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.

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

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

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

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

$21$

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

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

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

$11$

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

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

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

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

$226$

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

$\mathrm{reduced}≔\left[⟨Lab\; :\; 59\; -1.54\; -15⟩\,⟨Lab\; :\; 21.4\; -0.302\; 11.1⟩\,⟨Lab\; :\; 91\; -1.18\; 4.78⟩\,⟨Lab\; :\; 61.1\; 1.37\; 25.1⟩\,⟨Lab\; :\; 40.7\; -1.41\; 11.8⟩\,⟨Lab\; :\; 76.5\; -2.01\; 11.7⟩\,⟨Lab\; :\; 70.9\; -1.52\; -4.01⟩\,⟨Lab\; :\; 50.5\; -0.931\; 6.44⟩\,⟨Lab\; :\; 50.7\; -1.82\; -4.97⟩\,⟨Lab\; :\; 64.9\; 0.0325\; 7.04⟩\,⟨Lab\; :\; 73.6\; 0.0941\; 24.9⟩\,⟨Lab\; :\; 52\; 1.21\; 23.4⟩\,⟨Lab\; :\; 78.1\; -1.56\; 0.00854⟩\,⟨Lab\; :\; 60.2\; -2.1\; -2.33⟩\,⟨Lab\; :\; 83.9\; -1.37\; 8.78⟩\,⟨Lab\; :\; 58\; -0.573\; 10.6⟩\,⟨Lab\; :\; 65\; -0.618\; -8.3⟩\,⟨Lab\; :\; 34.2\; -0.502\; 10.3⟩\,⟨Lab\; :\; 27.7\; -0.271\; 12.1⟩\,⟨Lab\; :\; 68\; 1.28\; 25.2⟩\right]$

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

$\mathrm{reduced}≔\left[⟨RGB\; :\; 0.529\; 0.577\; 0.631⟩\,⟨RGB\; :\; 0.224\; 0.2\; 0.137⟩\,⟨RGB\; :\; 0.905\; 0.9\; 0.863⟩\,⟨RGB\; :\; 0.694\; 0.62\; 0.451⟩\,⟨RGB\; :\; 0.397\; 0.376\; 0.301⟩\,⟨RGB\; :\; 0.549\; 0.478\; 0.329⟩\,⟨RGB\; :\; 0.745\; 0.761\; 0.757⟩\,⟨RGB\; :\; 0.743\; 0.72\; 0.643⟩\right]$

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.