{"slug":"text-animation","name":"Text Animation","description":"Animated text primitives for reveal sequences, shimmer loading states and letter-cascade swaps.","category":"motion","source_url":"https://beui.dev/r/text-animation/raw","detail_url":"https://beui.dev/r/text-animation","raw_url":"https://beui.dev/r/text-animation/raw","page_url":"https://beui.dev/components/motion/text-animation","dependencies":["clsx","motion","react","tailwind-merge"],"internal":["./action-swap","@/components/motion/text-reveal","@/components/motion/text-shimmer","@/lib/ease","@/lib/utils"],"files":[{"path":"components/motion/text-reveal.tsx","type":"component","content":"\"use client\";\n\nimport { motion, type Transition, useInView, useReducedMotion } from \"motion/react\";\nimport { useRef, type ElementType, type ReactNode } from \"react\";\nimport { EASE_OUT } from \"@/lib/ease\";\nimport { cn } from \"@/lib/utils\";\n\ntype SplitMode = \"word\" | \"char\";\n\nexport interface TextRevealProps {\n  text: string | string[];\n  as?: ElementType;\n  className?: string;\n  split?: SplitMode;\n  stagger?: number;\n  delay?: number;\n  blur?: number;\n  yOffset?: string | number;\n  spring?: { stiffness?: number; damping?: number; mass?: number };\n  once?: boolean;\n  whileInView?: boolean;\n  children?: ReactNode;\n}\n\nconst DEFAULT_SPRING = { stiffness: 140, damping: 26, mass: 1.2 };\n\nexport function TextReveal({\n  text,\n  as: Comp = \"span\",\n  className,\n  split = \"word\",\n  stagger = 0.09,\n  delay = 0,\n  blur = 12,\n  yOffset = \"40%\",\n  spring,\n  once = true,\n  whileInView = false,\n  children,\n}: TextRevealProps) {\n  const ref = useRef<HTMLElement>(null);\n  const inView = useInView(ref, { once, amount: 0.4 });\n  const reduce = useReducedMotion();\n  const shouldAnimate = whileInView ? inView : true;\n\n  const lines = Array.isArray(text) ? text : [text];\n  const s = { ...DEFAULT_SPRING, ...spring };\n\n  let unitIndex = 0;\n  const lineCounts = new Map<string, number>();\n\n  return (\n    <Comp ref={ref} className={cn(\"block\", className)}>\n      {lines.map((line) => {\n        const units = split === \"word\" ? line.split(\" \") : Array.from(line);\n        const lineCount = lineCounts.get(line) ?? 0;\n        lineCounts.set(line, lineCount + 1);\n        const lineKey = `${line}-${lineCount}`;\n        const unitCounts = new Map<string, number>();\n\n        return (\n          <span key={lineKey} className=\"block\">\n            {units.map((unit, i) => {\n              const d = delay + unitIndex * stagger;\n              unitIndex += 1;\n              const unitCount = unitCounts.get(unit) ?? 0;\n              unitCounts.set(unit, unitCount + 1);\n              const unitKey = `${unit}-${unitCount}`;\n              const initial = reduce\n                ? { opacity: 0 }\n                : { y: yOffset, opacity: 0, filter: `blur(${blur}px)` };\n              const animate = shouldAnimate\n                ? reduce\n                  ? { opacity: 1 }\n                  : { y: 0, opacity: 1, filter: \"blur(0px)\" }\n                : initial;\n              const transition: Transition = reduce\n                ? { opacity: { duration: 0.25, ease: EASE_OUT, delay: d * 0.3 } }\n                : {\n                    y: { type: \"spring\" as const, ...s, delay: d },\n                    opacity: { duration: 0.7, ease: EASE_OUT, delay: d },\n                    filter: { duration: 0.9, ease: EASE_OUT, delay: d },\n                  };\n              return (\n                <motion.span\n                  key={unitKey}\n                  initial={initial}\n                  animate={animate}\n                  transition={transition}\n                  className=\"inline-block will-change-transform\"\n                >\n                  {unit}\n                  {split === \"word\" && i < units.length - 1 ? (\n                    <span className=\"inline-block\">&nbsp;</span>\n                  ) : null}\n                </motion.span>\n              );\n            })}\n          </span>\n        );\n      })}\n      {children}\n    </Comp>\n  );\n}\n"},{"path":"components/motion/text-shimmer.tsx","type":"component","content":"import { cn } from \"@/lib/utils\";\nimport type { ElementType, ReactNode } from \"react\";\n\nexport interface TextShimmerProps {\n  children: ReactNode;\n  as?: ElementType;\n  duration?: number;\n  className?: string;\n}\n\nexport function TextShimmer({ children, as: Comp = \"span\", duration = 2.5, className }: TextShimmerProps) {\n  return (\n    <>\n      <style>\n        {`@keyframes beui-text-shimmer{from{background-position:200% 0}to{background-position:-200% 0}}`}\n      </style>\n      <Comp\n        style={{ animation: `beui-text-shimmer ${duration}s linear infinite` }}\n        className={cn(\n          \"inline-block bg-[length:200%_100%] bg-clip-text text-transparent\",\n          \"bg-[linear-gradient(110deg,var(--muted-foreground)_30%,var(--foreground)_50%,var(--muted-foreground)_70%)]\",\n          className,\n        )}\n      >\n        {children}\n      </Comp>\n    </>\n  );\n}\n"},{"path":"components/motion/text-cascade.tsx","type":"component","content":"\"use client\";\n\nimport { ActionSwapText } from \"./action-swap\";\n\nexport interface TextCascadeProps {\n  /** Current text. Changing it cascades the letters to the new value. */\n  text: string;\n  className?: string;\n}\n\n/**\n * Letter-by-letter slot roll for standalone text — the old letters drop away\n * as the new ones land, left to right. Same motion as the action-swap\n * cascade variant, with a text-first API.\n */\nexport function TextCascade({ text, className }: TextCascadeProps) {\n  return (\n    <ActionSwapText value={text} animation=\"cascade\" className={className}>\n      {text}\n    </ActionSwapText>\n  );\n}\n"},{"path":"lib/ease.ts","type":"util","content":"// Shared motion tokens. Easing curves mirror the CSS custom properties in\n// globals.css; springs are the canonical physics used across components.\n// Strong custom variants — defaults like `ease-in`/`ease-out` feel weak.\n\nexport const EASE_OUT = [0.16, 1, 0.3, 1] as const;\nexport const EASE_IN_OUT = [0.77, 0, 0.175, 1] as const;\nexport const EASE_DRAWER = [0.32, 0.72, 0, 1] as const;\n\n/** CSS string form of EASE_OUT for inline style transitions. */\nexport const EASE_OUT_CSS = \"cubic-bezier(0.16, 1, 0.3, 1)\";\n\n/** Press feedback on buttons and other tappable surfaces. */\nexport const SPRING_PRESS = {\n  type: \"spring\",\n  stiffness: 500,\n  damping: 30,\n  mass: 0.6,\n} as const;\n\n/** Content swaps — label/icon slots trading places inside a control. */\nexport const SPRING_SWAP = {\n  type: \"spring\",\n  stiffness: 460,\n  damping: 30,\n  mass: 0.55,\n} as const;\n\n/** Overlay panel entrances — modals and sheets summoned by pointer. */\nexport const SPRING_PANEL = {\n  type: \"spring\",\n  stiffness: 420,\n  damping: 40,\n  mass: 0.5,\n} as const;\n\n/** Shared-layout glides — pills, indicators and panels morphing between positions. */\nexport const SPRING_LAYOUT = {\n  type: \"spring\",\n  stiffness: 360,\n  damping: 32,\n  mass: 0.6,\n} as const;\n\n/** Cursor-follow physics for decorative mouse tracking (magnetic, tilt, dock). */\nexport const SPRING_MOUSE = {\n  stiffness: 200,\n  damping: 15,\n  mass: 0.3,\n} as const;\n"},{"path":"lib/utils.ts","type":"util","content":"import { clsx, type ClassValue } from \"clsx\"\nimport { twMerge } from \"tailwind-merge\"\n\nexport function cn(...inputs: ClassValue[]) {\n  return twMerge(clsx(inputs))\n}\n"},{"path":"components/motion/action-swap.tsx","type":"util","content":"\"use client\";\n\nimport { AnimatePresence, motion, useReducedMotion, type HTMLMotionProps, type Variants } from \"motion/react\";\nimport { useLayoutEffect, useRef, useState, type ReactNode } from \"react\";\nimport { EASE_OUT, EASE_OUT_CSS, SPRING_PRESS, SPRING_SWAP } from \"@/lib/ease\";\nimport { cn } from \"@/lib/utils\";\n\nexport type ActionSwapItem = {\n  id: string;\n  label: ReactNode;\n  icon?: ReactNode;\n  ariaLabel?: string;\n};\n\nexport type ActionSwapButtonVariant = \"primary\" | \"secondary\" | \"outline\" | \"ghost\";\nexport type ActionSwapButtonSize = \"sm\" | \"md\" | \"lg\" | \"icon\";\nexport type ActionSwapAnimation = \"blur\" | \"roll\" | \"cascade\";\n\n/** Animations with a single-element variant set (cascade animates per letter). */\ntype CoreAnimation = \"blur\" | \"roll\";\n\nexport interface ActionSwapButtonProps extends Omit<\n  HTMLMotionProps<\"button\">,\n  \"children\" | \"onChange\"\n> {\n  items: ActionSwapItem[];\n  value?: string;\n  defaultValue?: string;\n  onValueChange?: (value: string, item: ActionSwapItem) => void;\n  variant?: ActionSwapButtonVariant;\n  size?: ActionSwapButtonSize;\n  animation?: ActionSwapAnimation;\n  iconOnly?: boolean;\n  cycle?: boolean;\n}\n\nexport interface ActionSwapTextProps {\n  value: string;\n  children: ReactNode;\n  animation?: ActionSwapAnimation;\n  className?: string;\n}\n\nexport interface ActionSwapIconProps {\n  value: string;\n  children: ReactNode;\n  animation?: ActionSwapAnimation;\n  className?: string;\n}\n\nconst BLUR_TRANSITION = { duration: 0.2, ease: \"easeInOut\" } as const;\nconst ROLL_TRANSITION = { duration: 0.24, ease: EASE_OUT } as const;\nconst SWAP_BLUR = \"blur(8px)\";\nconst ROLL_BLUR = \"blur(6px)\";\n\n// Cascade rolls the label one letter at a time, left to right. The leaving\n// and landing strings overlap as independent layers (no shared cells), so\n// proportional glyph widths never jitter. Exits cascade at half the enter\n// stagger so the tail of the old label lingers briefly.\nconst CASCADE_STAGGER = 0.025;\n\nconst CASCADE_LETTER_VARIANTS: Variants = {\n  initial: { opacity: 0, y: \"105%\", filter: ROLL_BLUR },\n  animate: (delay: number = 0) => ({\n    opacity: 1,\n    y: \"0%\",\n    filter: \"blur(0px)\",\n    transition: { ...SPRING_SWAP, delay },\n  }),\n  exit: (delay: number = 0) => ({\n    opacity: 0,\n    y: \"-105%\",\n    filter: ROLL_BLUR,\n    transition: { duration: 0.16, ease: EASE_OUT, delay: delay * 0.5 },\n  }),\n};\n\nconst TEXT_VARIANTS: Record<CoreAnimation, Variants> = {\n  blur: {\n    initial: { opacity: 0, scale: 0.94, filter: SWAP_BLUR },\n    animate: {\n      opacity: 1,\n      scale: 1,\n      filter: \"blur(0px)\",\n      transition: BLUR_TRANSITION,\n    },\n    exit: {\n      opacity: 0,\n      scale: 0.94,\n      filter: SWAP_BLUR,\n      transition: BLUR_TRANSITION,\n    },\n  },\n  roll: {\n    initial: { opacity: 0, y: \"115%\", filter: ROLL_BLUR },\n    animate: {\n      opacity: 1,\n      y: \"0%\",\n      filter: \"blur(0px)\",\n      transition: ROLL_TRANSITION,\n    },\n    exit: {\n      opacity: 0,\n      y: \"-115%\",\n      filter: ROLL_BLUR,\n      transition: { duration: 0.18, ease: \"easeInOut\" },\n    },\n  },\n};\n\nconst ICON_VARIANTS: Record<CoreAnimation, Variants> = {\n  blur: {\n    initial: { opacity: 0, scale: 0.25, filter: SWAP_BLUR },\n    animate: {\n      opacity: 1,\n      scale: 1,\n      filter: \"blur(0px)\",\n      transition: BLUR_TRANSITION,\n    },\n    exit: {\n      opacity: 0,\n      scale: 0.25,\n      filter: SWAP_BLUR,\n      transition: BLUR_TRANSITION,\n    },\n  },\n  roll: {\n    initial: { opacity: 0, y: 16, filter: ROLL_BLUR },\n    animate: {\n      opacity: 1,\n      y: 0,\n      filter: \"blur(0px)\",\n      transition: ROLL_TRANSITION,\n    },\n    exit: {\n      opacity: 0,\n      y: -16,\n      filter: ROLL_BLUR,\n      transition: { duration: 0.18, ease: \"easeInOut\" },\n    },\n  },\n};\n\nconst VARIANT_CLASS: Record<ActionSwapButtonVariant, string> = {\n  primary: \"bg-primary text-primary-foreground hover:bg-primary/90\",\n  secondary: \"border border-border bg-card text-foreground hover:border-border\",\n  outline: \"border border-border bg-transparent text-foreground hover:bg-primary/5\",\n  ghost: \"text-muted-foreground hover:bg-primary/5 hover:text-foreground\",\n};\n\nconst SIZE_CLASS: Record<ActionSwapButtonSize, string> = {\n  sm: \"h-8 gap-1.5 rounded-full px-3 text-xs\",\n  md: \"h-10 gap-2 rounded-full px-4 text-sm\",\n  lg: \"h-12 gap-2.5 rounded-full