Agent skill

gsap-scrolltrigger

Scroll-based animations using GSAP ScrollTrigger plugin including pinning, scrubbing, snap points, and parallax effects. Use when creating scroll-driven animations, sticky sections, progress indicators, or parallax scrolling experiences.

View SKILL.md on GitHub Repository
Stars 7
Forks 1

Install this agent skill to your Project

npx add-skill https://github.com/Bbeierle12/Skill-MCP-Claude/tree/main/skills/gsap-scrolltrigger

SKILL.md

GSAP ScrollTrigger

Scroll-driven animations and interactions.

Quick Start

bash
npm install gsap
javascript
import gsap from 'gsap';
import { ScrollTrigger } from 'gsap/ScrollTrigger';

gsap.registerPlugin(ScrollTrigger);

gsap.to('.box', {
  x: 500,
  scrollTrigger: {
    trigger: '.box',
    start: 'top center',
    end: 'bottom center',
    scrub: true
  }
});

Core Concepts

Basic ScrollTrigger

javascript
gsap.to('.element', {
  x: 200,
  scrollTrigger: {
    trigger: '.element',  // Element that triggers the animation
    start: 'top center',  // When trigger hits viewport center
    end: 'bottom center', // When trigger leaves viewport center
    toggleActions: 'play pause resume reset'
  }
});

Start/End Positions

javascript
// Format: "trigger-position viewport-position"
start: 'top center'      // Trigger's top hits viewport center
start: 'top 80%'         // Trigger's top hits 80% down viewport
start: 'center center'   // Trigger's center hits viewport center
start: 'bottom top'      // Trigger's bottom hits viewport top
start: 'top top+=100'    // Trigger's top hits 100px below viewport top

Position Reference

Value Description
top Top edge
center Center
bottom Bottom edge
80% 80% from top
+=100 Plus 100 pixels
-=50 Minus 50 pixels

Scrub Animations

Basic Scrub

javascript
// Animation progress tied to scroll position
gsap.to('.progress-bar', {
  scaleX: 1,
  scrollTrigger: {
    trigger: '.content',
    start: 'top top',
    end: 'bottom bottom',
    scrub: true  // Directly linked to scroll
  }
});

Smooth Scrub

javascript
gsap.to('.element', {
  x: 500,
  scrollTrigger: {
    trigger: '.section',
    scrub: 1,    // 1 second smoothing
    // scrub: 0.5  // 0.5 second smoothing
    // scrub: 2    // 2 second smoothing (laggy feel)
  }
});

Scrub with Timeline

javascript
const tl = gsap.timeline({
  scrollTrigger: {
    trigger: '.container',
    start: 'top top',
    end: '+=3000',  // Scroll distance
    scrub: 1,
    pin: true
  }
});

tl.to('.step1', { opacity: 1 })
  .to('.step2', { opacity: 1 })
  .to('.step3', { opacity: 1 });

Pinning

Basic Pin

javascript
ScrollTrigger.create({
  trigger: '.panel',
  start: 'top top',
  end: '+=500',      // Pin for 500px of scroll
  pin: true
});

Pin with Animation

javascript
gsap.to('.content', {
  x: '-200%',
  ease: 'none',
  scrollTrigger: {
    trigger: '.horizontal-section',
    start: 'top top',
    end: () => '+=' + document.querySelector('.horizontal-section').offsetWidth,
    pin: true,
    scrub: 1
  }
});

Pin Spacing

javascript
ScrollTrigger.create({
  trigger: '.section',
  pin: true,
  pinSpacing: true,   // Default: adds space for pinned duration
  // pinSpacing: false  // No extra space (content overlaps)
  // pinSpacing: '500px' // Custom spacing
});

Toggle Actions

Action Syntax

javascript
// Format: "onEnter onLeave onEnterBack onLeaveBack"
toggleActions: 'play pause resume reset'

// Common combinations:
toggleActions: 'play none none none'     // Play once
toggleActions: 'play reverse play reverse' // Toggle direction
toggleActions: 'restart none none none'  // Restart each time
toggleActions: 'play complete reverse reset'

Action Values

Action Effect
play Play forward
pause Pause
resume Resume from paused
reverse Play backward
restart Restart from beginning
reset Reset to start (no animation)
complete Jump to end
none Do nothing

