Fixed off by one error in image generation and decoding

agg23 · Sep 21, 2023 · 122948e · 122948e
1 parent 9c904a6
commit 122948e
Show file tree

Hide file tree

Showing 4 changed files with 23 additions and 19 deletions.
diff --git a/.gitignore b/.gitignore
@@ -1 +1,3 @@
-node_modules/
+node_modules/
+*.png
+*.bin
diff --git a/package-lock.json b/package-lock.json
diff --git a/src/create.js b/src/create.js
@@ -26,7 +26,9 @@ const create = async () => {
       byte = 0;
     }
 
+    // Brightness byte
     image[i / 2] = byte;
+    // Reserved byte
     image[i / 2 + 1] = 0;
   }
 
@@ -39,7 +41,7 @@ const create = async () => {
     const prevColumn = i % width;
     const prevRow = Math.floor(i / width);
 
-    const row = width - prevColumn;
+    const row = width - 1 - prevColumn;
     const column = prevRow;
 
     rotatedImage[(row * height + column) * 2] = byte1;

diff --git a/src/extract.js b/src/extract.js
@@ -43,7 +43,7 @@ for (let i = 0; i < rgba.length / 4; i++) {
   const prevRow = Math.floor(i / width);
 
   const row = prevColumn;
-  const column = height - prevRow;
+  const column = height - 1 - prevRow;
 
   const outputPos = (row * height + column) * 4;
   rotatedImage[outputPos] = byte1;