frontend/src/pages/GekanatorPage.tsx

@@ -2753,26 +2753,13 @@ const GekanatorBackdrop: FC<{
       nextThumbnails)
   const [flipVisualSeed, setFlipVisualSeed] = useState (visualSeed)
   const [isFlippingTiles, setIsFlippingTiles] = useState (false)
-  const [isCrossfading, setIsCrossfading] = useState (false)
 
-  const isLeavingGuessBackdrop = displayedBackdropMode === 'guess' && backdropMode !== 'guess'
-
-  const renderBackdropMode = isLeavingGuessBackdrop ? backdropMode : displayedBackdropMode
-
-  const renderWinningRunCount = (isLeavingGuessBackdrop
-				 ? winningRunQuestionCount
-				 : displayedWinningRunCount)
-
-  const renderThumbnails = isLeavingGuessBackdrop ? nextThumbnails : displayedThumbnails
-
-  const renderIsCrossfading = isCrossfading && !(isLeavingGuessBackdrop)
-
-  const renderedSettings = settingsForMode (renderBackdropMode)
+  const renderedSettings = settingsForMode (displayedBackdropMode)
   const renderedTileCount = renderedSettings.columns * renderedSettings.rows
-  const renderedScale = scaleForMode (renderBackdropMode, renderWinningRunCount)
+  const renderedScale = scaleForMode (displayedBackdropMode, displayedWinningRunCount)
 
-  const isGuessPresentation = backdropMode === 'guess'
-  const crossfadeDuration = motionMode === 'calm' ? .95 : .75
+  const isGuessPresentation =
+      backdropMode === 'guess' || displayedBackdropMode === 'guess'
 
   useEffect (() => {
     guessAnimationControlsRef.current.forEach (control => control.stop ())
@@ -2866,7 +2853,6 @@ const GekanatorBackdrop: FC<{
       {
 	applyDirection ()
 	setIsFlippingTiles (false)
-	setIsCrossfading (false)
 	setFlipVisualSeed (visualSeed)
 	return
       }
@@ -2874,7 +2860,6 @@ const GekanatorBackdrop: FC<{
     if (backdropMode === 'guess' && guessThumbnail)
       {
 	setIsFlippingTiles (false)
-	setIsCrossfading (false)
 	setDisplayedBackdropMode ('guess')
 	setDisplayedWinningRunCount (winningRunQuestionCount)
 	setDisplayedThumbnails (nextThumbnails)
@@ -2894,7 +2879,6 @@ const GekanatorBackdrop: FC<{
 	setFromThumbnails (nextThumbnails)
 	setToThumbnails (nextThumbnails)
 	setIsFlippingTiles (false)
-	setIsCrossfading (false)
 	setFlipVisualSeed (visualSeed)
 	return
       }
@@ -2903,23 +2887,6 @@ const GekanatorBackdrop: FC<{
       {
 	applyDirection ()
 	setIsFlippingTiles (false)
-	setIsCrossfading (false)
-	setFlipVisualSeed (visualSeed)
-	return
-      }
-
-    if (displayedBackdropMode === 'guess' && backdropMode !== 'guess')
-      {
-	applyDirection ()
-	x.set (0)
-	y.set (0)
-	setIsFlippingTiles (false)
-	setIsCrossfading (false)
-	setDisplayedBackdropMode (backdropMode)
-	setDisplayedWinningRunCount (winningRunQuestionCount)
-	setDisplayedThumbnails (nextThumbnails)
-	setFromThumbnails (nextThumbnails)
-	setToThumbnails (nextThumbnails)
 	setFlipVisualSeed (visualSeed)
 	return
       }
@@ -2942,10 +2909,7 @@ const GekanatorBackdrop: FC<{
 
     setFromThumbnails (currentThumbnails)
     setToThumbnails (nextThumbnails)
-    const shouldCrossfade =
-	displayedBackdropMode === 'winning_run' && backdropMode === 'normal'
-    setIsCrossfading (shouldCrossfade)
-    setIsFlippingTiles (!(shouldCrossfade))
+    setIsFlippingTiles (true)
 
     flipTimerRef.current = window.setTimeout (() => {
       setDisplayedBackdropMode (backdropMode)
@@ -2954,11 +2918,10 @@ const GekanatorBackdrop: FC<{
       setFromThumbnails (nextThumbnails)
       setToThumbnails (nextThumbnails)
       setIsFlippingTiles (false)
-      setIsCrossfading (false)
       applyDirection ()
       setFlipVisualSeed (visualSeed)
       flipTimerRef.current = null
-    }, (shouldCrossfade ? crossfadeDuration : tileFlipDuration) * 1000)
+    }, tileFlipDuration * 1000)
 
     return () => {
       if (flipTimerRef.current !== null)
@@ -2978,126 +2941,10 @@ const GekanatorBackdrop: FC<{
       visualSeed,
       activeDirection,
       winningRunQuestionCount,
-      crossfadeDuration,
       tileFlipDuration,
       x,
       y])
 
