# NamedColorPatches

VTKExamples/Python/Visualization/NamedColorPatches

### Description

This example shows how to produce a HTML page called VTKNamedColorPatches showing the available colors in vtkNamedColors.

It also shows how to select the text color based on luminance. In this case, Digital CCIR601 is used, which gives less weight to the red and blue components of a color.

In the class HTMLTableMaker there are four methods for generating HTML pages:

- MakeCombinedColorPage() -- Makes an indexed page with all the colors and names in the class vtkNamedColors (the default).
- MakeWebColorPage() -- Makes a page of just the colors and names known to Web Browsers.
- MakeVTKColorPage() -- Makes a page of colors and names corresponding to to additional colors commonly used in VTK.
- MakeSynonymColorPage() -- Makes a page of color names and their synonyms.

Other Languages

See (Cxx)

### Code

NamedColorPatches.py

    #!/usr/bin/env python
    # -*- coding: utf-8 -*-

    """
    Produce a HTML page called VTKNamedColorPatches.html showing the available
     colors in vtkNamedColors.

    It also shows how to select the text color based on luminance.
    In this case Digital CCIR601 is used which gives less weight to the
     red and blue components of a color.

    """

    from __future__ import print_function

    import vtk

    def main():
        ncp = HTMLTableMaker()
        res = ncp.MakeCombinedColorPage()
        # res = ncp.MakeWebColorPage()
        # res = ncp.MakeVTKColorPage()
        # res = ncp.MakeSynonymColorPage()
        f = open("VTKNamedColorPatches.html", "w", newline="\n")
        f.write(res)
        f.close()

    class HTMLToFromRGBAColor:

        @staticmethod
        def RGBToHTMLColor(rgb):
            """
            Convert an [R, G, B] list to #RRGGBB.
            :param: rgb - The elements of the array rgb are unsigned chars (0..255).
            :return: The html color.
            """
            hexcolor = "#" + ''.join(['{:02x}'.format(x) for x in rgb])
            return hexcolor

        @staticmethod
        def HTMLColorToRGB(colorString):
            """
            Convert #RRGGBB to a [R, G, B] list.
            :param: colorString a string in the form: #RRGGBB where RR, GG, BB are hexadecimal.
            The elements of the array rgb are unsigned chars (0..255).
            :return: The red, green and blue components as a list.
            """
            colorString = colorString.strip()
            if colorString[0] == '#':
                colorString = colorString[1:]
            if len(colorString) != 6:
                raise ValueError("Input #%s is not in #RRGGBB format" % colorString)
            r, g, b = colorString[:2], colorString[2:4], colorString[4:]
            r, g, b = [int(n, 16) for n in (r, g, b)]
            return [r, g, b]

        @staticmethod
        def RGBToLumaCCIR601(rgb):
            """
            RGB -> Luma conversion
            Digital CCIR601 (gives less weight to the R and B components)
            :param: rgb - The elements of the array rgb are unsigned chars (0..255).
            :return: The luminance.
            """
            Y = 0.299 * rgb[0] + 0.587 * rgb[1] + 0.114 * rgb[2]
            return Y

        @staticmethod
        def FormatRGBForHTML(rgb):
            """
            Format the rgb colors for display on a html table.
            :param: rgb - The elements of the array rgb are unsigned chars (0..255).
            :return: A formatted string for the html table.
            """
            s = ','.join(['{:3d}'.format(x) for x in rgb])
            s = s.replace(' ', '&#160;')
            s = s.replace(',', '&#160;&#160;')
            return s

    class ColorStructures:
        """
        Holds the color names, grouped by color class, and information about table
        layout and ordering.
        """

