Adding hex2rgb and rgb2hex function. Adding dvips colors (#14)

* Adding hex2rgb and rgb2hex function. 
* Adding dvips colors.
* Switching off oldest gcc in CI.

.travis.yml

@@ -7,14 +7,6 @@ env:
 matrix:
   fast_finish: true
   include:
-    - os: linux
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-          packages:
-            - g++-4.9
-      env: COMPILER=gcc GCC=4.9
     - os: linux
       addons:
         apt:

README.md

@@ -24,6 +24,14 @@ C++ and Python library specifying colormaps.
     <img src="./examples/overview/monocolor.png">
 </p>
 
+<p align="center"> 
+    <img src="./examples/overview/monocolor_dvips_1.png">
+</p>
+
+<p align="center"> 
+    <img src="./examples/overview/monocolor_dvips_2.png">
+</p>
+
 <p align="center"> 
     <img src="./examples/overview/Qualitative.png">
 </p>
@@ -49,9 +57,9 @@ C++ and Python library specifying colormaps.
     - [Example](#example)
 - [Available colormaps](#available-colormaps)
     - [ColorBrewer](#colorbrewer)
-    - [Matplotlib](#matplotlib)
-    - [Monochromatic colormaps](#monochromatic-colormaps)
-- [Available color-cycles](#available-color-cycles)
+    - [matplotlib](#matplotlib)
+    - [monocolor](#monocolor)
+- [Available colorcycles](#available-colorcycles)
     - [Xterm](#xterm)
     - [Eindhoven University of Technology](#eindhoven-university-of-technology)
 
@@ -122,7 +130,7 @@ int main()
 }
 ```
 
-Note that the colorcycles are not interpolatable. Consequently the functions do have a size option. Note also that the colormaps can also be called directly, e.g.
+Note that the colorcycles are not interpolatable. Consequently the functions do have a size option. Note also that the colormaps and colorcycles can also be called directly, e.g.
 
 ```cpp
 #include <cppcolormap.h>
@@ -237,11 +245,11 @@ N = 256
 
 # specify the colormap as string
 cols = cm.colormap("Reds", N)
-cols = cm.colorcycle("tue", N)
+cols = cm.colorcycle("tue")
 