-  const renderTileSet = (
-      { mode,
-	thumbnails,
-	settings,
-	tileCount,
-	scale,
-	opacity,
-	withFlip }: { mode:       'normal' | 'winning_run' | 'guess'
-		      thumbnails: string[]
-		      settings:   { columns: number; rows: number; opacity: number }
-		      tileCount:  number
-		      scale:      number
-		      opacity?:   number
-		      withFlip?:  boolean }) => {
-    const guessModeFlg = mode === 'guess'
-
-    return (
-	<motion.div
-	    className="absolute inset-0"
-	    initial={guessModeFlg
-		     ? false
-		     : (opacity == null
-		        ? undefined
-		        : { opacity: opacity === 0 ? 1 : 0, scale, x: '0%', y: '0%' })}
-	    animate={{ opacity: opacity ?? 1,
-		       scale,
-		       x: guessModeFlg ? guessFocusOffset.x : '0%',
-		       y: guessModeFlg ? guessFocusOffset.y : '0%' }}
-	    transition={guessModeFlg
-			? { duration: 0 }
-			: (mode === 'winning_run'
-			   ? { duration: crossfadeDuration, ease: [.16, 1, .3, 1] }
-			   : { duration: .2 })}>
-	  {Array.from ({ length: 9 }, (_, duplicate) => {
-	    const column = duplicate % 3
-	    const row = Math.floor (duplicate / 3)
-
-	    return (
-		<motion.div
-		    key={`${ mode }:${ duplicate }`}
-		    className="absolute grid overflow-hidden"
-		    layout={mode === 'winning_run'}
-		    style={{
-			left: `${ column * 33.333333 }%`,
-			top: `${ row * 33.333333 }%`,
-			width: '33.333333%',
-			height: '33.333333%',
-			gridTemplateColumns:
-			    `repeat(${ settings.columns }, minmax(0, 1fr))`,
-			gridTemplateRows:
-			    `repeat(${ settings.rows }, minmax(0, 1fr))` }}
-		    transition={{ duration: tileFlipDuration, ease: 'easeInOut' }}>
-		  {Array.from ({ length: tileCount }, (_, index) => {
-		    const currentThumbnail =
-			thumbnails[index % Math.max (thumbnails.length, 1)]
-		    const frontThumbnail =
-			withFlip
-			  ? fromThumbnails[index % Math.max (fromThumbnails.length, 1)]
-			  : currentThumbnail
-		    const backThumbnail =
-			withFlip
-			  ? toThumbnails[index % Math.max (toThumbnails.length, 1)]
-			  : currentThumbnail
-		    const thumbnail = currentThumbnail
-		    if (!(thumbnail) || !(frontThumbnail) || !(backThumbnail))
-		      return null
-
-		    return (
-			<motion.div
-			    key={`${ mode }:${ duplicate }:${ index }`}
-			    className="relative overflow-hidden"
-			    layout={mode === 'winning_run'}
-			    transition={{ duration: tileFlipDuration, ease: 'easeInOut' }}
-			    style={{ perspective: 1600 }}>
-			  {(mode !== 'normal' || !(withFlip))
-			   ? (
-			      <img
-				  src={['intro', 'end'].includes (phase)
-				       ? mascotAsset
-				       : thumbnail}
-				  alt=""
-				  className="absolute inset-0 h-full w-full object-cover"
-				  style={{ opacity: settings.opacity }}/>)
-			   : (
-			      <motion.div
-				  className="absolute inset-0"
-				  initial={{ rotateY: 0 }}
-				  animate={{ rotateY: 180 }}
-				  transition={{
-				      duration: tileFlipDuration,
-				      ease: 'easeInOut' }}
-				  style={{ transformStyle: 'preserve-3d' }}>
-				<img
-				    src={backThumbnail}
-				    alt=""
-				    className="absolute inset-0 h-full w-full object-cover"
-				    style={{
-					backfaceVisibility: 'hidden',
-					opacity: settings.opacity,
-					transform: 'rotateY(180deg)' }}/>
-				<img
-				    src={frontThumbnail}
-				    alt=""
-				    className="absolute inset-0 h-full w-full object-cover"
-				    style={{
-					backfaceVisibility: 'hidden',
-					opacity: settings.opacity }}/>
-			      </motion.div>)}
-			</motion.div>)
-		  })}
-		</motion.div>)
-	  })}
-	</motion.div>)
-  }
-
   if (motionMode === 'off' || nextThumbnails.length === 0)
     return (
 	<div className="absolute inset-0 bg-gradient-to-br from-yellow-50 via-white
@@ -3113,34 +2960,99 @@ const GekanatorBackdrop: FC<{
 		  width: 'calc(max(100vw, 100vh) * 3)',
 		  height: 'calc(max(100vw, 100vh) * 3)' }}>
 	    <motion.div
-		className="relative h-full w-full">
-	      {renderIsCrossfading
-	       ? (
-		  <>
-		    {renderTileSet ({
-			mode: displayedBackdropMode,
-			thumbnails: fromThumbnails,
-			settings: settingsForMode (displayedBackdropMode),
