From 20e76e75cf7179dadcc9b98aa31fc05abe258c50 Mon Sep 17 00:00:00 2001
From: David Haz <davidhzdev@gmail.com>
Date: Fri, 18 Jul 2025 15:11:59 +0300
Subject: [PATCH] Migrate ScrollVelocity component

---
 src/constants/Categories.ts                   |   3 +-
 src/constants/Components.ts                   |   1 +
 .../code/TextAnimations/scrollVelocityCode.ts |  24 ++
 .../ScrollVelocity/ScrollVelocity.vue         | 236 ++++++++++++++++++
 src/demo/Components/ChromaGridDemo.vue        |   3 +-
 .../TextAnimations/ScrollVelocityDemo.vue     | 132 ++++++++++
 6 files changed, 397 insertions(+), 2 deletions(-)
 create mode 100644 src/constants/code/TextAnimations/scrollVelocityCode.ts
 create mode 100644 src/content/TextAnimations/ScrollVelocity/ScrollVelocity.vue
 create mode 100644 src/demo/TextAnimations/ScrollVelocityDemo.vue

diff --git a/src/constants/Categories.ts b/src/constants/Categories.ts
index 1dadbea..e693c91 100644
--- a/src/constants/Categories.ts
+++ b/src/constants/Categories.ts
@@ -25,7 +25,8 @@ export const CATEGORIES = [
       'Scroll Float',
       'Scroll Reveal',
       'Rotating Text',
-      'Glitch Text'
+      'Glitch Text',
+      'Scroll Velocity'
     ]
   },
   {
diff --git a/src/constants/Components.ts b/src/constants/Components.ts
index 27f8cfa..d9b17b0 100644
--- a/src/constants/Components.ts
+++ b/src/constants/Components.ts
@@ -37,6 +37,7 @@ const textAnimations = {
   'scroll-reveal': () => import("../demo/TextAnimations/ScrollRevealDemo.vue"),
   'rotating-text': () => import("../demo/TextAnimations/RotatingTextDemo.vue"),
   'glitch-text': () => import("../demo/TextAnimations/GlitchTextDemo.vue"),
+  'scroll-velocity': () => import("../demo/TextAnimations/ScrollVelocityDemo.vue"),
 };
 
 const components = {
diff --git a/src/constants/code/TextAnimations/scrollVelocityCode.ts b/src/constants/code/TextAnimations/scrollVelocityCode.ts
new file mode 100644
index 0000000..088ba86
--- /dev/null
+++ b/src/constants/code/TextAnimations/scrollVelocityCode.ts
@@ -0,0 +1,24 @@
+import code from '@content/TextAnimations/ScrollVelocity/ScrollVelocity.vue?raw';
+import type { CodeObject } from '../../../types/code';
+
+export const scrollVelocity: CodeObject = {
+  cli: `npx jsrepo add https://vue-bits.dev/ui/TextAnimations/ScrollVelocity`,
+  installation: `npm install gsap`,
+  usage: `<template>
+  <ScrollVelocity
+    :texts="['Vue Bits', 'Scroll Down']"
+    :velocity="100"
+    :damping="50"
+    :stiffness="400"
+    :velocity-mapping="{ input: [0, 1000], output: [0, 5] }"
+    class-name="custom-scroll-text"
+    parallax-class-name="custom-parallax"
+    scroller-class-name="custom-scroller"
+  />
+</template>
+
+<script setup lang="ts">
+  import ScrollVelocity from "./ScrollVelocity.vue";
+</script>`,
+  code
+};
diff --git a/src/content/TextAnimations/ScrollVelocity/ScrollVelocity.vue b/src/content/TextAnimations/ScrollVelocity/ScrollVelocity.vue
new file mode 100644
index 0000000..74ca0c6
--- /dev/null
+++ b/src/content/TextAnimations/ScrollVelocity/ScrollVelocity.vue
@@ -0,0 +1,236 @@
+<template>
+  <section>
+    <div
+      v-for="(text, index) in texts"
+      :key="index"
+      ref="containerRef"
+      :class="`${parallaxClassName} relative overflow-hidden`"
+      :style="parallaxStyle"
+    >
+      <div
+        ref="scrollerRef"
+        :class="`${scrollerClassName} flex whitespace-nowrap text-center font-sans text-4xl font-bold tracking-[-0.02em] drop-shadow md:text-[5rem] md:leading-[5rem]`"
+        :style="{ transform: `translateX(${scrollTransforms[index] || '0px'})`, ...scrollerStyle }"
+      >
+        <span
+          v-for="spanIndex in calculatedCopies[index] || 15"
+          :key="spanIndex"
+          :class="`flex-shrink-0 ${className}`"
