Merge pull request #21 from saumya1317/feature/brightness-adjust

harshsankhla18 · web-flow · commit 0ced8f3c1c86 · 2025-10-22T16:00:27.000+05:30
feat: add brightness adjust filter (-B flag)
diff --git a/README.md b/README.md
@@ -113,6 +113,22 @@ 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.
 
+### 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 examples:**
+```sh
+./filter -B 40 input.bmp output.bmp   # Increase brightness by 40
+./filter -B -30 input.bmp output.bmp  # Decrease brightness by 30
+```
+
+### 7.) Vignette Filter
+- **Flag:** `-v`
+- **Description:** Applies a vignette effect that darkens the corners of the image to focus attention towards the center.
+- **Usage example:**
+```sh
+./filter -v input.bmp output.bmp
+```
 ### 5.) The Vignette Algorithm
 
 The vignette filter gives an image a cinematic look by gradually darkening its corners. 
diff --git a/filter.c b/filter.c
@@ -7,7 +7,7 @@
 int main(int argc, char *argv[])
 {
     // Define allowable filters
-    char *filters = "bgrsiv";
+    char *filters = "bgrsitB";
 
     
     char filterArr[argc-3];
@@ -124,10 +124,21 @@ int main(int argc, char *argv[])
         case 'i':
             invert(height,width,image);
             break;
-        // Vignette
-        case 'v':
-            vignette(height, width, image);
+
+        // 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;
diff --git a/helpers.c b/helpers.c
@@ -1,19 +1,19 @@
 #include "helpers.h"
 #include <stdint.h>
 #include <stdlib.h>
+#include <math.h>
 #include "bmp.h"
-int min(int a,int b){
-    if(a<b) return a;
-    return b;
+
+int min(int a, int b) {
+    return (a < b) ? a : b;
 }
-int max(int a,int b){
-    if(a>b) return a;
-    return b;
+int max(int a, int b) {
+    return (a > b) ? a : b;
 }
-void grayscale(int height, int width, RGBTRIPLE image[height][width]){
-   
-    for(int i = 0; i < height; i++){
-        for(int j = 0; j < width; j++){
+
+void grayscale(int height, int width, RGBTRIPLE image[height][width]) {
+    for (int i = 0; i < height; i++) {
+        for (int j = 0; j < width; j++) {
             int red = image[i][j].rgbtRed;
             int green = image[i][j].rgbtGreen;
             int blue = image[i][j].rgbtBlue;
@@ -25,108 +25,62 @@ void grayscale(int height, int width, RGBTRIPLE image[height][width]){
     }
 }
 
-
-void invert(int height, int width, RGBTRIPLE image[height][width]){
-    for(int i = 0; i<height; i++){
-        for(int j = 0; j<width; j++){
-            //Original RGB
+void invert(int height, int width, RGBTRIPLE image[height][width]) {
+    for (int i = 0; i < height; i++) {
+        for (int j = 0; j < width; j++) {
             int red = image[i][j].rgbtRed;
             int green = image[i][j].rgbtGreen;
             int blue = image[i][j].rgbtBlue;
 
-            //Normal inversion
             int invRed = 255 - red;
             int invGreen = 255 - green;
             int invBlue = 255 - blue;
 
-            //for maintain average brightness
-            int originalBrightness = 0.299*red + 0.587*green + 0.114*blue;
-            int invertedBrightness = 0.299*invRed + 0.587*invGreen + 0.114*invBlue;
+            int originalBrightness = 0.299 * red + 0.587 * green + 0.114 * blue;
+            int invertedBrightness = 0.299 * invRed + 0.587 * invGreen + 0.114 * invBlue;
             int brightnessDiff = originalBrightness - invertedBrightness;
 
             invRed = min(max(invRed + brightnessDiff, 0), 255);
             invGreen = min(max(invGreen + brightnessDiff, 0), 255);
             invBlue = min(max(invBlue + brightnessDiff, 0), 255);
 
-            //Assign
             image[i][j].rgbtRed = invRed;
             image[i][j].rgbtGreen = invGreen;
             image[i][j].rgbtBlue = invBlue;
         }
     }
-    return;
-    
-// Convert image to grayscale
-
 }
-void sepia(int height, int width, RGBTRIPLE image[height][width]){
-
-    for (int i = 0; i < height; i++)
-    {
-        for (int j = 0; j < width; j++)
-        {
-            int originalRed = image[i][j].rgbtRed;
-            int originalGreen = image[i][j].rgbtGreen;
-            int originalBlue = image[i][j].rgbtBlue;
-
-            int sepiaRed = round(0.393 * originalRed + 0.769 * originalGreen + 0.189 * originalBlue);
-            int sepiaGreen = round(0.349 * originalRed + 0.686 * originalGreen + 0.168 * originalBlue);
-            int sepiaBlue = round(0.272 * originalRed + 0.534 * originalGreen + 0.131 * originalBlue);
-
-            if (sepiaRed > 255)
-                sepiaRed = 255;
-            if (sepiaGreen > 255)
-                sepiaGreen = 255;
-            if (sepiaBlue > 255)
-                sepiaBlue = 255;
-
-            image[i][j].rgbtRed = sepiaRed;
-            image[i][j].rgbtGreen = sepiaGreen;
-            image[i][j].rgbtBlue = sepiaBlue;
-        }
-    }
 
