Data commit

Task/Mandelbrot-set/Swift/mandelbrot-set.swift

@@ -0,0 +1,88 @@
+import Foundation
+import Numerics
+import QDBMP
+
+public typealias Color = (red: UInt8, green: UInt8, blue: UInt8)
+
+public class BitmapDrawer {
+  public let imageHeight: Int
+  public let imageWidth: Int
+
+  var grid: [[Color?]]
+
+  private let bmp: OpaquePointer
+
+  public init(height: Int, width: Int) {
+    self.imageHeight = height
+    self.imageWidth = width
+    self.grid = [[Color?]](repeating: [Color?](repeating: nil, count: height), count: width)
+    self.bmp = BMP_Create(UInt(width), UInt(height), 24)
+
+    checkError()
+  }
+
+  deinit {
+    BMP_Free(bmp)
+  }
+
+  private func checkError() {
+    let err = BMP_GetError()
+
+    guard err == BMP_STATUS(0) else {
+      fatalError("\(err)")
+    }
+  }
+
+  public func save(to path: String = "~/Desktop/out.bmp") {
+    for x in 0..<imageWidth {
+      for y in 0..<imageHeight {
+        guard let color = grid[x][y] else { continue }
+
+        BMP_SetPixelRGB(bmp, UInt(x), UInt(y), color.red, color.green, color.blue)
+        checkError()
+      }
+    }
+
+    (path as NSString).expandingTildeInPath.withCString {s in
+      BMP_WriteFile(bmp, s)
+    }
+  }
+
+  public func setPixel(x: Int, y: Int, to color: Color?) {
+    grid[x][y] = color
+  }
+}
+
+let imageSize = 10_000
+let canvas = BitmapDrawer(height: imageSize, width: imageSize)
+let maxIterations = 256
+let cxMin = -2.0
+let cxMax = 1.0
+let cyMin = -1.5
+let cyMax = 1.5
+let scaleX = (cxMax - cxMin) / Double(imageSize)
+let scaleY = (cyMax - cyMin) / Double(imageSize)
+
+for x in 0..<imageSize {
+  for y in 0..<imageSize {
+    let cx = cxMin + Double(x) * scaleX
+    let cy = cyMin + Double(y) * scaleY
+
+    let c = Complex(cx, cy)
+    var z = Complex(0.0, 0.0)
+    var i = 0
+
+    for t in 0..<maxIterations {
+      if z.magnitude > 2 {
+        break
+      }
+
+      z = z * z + c
+      i = t
+    }
+
+    canvas.setPixel(x: x, y: y, to: Color(red: UInt8(i), green: UInt8(i), blue: UInt8(i)))
+  }
+}
+
+canvas.save()