+          :ref="spanIndex === 1 ? el => setCopyRef(el, index) : undefined"
+        >
+          {{ text }}&nbsp;
+        </span>
+      </div>
+    </div>
+  </section>
+</template>
+
+<script setup lang="ts">
+import { ref, computed, onMounted, onUnmounted, nextTick, type ComponentPublicInstance } from 'vue';
+import { gsap } from 'gsap';
+import { ScrollTrigger } from 'gsap/ScrollTrigger';
+
+gsap.registerPlugin(ScrollTrigger);
+
+interface VelocityMapping {
+  input: [number, number];
+  output: [number, number];
+}
+
+interface ScrollVelocityProps {
+  scrollContainerRef?: HTMLElement | null;
+  texts?: string[];
+  velocity?: number;
+  className?: string;
+  damping?: number;
+  stiffness?: number;
+  velocityMapping?: VelocityMapping;
+  parallaxClassName?: string;
+  scrollerClassName?: string;
+  parallaxStyle?: Record<string, string | number>;
+  scrollerStyle?: Record<string, string | number>;
+}
+
+const props = withDefaults(defineProps<ScrollVelocityProps>(), {
+  texts: () => [],
+  velocity: 100,
+  className: '',
+  damping: 50,
+  stiffness: 400,
+  velocityMapping: () => ({ input: [0, 1000], output: [0, 5] }),
+  parallaxClassName: '',
+  scrollerClassName: '',
+  parallaxStyle: () => ({}),
+  scrollerStyle: () => ({})
+});
+
+const containerRef = ref<HTMLDivElement[]>([]);
+const scrollerRef = ref<HTMLDivElement[]>([]);
+const copyRefs = ref<HTMLSpanElement[]>([]);
+
+const baseX = ref<number[]>([]);
+const scrollVelocity = ref(0);
+const smoothVelocity = ref(0);
+const velocityFactor = ref(0);
+const copyWidths = ref<number[]>([]);
+const directionFactors = ref<number[]>([]);
+const calculatedCopies = ref<number[]>([]);
+
+let rafId: number | null = null;
+let scrollTriggerInstance: ScrollTrigger | null = null;
+let lastScrollY = 0;
+let lastTime = 0;
+let resizeTimeout: number | null = null;
+
+const setCopyRef = (el: Element | ComponentPublicInstance | null, index: number) => {
+  if (el && el instanceof HTMLSpanElement) {
+    copyRefs.value[index] = el;
+  }
+};
+
+const updateWidths = () => {
+  props.texts.forEach((_, index) => {
+    if (copyRefs.value[index] && containerRef.value[index]) {
+      const singleCopyWidth = copyRefs.value[index].offsetWidth;
+      const containerWidth = containerRef.value[index].offsetWidth;
+      const viewportWidth = window.innerWidth;
+
+      const effectiveWidth = Math.max(containerWidth, viewportWidth);
+      const minCopies = Math.ceil((effectiveWidth * 2.5) / singleCopyWidth);
+      const optimalCopies = Math.max(minCopies, 8);
+
+      copyWidths.value[index] = singleCopyWidth;
+      calculatedCopies.value[index] = optimalCopies;
+    }
+  });
+};
+
+const debouncedUpdateWidths = () => {
+  if (resizeTimeout) {
+    clearTimeout(resizeTimeout);
+  }
+  resizeTimeout = window.setTimeout(() => {
+    updateWidths();
+    resizeTimeout = null;
+  }, 150);
+};
+
+const wrap = (min: number, max: number, v: number): number => {
+  const range = max - min;
+  if (range === 0) return min;
+  const mod = (((v - min) % range) + range) % range;
+  return mod + min;
+};
+
+const scrollTransforms = computed(() => {
+  return props.texts.map((_, index) => {
+    const singleWidth = copyWidths.value[index];
+    if (singleWidth === 0) return '0px';
+    return `${wrap(-singleWidth, 0, baseX.value[index] || 0)}px`;
+  });
+});
+
+const updateSmoothVelocity = () => {
+  const dampingFactor = props.damping / 1000;
+  const stiffnessFactor = props.stiffness / 1000;
+
+  const velocityDiff = scrollVelocity.value - smoothVelocity.value;
+  smoothVelocity.value += velocityDiff * stiffnessFactor;
+  smoothVelocity.value *= 1 - dampingFactor;
+};
+
+const updateVelocityFactor = () => {
+  const { input, output } = props.velocityMapping;
+  const inputRange = input[1] - input[0];
