feat: image preview enhancement (#682)

web/src/components/PreviewImageDialog.tsx

-import { useState } from "react";
+import React, { useState } from "react";
 import * as utils from "../helpers/utils";
 import Icon from "./Icon";
 import { generateDialog } from "./Dialog";
 import "../less/preview-image-dialog.less";
 
+const MIN_SCALE = 0.5;
+const MAX_SCALE = 5;
+const SCALE_UNIT = 0.25;
+
 interface Props extends DialogProps {
   imgUrls: string[];
   initialIndex: number;
 }
 
+interface State {
+  angle: number;
+  scale: number;
+  originX: number;
+  originY: number;
+}
+
 const PreviewImageDialog: React.FC<Props> = ({ destroy, imgUrls, initialIndex }: Props) => {
   const [currentIndex, setCurrentIndex] = useState(initialIndex);
+  const [state, setState] = useState<State>({
+    angle: 0,
+    scale: 1,
+    originX: -1,
+    originY: -1,
+  });
 
   const handleCloseBtnClick = () => {
     destroy();
@@ -39,6 +56,38 @@ const PreviewImageDialog: React.FC<Props> = ({ destroy, imgUrls, initialIndex }:
     }
   };
 
+  const handleImgRotate = (event: React.MouseEvent, angle: number) => {
+    const curImgAngle = (state.angle + angle + 360) % 360;
+    setState({
+      ...state,
+      originX: -1,
+      originY: -1,
+      angle: curImgAngle,
+    });
+  };
+
+  const handleImgContainerScroll = (event: React.WheelEvent) => {
+    const offsetX = event.nativeEvent.offsetX;
+    const offsetY = event.nativeEvent.offsetY;
+    const sign = event.deltaY < 0 ? 1 : -1;
+    const curAngle = Math.max(MIN_SCALE, Math.min(MAX_SCALE, state.scale + sign * SCALE_UNIT));
+    setState({
+      ...state,
+      originX: offsetX,
+      originY: offsetY,
+      scale: curAngle,
+    });
+  };
+
+  const getImageComputedStyle = () => {
+    return {
+      transform: `scale(${state.scale}) rotate(${state.angle}deg)`,
+      transformOrigin: `${state.originX === -1 ? "center" : `${state.originX}px`} ${
+        state.originY === -1 ? "center" : `${state.originY}px`
+      }`,
+    };
+  };
+
   return (
     <>
       <div className="btns-container">
@@ -48,9 +97,20 @@ const PreviewImageDialog: React.FC<Props> = ({ destroy, imgUrls, initialIndex }:
         <button className="btn" onClick={handleDownloadBtnClick}>
           <Icon.Download className="icon-img" />
         </button>
+        <button className="btn" onClick={(e) => handleImgRotate(e, -90)}>
+          <Icon.RotateCcw className="icon-img" />
+        </button>
+        <button className="btn" onClick={(e) => handleImgRotate(e, 90)}>
+          <Icon.RotateCw className="icon-img" />
+        </button>
       </div>
       <div className="img-container" onClick={handleImgContainerClick}>
-        <img onClick={(e) => e.stopPropagation()} src={imgUrls[currentIndex]} />
+        <img
+          onClick={(e) => e.stopPropagation()}
+          src={imgUrls[currentIndex]}
+          onWheel={handleImgContainerScroll}
+          style={getImageComputedStyle()}
+        />
       </div>
     </>
   );