[magick-users] spreading edge colors

[Anthony Thyssen]

On Thu, 08 Jan 2009 11:48:38 +0100
Cedric Pinson <mornifle at plopbyte.net> wrote:

| Hi Anthony,
| 
| I will try to answer inline because i am not sure i understand all details
| 
| 
| I dont understand why you are saying what i did is pure luck :)
| because i put the original alpha mask of the original image on the final
| because i dont want the alpha mask changed in final image. Are you 
| saying that
| my use of morphology is not correct to expand the ? in this case i will 
| understand.
| Could you send me your circle_halves.png in order i test with it to see 
| the result
| 
| anyway if you have a morphology that dont touch the alpha mask it will 
| avoid me to extract
| and copy the original image mask to the final alpha_mask.
| 
| 
| Maybe i miss something, can you point me precisely where i am wrong ?
| thank you for your helps and suggestion.
| 
| Cheers,
| Cedric
| 
| Anthony Thyssen wrote:
| > On Wed, 07 Jan 2009 21:01:13 +0100
| > Cedric Pinson <mornifle at plopbyte.net> wrote:
| >
| > | Hi,
| > | 
| > | Here the script i use it seems to work fine for all my cases right now, 
| > | i will try on futur data and tell if it works
| > | for most cases
| > | 
| > | #!/bin/bash
| > | set -e
| > | set -x
| > | file=$1
| > | filewithoutext=$(echo $1 | sed 's/.png//g')
| > | name=$(basename $1 | sed 's/.png//g')
| > | ./morphology -m grayscale -t erode -i 1 $file /tmp/${name}_0.png
| > | convert $file -alpha extract /tmp/${name}_alpha.png
| > | composite -gravity center $1 /tmp/${name}_0.png /tmp/${name}_2.png
| > | convert  /tmp/${name}_2.png /tmp/${name}_alpha.png -alpha off -compose 
| > | Copy_Opacity  -composite ${filewithoutext}_final.png
| > | 
| > I can see the results your script produces using my "circle_halves.png"
| > test image. though there appears to be a couple of unusual extraneous
| > pixels. in the results.
| >   
| Could you send me your picture in order i test please
| > However I would not depend on morphology from expanding (or contracting)
| > the image mask as you are using it for.  What should do is undefined,
| > and in fact logically it is doing the oppisite of what it should be doing.
| >   
| Yes that's why i dont use the result of alpha mask from morphology i use 
| the original
| because i want the mask not changed. But maybe i miss something in this 
| line:
| 
| composite -gravity center $1 /tmp/${name}_0.png /tmp/${name}_2.png
| 
| > The fact that it does so is pure luck.  I just submitted back to Fred
| > a improved and about 7 times faster version of grayscale morphology,
| > however it does not erode/dilate the transparency mask of the image!
| >   
| It's better for sure
| > I suggest you extract the alpha mask first, the dilate it separatally.
| >   
| that's why i do or again maybe my composite line i miss something.
| > ASIDE: the new version also has the interative blur spreading operator
| > that I developed in the previous email.
| >
| > I'll include a copy of that script to you.
| >
| > Fred.... Please note there is a small change to the previous one so this
| > version does at least preverse transparency in greyscale morphology. The
| > previous one wiped out transparency rather than preserve it.
| >
| >   
| If i understand correctly you are saying is for this line:
| 
| composite -gravity center $1 /tmp/${name}_0.png /tmp/${name}_2.png
| 
| /tmp/${name}_0.png should not have the mask extended from morphology is 
| that correct ?
| or did i miss other thing ?
| 
PS:  both IM and morphology can use pipelines to pass images from one
command into the next.

for example...
  
   convert circle_halves.png -alpha extract miff:- | \
      morphology -m grayscale -t dilate -i 5 - show:

The '-' means read from stdin,   'show:' means display the result
on screen and quit (leaving it displayed in background) without
saving this 'test run' into a file.


PPS:  The circle_halves.png was given as an IM command in that long
exploration I did in a previous mail....  I'll repeat it here...

  convert -size 100x100 xc:none \
          -draw "fill magenta path 'M 30,60  A 1,1 0 0,0 70,40 z'" \
          -draw "fill cyan    path 'M 30,60  A 1,1 0 1,1 70,40 z'" \
          -draw "fill blue    circle 50,50 37,37'" \
          circle_halves.png


  Anthony Thyssen ( System Programmer )    <A.Thyssen at griffith.edu.au>
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