Snap Points

Basic Snap

javascript
ScrollTrigger.create({
  trigger: '.sections',
  start: 'top top',
  end: 'bottom bottom',
  snap: 1 / 4  // Snap to quarters
});

Snap to Labels

javascript
const tl = gsap.timeline({
  scrollTrigger: {
    trigger: '.container',
    scrub: 1,
    snap: {
      snapTo: 'labels',
      duration: 0.5,
      ease: 'power2.inOut'
    }
  }
});

tl.addLabel('intro')
  .to('.a', { opacity: 1 })
  .addLabel('middle')
  .to('.b', { opacity: 1 })
  .addLabel('end');

Snap Configuration

javascript
snap: {
  snapTo: [0, 0.25, 0.5, 0.75, 1],  // Snap to specific points
  duration: { min: 0.2, max: 0.6 }, // Snap duration range
  delay: 0,                          // Delay before snap
  ease: 'power1.inOut',             // Snap easing
  directional: true                  // Snap in scroll direction
}

Callbacks

ScrollTrigger Callbacks

javascript
ScrollTrigger.create({
  trigger: '.section',
  onEnter: () => console.log('Entered'),
  onLeave: () => console.log('Left'),
  onEnterBack: () => console.log('Entered from bottom'),
  onLeaveBack: () => console.log('Left going up'),
  onUpdate: (self) => console.log('Progress:', self.progress),
  onToggle: (self) => console.log('Active:', self.isActive),
  onRefresh: () => console.log('Refreshed')
});

Progress-Based Updates

javascript
ScrollTrigger.create({
  trigger: '.section',
  start: 'top bottom',
  end: 'bottom top',
  onUpdate: (self) => {
    // self.progress: 0 to 1
    // self.direction: 1 (down) or -1 (up)
    // self.velocity: scroll speed
    updateElement(self.progress);
  }
});

Parallax Effects

Basic Parallax

javascript
// Background moves slower than scroll
gsap.to('.background', {
  yPercent: -50,
  ease: 'none',
  scrollTrigger: {
    trigger: '.section',
    scrub: true
  }
});

// Foreground moves faster
gsap.to('.foreground', {
  yPercent: 50,
  ease: 'none',
  scrollTrigger: {
    trigger: '.section',
    scrub: true
  }
});

Multi-Layer Parallax

javascript
const layers = [
  { selector: '.layer-1', speed: -20 },
  { selector: '.layer-2', speed: -40 },
  { selector: '.layer-3', speed: -60 },
  { selector: '.layer-4', speed: -80 }
];

layers.forEach(layer => {
  gsap.to(layer.selector, {
    yPercent: layer.speed,
    ease: 'none',
    scrollTrigger: {
      trigger: '.parallax-section',
      start: 'top bottom',
      end: 'bottom top',
      scrub: true
    }
  });
});

Horizontal Scrolling

Horizontal Section

javascript
const sections = gsap.utils.toArray('.panel');

gsap.to(sections, {
  xPercent: -100 * (sections.length - 1),
  ease: 'none',
  scrollTrigger: {
    trigger: '.horizontal-container',
    pin: true,
    scrub: 1,
    snap: 1 / (sections.length - 1),
    end: () => '+=' + document.querySelector('.horizontal-container').offsetWidth
  }
});

Markers (Development)

javascript
ScrollTrigger.create({
  trigger: '.section',
  start: 'top center',
  end: 'bottom center',
  markers: true,  // Show visual markers
  // markers: { startColor: 'green', endColor: 'red', fontSize: '12px' }
});

Batch Animations

Stagger on Scroll

javascript
ScrollTrigger.batch('.card', {
  onEnter: (elements) => {
    gsap.from(elements, {
      opacity: 0,
      y: 50,
      stagger: 0.1,
      duration: 0.5
    });
  },
  start: 'top 85%'
});

Batch Configuration

javascript
ScrollTrigger.batch('.item', {
  interval: 0.1,  // Time between batches
  batchMax: 3,    // Max items per batch
  onEnter: batch => gsap.to(batch, { opacity: 1, y: 0, stagger: 0.1 }),
  onLeave: batch => gsap.to(batch, { opacity: 0, y: 20 }),
  onEnterBack: batch => gsap.to(batch, { opacity: 1, y: 0 }),
  onLeaveBack: batch => gsap.to(batch, { opacity: 0, y: -20 })
});

