diff --git a/src/java/clj_image2ascii/java/ImageToAscii.java b/src/java/clj_image2ascii/java/ImageToAscii.java
new file mode 100644
index 0000000..a9d0f20
--- /dev/null
+++ b/src/java/clj_image2ascii/java/ImageToAscii.java
@@ -0,0 +1,64 @@
+package clj_image2ascii.java;
+
+import java.awt.image.BufferedImage;
+
+// This method of converting an image to ascii representation is based on the method used in
+// Claskii (https://github.com/LauJensen/Claskii). Some improvements have been made, such as
+// a better way of calculating pixel brightness and little tweaks to how the right ASCII
+// character is selected, as well as obviously a conversion to Java purely for performance.
+
+public class ImageToAscii {
+ static final char[] asciiChars = {'#', 'A', '@', '%', '$', '+', '=', '*', ':', ',', '.', ' '};
+ static final int numAsciiChars = asciiChars.length - 1;
+ static final int spanLength = "X".length();
+ static final int lineTerminatorLength = "
".length();
+
+ public static String convert(BufferedImage image, boolean useColor) {
+ final int width = image.getWidth();
+ final int height = image.getHeight();
+
+ final int maxLength = (useColor ?
+ (width * height * spanLength) + (height * lineTerminatorLength) :
+ (width * height) + height);
+
+ final MicroStringBuilder sb = new MicroStringBuilder(maxLength);
+
+ final int[] pixels = image.getRGB(0, 0, width, height, null, 0, width);
+
+ for (int y = 0; y < height; ++y) {
+ for (int x = 0; x < width; ++x) {
+ final int argb = pixels[(y * width) + x];
+ final int r = (0x00ff0000 & argb) >> 16;
+ final int g = (0x0000ff00 & argb) >> 8;
+ final int b = (0x000000ff & argb);
+ final double brightness = Math.sqrt((r * r * 0.241f) +
+ (g * g * 0.691f) +
+ (b * b * 0.068f));
+ int charIndex;
+ if (brightness == 0.0f)
+ charIndex = numAsciiChars;
+ else
+ charIndex = (int)((brightness / 255.0f) * numAsciiChars);
+
+ final char pixelChar = asciiChars[charIndex > 0 ? charIndex : 0];
+
+ if (useColor) {
+ sb.append("");
+ sb.append(pixelChar);
+ sb.append("");
+ } else
+ sb.append(pixelChar);
+ }
+ if (useColor)
+ sb.append("
");
+ else
+ sb.append('\n');
+ }
+
+ return sb.toString();
+ }
+}
diff --git a/src/java/clj_image2ascii/java/MicroStringBuilder.java b/src/java/clj_image2ascii/java/MicroStringBuilder.java
new file mode 100644
index 0000000..9f106b6
--- /dev/null
+++ b/src/java/clj_image2ascii/java/MicroStringBuilder.java
@@ -0,0 +1,58 @@
+package clj_image2ascii.java;
+
+// I wanted a StringBuilder that had an append() method which allowed appending unsigned byte values
+// as a 2-char hex representation (e.g. 255 => "FF") in a way that did not allocate any extra memory
+// and could be done "in-place" with the StringBuilder's internal character array. This kind of evolved
+// into this class being added since I was only using 2 append() methods from java.lang.StringBuilder
+// anyway. Except for the appendAsHex(), this class does not perform noticeably faster then
+// java.lang.StringBuilder does.
+
+public class MicroStringBuilder {
+ // copied from java.lang.Integer.digits (which is private so we can't just reference it, boourns)
+ static final char[] digits = {
+ '0' , '1' , '2' , '3' , '4' , '5' ,
+ '6' , '7' , '8' , '9' , 'a' , 'b' ,
+ 'c' , 'd' , 'e' , 'f' , 'g' , 'h' ,
+ 'i' , 'j' , 'k' , 'l' , 'm' , 'n' ,
+ 'o' , 'p' , 'q' , 'r' , 's' , 't' ,
+ 'u' , 'v' , 'w' , 'x' , 'y' , 'z'
+ };
+
+ final char[] chars;
+ int length;
+
+ public MicroStringBuilder(int capacity) {
+ chars = new char[capacity];
+ length = 0;
+ }
+
+ public void append(final String s) {
+ final int srcLength = s.length();
+ s.getChars(0, srcLength, chars, length);
+ length += srcLength;
+ }
+
+ public void append(final char c) {
+ chars[length] = c;
+ ++length;
+ }
+
+ // modification of java.lang.Integer.toUnsignedString -- no garbage generated, but limited to max value
+ // of 255 ...hence the 'unsigned byte' thing :)
+ public void appendAsHex(int unsignedByte) {
+ for (int i = 0; i < 2; ++i) {
+ final int index = length + 1 - i;
+ if (unsignedByte != 0) {
+ chars[index] = digits[unsignedByte & 15];
+ unsignedByte >>>= 4;
+ } else
+ chars[index] = '0';
+ }
+ length += 2;
+ }
+
+ @Override
+ public String toString() {
+ return new String(chars, 0, length);
+ }
+}