+  const outputRange = output[1] - output[0];
+
+  let normalizedVelocity = (Math.abs(smoothVelocity.value) - input[0]) / inputRange;
+  normalizedVelocity = Math.max(0, Math.min(1, normalizedVelocity));
+
+  velocityFactor.value = output[0] + normalizedVelocity * outputRange;
+  if (smoothVelocity.value < 0) velocityFactor.value *= -1;
+};
+
+const animate = (currentTime: number) => {
+  if (lastTime === 0) lastTime = currentTime;
+  const delta = currentTime - lastTime;
+  lastTime = currentTime;
+
+  updateSmoothVelocity();
+  updateVelocityFactor();
+
+  props.texts.forEach((_, index) => {
+    const baseVelocity = index % 2 !== 0 ? -props.velocity : props.velocity;
+
+    let moveBy = directionFactors.value[index] * baseVelocity * (delta / 1000);
+
+    if (velocityFactor.value < 0) {
+      directionFactors.value[index] = -1;
+    } else if (velocityFactor.value > 0) {
+      directionFactors.value[index] = 1;
+    }
+
+    moveBy += directionFactors.value[index] * moveBy * velocityFactor.value;
+    baseX.value[index] = (baseX.value[index] || 0) + moveBy;
+  });
+
+  rafId = requestAnimationFrame(animate);
+};
+
+const updateScrollVelocity = () => {
+  const container = props.scrollContainerRef || window;
+  const currentScrollY = container === window ? window.scrollY : (container as HTMLElement).scrollTop;
+
+  const currentTime = performance.now();
+  const timeDelta = currentTime - lastTime;
+
+  if (timeDelta > 0) {
+    const scrollDelta = currentScrollY - lastScrollY;
+    scrollVelocity.value = (scrollDelta / timeDelta) * 1000;
+  }
+
+  lastScrollY = currentScrollY;
+};
+
+onMounted(async () => {
+  await nextTick();
+
+  baseX.value = new Array(props.texts.length).fill(0);
+  copyWidths.value = new Array(props.texts.length).fill(0);
+  calculatedCopies.value = new Array(props.texts.length).fill(15);
+  directionFactors.value = new Array(props.texts.length).fill(1);
+
+  setTimeout(() => {
+    updateWidths();
+  }, 100);
+
+  updateWidths();
+
+  if (containerRef.value && containerRef.value.length > 0) {
+    scrollTriggerInstance = ScrollTrigger.create({
+      trigger: containerRef.value[0],
+      start: 'top bottom',
+      end: 'bottom top',
+      onUpdate: updateScrollVelocity,
+      ...(props.scrollContainerRef && { scroller: props.scrollContainerRef })
+    });
+  }
+
+  rafId = requestAnimationFrame(animate);
+
+  window.addEventListener('resize', debouncedUpdateWidths, { passive: true });
+});
+
+onUnmounted(() => {
+  if (rafId) {
+    cancelAnimationFrame(rafId);
+  }
+  if (scrollTriggerInstance) {
+    scrollTriggerInstance.kill();
+  }
+  if (resizeTimeout) {
+    clearTimeout(resizeTimeout);
+  }
+  window.removeEventListener('resize', debouncedUpdateWidths);
+});
+</script>
diff --git a/src/demo/Components/ChromaGridDemo.vue b/src/demo/Components/ChromaGridDemo.vue
index bebf292..96f4b09 100644
--- a/src/demo/Components/ChromaGridDemo.vue
+++ b/src/demo/Components/ChromaGridDemo.vue
@@ -1,7 +1,7 @@
 <template>
   <TabbedLayout>
     <template #preview>
-      <div class="demo-container relative overflow-hidden py-6">
+      <div class="demo-container relative overflow-hidden">
         <ChromaGrid />
       </div>
 
@@ -72,5 +72,6 @@ const propData = [
 <style scoped>
 .demo-container {
   height: auto;
+  padding: 4em 0;
 }
 </style>
diff --git a/src/demo/TextAnimations/ScrollVelocityDemo.vue b/src/demo/TextAnimations/ScrollVelocityDemo.vue
new file mode 100644
index 0000000..9fab06b
--- /dev/null
+++ b/src/demo/TextAnimations/ScrollVelocityDemo.vue
@@ -0,0 +1,132 @@
+<template>
+  <TabbedLayout>
+    <template #preview>
+      <div class="demo-container overflow-hidden">
+        <div class="relative flex justify-center items-center">
+          <ScrollVelocity