Common Patterns

Reveal on Scroll

javascript
gsap.utils.toArray('.reveal').forEach(elem => {
  gsap.from(elem, {
    opacity: 0,
    y: 50,
    duration: 0.8,
    scrollTrigger: {
      trigger: elem,
      start: 'top 80%',
      toggleActions: 'play none none none'
    }
  });
});

Progress Indicator

javascript
gsap.to('.progress-bar', {
  scaleX: 1,
  transformOrigin: 'left center',
  ease: 'none',
  scrollTrigger: {
    trigger: 'body',
    start: 'top top',
    end: 'bottom bottom',
    scrub: 0.3
  }
});

Sticky Header Transform

javascript
ScrollTrigger.create({
  start: 'top -80',
  onUpdate: (self) => {
    if (self.direction === 1) {
      gsap.to('.header', { y: -80, duration: 0.3 });
    } else {
      gsap.to('.header', { y: 0, duration: 0.3 });
    }
  }
});

Temporal Collapse Patterns

Countdown Scroll Reveal

javascript
// Reveal countdown sections as user scrolls
const sections = ['days', 'hours', 'minutes', 'seconds'];

sections.forEach((section, i) => {
  gsap.from(`.countdown-${section}`, {
    opacity: 0,
    scale: 0.8,
    y: 50,
    duration: 0.8,
    ease: 'power3.out',
    scrollTrigger: {
      trigger: `.countdown-${section}`,
      start: 'top 80%',
      toggleActions: 'play none none none'
    }
  });
});

Scroll-Based Time Dilation Effect

javascript
gsap.timeline({
  scrollTrigger: {
    trigger: '.time-section',
    start: 'top center',
    end: 'bottom center',
    scrub: 1
  }
})
.to('.time-digit', {
  textShadow: '0 0 50px #00F5FF, 0 0 100px #00F5FF',
  scale: 1.1
})
.to('.particles', {
  opacity: 1,
  filter: 'blur(0px)'
}, '<');

Performance Tips

javascript
// Disable on mobile if needed
ScrollTrigger.matchMedia({
  '(min-width: 768px)': function() {
    // Desktop animations
  },
  '(max-width: 767px)': function() {
    // Simpler mobile animations
  }
});

// Refresh on resize
ScrollTrigger.refresh();

// Kill all ScrollTriggers
ScrollTrigger.killAll();

// Kill specific trigger
const st = ScrollTrigger.create({ ... });
st.kill();

Reference

  • See gsap-fundamentals for animation basics
  • See gsap-sequencing for timeline composition
  • See gsap-react for React integration with ScrollTrigger

Recommended Agent Skills

Expand your agent's capabilities with these related and highly-rated skills.

Bbeierle12/Skill-MCP-Claude

r3f-materials

Three.js materials in R3F, built-in materials (Standard, Physical, Basic, etc.), ShaderMaterial with custom GLSL, uniforms binding and animation, and material properties. Use when choosing materials, creating custom shaders, or binding dynamic uniforms.

7 1
Explore
Bbeierle12/Skill-MCP-Claude

audio-router

Router for audio domain including playback, analysis, and audio-reactive visuals. Use when implementing any audio functionality including music, sound effects, visualizers, or audio-driven animations. Routes to 3 specialized skills.

7 1
Explore
Bbeierle12/Skill-MCP-Claude

case-studies-reference

Game building mechanics case studies and decision frameworks. Use when designing building systems, evaluating trade-offs, or learning from existing games. Reference-only skill with detailed analysis of Fortnite, Rust, Valheim, Minecraft, No Man's Sky, and Satisfactory building systems.

7 1
Explore
Bbeierle12/Skill-MCP-Claude

brainstorming

Use when starting any feature, project, or design work. Guides collaborative design refinement through incremental questioning before any code is written.

7 1
Explore
Bbeierle12/Skill-MCP-Claude

shader-router

Decision framework for GLSL shader projects. Routes to specialized shader skills (fundamentals, noise, SDF, effects) based on task requirements. Use when starting a shader project or needing guidance on which shader techniques to combine.

7 1
Explore
Bbeierle12/Skill-MCP-Claude

audio-playback

Audio playback using Tone.js including players, transport, scheduling, and loading audio. Use when implementing background music, sound effects, audio synchronization, or timed audio events. Essential for any audio-enabled web application.

7 1
Explore

Didn't find tool you were looking for?

Be as detailed as possible for better results