From 4c3895e96cbb264b4be34b77dd85624e7cc552c3 Mon Sep 17 00:00:00 2001
From: Alexander Smorkalov <alexander.smorkalov@opencv.ai>
Date: Mon, 13 Jul 2026 10:45:42 +0300
Subject: [PATCH] Samples build warning fix on Ubuntu 26.04

---
 .../cpp/tutorial_code/ImgProc/BasicLinearTransforms.cpp   | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/samples/cpp/tutorial_code/ImgProc/BasicLinearTransforms.cpp b/samples/cpp/tutorial_code/ImgProc/BasicLinearTransforms.cpp
index dc7b849f42..d1db4954fc 100644
--- a/samples/cpp/tutorial_code/ImgProc/BasicLinearTransforms.cpp
+++ b/samples/cpp/tutorial_code/ImgProc/BasicLinearTransforms.cpp
@@ -30,6 +30,12 @@ int main( int argc, char** argv )
       cout << "Usage: " << argv[0] << " <Input image>" << endl;
       return -1;
     }
+    if (image.channels() != 3)
+    {
+        cout << "The tutorial expects 3 channel image as input!\n" << endl;
+        cout << "Usage: " << argv[0] << " <Input image>" << endl;
+        return -1;
+    }
     //! [basic-linear-transform-load]
 
     //! [basic-linear-transform-output]
@@ -54,7 +60,7 @@ int main( int argc, char** argv )
     //! [basic-linear-transform-operation]
     for( int y = 0; y < image.rows; y++ ) {
         for( int x = 0; x < image.cols; x++ ) {
-            for( int c = 0; c < image.channels(); c++ ) {
+            for( int c = 0; c < 3; c++ ) {
                 new_image.at<Vec3b>(y,x)[c] =
                   saturate_cast<uchar>( alpha*image.at<Vec3b>(y,x)[c] + beta );
             }