refactor + add colors

lab_2/src/main/kotlin/Form1.kt

@@ -11,13 +11,10 @@ class Form1 {
     private val bin = Bin
     val view = View()
 
-    private var minTF = -3000
-    private var widthTF = 2000
-
     private var frameCount = 0
     private var nextFPSUpdate = System.currentTimeMillis() + 1000
 
-    fun displayFPS() {
+    private fun displayFPS() {
         if (System.currentTimeMillis() >= nextFPSUpdate) {
             println("CT Visualizer (fps = $frameCount)")
             nextFPSUpdate = System.currentTimeMillis() + 1000
@@ -26,7 +23,7 @@ class Form1 {
         frameCount++
     }
 
-    fun openFileDialog() {
+    private fun openFileDialog() {
         val fileChooser = JFileChooser()
         fileChooser.fileFilter = FileNameExtensionFilter("BIN Files", "bin")
         val result = fileChooser.showOpenDialog(null)

lab_2/src/main/kotlin/Main.kt

@@ -7,18 +7,16 @@ import org.lwjgl.system.MemoryUtil.NULL
 import kotlin.system.exitProcess
 
 fun main() {
-    if (!glfwInit()) {
+    if (!glfwInit())
         throw IllegalStateException("Unable to initialize GLFW")
-    }
 
     glfwDefaultWindowHints()
     glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE)
     glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE)
 
     val window = glfwCreateWindow(800, 600, "CT Visualizer", NULL, NULL)
-    if (window == NULL) {
+    if (window == NULL)
         throw RuntimeException("Failed to create the GLFW window")
-    }
 
     glfwSetFramebufferSizeCallback(window) { _: Long, width: Int, height: Int ->
         glViewport(0, 0, width, height)

lab_2/src/main/kotlin/TransferHelper.kt

@@ -3,8 +3,8 @@ package org.exampl
 import java.awt.Color
 
 object TransferHelper {
-    private var min = -3000
+    private var min = -3100
-    private var max = 16000
+    private var max = 5000
 
     fun setTF(newMin: Int, newMax: Int) {
         min = newMin
@@ -12,7 +12,38 @@ object TransferHelper {
     }
 
     fun transferFunction(value: Short): Color {
-        val newVal = Math.max(0, Math.min((value - min) * 255 / (max - min), 255))
+        val k = value.toFloat().map(min.toFloat()..max.toFloat(), 0f..1f)
-        return Color(newVal, newVal, newVal)
+
+        /*
+          0 -> black  (0, 0, 0)
+        .25 -> blue   (0, 0, f)
+        .5  -> green  (0, f, 0)
+        .75 -> yellow (f, f, 0)
+          1 -> white  (f, f, f)
+         */
+
+        return when (k) {
+            in 0f..0.25f -> Color(0, 0, (k * 4 * 255).toInt())
+            in 0.25f..0.5f -> {
+                val g = k.map(0.25f..0.5f, 0f..255f).toInt()
+                Color(0, g, 255 - g)
+            }
+            in 0.5f..0.75f -> {
+                val r = k.map(0.5f..0.75f, 0f..255f).toInt()
+                Color(r, 255, 0)
+            }
+            in 0.75f..1f -> {
+                val b = k.map(0.75f..1f, 0f..255f).toInt()
+                Color(255, 255, b)
+            }
+            else -> throw IllegalArgumentException("$value not in range [$min..$max]")
+        }
+    }
+
+    fun Float.map(fromRange: ClosedRange<Float>, toRange: ClosedRange<Float>): Float {
+        if (fromRange.start == fromRange.endInclusive)
+            return (toRange.start + toRange.endInclusive) / 2
+        return (this - fromRange.start) * (toRange.endInclusive - toRange.start) /
+                (fromRange.endInclusive - fromRange.start) + toRange.start
     }
 }