Generating a text matrix with pixel values

[anthony]

nI am not an expert on the conversion to pgm, but it should be possible to convert to the text/plain format. However, when I just do

convert image -colorspace gray P2:image.pgm

Unfortunately, I get the binary format and the not the text/plain format.

Add -compress none and you will get the text sub-format. The "P2:" is not needed.

Or filter the PGM though the NetPBM utility "pnmnoraw" to make it text.

[anthony]

listArr=(`convert rose:[10x10+0+0] -colorspace gray txt:- | tail -n 100 |\
tr -cs '0-9\012' ' ' | cut -d\ -f3`)

basically converts a 10x10 set of pixels to colorspace gray and then outputs it to the IM txt format. The tail -n 100 removes the first header line and leaves the remaining 100 lines containing the location of each pixel and all the color values in different formats. The tr part removes all characters but numbers and spaces. The cut line simply extracts the graylevel value. So the result is a list, actually in this case the (..) makes it into an array of graylevel values.

The remaining lines of code loop over the array and format it to 10 rows of 10 values with a row number at the beginning.

It is better to use "tail -n +2" to remove just the first line, rather than rely on the count of the number of pixels.

[anthony]

Note for Windows Users All these utilities is available under Windows, including a BASH shell, using the cygwin package.

Okay you want an array, try this in unix command

First get the PGM output as one number per line (after striping of the header)

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convert rose:[10x10+0+0] -colorspace gray -compress none -depth 8 PGM:- | 
       tail -n +4 | tr -s ' \012' '\012'

Now make it 10 numbers per row...

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   ... | paste - - - - - - - - - -

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47      48      51      52      52      52      50      51      50      50
46      47      49      50      51      50      49      51      51      51
44      44      47      47      45      46      45      46      45      46
45      45      45      45      43      43      43      43      44      44
46      46      46      46      43      43      42      39      42      43
47      47      48      49      49      48      46      43      43      42
50      51      51      54      54      52      50      47      49      46
55      55      56      58      61      60      59      56      56      54
56      57      61      63      64      66      65      65      65      62
54      55      60      64      66      68      68      69      68      63

this will let you adjust the number of columns. the number is 8 * pixels_per_row

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   ... | column -x -c80 

If you don't mind the data 'transposed' diagonally you can use a VERY old command
called pr

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   ... | pr -t -10 -l10 

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47     46     44     45     46     47     50     55     56     54
48     47     44     45     46     47     51     55     57     55
51     49     47     45     46     48     51     56     61     60
52     50     47     45     46     49     54     58     63     64
52     51     45     43     43     49     54     61     64     66
52     50     46     43     43     48     52     60     66     68
50     49     45     43     42     46     50     59     65     68
51     51     46     43     39     43     47     56     65     69
50     51     45     44     42     43     49     56     65     68
50     51     46     44     43     42     46     54     62     63

the first number in pr is number of 'lines' (image width as image is transposed)
the second the number of columns per line (image height)
You could transpose the image before outputting so 'pr' can transpose back correctly.

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convert rose:[10x10+0+0] -colorspace gray -transpose -compress none -depth 8 PGM:- | 
         tail -n +4 | tr -s ' \012' '\012' | pr -t -10 -l10

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47     48     51     52     52     52     50     51     50     50
46     47     49     50     51     50     49     51     51     51
44     44     47     47     45     46     45     46     45     46
45     45     45     45     43     43     43     43     44     44
46     46     46     46     43     43     42     39     42     43
47     47     48     49     49     48     46     43     43     42
50     51     51     54     54     52     50     47     49     46
55     55     56     58     61     60     59     56     56     54
56     57     61     63     64     66     65     65     65     62
54     55     60     64     66     68     68     69     68     63

Their are lots of solutions in UNIX. Basically because UNIX has been around longer and comes of the days before fancy iterative graphics!

[anthony]

The IM -print may behave more like printf. You can try that. see http://www.imagemagick.org/script/comma ... .php#print but it does not say much about formatting.

IM -print has no formatting options! At least not at this time. You get what you get.
The only control you do have is for -precision whcih is number of floating point digits to include. But not all IM output uses this yet (for example -verbose -distort does not use this yet though 'showkernel' with morphology kernel output does, but this will change).