-			tileCount: (settingsForMode (displayedBackdropMode).columns
-				    * settingsForMode (displayedBackdropMode).rows),
-			scale: scaleForMode (displayedBackdropMode, displayedWinningRunCount),
-			opacity: 0 })}
-		    {renderTileSet ({
-			mode: backdropMode,
-			thumbnails: toThumbnails,
-			settings: targetSettings,
-			tileCount: targetTileCount,
-			scale: scaleForMode (backdropMode, winningRunQuestionCount),
-			opacity: 1 })}
-		  </>)
-	       : (
-		  renderTileSet ({
-		      mode: renderBackdropMode,
-		      thumbnails: renderThumbnails,
-		      settings: renderedSettings,
-		      tileCount: renderedTileCount,
-		      scale: renderedScale,
-		      withFlip: isFlippingTiles && !(isLeavingGuessBackdrop) }))}
+		className="relative h-full w-full"
+		animate={{ scale: renderedScale,
+			   x: displayedBackdropMode === 'guess' ? guessFocusOffset.x : '0%',
+			   y: displayedBackdropMode === 'guess' ? guessFocusOffset.y : '0%' }}
+		transition={(displayedBackdropMode === 'winning_run'
+			     || displayedBackdropMode === 'guess')
+			    ? { duration: motionMode === 'calm' ? .95 : .75,
+				ease: [.16, 1, .3, 1] }
+			    : { duration: .2 }}>
+	      {Array.from ({ length: 9 }, (_, duplicate) => {
+		const column = duplicate % 3
+		const row = Math.floor (duplicate / 3)
+
+		return (
+		    <motion.div
+			key={duplicate}
+			className="absolute grid overflow-hidden"
+			layout={displayedBackdropMode !== 'normal'}
+			style={{
+			    left: `${ column * 33.333333 }%`,
+			    top: `${ row * 33.333333 }%`,
+			    width: '33.333333%',
+			    height: '33.333333%',
+			    gridTemplateColumns:
+				`repeat(${ renderedSettings.columns }, minmax(0, 1fr))`,
+			    gridTemplateRows:
+				`repeat(${ renderedSettings.rows }, minmax(0, 1fr))` }}
+			transition={{ duration: tileFlipDuration, ease: 'easeInOut' }}>
+		      {Array.from ({ length: renderedTileCount }, (_, index) => {
+			const currentThumbnail =
+			    displayedThumbnails[
+				index % Math.max (displayedThumbnails.length, 1)]
+			const frontThumbnail =
+			    isFlippingTiles
+			      ? fromThumbnails[index % Math.max (fromThumbnails.length, 1)]
+			      : currentThumbnail
+			const backThumbnail =
+			    isFlippingTiles
+			      ? toThumbnails[index % Math.max (toThumbnails.length, 1)]
+			      : currentThumbnail
+			const thumbnail =
+			    displayedBackdropMode === 'winning_run'
+			    || displayedBackdropMode === 'guess'
+			      ? nextThumbnails[index % Math.max (nextThumbnails.length, 1)]
+			      : currentThumbnail
+			if (!(thumbnail) || !(frontThumbnail) || !(backThumbnail))
+			  return null
+
+			return (
+			    <motion.div
+				key={`${ duplicate }:${ index }`}
+				className="relative overflow-hidden"
+				layout={displayedBackdropMode !== 'normal'}
+				transition={{ duration: tileFlipDuration, ease: 'easeInOut' }}
+				style={{ perspective: 1600 }}>
+			      {(displayedBackdropMode !== 'normal' || !(isFlippingTiles))
+			       ? (
+				  <img
+				      src={['intro', 'end'].includes (phase)
+					   ? mascotAsset
+					   : thumbnail}
+				      alt=""
+				      className="absolute inset-0 h-full w-full object-cover"
+				      style={{ opacity: renderedSettings.opacity }}/>)
+			       : (
+				  <motion.div
+				      className="absolute inset-0"
+				      initial={{ rotateY: 0 }}
+				      animate={{ rotateY: 180 }}
+				      transition={{
+					  duration: tileFlipDuration,
+					  ease: 'easeInOut' }}
+				      style={{ transformStyle: 'preserve-3d' }}>
+				    <img
+					src={backThumbnail}
+					alt=""
+					className="absolute inset-0 h-full w-full object-cover"
+					style={{
+					    backfaceVisibility: 'hidden',
+					    opacity: renderedSettings.opacity,
+					    transform: 'rotateY(180deg)' }}/>
+				    <img
+					src={frontThumbnail}
+					alt=""
+					className="absolute inset-0 h-full w-full object-cover"
+					style={{
+					    backfaceVisibility: 'hidden',
+					    opacity: renderedSettings.opacity }}/>
+				  </motion.div>)}
+			    </motion.div>)
+		      })}
+		    </motion.div>)
+	      })}
 	    </motion.div>
 	  </motion.div>
 	</div>