        def __init__(self):
            self.cn = {
                'Red': ['IndianRed', 'LightCoral', 'Salmon', 'DarkSalmon',
                        'LightSalmon', 'Red', 'Crimson', 'FireBrick', 'DarkRed'],
                'Pink': ['Pink', 'LightPink', 'HotPink', 'DeepPink',
                         'MediumVioletRed', 'PaleVioletRed'],
                'Orange': ['LightSalmon', 'Coral', 'Tomato', 'OrangeRed',
                           'DarkOrange', 'Orange'],
                'Yellow': ['Gold', 'Yellow', 'LightYellow', 'LemonChiffon',
                           'LightGoldenrodYellow', 'PapayaWhip', 'Moccasin',
                           'PeachPuff', 'PaleGoldenrod', 'Khaki', 'DarkKhaki'],
                'Purple': ['Lavender', 'Thistle', 'Plum', 'Violet', 'Orchid',
                           'Fuchsia', 'Magenta', 'MediumOrchid', 'MediumPurple',
                           'BlueViolet', 'DarkViolet', 'DarkOrchid', 'DarkMagenta',
                           'Purple', 'Indigo', 'DarkSlateBlue', 'SlateBlue',
                           'MediumSlateBlue'],
                'Green': ['GreenYellow', 'Chartreuse', 'LawnGreen', 'Lime',
                          'LimeGreen', 'PaleGreen', 'LightGreen',
                          'MediumSpringGreen', 'SpringGreen', 'MediumSeaGreen',
                          'SeaGreen', 'ForestGreen', 'Green', 'DarkGreen',
                          'YellowGreen', 'OliveDrab', 'Olive', 'DarkOliveGreen',
                          'MediumAquamarine', 'DarkSeaGreen', 'LightSeaGreen',
                          'DarkCyan', 'Teal'],
                'Blue/Cyan': ['Aqua', 'Cyan', 'LightCyan', 'PaleTurquoise',
                              'Aquamarine', 'Turquoise', 'MediumTurquoise',
                              'DarkTurquoise', 'CadetBlue', 'SteelBlue',
                              'LightSteelBlue', 'PowderBlue', 'LightBlue',
                              'SkyBlue', 'LightSkyBlue', 'DeepSkyBlue',
                              'DodgerBlue', 'CornflowerBlue', 'RoyalBlue', 'Blue',
                              'MediumBlue', 'DarkBlue', 'Navy', 'MidnightBlue'],
                'Brown': ['Cornsilk', 'BlanchedAlmond', 'Bisque', 'NavajoWhite',
                          'Wheat', 'BurlyWood', 'Tan', 'RosyBrown', 'SandyBrown',
                          'Goldenrod', 'DarkGoldenrod', 'Peru', 'Chocolate',
                          'SaddleBrown', 'Sienna', 'Brown', 'Maroon'],
                'White': ['White', 'Snow', 'Honeydew', 'MintCream', 'Azure',
                          'AliceBlue', 'GhostWhite', 'WhiteSmoke', 'Seashell',
                          'Beige', 'OldLace', 'FloralWhite', 'Ivory',
                          'AntiqueWhite', 'Linen',
                          'LavenderBlush', 'MistyRose'],
                'Gray': ['Gainsboro', 'LightGrey', 'Silver', 'DarkGray', 'Gray',
                         'DimGray', 'LightSlateGray', 'SlateGray', 'DarkSlateGray',
                         'Black']
            }
            # Ordering of the tables and when to start and end a column of tables
            # in the layout.
            self.cnOrder = ['Red', 'Pink', 'Orange', 'Yellow', 'Purple', 'Green',
                            'Blue/Cyan', 'Brown', 'White', 'Gray']
            self.cnStartTable = ['Red', 'Green', 'Brown']
            self.cnEndTable = ['Purple', 'Blue/Cyan', 'Gray']