 # or call the functions directly
 cols = cm.Reds(N)
-cols = cm.tue(N)
+cols = cm.tue()
 ```
 
 (see lists of [colormaps](#available-colormaps) and [color-cycles](#available-color-cycles) below).
@@ -269,7 +277,7 @@ x, y = np.meshgrid(
   np.linspace(0, 1, 100), 
   np.linspace(0, 1, 100))
 
-d = np.sqrt(x**2 + y**2)
+d = np.sqrt(x ** 2.0 + y ** 2.0)
 
 C = cm.Reds(256)
 C = np.c_[C, np.ones(C.shape[0])]
@@ -328,7 +336,7 @@ plt.show()
 >   
 >   [colorbrewer2.org](http://colorbrewer2.org)
 
-## Matplotlib
+## matplotlib
 
 | Name     | Inverse colormap |
 |----------|------------------|
@@ -345,35 +353,107 @@ plt.show()
 >   
 >   [GitHub](https://github.com/BIDS/colormap)
 
-## Monochromatic colormaps
-
-| Name     | Inverse colormap |
-|----------|------------------|
-| White    | -                |    
-| Grey     | -                |   
-| Black    | -                |    
-| Red      | -                |  
-| Blue     | -                |   
-
-# Available color-cycles
+## monocolor
+
+| Name           | Inverse colormap | Source |
+|----------------|------------------|--------|
+| White          | -                | -      |
+| Grey           | -                | -      |
+| Black          | -                | -      |
+| Red            | -                | -      |
+| Blue           | -                | -      |
+| tuedarkblue    | -                | 1      |
+| tueblue        | -                | 1      |
+| tuelightblue   | -                | 1      |
+| tuewarmred     | -                | 1      |
+| Apricot        | -                | 2      |  
+| Aquamarine     | -                | 2      |  
+| Bittersweet    | -                | 2      |  
+| Black          | -                | 2      |  
+| Blue           | -                | 2      |  
+| BlueGreen      | -                | 2      |  
+| BlueViolet     | -                | 2      |  
+| BrickRed       | -                | 2      |  
+| Brown          | -                | 2      |  
+| BurntOrange    | -                | 2      |  
+| CadetBlue      | -                | 2      |  
+| CarnationPink  | -                | 2      |  
+| Cerulean       | -                | 2      |  
+| CornflowerBlue | -                | 2      |  
+| Cyan           | -                | 2      |  
+| Dandelion      | -                | 2      |  
+| DarkOrchid     | -                | 2      |  
+| Emerald        | -                | 2      |  
+| ForestGreen    | -                | 2      |  
+| Fuchsia        | -                | 2      |  
+| Goldenrod      | -                | 2      |  
+| Gray           | -                | 2      |  
+| Green          | -                | 2      |  
+| GreenYellow    | -                | 2      |  
+| JungleGreen    | -                | 2      |  
+| Lavender       | -                | 2      |  
+| LimeGreen      | -                | 2      |  
+| Magenta        | -                | 2      |  
+| Mahogany       | -                | 2      |  
+| Maroon         | -                | 2      |  
+| Melon          | -                | 2      |  
+| MidnightBlue   | -                | 2      |  
+| Mulberry       | -                | 2      |  
+| NavyBlue       | -                | 2      |  
+| OliveGreen     | -                | 2      |  
+| Orange         | -                | 2      |  
+| OrangeRed      | -                | 2      |  
+| Orchid         | -                | 2      |  
+| Peach          | -                | 2      |  
+| Periwinkle     | -                | 2      |  
+| PineGreen      | -                | 2      |  
+| Plum           | -                | 2      |  
+| ProcessBlue    | -                | 2      |  
+| Purple         | -                | 2      |  
+| RawSienna      | -                | 2      |  
+| Red            | -                | 2      |  
+| RedOrange      | -                | 2      |  
+| RedViolet      | -                | 2      |  
+| Rhodamine      | -                | 2      |  
+| RoyalBlue      | -                | 2      |  
+| RoyalPurple    | -                | 2      |  
+| RubineRed      | -                | 2      |  
+| Salmon         | -                | 2      |  
+| SeaGreen       | -                | 2      |  
+| Sepia          | -                | 2      |  
+| SkyBlue        | -                | 2      |  
+| SpringGreen    | -                | 2      |  
+| Tan            | -                | 2      |  
+| TealBlue       | -                | 2      |  
+| Thistle        | -                | 2      |  
+| Turquoise      | -                | 2      |  
+| Violet         | -                | 2      |  
+| VioletRed      | -                | 2      |  
+| White          | -                | 2      |  
+| WildStrawberry | -                | 2      |  
+| Yellow         | -                | 2      |  
+| YellowGreen    | -                | 2      |  
+| YellowOrange   | -                | 2      |  
+
