af;
  --carousel-nav-active: var(--accent);
  --carousel-focus-color: var(--accent-2);
}

nav-list {
  --nav-list-bg: var(--card);
  --nav-list-border-color: var(--line);
  --nav-list-selected-border-color: var(--accent);
  --nav-list-selected-bg: var(--surface-2);
  --nav-list-hover-bg: var(--surface-2);
  --nav-list-selected-color: var(--text);
}

theme-toggle {
  --theme-toggle-bg: var(--card);
  --theme-toggle-icon-color: var(--muted);
  --theme-toggle-hover-bg: var(--surface-2);
  --theme-toggle-active-bg: var(--surface-1);
  --theme-toggle-active-color: var(--text);
  --theme-toggle-dark-bg: var(--card);
  --theme-toggle-dark-border: var(--line);
  --theme-toggle-dark-icon-color: var(--muted);
  --theme-toggle-dark-active-bg: var(--surface-1);
  --theme-toggle-dark-active-color: var(--text);
  --theme-toggle-dark-hover-bg: var(--surface-2);
}

qr-code {
  --qr-fg: #0f1117;
  --qr-bg: #f3f6ff;
}

click-clock {
  --clock-color: var(--text);
  --clock-bg: var(--card);
  --clock-muted-color: var(--muted);
}

historical-line {
  --title-color: var(--text);
  --border-color: var(--line);
  --year-bg: var(--surface-1);
}

circle-steps {
  --steps-muted: var(--muted);
  --steps-text: var(--text);
  --steps-pending: var(--surface-2);
}

rich-inputfile {
  --input-border: var(--line);
  --input-border-focus: var(--accent-2);
  --input-bg: var(--card);
  --input-label-color: var(--text);
  --input-hover-bg: var(--surface-2);
  --input-drag-bg: var(--accent-soft);
  --input-disabled-bg: var(--surface-1);
  --input-success-border: #22c55e;
  --input-success-bg: rgba(34, 197, 94, 0.12);
  --input-icon-color: #94a3b8;
  --input-text-color: var(--muted);
  --input-accent-color: var(--accent-2);
  --input-file-bg: var(--surface-1);
  --input-preview-bg: var(--surface-1);
  --input-file-name-color: var(--text);
  --input-file-size-color: var(--muted);
  --input-error-color: #ef4444;
  --input-hint-color: var(--muted);
}

data-card {
  --data-card-bg: var(--card);
  --data-card-border-color: var(--line);
  --data-card-title-color: var(--text);
  --data-card-desc-color: var(--muted);
  --data-card-info-bg: var(--overlay-bg);
  --data-card-info-close-bg: var(--surface-2);
  --data-card-info-close-color: var(--text);
  --data-card-info-close-hover-bg: var(--surface-1);
  --data-card-info-text: var(--text);
  --data-card-loading-color: var(--muted);
  --data-card-info-trigger-hover: var(--accent);
}

app-modal {
  --app-modal-bg: var(--card);
  --app-modal-body-color: var(--text);
  --app-modal-standalone-bg: rgba(255, 176, 0, 0.35);
  --app-modal-standalone-color: #111;
  --app-modal-standalone-hover-bg: rgba(255, 176, 0, 0.6);
}

JS (js)

document.querySelectorAll('.footer-year').forEach(el => el.textContent = new Date().getFullYear());

    const controlled = document.getElementById('controlled');
    const log = document.getElementById('event-log');
    controlled.addEventListener('before-after-change', (e) => {
      log.textContent = `before-after-change: position = ${e.detail.position.toFixed(1)}%`;
    });
    controlled.addEventListener('before-after-input', (e) => {
      log.textContent = `before-after-input: position = ${e.detail.position.toFixed(1)}%`;
    });
  

    import "https://esm.sh/@manufosela/before-after";
  

    import '../../theme-toggle/src/theme-toggle.js';

    const root = document.documentElement;
    root.classList.add('dark');

    const toggle = document.querySelector('theme-toggle');
    if (toggle) {
      toggle.theme = root.classList.contains('dark') ? 'dark' : 'light';
      toggle.addEventListener('theme-changed', (event) => {
        const theme = event.detail?.theme;
        if (!theme) return;
        root.classList.toggle('dark', theme === 'dark');
      });
    }