feat: loading transition (#277)

* refactor: change hires loader function name

* feat: add loading transition animation and improve performance

* refactor: refactor mutation handling in desktop codebase

- Modify the `initStage` function in `assets/ts/desktop/stage.ts`:
  - Change the `onMutation` callback to accept a single mutation instead of an array of mutations.
  - Update the conditions inside the callback to use `hold` instead of `skip`.
- Modify the `onMutation` function in `assets/ts/desktop/utils.ts`:
  - Change the `callback` parameter to `trigger`.
  - Update the implementation of the function to iterate over each mutation and check if it triggers the `trigger` function. If it does, disconnect the observer and break the loop.

* style: refactor state section and remove unnecessary code

- Remove the declaration of `lastIndex` on line 21
- Add a comment block for the state section
- Add a declaration of `lastIndex` for the state section

* refactor: refactor mobile collection and intersection functions

- Modify the `initCollection` function in `assets/ts/mobile/collection.ts`
- Remove the nested loop in the `initCollection` function
- Modify the `onIntersection` function in `assets/ts/mobile/utils.ts`
- Replace the callback parameter with a trigger parameter in the `onIntersection` function
- Remove the nested loop in the `onIntersection` function

* refactor: refactor Watchable class constructor to include lazy parameter

- Add a second parameter `lazy` in the constructor of the `Watchable` class in `globalUtils.ts`
- Set the default value of `lazy` to `true` in the constructor
- Add a condition to check if `e` is equal to `this.obj` and `this.lazy` is `true` to return in `watch`
- Delete the previous constructor definition in the `Watchable` class in `globalUtils.ts`

* fix: set state's lazy param to false

* refactor: refactor third party lib import

assets/ts/mobile/collection.ts

@@ -64,18 +64,15 @@ export function initCollection(ijs: ImageJSON[]): void {
       { passive: true }
     )
     // preload
-    onIntersection(img, (entries, observer) => {
-      entries.every((entry) => {
-        // no intersection, skip
-        if (entry.intersectionRatio <= 0) return true
-        // preload the i + 5th image
-        if (i + 5 < imgs.length) {
-          imgs[i + 5].src = imgs[i + 5].dataset.src
-        }
-        // disconnect observer and return false to break the loop
-        observer.disconnect()
-        return false
-      })
+    onIntersection(img, (entry) => {
+      // no intersection, hold
+      if (entry.intersectionRatio <= 0) return false
+      // preload the i + 5th image, if it exists
+      if (i + 5 < imgs.length) {
+        imgs[i + 5].src = imgs[i + 5].dataset.src
+      }
+      // triggered
+      return true
     })
   })
 }

assets/ts/mobile/gallery.ts

@@ -1,4 +1,4 @@
-import { type Power3, type gsap } from 'gsap'
+import { type gsap } from 'gsap'
 import { type Swiper } from 'swiper'
 
 import { container, scrollable } from '../container'
@@ -17,16 +17,18 @@ import { capitalizeFirstLetter, loadSwiper, type MobileImage } from './utils'
 let swiperNode: HTMLDivElement
 let gallery: HTMLDivElement
 let curtain: HTMLDivElement
-let swiper: Swiper
-let lastIndex = -1
 let indexDispNums: HTMLSpanElement[] = []
 let galleryImages: MobileImage[] = []
 let collectionImages: MobileImage[] = []
 
-let _Swiper: typeof Swiper
 let _gsap: typeof gsap
-let _Power3: typeof Power3
+let _swiper: Swiper
 
+/**
+ * state
+ */
+
+let lastIndex = -1
 let libLoaded = false
 
 /**
@@ -44,7 +46,7 @@ export function slideUp(): void {
 
   _gsap.to(gallery, {
     y: 0,
-    ease: _Power3.easeInOut,
+    ease: 'power3.inOut',
     duration: 1,
     delay: 0.4
   })
@@ -63,7 +65,7 @@ function slideDown(): void {
 
   _gsap.to(gallery, {
     y: '100%',
-    ease: _Power3.easeInOut,
+    ease: 'power3.inOut',
     duration: 1
   })
 
@@ -128,17 +130,15 @@ export function initGallery(ijs: ImageJSON[]): void {
     () => {
       loadGsap()
         .then((g) => {
-          _gsap = g[0]
-          _Power3 = g[1]
+          _gsap = g
         })
         .catch((e) => {
           console.log(e)
         })
       loadSwiper()
-        .then((s) => {
-          _Swiper = s
-          swiper = new _Swiper(swiperNode, { spaceBetween: 20 })
-          swiper.on('slideChange', ({ realIndex }) => {
+        .then((S) => {
+          _swiper = new S(swiperNode, { spaceBetween: 20 })
+          _swiper.on('slideChange', ({ realIndex }) => {
             setIndex(realIndex)
           })
         })
@@ -159,7 +159,7 @@ export function initGallery(ijs: ImageJSON[]): void {
 
 function changeSlide(slide: number): void {
   galleryLoadImages()
-  swiper.slideTo(slide, 0)
+  _swiper.slideTo(slide, 0)
 }
 
 function scrollToActive(): void {
@@ -237,13 +237,18 @@ function createGallery(ijs: ImageJSON[]): void {
     e.height = ij.hiImgH
     e.width = ij.hiImgW
     e.alt = ij.alt
-    e.classList.add('hide')
+    e.style.opacity = '0'
     // load event
     e.addEventListener(
       'load',
       () => {
-        e.classList.remove('hide')
-        l.classList.add('hide')
+        if (state.get().index !== ij.index) {
+          _gsap.set(e, { opacity: 1 })
+          _gsap.set(l, { opacity: 0 })
+        } else {
+          _gsap.to(e, { opacity: 1, delay: 0.5, duration: 0.5, ease: 'power3.out' })
+          _gsap.to(l, { opacity: 0, duration: 0.5, ease: 'power3.in' })
+        }
       },
       { once: true, passive: true }
     )

assets/ts/mobile/utils.ts

@@ -20,10 +20,15 @@ export function getRandom(min: number, max: number): number {
 
 export function onIntersection<T extends HTMLElement>(
   element: T,
-  callback: (arg0: IntersectionObserverEntry[], arg1: IntersectionObserver) => void
+  trigger: (arg0: IntersectionObserverEntry) => boolean
 ): void {
   new IntersectionObserver((entries, observer) => {
-    callback(entries, observer)
+    for (const entry of entries) {
+      if (trigger(entry)) {
+        observer.disconnect()
+        break
+      }
+    }
   }).observe(element)
 }