From 0a6c0b5950d3bbd638854a3cd3784e5633a99a68 Mon Sep 17 00:00:00 2001
From: Gabriel Gomes <gabrielsousagomes@hotmail.com>
Date: Sat, 29 Mar 2025 21:18:20 +0000
Subject: [PATCH] some minor improvements

---
 packages/excalidraw/data/image.ts | 17 +++++++++--------
 packages/excalidraw/global.d.ts   | 15 ++++++++-------
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/packages/excalidraw/data/image.ts b/packages/excalidraw/data/image.ts
index d1425b804..399ba87d3 100644
--- a/packages/excalidraw/data/image.ts
+++ b/packages/excalidraw/data/image.ts
@@ -17,7 +17,7 @@ export const getMetadataChunk = async (
 ): Promise<{ keyword: string; text: string } | null> => {
   const chunks = decodePng(new Uint8Array(await blobToArrayBuffer(blob)));
   
-  const iTXtChunk = chunks.find((chunk) => chunk.name === "iTXt");
+  const iTXtChunk = chunks.find((chunk) => chunk.name === PNGChunkType.iTXt);
   if (iTXtChunk) {
     try {
       const decoded = decodeITXt(iTXtChunk.data);
@@ -27,7 +27,7 @@ export const getMetadataChunk = async (
     }
   }
   
-  const tEXtChunk = chunks.find((chunk) => chunk.name === "tEXt");
+  const tEXtChunk = chunks.find((chunk) => chunk.name === PNGChunkType.tEXt);
   if (tEXtChunk) {
     return tEXt.decode(tEXtChunk.data);
   }
@@ -48,9 +48,9 @@ export const encodePngMetadata = async ({
   
   const filteredChunks = chunks.filter(
     (chunk) => 
-      !(chunk.name === "tEXt" && 
+      !(chunk.name === PNGChunkType.tEXt && 
         tEXt.decode(chunk.data).keyword === MIME_TYPES.excalidraw) &&
-      !(chunk.name === "iTXt" && 
+      !(chunk.name === PNGChunkType.iTXt && 
         decodeITXt(chunk.data).keyword === MIME_TYPES.excalidraw)
   );
   
@@ -68,7 +68,8 @@ export const encodePngMetadata = async ({
         MIME_TYPES.excalidraw,
         encodedData,
         { 
-          compressed: false, //Already compressed in encode
+          compressed: true,
+          compressedMethod: 0,
           language: "en",
           translated: ""
         }
@@ -101,13 +102,13 @@ export const decodePngMetadata = async (blob: Blob) => {
         ) {
           return metadata.text;
         }
-        throw new Error("FAILED");
+        throw new Error("Malformed or unexpected metadata format");
       }
       return decode(encodedData);
     } catch (error: any) {
       console.error(error);
-      throw new Error("FAILED");
+      throw new Error("Malformed or unexpected metadata format");
     }
   }
-  throw new Error("INVALID");
+  throw new Error("Invalid or unsupported PNG metadata format");
 };
diff --git a/packages/excalidraw/global.d.ts b/packages/excalidraw/global.d.ts
index f3c2e2f26..401039b13 100644
--- a/packages/excalidraw/global.d.ts
+++ b/packages/excalidraw/global.d.ts
@@ -32,23 +32,26 @@ interface Clipboard extends EventTarget {
 
 // PNG encoding/decoding
 // -----------------------------------------------------------------------------
+enum PNGChunkType {
+  tEXt = "tEXt",
+  iTXt = "iTXt",
+}
+
 type TEXtChunk = { name: "tEXt"; data: Uint8Array };
 type ITXtChunk = { name: "iTXt"; data: Uint8Array };
-
 declare module "png-chunk-text" {
   function encode(
     name: string,
     value: string,
-  ): { name: "tEXt"; data: Uint8Array };
+  ): { name: PNGChunkType.tEXt; data: Uint8Array };
   function decode(data: Uint8Array): { keyword: string; text: string };
 }
-
 declare module "png-chunk-itxt" {
   function encode(
     keyword: string,
     text: string,
-    options?: { compressed?: boolean; language?: string; translated?: string },
-  ): { name: "iTXt"; data: Uint8Array };
+    options?: { compressed?: boolean; compressedMethod: number; language?: string; translated?: string },
+  ): { name: PNGChunkType.iTXt; data: Uint8Array };
   function decode(data: Uint8Array): { 
     keyword: string; 
     text: string;
@@ -57,12 +60,10 @@ declare module "png-chunk-itxt" {
   };
   export { encode, decode };
 }
-
 declare module "png-chunks-encode" {
   function encode(chunks: (TEXtChunk | ITXtChunk)[]): Uint8Array;
   export = encode;
 }
-
 declare module "png-chunks-extract" {
   function extract(buffer: Uint8Array): (TEXtChunk | ITXtChunk)[];
   export = extract;