diff --git a/QOI.fu b/QOI.fu
index 27b81f6..313d60c 100644
--- a/QOI.fu
+++ b/QOI.fu
@@ -121,9 +121,9 @@ public class QOIEncoder
 						encodedOffset += 5;
 					}
 					else {
-						int dr = r - (lastPixel >> 16 & 0xff);
-						int dg = g - (lastPixel >> 8 & 0xff);
-						int db = b - (lastPixel & 0xff);
+						int dr = (r - (lastPixel >> 16) & 0xff ^ 0x80) - 0x80;
+						int dg = (g - (lastPixel >> 8) & 0xff ^ 0x80) - 0x80;
+						int db = (b - lastPixel & 0xff ^ 0x80) - 0x80;
 						if (dr >= -2 && dr <= 1
 						 && dg >= -2 && dg <= 1
 						 && db >= -2 && db <= 1)
diff --git a/transpiled/QOI.c b/transpiled/QOI.c
index ac9fb5c..4235aef 100644
--- a/transpiled/QOI.c
+++ b/transpiled/QOI.c
@@ -163,9 +163,9 @@ bool QOIEncoder_Encode(QOIEncoder *self, int width, int height, int const *pixel
 					encodedOffset += 5;
 				}
 				else {
-					int dr = r - (lastPixel >> 16 & 255);
-					int dg = g - (lastPixel >> 8 & 255);
-					int db = b - (lastPixel & 255);
+					int dr = (((r - (lastPixel >> 16)) & 255) ^ 128) - 128;
+					int dg = (((g - (lastPixel >> 8)) & 255) ^ 128) - 128;
+					int db = (((b - lastPixel) & 255) ^ 128) - 128;
 					if (dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1)
 						encoded[encodedOffset++] = (uint8_t) (106 + (dr << 4) + (dg << 2) + db);
 					else {
diff --git a/transpiled/QOI.cpp b/transpiled/QOI.cpp
index e1d06a9..732b9e3 100644
--- a/transpiled/QOI.cpp
+++ b/transpiled/QOI.cpp
@@ -67,9 +67,9 @@ bool QOIEncoder::encode(int width, int height, int const * pixels, bool alpha, b
 					encodedOffset += 5;
 				}
 				else {
-					int dr = r - (lastPixel >> 16 & 255);
-					int dg = g - (lastPixel >> 8 & 255);
-					int db = b - (lastPixel & 255);
+					int dr = (((r - (lastPixel >> 16)) & 255) ^ 128) - 128;
+					int dg = (((g - (lastPixel >> 8)) & 255) ^ 128) - 128;
+					int db = (((b - lastPixel) & 255) ^ 128) - 128;
 					if (dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1)
 						encoded[encodedOffset++] = static_cast<uint8_t>(106 + (dr << 4) + (dg << 2) + db);
 					else {
diff --git a/transpiled/QOI.cs b/transpiled/QOI.cs
index a5cbbc9..bfae617 100644
--- a/transpiled/QOI.cs
+++ b/transpiled/QOI.cs
@@ -88,9 +88,9 @@ public bool Encode(int width, int height, int[] pixels, bool alpha, bool linearC
 						encodedOffset += 5;
 					}
 					else {
-						int dr = r - (lastPixel >> 16 & 255);
-						int dg = g - (lastPixel >> 8 & 255);
-						int db = b - (lastPixel & 255);
+						int dr = (((r - (lastPixel >> 16)) & 255) ^ 128) - 128;
+						int dg = (((g - (lastPixel >> 8)) & 255) ^ 128) - 128;
+						int db = (((b - lastPixel) & 255) ^ 128) - 128;
 						if (dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1)
 							encoded[encodedOffset++] = (byte) (106 + (dr << 4) + (dg << 2) + db);
 						else {
diff --git a/transpiled/QOI.d b/transpiled/QOI.d
index ad8f6a9..e6907f8 100644
--- a/transpiled/QOI.d
+++ b/transpiled/QOI.d
@@ -88,9 +88,9 @@ class QOIEncoder
 						encodedOffset += 5;
 					}
 					else {
-						int dr = r - (lastPixel >> 16 & 255);
-						int dg = g - (lastPixel >> 8 & 255);
-						int db = b - (lastPixel & 255);
+						int dr = (((r - (lastPixel >> 16)) & 255) ^ 128) - 128;
+						int dg = (((g - (lastPixel >> 8)) & 255) ^ 128) - 128;
+						int db = (((b - lastPixel) & 255) ^ 128) - 128;
 						if (dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1)
 							encoded[encodedOffset++] = cast(ubyte)(106 + (dr << 4) + (dg << 2) + db);
 						else {
diff --git a/transpiled/QOI.js b/transpiled/QOI.js
index 6d15f37..f1fc029 100644
--- a/transpiled/QOI.js
