number=positive integer - maximum number of colors to return, 20 by default

space=string - the color space of the output color objects, "Lab" by default

This command reduces a large list of colors down to a small representative list of less than 20 colors.

$\mathrm{with}\left(\mathrm{ColorTools}\right)\:$

$\mathrm{full}≔\left[\mathrm{seq}\left(\mathrm{Color}\left(''RGB''\,\left[1-i\,i\,1-i\right]\right)\,i=0..1\,0.05\right)\right]$

$\mathrm{full}≔\left[⟨RGB\; :\; 1\; 0\; 1⟩\,⟨RGB\; :\; 0.95\; 0.05\; 0.95⟩\,⟨RGB\; :\; 0.9\; 0.1\; 0.9⟩\,⟨RGB\; :\; 0.85\; 0.15\; 0.85⟩\,⟨RGB\; :\; 0.8\; 0.2\; 0.8⟩\,⟨RGB\; :\; 0.75\; 0.25\; 0.75⟩\,⟨RGB\; :\; 0.7\; 0.3\; 0.7⟩\,⟨RGB\; :\; 0.65\; 0.35\; 0.65⟩\,⟨RGB\; :\; 0.6\; 0.4\; 0.6⟩\,⟨RGB\; :\; 0.55\; 0.45\; 0.55⟩\,⟨RGB\; :\; 0.5\; 0.5\; 0.5⟩\,⟨RGB\; :\; 0.45\; 0.55\; 0.45⟩\,⟨RGB\; :\; 0.4\; 0.6\; 0.4⟩\,⟨RGB\; :\; 0.35\; 0.65\; 0.35⟩\,⟨RGB\; :\; 0.3\; 0.7\; 0.3⟩\,⟨RGB\; :\; 0.25\; 0.75\; 0.25⟩\,⟨RGB\; :\; 0.2\; 0.8\; 0.2⟩\,⟨RGB\; :\; 0.15\; 0.85\; 0.15⟩\,⟨RGB\; :\; 0.1\; 0.9\; 0.1⟩\,⟨RGB\; :\; 0.05\; 0.95\; 0.05⟩\,⟨RGB\; :\; 0\; 1\; 0⟩\right]$

$\mathrm{numelems}\left(\mathrm{full}\right)$

$21$

$\mathrm{reduced}≔\mathrm{ReducePalette}\left(\mathrm{full}\right)$

$\mathrm{reduced}≔\left[⟨Lab\; :\; 56.4\; 91.1\; -56.5⟩\,⟨Lab\; :\; 60.3\; 98.3\; -60.8⟩\,⟨Lab\; :\; 49.5\; 55\; -35.3⟩\,⟨Lab\; :\; 51.3\; 74.8\; -46.9⟩\,⟨Lab\; :\; 50.2\; 29.1\; -19.5⟩\,⟨Lab\; :\; 53.4\; 0.00446\; -0.00714⟩\,⟨Lab\; :\; 58.6\; -27.7\; 21.6⟩\,⟨Lab\; :\; 65.1\; -50.2\; 42.7⟩\,⟨Lab\; :\; 72.3\; -66.6\; 60.8⟩\,⟨Lab\; :\; 85.8\; -84.2\; 81.1⟩\,⟨Lab\; :\; 80\; -78\; 74.1⟩\right]$

$\mathrm{numelems}\left(\mathrm{reduced}\right)$

$11$

$\mathrm{imgfile}≔\mathrm{cat}\left(\mathrm{kernelopts}\left(\mathrm{datadir}\right)\,''/images/antennas.jpg''\right)\:$

$\mathrm{ImageTools}:-\mathrm{Embed}\left(\mathrm{ImageTools}:-\mathrm{Read}\left(\mathrm{imgfile}\right)\right)$

$\mathrm{full}≔\mathrm{ColorsFromImage}\left(\mathrm{imgfile}\right)\:$

$\mathrm{numelems}\left(\mathrm{full}\right)$

$226$

$\mathrm{reduced}≔\mathrm{ReducePalette}\left(\mathrm{full}\right)$

$\mathrm{reduced}≔\left[⟨Lab\; :\; 62.8\; -1.33\; -14.4⟩\,⟨Lab\; :\; 21.4\; -0.302\; 11.1⟩\,⟨Lab\; :\; 73.6\; 0.0941\; 24.9⟩\,⟨Lab\; :\; 48.3\; -1.06\; 10.5⟩\,⟨Lab\; :\; 91.4\; -0.834\; 2.85⟩\,⟨Lab\; :\; 58.2\; 0.733\; 23.9⟩\,⟨Lab\; :\; 78.1\; -1.56\; 0.00854⟩\,⟨Lab\; :\; 34.2\; -0.502\; 10.3⟩\,⟨Lab\; :\; 64.9\; 0.0325\; 7.04⟩\,⟨Lab\; :\; 83.4\; -1.77\; 9.21⟩\,⟨Lab\; :\; 54.9\; -1.49\; -5.23⟩\,⟨Lab\; :\; 71.3\; -1.72\; -5.04⟩\,⟨Lab\; :\; 73.5\; -1.44\; 6.35⟩\,⟨Lab\; :\; 64.7\; -1.15\; -1.59⟩\,⟨Lab\; :\; 56.9\; -2.31\; 10.6⟩\,⟨Lab\; :\; 40.7\; -1.41\; 11.8⟩\,⟨Lab\; :\; 67.3\; 1.03\; 25.1⟩\,⟨Lab\; :\; 27.7\; -0.271\; 12.1⟩\,⟨Lab\; :\; 52.3\; 3.36\; 14.6⟩\,⟨Lab\; :\; 60.4\; -1.58\; -6.56⟩\right]$

$\mathrm{reduced}≔\mathrm{ReducePalette}\left(\mathrm{full}\,'\mathrm{number}'=8\,'\mathrm{space}'=''RGB''\right)$

$\mathrm{reduced}≔\left[⟨RGB\; :\; 0.49\; 0.573\; 0.667⟩\,⟨RGB\; :\; 0.224\; 0.2\; 0.137⟩\,⟨RGB\; :\; 0.776\; 0.703\; 0.53⟩\,⟨RGB\; :\; 0.471\; 0.449\; 0.38⟩\,⟨RGB\; :\; 0.907\; 0.905\; 0.882⟩\,⟨RGB\; :\; 0.612\; 0.541\; 0.384⟩\,⟨RGB\; :\; 0.745\; 0.761\; 0.757⟩\,⟨RGB\; :\; 0.337\; 0.314\; 0.251⟩\right]$

The ColorTools[ReducePalette] command was introduced in Maple 18.

For more information on Maple 18 changes, see Updates in Maple 18.

The ColorTools[ReducePalette] command was updated in Maple 2020.

The number and space options were introduced in Maple 2020.

For more information on Maple 2020 changes, see Updates in Maple 2020.