Create initial version of shard.

.editorconfig

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+root = true
+
+[*.cr]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true

.gitignore

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+/docs/
+/lib/
+/bin/
+/.shards/
+*.dwarf
+
+# Libraries don't need dependency lock
+# Dependencies will be locked in application that uses them
+/shard.lock

.travis.yml

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+language: crystal

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2018 Danila Fedorin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# golden-color
+
+A simple shard to generate colors using the golden ratio method.
+
+## Installation
+
+Add this to your application's `shard.yml`:
+
+```yaml
+dependencies:
+  golden-color:
+    git: https://dev.danilafe.com/DanilaFe/golden-color
+```
+
+## Usage
+
+The first step to using golden-color is to create a color generator.
+The saturation and value parameters can be used to ajust the colors
+that are produced. Additionally, the seed parameter can be modified
+to change the starting hue. Colors can then be generated by repeated
+calls to "generate".
+
+```crystal
+require "golden-color"
+
+generator = GoldenColor::ColorGen.new saturation: 0.5, value: 0.95
+color = generator.generate
+```
+
+## Contributing
+
+1. Fork it
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Commit your changes (`git commit -am 'Add some feature'`)
+4. Push to the branch (`git push origin my-new-feature`)
+5. Create a new Pull Request
+
+## Contributors
+
+- [DanilaFe](https://dev.danilafe.com/DanilaFe) Danila Fedorin - creator, maintainer

shard.yml

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+name: golden-color
+version: 0.1.0
+
+authors:
+  - Danila Fedorin <danila.fedorin@gmail.com>
+
+crystal: 0.26.1
+
+license: MIT

spec/golden-color_spec.cr

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+require "./spec_helper"
+
+describe GoldenColor do
+    describe ".from_rgb" do
+        it "Correctly creates a color from red, green and blue" do
+            c = GoldenColor::Color.from_rgb 0.0, 0.5, 1.0
+            c.r.should eq 0.0
+            c.g.should eq 0.5
+            c.b.should eq 1.0
+        end
+
+        it "Correctly creates a color from hue, saturation and value" do
+            c = GoldenColor::Color.from_hsv 0.0, 0.5, 0.95
+            c.r.should eq 0.95
+            c.g.should eq 0.475
+            c.b.should eq 0.475
+        end
+
+        it "Correctly reports a tuple of red, green, and blue" do
+            c = GoldenColor::Color.from_rgb 0.0, 0.5, 1.0
+            r, g, b = c.rgb
+            r.should eq c.r
+            g.should eq c.g
+            b.should eq c.b
+        end
+    end
+end

spec/spec_helper.cr

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+require "spec"
+require "../src/golden-color"

src/golden-color.cr

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+module GoldenColor
+  VERSION = "0.1.0"
+
+  struct Color
+      getter r : Float64
+      getter g : Float64
+      getter b : Float64
+
+      def initialize(@r = 0, @g = 0, @b = 0)
+      end
+
+      def self.from_rgb(r, g, b)
+          self.new r, g, b
+      end
+
+      def self.from_hsv(h, s, v)
+          h *= 6.0
+          chroma = s * v
+          x = chroma * (1.0 - (h.modulo(2.0) - 1.0).abs)
+
+          r, g, b = if h >= 0.0 && h <= 1.0 
+                        {chroma, x, 0.0}
+                    elsif h >= 1.0 && h <= 2.0
+                        {x, chroma, 0.0}
+                    elsif h >= 2.0 && h <= 3.0
+                        {0.0, chroma, x}
+                    elsif h >= 3.0 && h <= 4.0
+                        {0.0, x, chroma}
+                    elsif h >= 4.0 && h <= 5.0
+                        {x, 0.0, chroma}
+                    else
+                        {chroma, 0.0, x}
+                    end
+          m = v - chroma
+
+          self.new(r + m, g + m, b + m)
+      end
+
+      def rgb
+          { r, g, b }
+      end
+  end
+
+  class ColorGen
+      getter seed : Float64
+
+      def initialize(@saturation = 0.5,
+                     @value = 0.95,
+                     @seed = Random.rand(1.0))
+      end
+
+      def generate
+          color = Color.from_hsv @seed, @saturation, @value
+          @seed = (@seed + 0.618033988749895).modulo(1.0)
+          color
+      end
+  end
+end