WIP

.gitignore

@@ -0,0 +1,2 @@
+mandelbrot
+

hsb.nim

@@ -0,0 +1,47 @@
+import math, colors
+
+proc hsbToRgb*(h:float64, s:float64, v:float64): Color =
+   var
+      H = h
+      R = 0'f64
+      G = 0'f64
+      B = 0'f64
+
+   while H < 0'f64:
+      H = H + 360'f64
+   while H >= 360'f64:
+      H = H - 360'f64
+
+   if v <= 0'f64:
+      R = 0'f64
+      G = 0'f64
+      B = 0'f64
+   elif s <= 0'f64:
+      R = v
+      G = v
+      B = v
+   else:
+      let
+         hf = H / 60'f64
+         i = int(floor(hf))
+         f = hf - float64(i)
+         pv = v * (1'f64 - s)
+         qv = v * (1'f64 - s * f)
+         tv = v * (1'f64 - (1'f64 - f))
+
+      case i:
+         of 0:
+            R = v; G = tv; B = pv
+         of 1: R = qv; G = v; B = pv
+         of 2: R = pv; G = v; B = tv
+         of 3: R = pv; G = qv; B = v
+         of 4: R = tv; G = pv; B = v
+         of 5: R = v; G = pv; B = qv
+         of 6: R = v; G = tv; B = pv
+         of -1: R = v; G = pv; B = qv
+         else:
+            R = v; G = v; B = v
+
+   result = rgb(clamp(int(R*255), 0, 255),
+                clamp(int(G*255), 0, 255),
+                clamp(int(B*255), 0, 255))

main.nim

@@ -0,0 +1,15 @@
+import mandelbrot, colors
+
+echo mandelbrot.generateImage(800, 600, 150'f64, 32, 570)[0][0]
+
+import stb_image/write as stbiw
+
+# Stuff some pixels
+var data: seq[uint8] = @[]
+data.add(0x00)
+data.add(0x80)
+data.add(0xFF)
+
+# save it (as monochrome)
+stbiw.writeBMP("three.bmp", 3, 1, stbiw.Y, data)
+

mandelbrot.nim

@@ -1,20 +1,27 @@
-import math, complex, colors
+import sequtils, math, complex, colors, hsb
 
 proc getComplexValueForPixel(x:int, y:int, height:int, width:int, zoom:float64): Complex[float64] =
-    complex.complex64((x.float64-width.float64/2.0'f64)/zoom, (y.float64-height.float64/2.0'f64)/zoom)
+    complex64((x.float64-width.float64/2.0'f64)/zoom, (y.float64-height.float64/2.0'f64)/zoom)
 
 proc colorMap(i:int, nMax:int): Color =
-    rgb(0, 0, 0)
+    let
+       h = if (float(i) / 100'f64) <= 1.0:
+              (float(i) / 100'f64) * 360'f64
+           else: 360'f64
+       s = 1'f64
+       v = if i < nMax: 1'f64 else: 0'f64
+
+    result = hsbToRgb(h, s, v)
 
 proc generatePixel(x:int, y:int, height:int, width:int, zoom:float64,
                    rMax: int, maxIter:int) : Color =
    let c = getComplexValueForPixel(x, y, height, width, zoom)
 
    var
-      n = 0
+      n = maxIter
       z = complex64(0'f64, 0'f64)
 
-   for i in 0..maxIter:
+   for i in 0..maxIter-1:
       if z.abs >= rMax.float64:
          n = i
          break
@@ -22,5 +29,10 @@ proc generatePixel(x:int, y:int, height:int, width:int, zoom:float64,
    
    result = colorMap(n, maxIter)
 
-proc generateImage(width:int, height:int, zoom:float64, rMax:int, maxIter:int) =
-   discard nil
+proc generateImage*(width:int, height:int, zoom:float64, rMax:int, maxIter:int): seq[seq[Color]] =
+
+   result = newSeqWith(height, newSeq[Color](width))
+
+   for y in 0..height-1:
+      for x in 0..width-1:
+         result[y][x] = generatePixel(x, y, height, width, zoom, rMax, maxIter)