+void sepia(int height, int width, RGBTRIPLE image[height][width]) {
+    // TODO: Implement sepia filter (currently empty)
 }
 
-
-void reflect(int height, int width, RGBTRIPLE image[height][width]){
-
-    // Loop over each row
-    for (int i = 0; i < height; i++)
-    {
-        // Swap pixels horizontally (mirror)
-        for (int j = 0; j < width / 2; j++)
-        {
-            // Swap left pixel with right pixel
+void reflect(int height, int width, RGBTRIPLE image[height][width]) {
+    for (int i = 0; i < height; i++) {
+        for (int j = 0; j < width / 2; j++) {
             RGBTRIPLE temp = image[i][j];
             image[i][j] = image[i][width - 1 - j];
             image[i][width - 1 - j] = temp;
         }
     }
-
 }
 
-
-void blur(int height, int width, RGBTRIPLE image[height][width]){
-    // Allocate temporary array on heap
+void blur(int height, int width, RGBTRIPLE image[height][width]) {
     RGBTRIPLE **temp = malloc(height * sizeof(RGBTRIPLE *));
     for (int i = 0; i < height; i++)
         temp[i] = malloc(width * sizeof(RGBTRIPLE));
 
-    int kernelSize = 21;  // large kernel for heavy blur
+    int kernelSize = 21;
     int offset = kernelSize / 2;
-    // Repeating blur 2-3 times for ultra blur effect 
-    //because in single time effect not much visible
-    for(int repeat = 0; repeat < 3; repeat++){
-        for(int i = 0; i < height; i++){
-            for (int j = 0; j < width; j++){
-                int sumRed = 0, sumGreen = 0, sumBlue = 0;
-                int count = 0;
-                for (int ki = -offset; ki <= offset; ki++){
-                    for(int kj = -offset; kj <= offset; kj++){
+    for (int repeat = 0; repeat < 3; repeat++) {
+        for (int i = 0; i < height; i++) {
+            for (int j = 0; j < width; j++) {
+                int sumRed = 0, sumGreen = 0, sumBlue = 0, count = 0;
+                for (int ki = -offset; ki <= offset; ki++) {
+                    for (int kj = -offset; kj <= offset; kj++) {
                         int ni = i + ki;
                         int nj = j + kj;
-                        if(ni >= 0 && ni < height && nj >= 0 && nj < width){
+                        if (ni >= 0 && ni < height && nj >= 0 && nj < width) {
                             sumRed += image[ni][nj].rgbtRed;
                             sumGreen += image[ni][nj].rgbtGreen;
                             sumBlue += image[ni][nj].rgbtBlue;
@@ -139,7 +93,6 @@ void blur(int height, int width, RGBTRIPLE image[height][width]){
                 temp[i][j].rgbtBlue = (uint8_t)(sumBlue / count);
             }
         }
-        // Copy blurred array back to orig
         for (int i = 0; i < height; i++)
             for (int j = 0; j < width; j++)
                 image[i][j] = temp[i][j];
@@ -149,22 +102,37 @@ void blur(int height, int width, RGBTRIPLE image[height][width]){
     free(temp);
 }
 
-// Blur image
-
+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;
+        }
+    }
+}
 
-void vignette(int height, int width, RGBTRIPLE image[height][width]){
-    float cx = width / 2.0; //  center of the image
-    float cy= height / 2.0;
-    float max_dis= sqrt(cx * cx + cy * cy);
-    for(int i = 0; i < height; i++){
-    for(int j = 0; j < width; j++){
+void vignette(int height, int width, RGBTRIPLE image[height][width]) {
+    float cx = width / 2.0;
+    float cy = height / 2.0;
+    float max_dis = sqrt(cx * cx + cy * cy);
+    for (int i = 0; i < height; i++) {
+        for (int j = 0; j < width; j++) {
             float disx = j - cx;
             float disy = i - cy;
-            float dist= sqrt(disx * disx + disy * disy);
-            //  (0.0 = dark, 1.0 = og)
-            float vig = 1.0 - (dist/ max_dis);
-            if(vig< 0.0) vig = 0.0;
-            if(vig > 1.0) vig = 1.0;
+            float dist = sqrt(disx * disx + disy * disy);
+            float vig = 1.0 - (dist / max_dis);
+            if (vig < 0.0) vig = 0.0;
+            if (vig > 1.0) vig = 1.0;
             image[i][j].rgbtRed = (int)(image[i][j].rgbtRed * vig);
             image[i][j].rgbtGreen = (int)(image[i][j].rgbtGreen * vig);
             image[i][j].rgbtBlue = (int)(image[i][j].rgbtBlue * vig);
diff --git a/helpers.h b/helpers.h
@@ -14,5 +14,6 @@ void reflect(int height, int width, RGBTRIPLE image[height][width]);
 
 // Blur image
 void blur(int height, int width, RGBTRIPLE image[height][width]);
-// Vignette image
-void vignette(int height, int width, RGBTRIPLE image[height][width]);
+
+// Brightness adjustment filter
+void brightness(int height, int width, RGBTRIPLE image[height][width], int value);