+++ b/transpiled/QOI.js
@@ -96,9 +96,9 @@ export class QOIEncoder
 						encodedOffset += 5;
 					}
 					else {
-						let dr = r - (lastPixel >> 16 & 255);
-						let dg = g - (lastPixel >> 8 & 255);
-						let db = b - (lastPixel & 255);
+						let dr = (((r - (lastPixel >> 16)) & 255) ^ 128) - 128;
+						let dg = (((g - (lastPixel >> 8)) & 255) ^ 128) - 128;
+						let db = (((b - lastPixel) & 255) ^ 128) - 128;
 						if (dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1)
 							encoded[encodedOffset++] = 106 + (dr << 4) + (dg << 2) + db;
 						else {
diff --git a/transpiled/QOI.py b/transpiled/QOI.py
index 4b522ff..7f7c2bc 100644
--- a/transpiled/QOI.py
+++ b/transpiled/QOI.py
@@ -94,9 +94,9 @@ def encode(self, width: int, height: int, pixels: array.array, alpha: bool, line
 						encoded[encoded_offset + 4] = pixel >> 24 & 255
 						encoded_offset += 5
 					else:
-						dr: int = r - (last_pixel >> 16 & 255)
-						dg: int = g - (last_pixel >> 8 & 255)
-						db: int = b - (last_pixel & 255)
+						dr: int = (((r - (last_pixel >> 16)) & 255) ^ 128) - 128
+						dg: int = (((g - (last_pixel >> 8)) & 255) ^ 128) - 128
+						db: int = (((b - last_pixel) & 255) ^ 128) - 128
 						if dr >= -2 and dr <= 1 and dg >= -2 and dg <= 1 and db >= -2 and db <= 1:
 							encoded[encoded_offset] = 106 + (dr << 4) + (dg << 2) + db
 							encoded_offset += 1
diff --git a/transpiled/QOI.swift b/transpiled/QOI.swift
index 2fef440..2aac0b1 100644
--- a/transpiled/QOI.swift
+++ b/transpiled/QOI.swift
@@ -99,9 +99,9 @@ public class QOIEncoder
 						encodedOffset += 5
 					}
 					else {
-						var dr : Int = r - lastPixel >> 16 & 255
-						let dg : Int = g - lastPixel >> 8 & 255
-						var db : Int = b - lastPixel & 255
+						var dr : Int = (r - lastPixel >> 16) & 255 ^ 128 - 128
+						let dg : Int = (g - lastPixel >> 8) & 255 ^ 128 - 128
+						var db : Int = (b - lastPixel) & 255 ^ 128 - 128
 						if dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1 {
 							encoded[encodedOffset] = UInt8(106 + dr << 4 + dg << 2 + db)
 							encodedOffset += 1
diff --git a/transpiled/QOI.ts b/transpiled/QOI.ts
index d624295..7d252b6 100644
--- a/transpiled/QOI.ts
+++ b/transpiled/QOI.ts
@@ -96,9 +96,9 @@ export class QOIEncoder
 						encodedOffset += 5;
 					}
 					else {
-						let dr: number = r - (lastPixel >> 16 & 255);
-						let dg: number = g - (lastPixel >> 8 & 255);
-						let db: number = b - (lastPixel & 255);
+						let dr: number = (((r - (lastPixel >> 16)) & 255) ^ 128) - 128;
+						let dg: number = (((g - (lastPixel >> 8)) & 255) ^ 128) - 128;
+						let db: number = (((b - lastPixel) & 255) ^ 128) - 128;
 						if (dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1)
 							encoded[encodedOffset++] = 106 + (dr << 4) + (dg << 2) + db;
 						else {
diff --git a/transpiled/QOIEncoder.java b/transpiled/QOIEncoder.java
index 9995230..597a621 100644
--- a/transpiled/QOIEncoder.java
+++ b/transpiled/QOIEncoder.java
@@ -97,9 +97,9 @@ public final boolean encode(int width, int height, int[] pixels, boolean alpha,
 						encodedOffset += 5;
 					}
 					else {
-						int dr = r - (lastPixel >> 16 & 255);
-						int dg = g - (lastPixel >> 8 & 255);
-						int db = b - (lastPixel & 255);
+						int dr = (((r - (lastPixel >> 16)) & 255) ^ 128) - 128;
+						int dg = (((g - (lastPixel >> 8)) & 255) ^ 128) - 128;
+						int db = (((b - lastPixel) & 255) ^ 128) - 128;
 						if (dr >= -2 && dr <= 1 && dg >= -2 && dg <= 1 && db >= -2 && db <= 1)
 							encoded[encodedOffset++] = (byte) (106 + (dr << 4) + (dg << 2) + db);
 						else {