From 00cec60c35b1c0a7579706851432bef3c553ff9b Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sat, 29 Jul 2023 21:05:33 +1000
Subject: [PATCH 1/2] Added CMYK to RGB unpacker

---
 Tests/test_lib_pack.py  |  4 ++++
 src/libImaging/Unpack.c | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/Tests/test_lib_pack.py b/Tests/test_lib_pack.py
index f7812f62bd8..963d35b067e 100644
--- a/Tests/test_lib_pack.py
+++ b/Tests/test_lib_pack.py
@@ -340,6 +340,10 @@ def test_RGB(self):
             self.assert_unpack("RGB", "G;16N", 2, (0, 1, 0), (0, 3, 0), (0, 5, 0))
             self.assert_unpack("RGB", "B;16N", 2, (0, 0, 1), (0, 0, 3), (0, 0, 5))
 
+        self.assert_unpack(
+            "RGB", "CMYK", 4, (250, 249, 248), (242, 241, 240), (234, 233, 233)
+        )
+
     def test_RGBA(self):
         self.assert_unpack("RGBA", "LA", 2, (1, 1, 1, 2), (3, 3, 3, 4), (5, 5, 5, 6))
         self.assert_unpack(
diff --git a/src/libImaging/Unpack.c b/src/libImaging/Unpack.c
index 206403ba6e0..6e86e723297 100644
--- a/src/libImaging/Unpack.c
+++ b/src/libImaging/Unpack.c
@@ -813,6 +813,20 @@ ImagingUnpackXBGR(UINT8 *_out, const UINT8 *in, int pixels) {
     }
 }
 
+static void
+cmyk2rgb(UINT8 *_out, const UINT8 *in, int pixels) {
+    int i, nk, tmp;
+    for (i = 0; i < pixels; i++) {
+        nk = 255 - in[3];
+        _out[0] = CLIP8(nk - MULDIV255(in[0], nk, tmp));
+        _out[1] = CLIP8(nk - MULDIV255(in[1], nk, tmp));
+        _out[2] = CLIP8(nk - MULDIV255(in[2], nk, tmp));
+        _out[3] = 255;
+        _out += 4;
+        in += 4;
+    }
+}
+
 /* Unpack to "RGBA" image */
 
 static void
@@ -1589,6 +1603,7 @@ static struct {
     {"RGB", "R;16B", 16, band016B},
     {"RGB", "G;16B", 16, band116B},
     {"RGB", "B;16B", 16, band216B},
+    {"RGB", "CMYK", 32, cmyk2rgb},
 
     /* true colour w. alpha */
     {"RGBA", "LA", 16, unpackRGBALA},

From b8c30655cc190d9e3fe7d36745b87c31be1708fb Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 6 Oct 2023 16:05:03 +1100
Subject: [PATCH 2/2] Include CMYK to RGB convert as unpacker

---
 src/libImaging/Convert.c |  2 +-
 src/libImaging/Convert.h |  2 ++
 src/libImaging/Unpack.c  | 15 +--------------
 3 files changed, 4 insertions(+), 15 deletions(-)
 create mode 100644 src/libImaging/Convert.h

diff --git a/src/libImaging/Convert.c b/src/libImaging/Convert.c
index 7677a81f72f..b08519d3045 100644
--- a/src/libImaging/Convert.c
+++ b/src/libImaging/Convert.c
@@ -564,7 +564,7 @@ rgb2cmyk(UINT8 *out, const UINT8 *in, int xsize) {
     }
 }
 
-static void
+void
 cmyk2rgb(UINT8 *out, const UINT8 *in, int xsize) {
     int x, nk, tmp;
     for (x = 0; x < xsize; x++) {
diff --git a/src/libImaging/Convert.h b/src/libImaging/Convert.h
new file mode 100644
index 00000000000..e688e301836
--- /dev/null
+++ b/src/libImaging/Convert.h
@@ -0,0 +1,2 @@
+extern void
+cmyk2rgb(UINT8 *out, const UINT8 *in, int xsize);
diff --git a/src/libImaging/Unpack.c b/src/libImaging/Unpack.c
index 6e86e723297..bef4bea6642 100644
--- a/src/libImaging/Unpack.c
+++ b/src/libImaging/Unpack.c
@@ -31,6 +31,7 @@
  */
 
 #include "Imaging.h"
+#include "Convert.h"
 
 #define R 0
 #define G 1
@@ -813,20 +814,6 @@ ImagingUnpackXBGR(UINT8 *_out, const UINT8 *in, int pixels) {
     }
 }
 
-static void
-cmyk2rgb(UINT8 *_out, const UINT8 *in, int pixels) {
-    int i, nk, tmp;
-    for (i = 0; i < pixels; i++) {
-        nk = 255 - in[3];
-        _out[0] = CLIP8(nk - MULDIV255(in[0], nk, tmp));
-        _out[1] = CLIP8(nk - MULDIV255(in[1], nk, tmp));
-        _out[2] = CLIP8(nk - MULDIV255(in[2], nk, tmp));
-        _out[3] = 255;
-        _out += 4;
-        in += 4;
-    }
-}
-
 /* Unpack to "RGBA" image */
 
 static void