From a9515d72d0ef5a80b9ff765bb14ba2b78928ccb0 Mon Sep 17 00:00:00 2001
From: deadprogram <ron@hybridgroup.com>
Date: Tue, 18 Mar 2025 18:27:12 +0100
Subject: [PATCH] photo: add Decolor() function

Signed-off-by: deadprogram <ron@hybridgroup.com>
---
 ROADMAP.md    |  2 +-
 photo.cpp     |  9 +++++++++
 photo.go      | 10 ++++++++++
 photo.h       |  1 +
 photo_test.go | 26 ++++++++++++++++++++++++++
 5 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/ROADMAP.md b/ROADMAP.md
index 84781a8..4efe58b 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -197,7 +197,7 @@ Your pull requests will be greatly appreciated!
     - [ ] [createTonemapDrago](https://docs.opencv.org/master/d6/df5/group__photo__hdr.html#ga72bf92bb6b8653ee4be650ac01cf50b6)
     - [ ] [createTonemapMantiuk](https://docs.opencv.org/master/d6/df5/group__photo__hdr.html#ga3b3f3bf083b7515802f039a6a70f2d21)
     - [ ] [createTonemapReinhard](https://docs.opencv.org/master/d6/df5/group__photo__hdr.html#gadabe7f6bf1fa96ad0fd644df9182c2fb)
-    - [ ] [decolor](https://docs.opencv.org/master/d4/d32/group__photo__decolor.html#ga4864d4c007bda5dacdc5e9d4ed7e222c)
+    - [X] [decolor](https://docs.opencv.org/master/d4/d32/group__photo__decolor.html#ga4864d4c007bda5dacdc5e9d4ed7e222c)
 
 - [ ] stitching. Images stitching
     - [ ] [Stitcher](https://docs.opencv.org/4.x/d2/d8d/classcv_1_1Stitcher.html)
diff --git a/photo.cpp b/photo.cpp
index c25d2a9..c438123 100644
--- a/photo.cpp
+++ b/photo.cpp
@@ -222,3 +222,12 @@ OpenCVResult PhotoInpaint(Mat src, Mat mask, Mat dst, float inpaint_radius, int
         return errorResult(e.code, e.what());
     }
 }
+
+OpenCVResult Decolor(Mat src, Mat grey, Mat boost) {
+    try {
+        cv::decolor(*src, *grey, *boost);
+        return successResult();
+    } catch(const cv::Exception& e) {
+        return errorResult(e.code, e.what());
+    }
+}
diff --git a/photo.go b/photo.go
index ac605bb..b7f9dad 100644
--- a/photo.go
+++ b/photo.go
@@ -317,3 +317,13 @@ const (
 func Inpaint(src Mat, mask Mat, dst *Mat, inpaintRadius float32, algorithmType InpaintMethods) error {
 	return OpenCVResult(C.PhotoInpaint(C.Mat(src.Ptr()), C.Mat(mask.Ptr()), C.Mat(dst.Ptr()), C.float(inpaintRadius), C.int(algorithmType)))
 }
+
+// Decolor Transforms a color image to a grayscale image.
+// It is a basic tool in digital printing, stylized black-and-white photograph rendering,
+// and in many single channel image processing applications
+//
+// For further details, please see:
+// https://docs.opencv.org/4.x/d4/d32/group__photo__decolor.html#ga4864d4c007bda5dacdc5e9d4ed7e222c
+func Decolor(src Mat, grey *Mat, boost *Mat) error {
+	return OpenCVResult(C.Decolor(src.p, grey.p, boost.p))
+}
diff --git a/photo.h b/photo.h
index d107929..f91b7cc 100644
--- a/photo.h
+++ b/photo.h
@@ -50,6 +50,7 @@ OpenCVResult PencilSketch(Mat src, Mat dst1, Mat dst2, float sigma_s, float sigm
 OpenCVResult Stylization(Mat src, Mat dst, float sigma_s, float sigma_r);
 
 OpenCVResult PhotoInpaint(Mat src, Mat mask, Mat dst, float inpaint_radius, int algorithm_type);
+OpenCVResult Decolor(Mat src, Mat grey, Mat boost);
 
 #ifdef __cplusplus
 }
diff --git a/photo_test.go b/photo_test.go
index 5cf558a..0e2e6cf 100644
--- a/photo_test.go
+++ b/photo_test.go
@@ -260,3 +260,29 @@ func TestInpaint(t *testing.T) {
 		t.Error("Invalid inpaint test")
 	}
 }
+
+func TestDecolor(t *testing.T) {
+	img := IMRead("images/face-detect.jpg", IMReadColor)
+	if img.Empty() {
+		t.Error("Invalid read of Mat in Decolor test")
+	}
+	defer img.Close()
+
+	grey := NewMat()
+	defer grey.Close()
+
+	boost := NewMat()
+	defer boost.Close()
+
+	if err := Decolor(img, &grey, &boost); err != nil {
+		t.Error("Error in Decolor test", err)
+	}
+
+	if grey.Empty() || img.Rows() != grey.Rows() || img.Cols() != grey.Cols() {
+		t.Error("Error in Decolor test")
+	}
+
+	if boost.Empty() || img.Rows() != boost.Rows() || img.Cols() != boost.Cols() {
+		t.Error("Error in Decolor test")
+	}
+}