Legacy ImageMagick Discussions Archive

"-define png:exclude-chunks=bkgd"

Thank you, that solved my problem.

convert rose: -colors 12 -type palette test.png
identify -verbose test.png

...
Colors: 12
Histogram:
581: ( 51, 51, 45) #33332D srgb(51,51,45)
155: ( 83, 76, 56) #534C38 srgb(83,76,56)
296: ( 94, 93, 79) #5E5D4F srgb(94,93,79)
217: ( 98, 57, 47) #62392F srgb(98,57,47)
272: (110,147, 86 ...

An update:
Boundaries between colors of the same intensity are not affected
Actually, the whole image is shifted, and result doesn't look right to me. Here is an exaggerated example:

convert +antialias -size 200x200 xc:#00FF00 -fill #FF0000 -draw "rectangle 50,50,150,150" -fill black -draw ...

Thanks a lot, it works exactly as you said. Boundaries between colors of the same intensity are not affected, and, yes, "Brightness" will suit perfectly, because image uses limited palette, and colors can be mapped to any set before processing and back afterwards.

I.e. can we have 2 colors, whose boundary will not be affected by intensity variants of morphology command? What's the exact formula for 'intensity'? It seems to be not

0.299*red + 0.587*green + 0.114*blue

because with

convert +antialias -size 200x200 xc:rgb(0%,100%,0%) -fill rgb(100%,70 ...

It should be, but it isn't? Strange results when supplying '-statistic median' with single numeric parameter are confusing, too. At least we can hope 'WxH' parameter is box size, indeed. Thanks for your answer.

Documentation says '-median' ' is legacy option from the method of the same name', so I'd expect them be identical. However, running 4 commands:
convert LOGO: -median 3x3 m33.png
convert LOGO: -median 3 m3.png
convert LOGO: -statistic median 3x3 sm33.png
convert LOGO: -statistic median 3 sm3.png ...