Add brightness adjust filter (-B flag), update documentation and filter logic

Author: saumya1317

README.md

@@ -123,6 +123,17 @@ If you apply the above algorithm to each pixel in the image, the result should l
 ./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.
+- **Usage example:**
+
+```sh
+./filter -B 40 input.bmp output.bmp # Increase brightness by 40
+./filter -B -30 input.bmp output.bmp # Decrease brightness by 30
+```
+
 You should not modify any of the function signatures, nor should you modify any other files other than helpers.c.
 
 Consider the following grid of pixels, where we’ve numbered each pixel.

filter.c

@@ -7,7 +7,7 @@
 int main(int argc, char *argv[])
 {
  // Define allowable filters
- char *filters = "bgrsit";
+ char *filters = "bgrsitB";
 
 
  char filterArr[argc-3];
@@ -130,6 +130,21 @@ int main(int argc, char *argv[])
  case 't':
  threshold(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;
+ }
+ brightness(height, width, image, brightness_value);
+ break;
+ }
  default:
  printf("%c", &filterArr[i]);
  break;

helpers.c

@@ -83,4 +83,23 @@ void threshold(int height, int width, RGBTRIPLE image[height][width]){
  }
  }
  }
+}
+
+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++) {
+ int r = image[i][j].rgbtRed + value;
+ int g = image[i][j].rgbtGreen + value;
+ int b = image[i][j].rgbtBlue + value;
+ if (r > 255) r = 255;
+ if (g > 255) g = 255;
+ if (b > 255) b = 255;
+ if (r < 0) r = 0;
+ if (g < 0) g = 0;
+ if (b < 0) b = 0;
+ image[i][j].rgbtRed = r;
+ image[i][j].rgbtGreen = g;
+ image[i][j].rgbtBlue = b;
+ }
+ }
 }

helpers.h

@@ -16,4 +16,7 @@ void reflect(int height, int width, RGBTRIPLE image[height][width]);
 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]);
+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);