            self.vtkcn = {
                'Whites': ['antique_white', 'azure', 'bisque', 'blanched_almond',
                           'cornsilk', 'eggshell', 'floral_white', 'gainsboro',
                           'ghost_white', 'honeydew', 'ivory', 'lavender',
                           'lavender_blush', 'lemon_chiffon', 'linen', 'mint_cream',
                           'misty_rose', 'moccasin', 'navajo_white', 'old_lace',
                           'papaya_whip', 'peach_puff', 'seashell', 'snow',
                           'thistle', 'titanium_white', 'wheat', 'white',
                           'white_smoke', 'zinc_white'],
                'Greys': ['cold_grey', 'dim_grey', 'grey', 'light_grey',
                          'slate_grey', 'slate_grey_dark', 'slate_grey_light',
                          'warm_grey'],
                'Blacks': ['black', 'ivory_black', 'lamp_black'],
                'Reds': ['alizarin_crimson', 'brick', 'cadmium_red_deep', 'coral',
                         'coral_light', 'deep_pink', 'english_red', 'firebrick',
                         'geranium_lake', 'hot_pink', 'indian_red', 'light_salmon',
                         'madder_lake_deep', 'maroon', 'pink', 'pink_light',
                         'raspberry', 'red', 'rose_madder', 'salmon', 'tomato',
                         'venetian_red'],
                'Browns': ['beige', 'brown', 'brown_madder', 'brown_ochre',
                           'burlywood', 'burnt_sienna', 'burnt_umber', 'chocolate',
                           'deep_ochre', 'flesh', 'flesh_ochre', 'gold_ochre',
                           'greenish_umber', 'khaki', 'khaki_dark', 'light_beige',
                           'peru', 'rosy_brown', 'raw_sienna', 'raw_umber', 'sepia',
                           'sienna', 'saddle_brown', 'sandy_brown', 'tan',
                           'van_dyke_brown'],
                'Oranges': ['cadmium_orange', 'cadmium_red_light', 'carrot',
                            'dark_orange', 'mars_orange', 'mars_yellow', 'orange',
                            'orange_red', 'yellow_ochre'],
                'Yellows': ['aureoline_yellow', 'banana', 'cadmium_lemon',
                            'cadmium_yellow', 'cadmium_yellow_light', 'gold',
                            'goldenrod', 'goldenrod_dark', 'goldenrod_light',
                            'goldenrod_pale', 'light_goldenrod', 'melon',
                            'naples_yellow_deep', 'yellow', 'yellow_light'],
                'Greens': ['chartreuse', 'chrome_oxide_green', 'cinnabar_green',
                           'cobalt_green', 'emerald_green', 'forest_green', 'green',
                           'green_dark', 'green_pale', 'green_yellow', 'lawn_green',
                           'lime_green', 'mint', 'olive', 'olive_drab',
                           'olive_green_dark', 'permanent_green', 'sap_green',
                           'sea_green', 'sea_green_dark', 'sea_green_medium',
                           'sea_green_light', 'spring_green', 'spring_green_medium',
                           'terre_verte', 'viridian_light', 'yellow_green'],
                'Cyans': ['aquamarine', 'aquamarine_medium', 'cyan', 'cyan_white',
                          'turquoise', 'turquoise_dark', 'turquoise_medium',
                          'turquoise_pale'],
                'Blues': ['alice_blue', 'blue', 'blue_light', 'blue_medium',
                          'cadet', 'cobalt', 'cornflower', 'cerulean', 'dodger_blue',
                          'indigo', 'manganese_blue', 'midnight_blue', 'navy',
                          'peacock', 'powder_blue', 'royal_blue', 'slate_blue',
                          'slate_blue_dark', 'slate_blue_light',
                          'slate_blue_medium', 'sky_blue', 'sky_blue_deep',
                          'sky_blue_light', 'steel_blue', 'steel_blue_light',
                          'turquoise_blue', 'ultramarine'],
                'Magentas': ['blue_violet', 'cobalt_violet_deep', 'magenta',
                             'orchid', 'orchid_dark', 'orchid_medium',
                             'permanent_red_violet', 'plum', 'purple',
                             'purple_medium', 'ultramarine_violet', 'violet',
                             'violet_dark', 'violet_red', 'violet_red_medium',
                             'violet_red_pale']
            }
            # Ordering of the tables and when to start and end a column of tables
            # in the layout.
            self.vtkcnOrder = ['Whites', 'Greys', 'Blacks', 'Reds', 'Oranges', 'Browns', 'Yellows', 'Greens', 'Cyans',
                               'Blues',
                               'Magentas']
            self.vtkcnStartTable = ['Whites', 'Browns', 'Cyans']
            self.vtkcnEndTable = ['Oranges', 'Greens', 'Magentas']

    class HTMLTableMaker:
        """
          This class creates HTML Tables displaying all the colors in
          the class vtkNamedColors grouped by various categories.
        """

        def __init__(self):
            self.cs = ColorStructures()
            self.nc = vtk.vtkNamedColors()
            self.htmlRGBA = HTMLToFromRGBAColor()