+            :texts="['Vue Bits', 'Scroll Down']"
+            :velocity="velocity"
+            :damping="damping"
+            :stiffness="stiffness"
+            :velocity-mapping="velocityMapping"
+            class-name="custom-scroll-text"
+          />
+        </div>
+      </div>
+
+      <Customize>
+        <PreviewSlider title="Velocity" v-model="velocity" :min="10" :max="500" :step="10" />
+        <PreviewSlider title="Damping" v-model="damping" :min="10" :max="100" :step="10" />
+        <PreviewSlider title="Stiffness" v-model="stiffness" :min="100" :max="1000" :step="50" />
+      </Customize>
+
+      <PropTable :data="propData" />
+
+      <Dependencies :dependency-list="['gsap']" />
+    </template>
+
+    <template #code>
+      <CodeExample :code-object="scrollVelocity" />
+    </template>
+
+    <template #cli>
+      <CliInstallation :command="scrollVelocity.cli" />
+    </template>
+  </TabbedLayout>
+</template>
+
+<script setup lang="ts">
+import { ref } from 'vue';
+import TabbedLayout from '../../components/common/TabbedLayout.vue';
+import PropTable from '../../components/common/PropTable.vue';
+import Dependencies from '../../components/code/Dependencies.vue';
+import CliInstallation from '../../components/code/CliInstallation.vue';
+import CodeExample from '../../components/code/CodeExample.vue';
+import Customize from '../../components/common/Customize.vue';
+import PreviewSlider from '../../components/common/PreviewSlider.vue';
+import ScrollVelocity from '../../content/TextAnimations/ScrollVelocity/ScrollVelocity.vue';
+import { scrollVelocity } from '@/constants/code/TextAnimations/scrollVelocityCode';
+
+const velocity = ref(100);
+const damping = ref(50);
+const stiffness = ref(400);
+const velocityMapping = ref<{ input: [number, number]; output: [number, number] }>({
+  input: [0, 1000],
+  output: [0, 5]
+});
+
+const propData = [
+  {
+    name: 'scrollContainerRef',
+    type: 'HTMLElement | null',
+    default: 'null',
+    description: 'Optional ref for a custom scroll container to track scroll position.'
+  },
+  {
+    name: 'texts',
+    type: 'string[]',
+    default: '[]',
+    description: 'Array of strings to display as scrolling text.'
+  },
+  {
+    name: 'velocity',
+    type: 'number',
+    default: '100',
+    description: 'Base velocity for scrolling; sign is flipped for odd indexed texts.'
+  },
+  {
+    name: 'className',
+    type: 'string',
+    default: '""',
+    description: 'CSS class applied to each text copy (span).'
+  },
+  {
+    name: 'damping',
+    type: 'number',
+    default: '50',
+    description: 'Damping value for the spring animation.'
+  },
+  {
+    name: 'stiffness',
+    type: 'number',
+    default: '400',
+    description: 'Stiffness value for the spring animation.'
+  },
+  {
+    name: 'velocityMapping',
+    type: '{ input: [number, number]; output: [number, number] }',
+    default: '{ input: [0, 1000], output: [0, 5] }',
+    description: 'Mapping from scroll velocity to a movement multiplier for dynamic scrolling.'
+  },
+  {
+    name: 'parallaxClassName',
+    type: 'string',
+    default: '""',
+    description: 'CSS class for the parallax container.'
+  },
+  {
+    name: 'scrollerClassName',
+    type: 'string',
+    default: '""',
+    description: 'CSS class for the scroller container.'
+  },
+  {
+    name: 'parallaxStyle',
+    type: 'Record<string, string | number>',
+    default: '{}',
+    description: 'Inline styles for the parallax container.'
+  },
+  {
+    name: 'scrollerStyle',
+    type: 'Record<string, string | number>',
+    default: '{}',
+    description: 'Inline styles for the scroller container.'
+  }
+];
+</script>
+
+<style scoped>
+.demo-container {
+  min-height: 400px;
+}
+</style>