June 2018 Update

Task/Color-quantization/Kotlin/color-quantization.kotlin

@@ -0,0 +1,41 @@
+// Version 1.2.41
+
+import java.io.BufferedReader
+import java.io.InputStreamReader
+
+fun main(args: Array<String>) {
+    // convert 'frog' to an image which uses only 16 colors, no dithering
+    val pb = ProcessBuilder(
+        "convert",
+        "Quantum_frog.png",
+        "-dither",
+        "None",
+        "-colors",
+        "16",
+        "Quantum_frog_16.png"
+    )
+    pb.directory(null)
+    val proc = pb.start()
+    proc.waitFor()
+
+    // now show the colors used
+    val pb2 = ProcessBuilder(
+       "convert",
+       "Quantum_frog_16.png",
+       "-format",
+       "%c",
+       "-depth",
+       "8",
+       "histogram:info:-"
+    )
+    pb2.directory(null)
+    pb.redirectOutput(ProcessBuilder.Redirect.PIPE)
+    val proc2 = pb2.start()
+    val br = BufferedReader(InputStreamReader(proc2.inputStream))
+    var clrNum = 0
+    while (true) {
+        val line = br.readLine() ?: break
+        System.out.printf("%2d->%s\n", clrNum++, line)
+    }
+    br.close()
+}

Task/Color-quantization/Sidef/color-quantization.sidef

@@ -0,0 +1,10 @@
+require('Image::Magick')
+
+func quantize_image(n = 16, input, output='output.png') {
+    var im = %O<Image::Magick>.new
+    im.Read(input)
+    im.Quantize(colors => n, dither => 1)    # 1 = None
+    im.Write(output)
+}
+
+quantize_image(input: 'Quantum_frog.png')