Fix brightness value being expected to have different range

Author: limzykenneth

src/data/examples/en/06_Image_Processing/01_ Histogram.js

@@ -1,9 +1,9 @@
 /*
  * @name Histogram
  * @description Calculates the histogram of an image. 
- * A histogram is the frequency distribution of the gray levels with the number of 
- * pure black values displayed on the left and number of pure white values on the right. 
- * Note that this sketch will behave differently on Android, since most images will 
+ * A histogram is the frequency distribution of the gray levels with the number of
+ * pure black values displayed on the left and number of pure white values on the right.
+ * Note that this sketch will behave differently on Android, since most images will
  * no longer be full 24-bit color.
  */
 
@@ -21,7 +21,7 @@ function setup() {
   image(img, 0, 0);
 
   // Initialize the histogram
-  for (let i = 0; i < 256; i++) {
+  for (let i = 0; i < 100; i++) {
     hist.push(0);
   }
 
@@ -40,8 +40,8 @@ function draw(){
   stroke(255);
   // Draw half of the histogram (skip every second value)
   for (let i = 0; i < img.width; i += 2) {
-    // Map i (from 0..img.width) to a location in the histogram (0..255)
-    let which = int(map(i, 0, img.width, 0, 255));
+    // Map i (from 0..img.width) to a location in the histogram (0..100)
+    let which = int(map(i, 0, img.width, 0, 100));
     // Convert the histogram value to a location between
     // the bottom and the top of the picture
     let y = int(map(hist[which], 0, histMax, img.height, 0));