+1.  [Eindhoven University of Technology](http://www.tue.nl)
+2.  [LaTeX xcolor (dvipsnames)](https://en.wikibooks.org/wiki/LaTeX/Colors)
+
+# Available colorcycles
 
 ## Xterm
 
-| Name     | Inverse colormap |
-|----------|------------------|
-| xterm    | xterm_r          |
+| Name  | Inverse colormap |
+|-------|------------------|
+| xterm | xterm_r          |
 
 >   See [this site](https://jonasjacek.github.io/colors/)
 
 ## Eindhoven University of Technology
 
-| Name         | Inverse colormap |
-|--------------|------------------|
-| tue          | tue_r            |
-| tuedarkblue  | -                |           
-| tueblue      | -                |       
-| tuelightblue | -                |            
-| tuewarmred   | -                |          
+| Name | Inverse colormap |
+|------|------------------|
+| tue  | tue_r            |
+
 
 >   Based on the corporate color scheme of the 
 >   [Eindhoven University of Technology](http://www.tue.nl).

examples/overview/order_dvips.py

@@ -0,0 +1,79 @@
+import cppcolormap as cm
+import numpy as np
+
+names = (
+    "Apricot",
+    "Aquamarine",
+    "Bittersweet",
+    "Black",
+    "Blue",
+    "BlueGreen",
+    "BlueViolet",
+    "BrickRed",
+    "Brown",
+    "BurntOrange",
+    "CadetBlue",
+    "CarnationPink",
+    "Cerulean",
+    "CornflowerBlue",
+    "Cyan",
+    "Dandelion",
+    "DarkOrchid",
+    "Emerald",
+    "ForestGreen",
+    "Fuchsia",
+    "Goldenrod",
+    "Gray",
+    "Green",
+    "GreenYellow",
+    "JungleGreen",
+    "Lavender",
+    "LimeGreen",
+    "Magenta",
+    "Mahogany",
+    "Maroon",
+    "Melon",
+    "MidnightBlue",
+    "Mulberry",
+    "NavyBlue",
+    "OliveGreen",
+    "Orange",
+    "OrangeRed",
+    "Orchid",
+    "Peach",
+    "Periwinkle",
+    "PineGreen",
+    "Plum",
+    "ProcessBlue",
+    "Purple",
+    "RawSienna",
+    "Red",
+    "RedOrange",
+    "RedViolet",
+    "Rhodamine",
+    "RoyalBlue",
+    "RoyalPurple",
+    "RubineRed",
+    "Salmon",
+    "SeaGreen",
+    "Sepia",
+    "SkyBlue",
+    "SpringGreen",
+    "Tan",
+    "TealBlue",
+    "Thistle",
+    "Turquoise",
+    "Violet",
+    "VioletRed",
+    "WildStrawberry",
+    "Yellow",
+    "YellowGreen",
+    "YellowOrange")
+
+dvips = np.array([list(cm.colormap(name, 1)[0, :]) for name in names])
+jet = cm.jet(256)
+
+
+idx = cm.match(dvips, jet, cm.metric.perceptual)
+jdx = np.argsort(idx)
+print('\n'.join([names[i] for i in jdx]))

examples/overview/overview.py

@@ -52,14 +52,80 @@
         "jet"),
     'monocolor' : (
         "White",
+        "Gray",
         "Grey",
         "Black",
         "Red",
         "Blue",
+        "Green",
+        "Yellow",
+        "Purple",
+        "Cyan",
+        "Orange",
         "tuewarmred",
         "tuedarkblue",
         "tueblue",
-        "tuelightblue")}
+        "tuelightblue"),
+    'monocolor - dvips (1)' : (
+        "Plum",
+        "Fuchsia",
+        "BlueViolet",
+        "Violet",
+        "RoyalPurple",
+        "MidnightBlue",
+        "NavyBlue",
+        "RoyalBlue",
+        "CadetBlue",
+        "Periwinkle",
+        "PineGreen",
+        "Cerulean",
+        "JungleGreen",
+        "Emerald",
+        "TealBlue",
+        "CornflowerBlue",
+        "ProcessBlue",
+        "Aquamarine",
+        "BlueGreen",
+        "Turquoise",
+        "SkyBlue",
+        "SeaGreen",
+        "ForestGreen",
+        "OliveGreen",
+        "YellowGreen",
+        "LimeGreen",
+        "SpringGreen",
+        "GreenYellow"),
+    'monocolor - dvips (2)' : (
+        "Goldenrod",
+        "Dandelion",
+        "Apricot",
+        "YellowOrange",
+        "Lavender",
+        "Melon",
+        "Tan",
+        "Peach",
+        "BurntOrange",
+        "Salmon",
+        "Thistle",
+        "CarnationPink",
+        "Orchid",
+        "RedOrange",
+        "VioletRed",
+        "Rhodamine",
+        "DarkOrchid",
+        "Bittersweet",
+        "WildStrawberry",
+        "OrangeRed",
+        "Magenta",
+        "RubineRed",
+        "BrickRed",
+        "Maroon",
+        "Mulberry",
+        "Mahogany",
+        "RedViolet",
+        "RawSienna",
+        "Sepia",
+        "Brown")}
 
 nrows = max(len(cmap_list) for cmap_category, cmap_list in cmaps.items())
 gradient = np.linspace(0, 1, 256)
@@ -83,7 +149,7 @@ def plot_color_gradients(cmap_category, cmap_list, nrows):
     for ax in axes:
         ax.set_axis_off()
 
-    plt.savefig(cmap_category + '.png')
+    plt.savefig(cmap_category.replace(' ', '_').replace('(','').replace(')','').replace('_-_', '_') + '.png')
     plt.close()
 
 for cmap_category, cmap_list in cmaps.items():
@@ -116,7 +182,7 @@ def plot_color_gradients(cmap_category, cmap_list, nrows):
     for ax in axes:
         ax.set_axis_off()
 
-    plt.savefig(cmap_category + '.png')
+    plt.savefig(cmap_category.replace(' ', '_').replace('(','').replace(')','').replace('_-_', '_') + '.png')
     plt.close()
 
 plot_color_gradients('Colorcycles', cmaps, nrows)