Add swipe navigation to lightbox

ui/v2.5/src/hooks/Lightbox/Lightbox.tsx

@@ -76,6 +76,7 @@ const CLASSNAME_FOOTER_RIGHT = `${CLASSNAME_FOOTER}-right`;
 const CLASSNAME_DISPLAY = `${CLASSNAME}-display`;
 const CLASSNAME_CAROUSEL = `${CLASSNAME}-carousel`;
 const CLASSNAME_INSTANT = `${CLASSNAME_CAROUSEL}-instant`;
+const CLASSNAME_SWIPE = `${CLASSNAME_CAROUSEL}-swipe`;
 const CLASSNAME_IMAGE = `${CLASSNAME_CAROUSEL}-image`;
 const CLASSNAME_IMAGE_CONTAINER = `${CLASSNAME_CAROUSEL}-image-container`;
 const CLASSNAME_NAVBUTTON = `${CLASSNAME}-navbutton`;
@@ -91,7 +92,7 @@ const SCROLL_ZOOM_TIMEOUT = 250;
 const ZOOM_NONE_EPSILON = 0.015;
 
 interface ILightboxCarouselProps {
-  instantTransition: boolean;
+  transition: string | null;
   currentIndex: number;
   images: ILightboxImage[];
   displayMode: GQL.ImageLightboxDisplayMode;
@@ -106,11 +107,12 @@ interface ILightboxCarouselProps {
   debouncedScrollReset: () => void;
   handleLeft: () => void;
   handleRight: () => void;
+  overrideTransition: (t: string) => void;
 }
 
 const LightboxCarousel = forwardRef(function (
   {
-    instantTransition,
+    transition,
     currentIndex,
     images,
     displayMode,
@@ -125,15 +127,36 @@ const LightboxCarousel = forwardRef(function (
     debouncedScrollReset,
     handleLeft,
     handleRight,
+    overrideTransition,
   }: ILightboxCarouselProps,
   carouselRef: ForwardedRef<HTMLDivElement>
 ) {
+  const [carouselShift, setCarouselShift] = useState(0);
+
+  function handleMoveCarousel(delta: number) {
+    overrideTransition(CLASSNAME_INSTANT);
+    setCarouselShift(carouselShift + delta);
+  }
+
+  function handleReleaseCarousel(
+    event: React.TouchEvent,
+    swipeDuration: number
+  ) {
+    const cappedDuration = Math.max(50, Math.min(500, swipeDuration)) / 1000;
+    const adjustedShift = carouselShift / (2 * cappedDuration);
+    if (adjustedShift < -window.innerWidth / 2) {
+      handleRight();
+    } else if (adjustedShift > window.innerWidth / 2) {
+      handleLeft();
+    }
+    setCarouselShift(0);
+    overrideTransition(CLASSNAME_SWIPE);
+  }
+
   return (
     <div
-      className={cx(CLASSNAME_CAROUSEL, {
+      className={CLASSNAME_CAROUSEL + (transition ? ` ${transition}` : "")}
-        [CLASSNAME_INSTANT]: instantTransition,
+      style={{ left: `calc(${currentIndex * -100}vw + ${carouselShift}px)` }}
-      })}
-      style={{ left: `${currentIndex * -100}vw` }}
       ref={carouselRef}
     >
       {images.map((image, i) => (
@@ -160,6 +183,8 @@ const LightboxCarousel = forwardRef(function (
               onLeft={handleLeft}
               onRight={handleRight}
               isVideo={isVideo(image.visual_files?.[0] ?? {})}
+              moveCarousel={handleMoveCarousel}
+              releaseCarousel={handleReleaseCarousel}
             />
           ) : undefined}
         </div>
@@ -203,7 +228,7 @@ export const LightboxComponent: React.FC<IProps> = ({
   const [index, setIndex] = useState<number | null>(null);
   const [movingLeft, setMovingLeft] = useState(false);
   const oldIndex = useRef<number | null>(null);
-  const [instantTransition, setInstantTransition] = useState(false);
+  const [transition, setTransition] = useState<string | null>(null);
   const [isSwitchingPage, setIsSwitchingPage] = useState(true);
   const [isFullscreen, setFullscreen] = useState(false);
   const [showOptions, setShowOptions] = useState(false);
@@ -315,15 +340,15 @@ export const LightboxComponent: React.FC<IProps> = ({
     }
   }, [isSwitchingPage, images, index]);
 
