Store source tex in Image data property

Resolves #193

src/lib/action.ts

@@ -3,6 +3,7 @@ import React from "react";
 import { PartialRecord } from "@mehra/ts";
 
 import AssertType from "../types/assert";
+import { FabricTeXImage } from "../types/fabric";
 
 import { Tool, Tools } from "./tools";
 import Pages from "./pages";
@@ -237,10 +238,10 @@ More details printed to console.`
       return "invalid latex";
     }
 
-    const img = await this.canvas.addImage(
+    const img: FabricTeXImage = await this.canvas.addImage(
       dataURL,
       {},
-      { scaleX: 3, scaleY: 3 }
+      { scaleX: 3, scaleY: 3, data: { texSource: text } }
     );
 
     this.history.add([img]);

src/lib/page.ts

@@ -71,7 +71,7 @@ export default class Page extends fabric.Canvas {
       // and https://github.com/cjquines/qboard/issues/176
       // for more details.
       // eslint-disable-next-line @typescript-eslint/no-explicit-any
-      (this as any)._toObject(obj, "toObject", ["strokeUniform"])
+      (this as any)._toObject(obj, "toObject", ["data", "strokeUniform"])
     );
   };
 

src/lib/pages.ts

@@ -42,6 +42,7 @@ export default class Pages {
   savePage = (): void => {
     this.pagesJSON[this.currentIndex] = this.canvas.toObject([
       "id",
+      "data",
       "strokeUniform",
     ]);
   };

src/types/fabric.ts

@@ -36,3 +36,13 @@ export function isFabricCollection(
 ): obj is fabric.Object & fabric.ICollection<unknown> {
   return "_objects" in obj;
 }
+
+export interface FabricTeXImage extends fabric.Image {
+  data: {
+    texSource: string;
+  };
+}
+
+export function isFabricTeXImage(image: fabric.Image): image is FabricTeXImage {
+  return typeof image?.data?.texSource === "string";
+}