From a7d2c74a8998252d79c76e0cbc61986b9ea91165 Mon Sep 17 00:00:00 2001
From: augustin64 <me.git@augustin64.fr>
Date: Thu, 3 Apr 2025 08:29:35 +0200
Subject: [PATCH] mask: use valid (>0) unsigned char

---
 src/seam-carving.cpp | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/seam-carving.cpp b/src/seam-carving.cpp
index e138076..d840206 100644
--- a/src/seam-carving.cpp
+++ b/src/seam-carving.cpp
@@ -28,7 +28,9 @@ bool nearly_equal(float a, float b) {
 
 std::pair<int, float> operator+(std::pair<int, float>& p1, std::pair<int, float>& p2) {
   return {
-    (p1.first==1) || (p2.first==1) ? 1 : std::max(p1.first, p2.first),
+    // If one of the two pixels is "protected" (ie 2), we want to prevent this line removing
+    // Else, we want to keep the information of "is there a pixel to remove in this seam" (ie 0)
+    (p1.first==2) || (p2.first==2) ? 2 : std::min(p1.first, p2.first),
     p1.second+p2.second
   };
 }
@@ -43,7 +45,7 @@ namespace limits {
         return std::numeric_limits<T>::max();
       }
       operator std::pair<int, float>() {
-        return {2, std::numeric_limits<float>::max()};
+        return {3, std::numeric_limits<float>::max()};
       }
   };  
 }
@@ -236,7 +238,7 @@ void recompute_energy_along_seam(
         compute_energy_for_pixel(
           carved_img, newWidth, newHeight,
           x, y, nbChannels,
-          nbColorChannels, output_energy[width*j+i]
+          nbColorChannels, output_energy[width*y+x]
         );
       }
     }
@@ -261,7 +263,7 @@ void recompute_energy_along_seam(
         compute_energy_for_pixel(
           carved_img, newWidth, newHeight,
           x, y, nbChannels,
-          nbColorChannels, output_energy[width*j+i].first
+          nbColorChannels, output_energy[width*y+x].first
         );
       }
     }
@@ -371,6 +373,14 @@ void seam_carving(unsigned char *source, int width, int height, int nbChannels,
       }
       if (nbChannels == 4)
         test_energy_output[nbChannels * k + 3] = source_img[nbChannels * k + 3];
+
+      if (mask) {
+        if (mask[k] == 2) // Green
+          test_energy_output[nbChannels*k + 1] = 125;
+        else if (mask[k] == 0) {// Red
+          test_energy_output[nbChannels * k] = 125;
+        }
+      }
     }
   }
 
@@ -482,17 +492,18 @@ int main(int argc, char **argv) {
       unsigned char r, g, b;
       for (auto i=0; i < width*height; i++) {
         r = mask[maskChannels*i];
-        g = mask[maskChannels*i];
-        b = mask[maskChannels*i];
-        bool positive = (g > r && g > b);
-        bool negative = (r > g && r > b);
-        mask[i] = positive ? 1 : (negative ? -1 : 0);
+        g = mask[maskChannels*i+1];
+        b = mask[maskChannels*i+2];
+        bool positive = (g > r && g > b && g > 100); // Mask images are not always the cleanest
+        bool negative = (r > g && r > b && r > 100);
+
+        mask[i] = positive ? 2 : (negative ? 0 : 1);
       }
       //* From now on, mask has the same dimensions as source and one single channel
       //* The values are:
-      //* . ( 1) we want to keep the pixel
-      //* . (-1) we want to remove the pixel
-      //* . ( 0) nothing in particular
+      //* . (2) we want to keep the pixel
+      //* . (1) nothing in particular
+      //* . (0) we want to remove the pixel
   }
 
   nbSeams = std::min(nbSeams, vertical ? width-1 : height-1); // We want to keep at least one row or column