        @staticmethod
        def MakeHTMLStyle():
            s = '  <style>\n'
            s += '  \n'
            s += '  body {\n'
            s += '    background-color: snow\n'
            s += '  }\n'
            s += '  h1 {text-align:left;}\n'
            s += '  h2 {text-align:left;}\n'
            s += '  h3 {text-align:left;}\n'
            s += '  h4 {text-align:left;}\n'
            s += '  h5 {text-align:left;}\n'
            s += '  h6 {text-align:left;}\n'
            s += '  \n'
            s += '  p {text-align:left;}\n'
            s += '  \n'
            s += '  table {\n'
            s += '    font-family: arial, sans-serif;\n'
            s += '    border-collapse: collapse;\n'
            s += '    font-size: medium;\n'
            s += '    padding: 4px;\n'
            s += '  }\n'
            s += '\n'
            s += '  th[colspan]:not([colspan="1"]) {\n'
            s += '    background: LightSteelBlue;\n'
            s += '    font-size: x-large;\n'
            s += '    text-align : center;'
            s += '    vertical-align : top;\n'
            s += '  }\n'
            s += '  th {\n'
            s += '    background: LightSteelBlue;\n'
            s += '  }\n'
            s += '  td, th {\n'
            s += '    border: 1px solid #dddddd;\n'
            s += '    text-align: left;\n'
            s += '    padding: 8px;\n'
            s += '    font-family: monospace;\n'
            s += '    font-size: medium;\n'
            s += '    font-weight: bold;\n'
            s += '  }\n'
            s += '\n'
            s += '  tr {\n'
            s += '    background: WhiteSmoke;\n'
            s += '    vertical-align : top;\n'
            s += '  }\n'
            s += '\n'
            s += '  td[colspan]:not([colspan="1"]) {\n'
            s += '    background: MintCream;\n'
            s += '    font-size: large;\n'
            s += '    text-align : center;'
            s += '    vertical-align : top;\n'
            s += '  }\n'
            s += '  td {\n'
            s += '    background: WhiteSmoke;\n'
            s += '  }\n'
            s += '\n'
            s += '  .cour {\n'
            s += '    font-family: Courier;\n'
            s += '  }\n'
            s += '\n'
            s += '  html, body {\n'
            s += '    height: 100%;\n'
            s += '  }\n'
            s += '\n'
            s += '  html {\n'
            s += '    display: table;\n'
            s += '    margin: auto;\n'
            s += '  }\n'
            s += '\n'
            s += '  body {\n'
            s += '    display: table-cell;\n'
            s += '    vertical-align: middle;\n'
            s += '  }\n'
            s += '\n'
            s += '  thead {color: DarkGreen;}\n'
            s += '  tbody {color: MidnightBlue;}\n'
            s += '  tfoot {color: SaddleBrown;}\n'
            s += '\n'
            s += '  </style>\n'
            return s

        @staticmethod
        def MakeHTMLHeader():
            s = '<!DOCTYPE html>\n'
            s += '<html lang="en">\n'
            s += '<head>\n'
            s += '<meta charset="UTF-8" />\n'
            s += '<title>vtkNamedColors</title>\n'
            s += HTMLTableMaker.MakeHTMLStyle()
            s += '</head>\n'
            return s

        @staticmethod
        def MakeHTMLIndex():
            s = '<h2>Index</h2>\n'
            s += '<ul>\n'
            s += '\t<li><a href="#WebColorNames">Web color Names</a>'
            s += ' These colors correspond to those in'
            s += ' <a href="http://en.wikipedia.org/wiki/Web_colors"'
            s += ' title="Web Colors">Web Colors</a>.\n'
            s += '</li>\n'
            s += '\t<li><a href="#VTKColorNames">VTK color Names</a>\n'
            s += ' The colors correspond to additional colors commonly used in VTK.\n'
            s += '<br>The web colors take precedence over colors with\n'
            s += ' the same name (case insensitive) here.\n'
            s += '</li>\n'
            s += '\t<li><a href="#Synonyms">Synonyms</a></li>\n'
            s += '</ul>\n'
            return s

        @staticmethod
        def MakeTableHeader(title):
            s = '<tr>\n'
            s += '<th>'
            s += title
            s += '</th>\n'
            s += '<th>Decimal code<br>\n'
            s += '&#160;&#160;R'
            s += '&#160;&#160;&#160;&#160;G'
            s += '&#160;&#160;&#160;&#160;B</th>\n'
            s += '</tr>\n'
            return s

