From 122948ee461295b0cda29bc23addb6a6c80ed2f0 Mon Sep 17 00:00:00 2001
From: Adam Gastineau <adam@agg.im>
Date: Wed, 20 Sep 2023 19:11:12 -0700
Subject: [PATCH] Fixed off by one error in image generation and decoding

---
 .gitignore        |  4 +++-
 package-lock.json | 32 ++++++++++++++++----------------
 src/create.js     |  4 +++-
 src/extract.js    |  2 +-
 4 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/.gitignore b/.gitignore
index 40b878d..d284f09 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
-node_modules/
\ No newline at end of file
+node_modules/
+*.png
+*.bin
\ No newline at end of file
diff --git a/package-lock.json b/package-lock.json
index 5e8620e..fef7483 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -54,9 +54,9 @@
       "integrity": "sha512-08kcGqnYf/YmjoRhfxyu+CLxBjUtHLXLXX/vUfx9l2LYzG3c1m61nrpyFUZI6zeS+Li/wWMMidD9KgrqtGq3mA=="
     },
     "aws4": {
-      "version": "1.11.0",
-      "resolved": "https://registry.npmjs.org/aws4/-/aws4-1.11.0.tgz",
-      "integrity": "sha512-xh1Rl34h6Fi1DC2WWKfxUTVqRsNnr6LsKz2+hfwDxQJWmrx8+c7ylaqBMcHfl1U1r2dsifOvKX3LQuLNZ+XSvA=="
+      "version": "1.12.0",
+      "resolved": "https://registry.npmjs.org/aws4/-/aws4-1.12.0.tgz",
+      "integrity": "sha512-NmWvPnx0F1SfrQbYwOi7OeaNGokp9XhzNioJ/CSBs8Qa4vxug81mhJEAVZwxXuBmYB5KDRfMq/F3RR0BIU7sWg=="
     },
     "bcrypt-pbkdf": {
       "version": "1.0.2",
@@ -259,6 +259,13 @@
         "pngjs": "^3.3.3",
         "to-array-buffer": "^3.0.0",
         "utif": "^2.0.1"
+      },
+      "dependencies": {
+        "jpeg-js": {
+          "version": "0.3.7",
+          "resolved": "https://registry.npmjs.org/jpeg-js/-/jpeg-js-0.3.7.tgz",
+          "integrity": "sha512-9IXdWudL61npZjvLuVe/ktHiA41iE8qFyLB+4VDTblEsWBzeg8WQTlktdUK4CdncUqtUgUg0bbOmTE2bKBKaBQ=="
+        }
       }
     },
     "image-encode": {
@@ -278,13 +285,6 @@
         "pxls": "^2.3.1",
         "to-array-buffer": "^3.0.0",
         "utif": "^2.0.1"
-      },
-      "dependencies": {
-        "jpeg-js": {
-          "version": "0.4.4",
-          "resolved": "https://registry.npmjs.org/jpeg-js/-/jpeg-js-0.4.4.tgz",
-          "integrity": "sha512-WZzeDOEtTOBK4Mdsar0IqEU5sMr3vSV2RqkAIzUEV2BHnUfKGyswWFPFwK5EeDo93K3FohSHbLAjj0s1Wzd+dg=="
-        }
       }
     },
     "image-palette": {
@@ -402,9 +402,9 @@
       "integrity": "sha512-Yljz7ffyPbrLpLngrMtZ7NduUgVvi6wG9RJ9IUcyCd59YQ911PBJphODUcbOVbqYfxe1wuYf/LJ8PauMRwsM/g=="
     },
     "jpeg-js": {
-      "version": "0.3.7",
-      "resolved": "https://registry.npmjs.org/jpeg-js/-/jpeg-js-0.3.7.tgz",
-      "integrity": "sha512-9IXdWudL61npZjvLuVe/ktHiA41iE8qFyLB+4VDTblEsWBzeg8WQTlktdUK4CdncUqtUgUg0bbOmTE2bKBKaBQ=="
+      "version": "0.4.4",
+      "resolved": "https://registry.npmjs.org/jpeg-js/-/jpeg-js-0.4.4.tgz",
+      "integrity": "sha512-WZzeDOEtTOBK4Mdsar0IqEU5sMr3vSV2RqkAIzUEV2BHnUfKGyswWFPFwK5EeDo93K3FohSHbLAjj0s1Wzd+dg=="
     },
     "jsbn": {
       "version": "0.1.1",
@@ -514,9 +514,9 @@
       "integrity": "sha512-E/ZsdU4HLs/68gYzgGTkMicWTLPdAftJLfJFlLUAAKZGkStNU72sZjT66SnMDVOfOWY/YAoiD7Jxa9iHvngcag=="
     },
     "punycode": {
-      "version": "2.1.1",
-      "resolved": "https://registry.npmjs.org/punycode/-/punycode-2.1.1.tgz",
-      "integrity": "sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A=="
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/punycode/-/punycode-2.3.0.tgz",
+      "integrity": "sha512-rRV+zQD8tVFys26lAGR9WUuS4iUAngJScM+ZRSKtvl5tKeZ2t5bvdNFdNHBW9FWR4guGHlgmsZ1G7BSm2wTbuA=="
     },
     "pxls": {
       "version": "2.3.2",
diff --git a/src/create.js b/src/create.js
index a622bd7..dfe09db 100644
--- 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
index 3231da1..78511b4 100644
--- 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;