Create <VariableProximity /> text animation

src/content/TextAnimations/VariableProximity/VariableProximity.vue

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+<template>
+  <span
+    ref="rootRef"
+    :class="[props.className]"
+    :style="{
+      display: 'inline',
+      ...props.style
+    }"
+    @click="props.onClick"
+  >
+    <span
+      v-for="(word, wordIndex) in words"
+      :key="wordIndex"
+      :style="{ display: 'inline-block', whiteSpace: 'nowrap' }"
+    >
+      <span
+        v-for="(letter, letterIndex) in word.split('')"
+        :key="getLetterKey(wordIndex, letterIndex)"
+        :style="{
+          display: 'inline-block',
+          fontVariationSettings: props.fromFontVariationSettings
+        }"
+        class="letter"
+        :data-index="getGlobalLetterIndex(wordIndex, letterIndex)"
+        aria-hidden="true"
+      >
+        {{ letter }}
+      </span>
+      <span
+        v-if="wordIndex < words.length - 1"
+        class="inline-block"
+      >&nbsp;</span>
+    </span>
+    <span class="absolute w-px h-px p-0 -m-px overflow-hidden whitespace-nowrap clip-rect-0 border-0">{{ props.label }}</span>
+  </span>
+</template>
+
+<script setup lang="ts">
+import { ref, computed, onMounted, onUnmounted, nextTick, type CSSProperties } from 'vue';
+
+export type FalloffType = 'linear' | 'exponential' | 'gaussian';
+
+interface VariableProximityProps {
+  label: string;
+  fromFontVariationSettings: string;
+  toFontVariationSettings: string;
+  containerRef?: HTMLElement | null | undefined;
+  radius?: number;
+  falloff?: FalloffType;
+  className?: string;
+  style?: CSSProperties;
+  onClick?: () => void;
+}
+
+const props = withDefaults(defineProps<VariableProximityProps>(), {
+  radius: 50,
+  falloff: 'linear',
+  className: '',
+  style: () => ({}),
+  onClick: undefined,
+});
+
+const rootRef = ref<HTMLElement | null>(null);
+const letterElements = ref<HTMLElement[]>([]);
+const mousePosition = ref({ x: 0, y: 0 });
+const lastPosition = ref<{ x: number | null; y: number | null }>({ x: null, y: null });
+const interpolatedSettings = ref<string[]>([]);
+
+let animationFrameId: number | null = null;
+
+const words = computed(() => props.label.split(' '));
+
+const parsedSettings = computed(() => {
+  const parseSettings = (settingsStr: string) => {
+    const result = new Map();
+    settingsStr.split(',').forEach(s => {
+      const parts = s.trim().split(' ');
+      if (parts.length === 2) {
+        const name = parts[0].replace(/['"]/g, '');
+        const value = parseFloat(parts[1]);
+        result.set(name, value);
+      }
+    });
+    return result;
+  };
+
+  const fromSettings = parseSettings(props.fromFontVariationSettings);
+  const toSettings = parseSettings(props.toFontVariationSettings);
+
+  return Array.from(fromSettings.entries()).map(([axis, fromValue]) => ({
+    axis,
+    fromValue,
+    toValue: toSettings.get(axis) ?? fromValue,
+  }));
+});
+
+const calculateDistance = (x1: number, y1: number, x2: number, y2: number) =>
+  Math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2);
+
+const calculateFalloff = (distance: number) => {
+  const norm = Math.min(Math.max(1 - distance / props.radius, 0), 1);
+  switch (props.falloff) {
+    case 'exponential': return norm ** 2;
+    case 'gaussian': return Math.exp(-((distance / (props.radius / 2)) ** 2) / 2);
+    case 'linear':
+    default: return norm;
+  }
+};
+
+const getLetterKey = (wordIndex: number, letterIndex: number) =>
+  `${wordIndex}-${letterIndex}`;
+
+const getGlobalLetterIndex = (wordIndex: number, letterIndex: number) => {
+  let globalIndex = 0;
+  for (let i = 0; i < wordIndex; i++) {
+    globalIndex += words.value[i].length;
+  }
+  return globalIndex + letterIndex;
+};
+
+const initializeLetterElements = () => {
+  if (!rootRef.value) return;
+
+  const elements = rootRef.value.querySelectorAll('.letter');
+  letterElements.value = Array.from(elements) as HTMLElement[];
+
+  console.log(`Found ${letterElements.value.length} letter elements`);
+};
+
+const handleMouseMove = (ev: MouseEvent) => {
+  const container = props.containerRef || rootRef.value;
+  if (!container) return;
+
+  const rect = container.getBoundingClientRect();
+  mousePosition.value = {
+    x: ev.clientX - rect.left,
+    y: ev.clientY - rect.top
+  };
+};
+
+const handleTouchMove = (ev: TouchEvent) => {
+  const container = props.containerRef || rootRef.value;
+  if (!container) return;
+
+  const touch = ev.touches[0];
+  const rect = container.getBoundingClientRect();
+  mousePosition.value = {
+    x: touch.clientX - rect.left,
+    y: touch.clientY - rect.top
+  };
+};
+
+const animationLoop = () => {
+  const container = props.containerRef || rootRef.value;
+  if (!container || letterElements.value.length === 0) {
+    animationFrameId = requestAnimationFrame(animationLoop);
+    return;
+  }
+
+  const containerRect = container.getBoundingClientRect();
+
+  if (lastPosition.value.x === mousePosition.value.x && lastPosition.value.y === mousePosition.value.y) {
+    animationFrameId = requestAnimationFrame(animationLoop);
+    return;
+  }
+
+  lastPosition.value = { x: mousePosition.value.x, y: mousePosition.value.y };
+
+  const newSettings = Array(letterElements.value.length).fill(props.fromFontVariationSettings);
+
+  letterElements.value.forEach((letterEl, index) => {
+    if (!letterEl) return;
+
+    const rect = letterEl.getBoundingClientRect();
+    const letterCenterX = rect.left + rect.width / 2 - containerRect.left;
+    const letterCenterY = rect.top + rect.height / 2 - containerRect.top;
+
+    const distance = calculateDistance(
+      mousePosition.value.x,
+      mousePosition.value.y,
+      letterCenterX,
+      letterCenterY
+    );
+
+    if (distance >= props.radius) {
+      return;
+    }
+
+    const falloffValue = calculateFalloff(distance);
+    const setting = parsedSettings.value
+      .map(({ axis, fromValue, toValue }) => {
+        const interpolatedValue = fromValue + (toValue - fromValue) * falloffValue;
+        return `'${axis}' ${interpolatedValue}`;
+      })
+      .join(', ');
+
+    newSettings[index] = setting;
+  });
+
+  interpolatedSettings.value = newSettings;
+
+  letterElements.value.forEach((letterEl, index) => {
+    letterEl.style.fontVariationSettings = interpolatedSettings.value[index];
+  });
+
+  animationFrameId = requestAnimationFrame(animationLoop);
+};
+
+onMounted(() => {
+  nextTick(() => {
+    initializeLetterElements();
+
+    window.addEventListener('mousemove', handleMouseMove);
+    window.addEventListener('touchmove', handleTouchMove);
+
+    animationFrameId = requestAnimationFrame(animationLoop);
+  });
+});
+
+onUnmounted(() => {
+  window.removeEventListener('mousemove', handleMouseMove);
+  window.removeEventListener('touchmove', handleTouchMove);
+
+  if (animationFrameId) {
+    cancelAnimationFrame(animationFrameId);
+  }
+});
+</script>