        @staticmethod
        def MakeTD(name):
            s = '<tr>\n'
            s += '<td colspan="2">'
            s += '<b>' + name + '</b>'
            s += '</td>\n'
            s += '</tr>\n'
            return s

        def MakeTR(self, name, rgb, textColor):
            """
              Use when the name is a color name known to the web browser.
            """
            s = '<tr>\n'
            s += '<td style="background:' + name + ';color:' + textColor
            s += '">' + name + '</td>\n'
            s += '<td style="background:' + name + ';color:' + textColor
            s += '">' + self.htmlRGBA.FormatRGBForHTML(rgb) + '</td>\n'
            s += '</tr>\n'
            return s

        def MakeTR_HTML(self, name, htmlColor, rgb, textColor):
            """
              Use when the name is not a color name known to the web browser.
            """
            s = '<tr>\n'
            s += '<td style="background:' + htmlColor + ';color:'
            s += textColor + '">' + name + '</td>\n'
            s += '<td style="background:' + htmlColor + ';color:'
            s += textColor + '">' + self.htmlRGBA.FormatRGBForHTML(rgb) + '</td>\n'
            s += '</tr>\n'
            return s

        def FindLongestColorName(self):
            """ Find the longest color name. """
            maxLength = -1
            for key, value in self.cs.cn.items():
                for val in value:
                    if len(val) > maxLength:
                        maxLength = len(val)
            for key, value in self.cs.vtkcn.items():
                for val in value:
                    if len(val) > maxLength:
                        maxLength = len(val)
            return maxLength

        def MakeWebColorTables(self):
            res = ''
            for key in self.cs.cnOrder:
                if key in self.cs.cnStartTable:
                    res += '<td>\n'
                    res += '<table>\n'
                    res += self.MakeTableHeader('HTML name')
                # Add in the name of the group in the color table.
                res += self.MakeTD(key + ' colors')
                values = self.cs.cn[key]
                for name in values:
                    rgb = self.nc.GetColor3ub(name)
                    Y = self.htmlRGBA.RGBToLumaCCIR601(rgb)
                    textColor = '#000000'  # Black
                    if Y < 255 / 2.0:
                        textColor = '#ffffff'  # White
                    # Make the row for each color in the group.
                    # Here we use the name to set the background color
                    #  as it is known to the web browser.
                    res += self.MakeTR(name, rgb, textColor)
                if key in self.cs.cnEndTable:
                    res += '</table>\n'
                    res += '</td>\n'
            return res

        def MakeVTKColorTables(self):
            res = ''
            for key in self.cs.vtkcnOrder:
                if key in self.cs.vtkcnStartTable:
                    res += '<td>\n'
                    res += '<table>\n'
                    res += self.MakeTableHeader('HTML name')
                # Add in the name of the group in the color table.
                res += self.MakeTD(key)
                values = self.cs.vtkcn[key]
                for name in values:
                    rgb = self.nc.GetColor3ub(name)
                    Y = self.htmlRGBA.RGBToLumaCCIR601(rgb)
                    textColor = '#000000'  # Black
                    if Y < 255 / 2.0:
                        textColor = '#ffffff'  # White
                    # We must set the background color to a specific
                    # HTML color as the color name may not be a standard
                    # name known to the web browser.
                    htmlColor = self.htmlRGBA.RGBToHTMLColor(rgb)
                    # Make the row for each color in the group.
                    res += self.MakeTR_HTML(name, htmlColor, rgb, textColor)
                if key in self.cs.vtkcnEndTable:
                    res += '</table>\n'
                    res += '</td>\n'
            return res