-  const disableInstantTransition = useDebounce(
+  const restoreTransition = useDebounce(() => setTransition(null), 400);
-    () => setInstantTransition(false),
-    400
-  );
 
-  const setInstant = useCallback(() => {
+  const overrideTransition = useCallback(
-    setInstantTransition(true);
+    (t: string) => {
-    disableInstantTransition();
+      setTransition(t);
-  }, [disableInstantTransition]);
+      restoreTransition();
+    },
+    [restoreTransition]
+  );
 
   useEffect(() => {
     if (images.length < 2) return;
@@ -487,12 +512,12 @@ export const LightboxComponent: React.FC<IProps> = ({
   const handleKey = useCallback(
     (e: KeyboardEvent) => {
       if (e.repeat && (e.key === "ArrowRight" || e.key === "ArrowLeft"))
-        setInstant();
+        overrideTransition(CLASSNAME_INSTANT);
       if (e.key === "ArrowLeft") handleLeft();
       else if (e.key === "ArrowRight") handleRight();
       else if (e.key === "Escape") close();
     },
-    [setInstant, handleLeft, handleRight, close]
+    [overrideTransition, handleLeft, handleRight, close]
   );
   const handleFullScreenChange = () => {
     if (clearIntervalCallback.current) {
@@ -934,7 +959,7 @@ export const LightboxComponent: React.FC<IProps> = ({
             </Button>
           )}
           <LightboxCarousel
-            instantTransition={instantTransition}
+            transition={transition}
             currentIndex={currentIndex}
             images={images}
             displayMode={displayMode}
@@ -949,6 +974,7 @@ export const LightboxComponent: React.FC<IProps> = ({
             debouncedScrollReset={debouncedScrollReset}
             handleLeft={handleLeft}
             handleRight={handleRight}
+            overrideTransition={overrideTransition}
           />
           {allowNavigation && (
             <Button

ui/v2.5/src/hooks/Lightbox/LightboxImage.tsx

@@ -102,6 +102,8 @@ interface IProps {
   debouncedScrollReset: () => void;
   onLeft: () => void;
   onRight: () => void;
+  moveCarousel: (v: number) => void;
+  releaseCarousel: (ev: React.TouchEvent, swipeDuration: number) => void;
   isVideo: boolean;
 }
 
@@ -123,9 +125,11 @@ export const LightboxImage: React.FC<IProps> = ({
   debouncedScrollReset,
   onLeft,
   onRight,
+  moveCarousel,
+  releaseCarousel,
   isVideo,
 }) => {
-  const [defaultZoom, setDefaultZoom] = useState(1);
+  const [defaultZoom, setDefaultZoom] = useState<number | null>(null);
   const [moving, setMoving] = useState(false);
   const [positionX, setPositionX] = useState(0);
   const [positionY, setPositionY] = useState(0);
@@ -139,6 +143,7 @@ export const LightboxImage: React.FC<IProps> = ({
   const resetPositionRef = useRef(resetPosition);
 
   const startPoints = useRef<number[]>([0, 0]);
+  const startTime = useRef<number>(0);
   const pointerCache = useRef<React.PointerEvent[]>([]);
   const prevDiff = useRef<number | undefined>();
 
@@ -200,7 +205,10 @@ export const LightboxImage: React.FC<IProps> = ({
     },
     [imageWidth, boxWidth, imageHeight, boxHeight]
   );
-  const panBounds = calcPanBounds(defaultZoom * zoom);
+  const panBounds =
+    defaultZoom !== null
+      ? calcPanBounds(defaultZoom * zoom)
+      : { minX: 0, maxX: 0, minY: 0, maxY: 0, nonZero: false };
 
   const minMaxY = useCallback(
     (appliedZoom: number) => {
@@ -279,6 +287,9 @@ export const LightboxImage: React.FC<IProps> = ({
   ]);
 
   useEffect(() => {
+    if (defaultZoom === null) {
+      return;
+    }
     if (resetPosition !== resetPositionRef.current) {
       resetPositionRef.current = resetPosition;
 
