added click to select instance

instance-labeler/app/canvas.tsx

@@ -149,6 +149,32 @@ export default function Canvas({ imageUrl, imageName }: { imageUrl: string, imag
     const pos = e.target.getStage()?.getPointerPosition();
     if (!pos) return;
 
+    const height = image?.height ? image.height : 1024;
+    const width = image?.width ? image.width : 1024;
+
+    console.log(groupRef.current.length);
+    for (let i = 0; i < groupRef.current.length && i < classList.length; i++) {
+      if (groupRef.current[i].children?.length === 0) continue;
+
+      const elt = groupRef.current[i].children![0];
+      const canvas = elt.toCanvas() as HTMLCanvasElement;
+      const imageData = canvas.getContext('2d')?.getImageData(0, 0, width, height);
+      if (!imageData) continue;
+      const r = imageData.data[(pos.x + pos.y * width) * 4];
+      const g = imageData.data[(pos.x + pos.y * width) * 4 + 1];
+      const b = imageData.data[(pos.x + pos.y * width) * 4 + 2];
+      if (r > 0 || g > 0 || b > 0) {
+        if (selectedInstanceRef.current !== i) {
+          selectedInstanceRef.current = i;
+          setSelectedInstanceStyle(true);
+        } else {
+          selectedInstanceRef.current = -1;
+          setSelectedInstanceStyle(false);
+        }
+        return;
+      }
+    }
+
     let labels = labelsRef.current;
     if (e.evt.button === 2) {
       labels = [...labels, 0];