        def MakeSynonymColorTable(self):
            syn = self.nc.GetSynonyms()
            # Convert to a list where each element is a list of the
            #  color and its synonyms.
            syn = syn.split('\n\n')
            synonyms = []
            for ele in syn:
                synonyms.append(ele.split('\n'))
            cn = list()
            for key, value in self.cs.cn.items():
                cn = cn + value
            # Create a dictionary where the key is the lowercase name.
            d = dict()
            for n in cn:
                d.update({n.lower(): n})
            #  End point of first table.
            end1 = len(synonyms) // 2
            if end1 * 2 < len(synonyms):
                end1 += 1
            res = '<td>\n'
            res += '<table>\n'
            res += self.MakeTableHeader('Synonyms')
            count = 0
            for colorNames in synonyms:
                if count == end1:
                    res += '</table>\n'
                    res += '</td>\n'
                    res += '<td>\n'
                    res += '<table>\n'
                    res += self.MakeTableHeader('Synonyms')
                for idx, name in enumerate(colorNames):
                    if name in d:
                        colorNames[idx] = d[name]
                colorNames.sort()
                name = ", ".join(colorNames)
                rgb = self.nc.GetColor3ub(colorNames[0])
                Y = self.htmlRGBA.RGBToLumaCCIR601(rgb)
                textColor = '#000000'  # Black
                if Y < 255 / 2.0:
                    textColor = '#ffffff'  # White
                # We must set the background color to a specific
                # HTML color  names is just a list of
                # synonyms for that particular color.
                htmlColor = self.htmlRGBA.RGBToHTMLColor(rgb)
                # Make the row for each color in the group.
                res += self.MakeTR_HTML(name, htmlColor, rgb, textColor)
                count += 1
            res += '</table>\n'
            res += '</td>\n'
            return res

        def MakeWebColorPage(self):
            res = self.MakeHTMLHeader()
            res += '<body>\n'
            res += '<h1>Colors available in vtkNamedColors</h1>\n'
            res += '<table>\n'
            res += '<tr>\n'
            res += '<th colspan="3">Web Color Names</th>\n'
            res += '</tr>\n'
            res += '<tr>\n'
            res += self.MakeWebColorTables()
            res += '</tr>\n'
            res += '</table>\n'
            res += '</body>\n'
            return res

        def MakeVTKColorPage(self):
            res = self.MakeHTMLHeader()
            res += '<body>\n'
            res += '<h1>Colors available in vtkNamedColors</h1>\n'
            res += 'The web colors take precedence over colors of the same'
            res += ' name in VTK Color Names.\n'
            res += '<table>\n'
            res += '<tr>\n'
            res += '<th colspan="3">VTK Color Names</th>\n'
            res += '</tr>\n'
            res += '<tr>\n'
            res += self.MakeVTKColorTables()
            res += '</tr>\n'
            res += '</table>\n'
            res += '</body>\n'
            return res

        def MakeSynonymColorPage(self):
            res = self.MakeHTMLHeader()
            res += '<body>\n'
            res += '<h1>Synonyms in vtkNamedColors</h1>\n'
            res += '<table>\n'
            res += '<tr>\n'
            res += '<th colspan="2">Synonyms</th>\n'
            res += '</tr>\n'
            res += '<tr>\n'
            res += self.MakeSynonymColorTable()
            res += '</tr>\n'
            res += '</table>\n'
            res += '</body>\n'
            return res

        def MakeCombinedColorPage(self):
            res = self.MakeHTMLHeader()
            res += '<body>\n'
            res += '<h1>Colors available in vtkNamedColors</h1>\n'
            res += 'The class vtkNamedColors provides color names and their'
            res += ' values for the convenience of the user.\n'
            res += '<br>The following tables show the available colors along with'
            res += ' their red, green and blue values.\n'
            res += self.MakeHTMLIndex()
            res += '<table>\n'
            res += '<tr>\n'
            res += '<th colspan="3"><a id="WebColorNames">Web color Names</a></th>\n'
            res += '</tr>\n'
            res += '<tr>\n'
            res += self.MakeWebColorTables()
            res += '</tr>\n'
            res += '</table>\n'
            res += '<br>\n'

            res += '<table>\n'
            res += '<tr>\n'
            res += '<th colspan="3"><a id="VTKColorNames">VTK color Names</a></th>\n'
            res += '</tr>\n'
            res += '<tr>\n'
            res += self.MakeVTKColorTables()
            res += '</tr>\n'
            res += '</table>\n'
            res += '<br>\n'

            res += '<table>\n'
            res += '<tr>\n'
            res += '<th colspan="2"><a id="Synonyms">Synonyms</a></th>\n'
            res += '</tr>\n'
            res += '<tr>\n'
            res += self.MakeSynonymColorTable()
            res += '</tr>\n'
            res += '</table>\n'
            res += '</body>\n'
            return res

    if __name__ == "__main__":
        main()