@@ -364,7 +375,7 @@ export const LightboxImage: React.FC<IProps> = ({
   }
 
   function onImageScrollPanY(ev: React.WheelEvent, infinite: boolean) {
-    if (!current) return;
+    if (!current || defaultZoom === null) return;
 
     const [minY, maxY] = minMaxY(zoom * defaultZoom);
 
@@ -466,6 +477,7 @@ export const LightboxImage: React.FC<IProps> = ({
 
   function onImageMouseDown(ev: React.MouseEvent) {
     startPoints.current = [ev.pageX, ev.pageY];
+    startTime.current = ev.timeStamp;
     setMoving(true);
 
     mouseDownEvent.current = ev.nativeEvent;
@@ -497,24 +509,58 @@ export const LightboxImage: React.FC<IProps> = ({
     }
   }
 
-  function onTouchStart(ev: React.TouchEvent) {
+  const onTouchStart = useCallback(
+    (ev: TouchEvent) => {
       ev.preventDefault();
       if (ev.touches.length === 1) {
         startPoints.current = [ev.touches[0].pageX, ev.touches[0].pageY];
+        startTime.current = ev.timeStamp;
         setMoving(true);
       }
+    },
+    [startPoints, startTime, setMoving]
+  );
+
+  useEffect(() => {
+    const container = containerRef.current;
+    if (!container) {
+      return;
     }
+    container.addEventListener("touchstart", onTouchStart);
+    return () => {
+      container.removeEventListener("touchstart", onTouchStart);
+    };
+  }, [containerRef, onTouchStart]);
 
   function onTouchMove(ev: React.TouchEvent) {
     if (!moving) return;
 
     if (ev.touches.length === 1) {
-      const posX = ev.touches[0].pageX - startPoints.current[0];
+      const deltaX = ev.touches[0].pageX - startPoints.current[0];
-      const posY = ev.touches[0].pageY - startPoints.current[1];
+      const deltaY = ev.touches[0].pageY - startPoints.current[1];
       startPoints.current = [ev.touches[0].pageX, ev.touches[0].pageY];
 
-      setPositionX(positionX + posX);
+      if (panBounds.minX != panBounds.maxX) {
-      setPositionY(positionY + posY);
+        const newPositionX = Math.max(
+          panBounds.minX,
+          Math.min(panBounds.maxX, positionX + deltaX)
+        );
+        const newPositionY = Math.max(
+          panBounds.minY,
+          Math.min(panBounds.maxY, positionY + deltaY)
+        );
+
+        setPositionX(newPositionX);
+        setPositionY(newPositionY);
+      } else {
+        moveCarousel(deltaX);
+      }
+    }
+  }
+
+  function onTouchEnd(ev: React.TouchEvent) {
+    if (ev.changedTouches.length === 1 && ev.touches.length === 0) {
+      releaseCarousel(ev, ev.timeStamp - startTime.current);
     }
   }
 
@@ -581,6 +627,8 @@ export const LightboxImage: React.FC<IProps> = ({
       })}
       style={{ touchAction: "none" }}
       onWheel={(e) => onContainerScroll(e)}
+      onTouchMove={onTouchMove}
+      onTouchEnd={onTouchEnd}
     >
       {defaultZoom ? (
         <picture>
@@ -603,8 +651,6 @@ export const LightboxImage: React.FC<IProps> = ({
             onMouseDown={onImageMouseDown}
             onMouseUp={onImageMouseUp}
             onMouseMove={onImageMouseOver}
-            onTouchStart={onTouchStart}
-            onTouchMove={onTouchMove}
             onPointerDown={onPointerDown}
             onPointerUp={onPointerUp}
             onPointerMove={onPointerMove}

ui/v2.5/src/hooks/Lightbox/lightbox.scss

@@ -144,6 +144,11 @@
       transition-duration: 0ms;
     }
 
+    &-swipe {
+      transition-duration: 200ms;
+      transition-timing-function: ease-out;
+    }
+
     &-image-container {
       content-visibility: auto;
       width: 100vw;