From 598549058b005ed627348c17d63f19d5e0665b7b Mon Sep 17 00:00:00 2001
From: Siarhei Balonikau <sergeibolonikov@gmail.com>
Date: Tue, 17 Sep 2024 14:21:17 +0400
Subject: [PATCH] fix/epmgcip-143/fix-calculation-ratio (#24)

Co-authored-by: Siarhei Balonikau <siarhei_balonikau@epam.com>
---
 .../organisms/ImageGallery/ImageGallery.tsx   | 86 +++++++++++++------
 1 file changed, 61 insertions(+), 25 deletions(-)

diff --git a/src/components/organisms/ImageGallery/ImageGallery.tsx b/src/components/organisms/ImageGallery/ImageGallery.tsx
index b40dc7d..10ca093 100644
--- a/src/components/organisms/ImageGallery/ImageGallery.tsx
+++ b/src/components/organisms/ImageGallery/ImageGallery.tsx
@@ -80,6 +80,47 @@ function ImageGallery({ images }: Props) {
     </div>
   ))
 
+  const loadImage = (url: string) => {
+    const image = new Image()
+    image.src = url
+    return new Promise<HTMLImageElement>((resolve) => {
+      image.onload = () => resolve(image)
+    })
+  }
+
+  const determineWrapperDimensions = (
+    image: { width: number; height: number },
+    carouselPadding: number,
+  ) => {
+    const { innerWidth, innerHeight } = window
+    const aspectRatio = image.width / image.height
+    let wrapperX = 0
+    let wrapperY = 0
+
+    if (image.height > window.innerHeight && image.width < window.innerWidth) {
+      wrapperY = Math.min(innerHeight - carouselPadding * 2, image.height)
+      wrapperX = wrapperY * aspectRatio
+    } else {
+      wrapperX = Math.min(innerWidth - carouselPadding * 2, image.width)
+      wrapperY = wrapperX / aspectRatio
+    }
+
+    return { wrapperX, wrapperY }
+  }
+
+  function calculateTranslationOffsets(
+    wrapperX: number,
+    wrapperY: number,
+    translateX: number,
+    translateY: number,
+    zoomValue: number,
+  ) {
+    const removeShift = 1 + 1 / zoomValue
+    const offsetX = (wrapperX / 100) * (translateX - 50) * removeShift
+    const offsetY = (wrapperY / 100) * (translateY - 50) * removeShift
+    return { offsetX, offsetY }
+  }
+
   return (
     <>
       <Slider
@@ -112,34 +153,29 @@ function ImageGallery({ images }: Props) {
           padding: carouselPadding,
         }}
         on={{
-          entered: () => {
+          entered: async () => {
             if (isOpeningWithZoom) {
-              const currentImage = new Image()
-              currentImage.src =
-                images.find((i) => i.id === galleryId)?.url || ''
-              currentImage.onload = () => {
-                // determining the container size for the translate
-                const wrapperX =
-                  window.innerWidth < currentImage.width
-                    ? window.innerWidth - carouselPadding * 2
-                    : currentImage.width
-                const wrapperY =
-                  window.innerHeight < currentImage.height
-                    ? window.innerHeight - carouselPadding * 2
-                    : currentImage.height
-
-                // removing shifting in the zoom plagin of the yet-another-react-lightbox
-                const removeShift = 1 + 1 / zoomValue
+              const imageUrl =
+                images.find((image) => image.id === galleryId)?.url || ''
+              if (!imageUrl) {
+                console.error('Image URL not found.')
+                return
+              }
 
-                // zoomOffset has top left corner as an origin, but translate will be from center of the screen
-                const translateX = zoomOffsetX - 50
-                const translateY = zoomOffsetY - 50
+              const currentImage = await loadImage(imageUrl)
+              const { wrapperX, wrapperY } = determineWrapperDimensions(
+                currentImage,
+                carouselPadding,
+              )
+              const { offsetX, offsetY } = calculateTranslationOffsets(
+                wrapperX,
+                wrapperY,
+                zoomOffsetX,
+                zoomOffsetY,
+                zoomValue,
+              )
 
-                // calculating the shift, considering that 'translateX/Y' is in percentages, but the yet-another-react-lightbox deals with pixels
-                const offsetX = (wrapperX / 100) * translateX * removeShift
-                const offsetY = (wrapperY / 100) * translateY * removeShift
-                zoomRef.current?.changeZoom(zoomValue, true, offsetX, offsetY)
-              }
+              zoomRef.current?.changeZoom(zoomValue, true, offsetX, offsetY)
             }
             setZoom(0, 0, 0)
             setIsOpeningWithZoom(false)