September 2017 Update

Task/Bitmap-Bresenhams-line-algorithm/Kotlin/bitmap-bresenhams-line-algorithm.kotlin

@@ -0,0 +1,81 @@
+// version 1.1.2
+
+import java.awt.*
+import javax.swing.*
+
+class Bresenham(w: Int, h: Int) : JPanel() {
+    private val centerX = w / 2
+    private val centerY = h / 2
+
+    init {
+        preferredSize = Dimension(w, h)
+        background = Color.blue
+    }
+
+    override fun paintComponent(g: Graphics) {
+        super.paintComponent(g)
+        drawLine(g, 0, 0, 8, 19)   // NNE
+        drawLine(g, 0, 0, 19, 8)   // ENE
+        drawLine(g, 0, 0, 19, -8)  // ESE
+        drawLine(g, 0, 0, 8, -19)  // SSE
+        drawLine(g, 0, 0, -8, -19) // SSW
+        drawLine(g, 0, 0, -19, -8) // WSW
+        drawLine(g, 0, 0, -19, 8)  // WNW
+        drawLine(g, 0, 0, -8, 19)  // NNW
+    }
+
+    private fun plot(g: Graphics, x: Int, y: Int) {
+        g.color = Color.white
+        g.drawOval(centerX + x * 10, centerY -y * 10, 10, 10)
+    }
+
+    private fun drawLine(g: Graphics, x1: Int, y1: Int, x2: Int, y2: Int) {
+        var d = 0
+        val dy = Math.abs(y2 - y1)
+        val dx = Math.abs(x2 - x1)
+        val dy2 = dy shl 1
+        val dx2 = dx shl 1
+        val ix = if (x1 < x2)  1 else -1
+        val iy = if (y1 < y2)  1 else -1
+        var xx = x1
+        var yy = y1
+
+        if (dy <= dx) {
+            while (true) {
+                plot(g, xx, yy)
+                if (xx == x2) break
+                xx += ix
+                d  += dy2
+                if (d > dx) {
+                    yy += iy
+                    d  -= dx2
+                }
+            }
+        }
+        else {
+            while (true) {
+                plot(g, xx, yy)
+                if (yy == y2) break
+                yy += iy
+                d  += dx2
+                if (d > dy) {
+                    xx += ix
+                    d  -= dy2
+                }
+            }
+        }
+    }
+}
+
+fun main(args: Array<String>) {
+    SwingUtilities.invokeLater {
+        val f = JFrame()
+        f.defaultCloseOperation = JFrame.EXIT_ON_CLOSE
+        f.isVisible = true
+        f.add(Bresenham(600, 500), BorderLayout.CENTER)
+        f.title = "Bresenham"
+        f.isResizable = false
+        f.pack()
+        f.setLocationRelativeTo(null)
+    }
+}