first Nim draft

huepaper.nim

@@ -0,0 +1,7 @@
+import huepaperlib
+
+let bc = getBaseColor()
+let cols = createColors(bc, hueMax = 0.5)
+let img = createBaseHuepaper(cols, 1920, 1080)
+
+img.saveHuepaper("test.png")

huepaperlib.nim

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+import chroma, pixie, random
+
+
+proc getBaseColor*(colorString: string = "", satMin: float = 0.2,
+    satMax: float = 1.0, lumMin: float = 0.2, lumMax: float = 0.9): ColorHSL =
+  ## Get base HSL color for a huepaper by `colorString`.
+
+  # If no color string is given, create a random color
+  if colorString == "":
+    randomize()
+    let
+      hue = 360 * rand(1.0)
+      sat = 100 * (satMin + rand(satMax - satMin))
+      lum = 100 * (lumMin + rand(lumMax - lumMin))
+    result = hsl(hue, sat, lum)
+
+  # Else try to parse string
+  else:
+    try:
+      result = colorString.parseHtmlColor.hsl
+    except InvalidColor:
+      result = ("#" & colorString).parseHtmlColor.hsl
+
+
+proc createColors*(baseColor: ColorHSL, hueMax: float = 0.1,
+    satMin: float = 0.2, satMax: float = 1.0, lumMin: float = 0.2,
+    lumMax: float = 0.9): array[4, ColorRGB] =
+  ## Create four RGB corner colors for a huepaper based on a HSL `baseColor`.
+  randomize()
+  
+  let
+    maxSatDiff = 0.1
+    maxLumDiff = 0.1
+
+  # Create four random colors similar to the given base_color
+  for i in 0 .. 3:
+    var
+      tmpHue = baseColor.h + 360 * (-hueMax / 2.0 + rand(hueMax))
+      tmpSat = baseColor.s + 100 * (-maxSatDiff + rand(2.0 * maxSatDiff))
+      tmpLum = baseColor.l + 100 * (-maxLumDiff + rand(2.0 * maxLumDiff))
+
+    # Correct hue
+    if tmpHue > 360.0:
+      tmpHue -= 360.0
+
+    # Clip saturation and luminance
+    tmpSat = min(100 * satMax, max(100 * satMin, tmpSat))
+    tmpLum = min(100 * lumMax, max(100 * lumMin, tmpLum))
+
+    result[i] = hsl(tmpHue, tmpSat, tmpLum).color.rgb
+
+
+func blend(c1, c2: ColorRGB, factor: float): ColorRGB =
+  ## Blends color `c1` to color `c2` with a `factor` from 0 to 1.
+  result.r = (uint8)((1.0 - factor) * (float)c1.r) + (uint8)(factor * (float)c2.r)
+  result.g = (uint8)((1.0 - factor) * (float)c1.g) + (uint8)(factor * (float)c2.g)
+  result.b = (uint8)((1.0 - factor) * (float)c1.b) + (uint8)(factor * (float)c2.b)
+
+
+func createBaseHuepaper*(colors: array[4, ColorRGB], width,
+    height: int): Image =
+  ## Creates a base huepaper with given `width` and `height`.
+  ## The `colors` are placed in clockwise order, beginning from top left.
+  result = newImage(width, height)
+
+  var
+    leftColor: ColorRGB
+    rightColor: ColorRGB
+
+  for y in 0 ..< height:
+    leftColor = colors[0].blend(colors[3], y / (height - 1))
+    rightColor = colors[1].blend(colors[2], y / (height - 1))
+    for x in 0 ..< width:
+      result[x, y] = leftColor.blend(rightColor, x / (width - 1))
+
+
+proc saveHuepaper*(huepaper: Image, filePath: string) =
+  ## Save `huepaper` at `filePath`.
+  huepaper.writeFile(filePath)