feat: adding oil paint effect filter

filter.c

@@ -7,7 +7,7 @@
 int main(int argc, char *argv[])
 {
     // Define allowable filters
-    char *filters = "bgrsivtdGB:";
+    char *filters = "bgrsivtdGoB:";
 
 
     char filterArr[argc-3];
@@ -146,6 +146,10 @@ int main(int argc, char *argv[])
         case 'G': 
             glow(height, width, image);
             break;
+        case 'o':
+            oilpaint(height, width, image);
+            break;
+
         default:
             printf("Unknown filter: %c\n", filterArr[i]);
             free(image);

helpers.c

@@ -3,6 +3,11 @@
 #include <stdlib.h>
 #include <math.h>
 #include "bmp.h"
+#include <string.h>
+
+#define LEVELS 16
+#define RADIUS 8
+
 int min(int a,int b){
     if(a<b) return a;
     return b;
@@ -11,6 +16,7 @@ int max(int a,int b){
     if(a>b) return a;
     return b;
 }
+
 void grayscale(int height, int width, RGBTRIPLE image[height][width]){
 
     for(int i = 0; i < height; i++){
@@ -356,3 +362,64 @@ void glow(int height, int width, RGBTRIPLE image[height][width])
     free(original);
     free(blurred);
 }
+// Oil Paint filter
+void oilpaint(int height, int width, RGBTRIPLE image[height][width]){ 
+     RGBTRIPLE **copy = malloc(height * sizeof(RGBTRIPLE *));
+    for (int i = 0; i < height; i++){
+        copy[i] = malloc(width * sizeof(RGBTRIPLE));
+        for (int j = 0; j < width; j++){
+            copy[i][j] = image[i][j];
+        }
+    }
+    // logic
+    for (int i = 0; i < height; i++){
+        for (int j = 0; j < width; j++){
+            int intensityCount[LEVELS];
+            long sumRed[LEVELS], sumGreen[LEVELS], sumBlue[LEVELS];
+            memset(intensityCount, 0, sizeof(intensityCount));
+            memset(sumRed, 0, sizeof(sumRed));
+            memset(sumGreen, 0, sizeof(sumGreen));
+            memset(sumBlue, 0, sizeof(sumBlue));
+
+            // Analyze neighborhood
+            for (int di = -RADIUS; di <= RADIUS; di++){
+                for (int dj = -RADIUS; dj <= RADIUS; dj++){
+                    int ni = i + di;
+                    int nj = j + dj;
+                    if (ni < 0 || ni >= height || nj < 0 || nj >= width)
+                        continue;
+
+                    RGBTRIPLE pixel = copy[ni][nj];
+                    int intensity = ((pixel.rgbtRed + pixel.rgbtGreen + pixel.rgbtBlue) / 3) * LEVELS / 256;
+                    if (intensity >= LEVELS)
+                        intensity = LEVELS - 1;
+
+                    intensityCount[intensity]++;
+                    sumRed[intensity] += pixel.rgbtRed;
+                    sumGreen[intensity] += pixel.rgbtGreen;
+                    sumBlue[intensity] += pixel.rgbtBlue;
+                }
+            }
+
+            int dominant = 0, maxCount = 0;
+            for (int k = 0; k < LEVELS; k++){
+                if (intensityCount[k] > maxCount){
+                    maxCount = intensityCount[k];
+                    dominant = k;
+                }
+            }
+            if (maxCount > 0){
+                int newRed = sumRed[dominant] / maxCount;
+                int newGreen = sumGreen[dominant] / maxCount;
+                int newBlue = sumBlue[dominant] / maxCount;
+
+                image[i][j].rgbtRed = (newRed / 32) * 32;
+                image[i][j].rgbtGreen = (newGreen / 32) * 32;
+                image[i][j].rgbtBlue = (newBlue / 32) * 32;
+            }
+        }
+    }
+    for (int i = 0; i < height; i++)
+        free(copy[i]);
+    free(copy);
+}

helpers.h

@@ -35,4 +35,6 @@ void vignette(int height, int width, RGBTRIPLE image[height][width]);
 
 // Glow filter
 void glow(int height, int width, RGBTRIPLE image[height][width]);
+// Oil Paint filter
+void oilpaint(int height, int width, RGBTRIPLE image[height][width]);
 #endif