feat: fix brightness filter implementation for proper GCC compatibility and argument parsing

Author: saumya1317

README.md

@@ -113,14 +113,6 @@ For a pixel along the edge or corner, like pixel 15, we would still look for all
 
 If you apply the above algorithm to each pixel in the image, the result should look like a blurry, out-of-focus version of the original.
 
-### 5.) Threshold Filter (Black & White)
-- **Flag:** `-t`
-- **Description:** Converts each pixel in the image to pure black or white based on its intensity. If the average of red, green, and blue is greater than or equal to 128, the pixel becomes white (255,255,255); otherwise, it becomes black (0,0,0).
-- **Usage example:**
-```sh
-./filter -t input.bmp output.bmp
-```
-
 ### 6.) Brightness Adjustment Filter
 - **Flag:** `-B <value>`
 - **Description:** Increases or decreases the brightness of the image by adding a fixed value to each pixel's R, G, and B channels. The value should be an integer—positive to increase, negative to decrease.

filter.c

@@ -7,20 +7,20 @@
 int main(int argc, char *argv[])
 {
     // Define allowable filters
-    char *filters = "bgrsitB";
+    char *filters = "bgrsivB:";
 
 
     char filterArr[argc-3];
+    int filterCount = 0;
 
     // gets all filter flags and checks validity
-    for(int i=0; i<argc; i++){
-        char temp = getopt(argc,argv,filters);
-        if(temp == -1) break;
-        filterArr[i]= temp;
-        if(filterArr[i] == '?') {
-            printf("Invalid filter option");
+    int opt;
+    while ((opt = getopt(argc, argv, filters)) != -1) {
+        if (opt == '?') {
+            printf("Invalid filter option\n");
             return 1;
         }
+        filterArr[filterCount++] = opt;
     }
 
 
@@ -98,7 +98,7 @@ int main(int argc, char *argv[])
     }
 
     // Filter image
-    for(int i=0; i<argc-3; i++){
+    for(int i=0; i<filterCount; i++){
     switch (filterArr[i])
     {
         // Blur
@@ -126,27 +126,19 @@ int main(int argc, char *argv[])
             invert(height,width,image);
             break;
 
-        // Threshold (black & white)
-        case 't':
-            threshold(height, width, image);
+        // Vignette
+        case 'v':
+            vignette(height, width, image);
             break;
 
         // Brightness Adjust
         case 'B': {
-            int brightness_value = 0;
-            // Get brightness value from argv, after -B flag (assume it appears as -B val)
-            if (optind < argc) {
-                brightness_value = atoi(argv[optind]);
-                optind++;
-            } else {
-                printf("Missing value for -B (brightness) flag.\n");
-                return 8;
-            }
+            int brightness_value = atoi(optarg);
             brightness(height, width, image, brightness_value);
             break;
         }
         default:
-            printf("%c", &filterArr[i]);
+            printf("Unknown filter: %c\n", filterArr[i]);
             break;
 
     }

helpers.c

@@ -102,23 +102,6 @@ void blur(int height, int width, RGBTRIPLE image[height][width]) {
     free(temp);
 }
 
-void threshold(int height, int width, RGBTRIPLE image[height][width]) {
-    for (int i = 0; i < height; i++) {
-        for (int j = 0; j < width; j++) {
-            int avg = (image[i][j].rgbtRed + image[i][j].rgbtGreen + image[i][j].rgbtBlue) / 3;
-            if (avg >= 128) {
-                image[i][j].rgbtRed = 255;
-                image[i][j].rgbtGreen = 255;
-                image[i][j].rgbtBlue = 255;
-            } else {
-                image[i][j].rgbtRed = 0;
-                image[i][j].rgbtGreen = 0;
-                image[i][j].rgbtBlue = 0;
-            }
-        }
-    }
-}
-
 void brightness(int height, int width, RGBTRIPLE image[height][width], int value) {
     for (int i = 0; i < height; i++) {
         for (int j = 0; j < width; j++) {

helpers.h

@@ -15,8 +15,8 @@ void reflect(int height, int width, RGBTRIPLE image[height][width]);
 // Blur image
 void blur(int height, int width, RGBTRIPLE image[height][width]);
 
-// Threshold filter (black and white)
-void threshold(int height, int width, RGBTRIPLE image[height][width]);
-
 // Brightness adjustment filter
-void brightness(int height, int width, RGBTRIPLE image[height][width], int value);
+void brightness(int height, int width, RGBTRIPLE image[height][width], int value);
+
+// Vignette filter
+void vignette(int height, int width, RGBTRIPLE image[height][width]);