px-5 text-base\",\n  icon: \"h-10 w-10 rounded-full\",\n};\n\nexport function ActionSwapText({\n  value,\n  children,\n  animation = \"blur\",\n  className,\n}: ActionSwapTextProps) {\n  const reduce = useReducedMotion();\n  const measureRef = useRef<HTMLSpanElement>(null);\n  const [width, setWidth] = useState<number>();\n\n  useLayoutEffect(() => {\n    const nextWidth = measureRef.current?.offsetWidth;\n    if (!nextWidth) return;\n    setWidth((currentWidth) => (currentWidth === nextWidth ? currentWidth : nextWidth));\n  });\n\n  // Cascade needs a plain string to split into letters; non-string content\n  // and reduced motion fall back to the closest single-element animation.\n  const label = typeof children === \"string\" ? children : null;\n  const cascade = animation === \"cascade\" && label !== null && !reduce;\n  const coreAnimation: CoreAnimation =\n    animation === \"cascade\" ? \"roll\" : animation;\n\n  return (\n    <span\n      className={cn(\"relative inline-block overflow-hidden whitespace-nowrap align-bottom\", className)}\n      style={{\n        width,\n        transition: reduce ? undefined : `width 220ms ${EASE_OUT_CSS}`,\n      }}\n    >\n      <span\n        ref={measureRef}\n        aria-hidden\n        className=\"invisible inline-block whitespace-nowrap\"\n      >\n        {children}\n      </span>\n      {cascade ? (\n        <>\n          {/* Letters are decorative fragments; readers get the whole label. */}\n          <span className=\"sr-only\">{label}</span>\n          <AnimatePresence initial={false}>\n            <motion.span\n              key={`cascade-${value}`}\n              aria-hidden\n              initial=\"initial\"\n              animate=\"animate\"\n              exit=\"exit\"\n              className=\"absolute left-0 top-0 inline-block whitespace-pre\"\n            >\n              {label.split(\"\").map((char, i) => (\n                <motion.span\n                  // biome-ignore lint/suspicious/noArrayIndexKey: position is the slot identity — the letter at a position is exactly what rolls.\n                  key={i}\n                  custom={i * CASCADE_STAGGER}\n                  variants={CASCADE_LETTER_VARIANTS}\n                  className=\"inline-block whitespace-pre will-change-[opacity,filter,transform]\"\n                >\n                  {char}\n                </motion.span>\n              ))}\n            </motion.span>\n          </AnimatePresence>\n        </>\n      ) : (\n        <AnimatePresence initial={false}>\n          <motion.span\n            key={`${animation}-${value}`}\n            variants={TEXT_VARIANTS[coreAnimation]}\n            initial={reduce ? false : \"initial\"}\n            animate={reduce ? { opacity: 1, filter: \"blur(0px)\", scale: 1, y: 0 } : \"animate\"}\n            exit={reduce ? undefined : \"exit\"}\n            className=\"absolute left-0 top-0 inline-block will-change-[opacity,filter,transform]\"\n          >\n            {children}\n          </motion.span>\n        </AnimatePresence>\n      )}\n    </span>\n  );\n}\n\nexport function ActionSwapIcon({\n  value,\n  children,\n  animation = \"blur\",\n  className,\n}: ActionSwapIconProps) {\n  const reduce = useReducedMotion();\n  // Icons are single elements — cascade maps to its closest motion, roll.\n  const coreAnimation: CoreAnimation =\n    animation === \"cascade\" ? \"roll\" : animation;\n\n  return (\n    <span className={cn(\"relative inline-grid shrink-0 place-items-center overflow-hidden\", className)}>\n      <AnimatePresence mode=\"popLayout\" initial={false}>\n        <motion.span\n          key={`${animation}-${value}`}\n          aria-hidden\n          variants={ICON_VARIANTS[coreAnimation]}\n          initial={reduce ? false : \"initial\"}\n          animate={reduce ? { opacity: 1, filter: \"blur(0px)\", scale: 1, y: 0 } : \"animate\"}\n          exit={reduce ? undefined : \"exit\"}\n          className=\"col-start-1 row-start-1 inline-flex items-center justify-center will-change-[opacity,filter,transform]\"\n        >\n          {children}\n        </motion.span>\n      </AnimatePresence>\n    </span>\n  );\n}\n\nexport function ActionSwapButton({\n  items,\n  value,\n  defaultValue,\n  onValueChange,\n  variant = \"secondary\",\n  size = \"md\",\n  animation = \"blur\",\n  iconOnly = size === \"icon\",\n  cycle = true,\n  className,\n  disabled,\n  onClick,\n  ...rest\n}: ActionSwapButtonProps) {\n  const reduce = useReducedMotion();\n  const [internalValue, setInternalValue] = useState(defaultValue ?? items[0]?.id);\n  const currentValue = value ?? internalValue;\n  const activeIndex = Math.max(0, items.findIndex((item) => item.id === currentValue));\n  const activeItem = items[activeIndex] ?? items[0];\n  const hasIcon = items.some((item) => item.icon);\n  const nextItem = cycle && items.length > 0 ? items[(activeIndex + 1) % items.length] : undefined;\n\n  if (!activeItem) return null;\n\n  const accessibleLabel = activeItem.ariaLabel ?? (iconOnly && typeof activeItem.label === \"string\" ? activeItem.label : undefined);\n\n  return (\n    <motion.button\n      type=\"button\"\n      disabled={disabled}\n      whileTap={reduce || disabled ? undefined : { scale: 0.97 }}\n      transition={SPRING_PRESS}\n      className={cn(\n        \"inline-flex items-center justify-center overflow-hidden font-medium transition-colors\",\n        \"disabled:pointer-events-none disabled:opacity-50\",\n        VARIANT_CLASS[variant],\n        SIZE_CLASS[size],\n        className,\n      )}\n      aria-label={accessibleLabel}\n      onClick={(event) => {\n        onClick?.(event);\n        if (event.defaultPrevented || disabled || !cycle || !nextItem) return;\n        if (value === undefined) setInternalValue(nextItem.id);\n        onValueChange?.(nextItem.id, nextItem);\n      }}\n      {...rest}\n    >\n      {hasIcon ? (\n        <ActionSwapIcon value={activeItem.id} animation={animation} className=\"h-4 w-4\">\n          {activeItem.icon ?? null}\n        </ActionSwapIcon>\n      ) : null}\n      {!iconOnly ? (\n        <ActionSwapText value={activeItem.id} animation={animation}>\n          {activeItem.label}\n        </ActionSwapText>\n      ) : null}\n    </motion.button>\n  );\n}\n"},{"path":"components/previews/motion/text-animation.preview.tsx","type":"preview","content":"\"use client\";\n\nimport { AnimatePresence, motion } from \"motion/react\";\nimport { EASE_OUT } from \"@/lib/ease\";\nimport { useEffect, useState } from \"react\";\nimport { TextReveal } from \"@/components/motion/text-reveal\";\nimport { TextShimmer } from \"@/components/motion/text-shimmer\";\n\nexport function TextAnimationPreview() {\n  const [variant, setVariant] = useState<\"reveal\" | \"shimmer\">(\"reveal\");\n\n  useEffect(() => {\n    const id = window.setInterval(() => {\n      setVariant((currentVariant) => currentVariant === \"reveal\" ? \"shimmer\" : \"reveal\");\n    }, 3000);\n    return () => window.clearInterval(id);\n  }, []);\n\n  return (\n    <div className=\"relative flex min-h-20 w-full items-center justify-center text-center\">\n      <AnimatePresence mode=\"wait\" initial={false}>\n        <motion.div\n          key={variant}\n          initial={{ opacity: 0, filter: \"blur(6px)\", transform: \"translateY(4px)\" }}\n          animate={{ opacity: 1, filter: \"blur(0px)\", transform: \"translateY(0px)\" }}\n          exit={{ opacity: 0, filter: \"blur(6px)\", transform: \"translateY(-4px)\" }}\n          transition={{ duration: 0.22, ease: EASE_OUT }}\n        >\n          {variant === \"reveal\" ? (\n            <TextReveal\n              as=\"h2\"\n              text=\"Motion in words.\"\n              stagger={0.045}\n              blur={6}\n              yOffset=\"18%\"\n              className=\"text-balance text-3xl font-semibold tracking-tight text-(--color-fg)\"\n            />\n          ) : (\n            <TextShimmer duration={1.8} className=\"text-xl font-semibold\">\n              Loading with shimmer\n            </TextShimmer>\n          )}\n        </motion.div>\n      </AnimatePresence>\n    </div>\n  );\n}\n"}]}