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Convert to Monochrome PCX doesn't work
Posted: 2012-12-04T08:51:03-07:00
by mfernandez
Hello,
I've been using imagemagick a lot of time ago, from little scripts to complex tasks, and I'm very happy with it.
However, this conversion doesn't work when using Imagemagick 6.7.7-10 (Ubuntu 12.10), because it generates 24-bit PCX images instead of monochrome ones:
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$ convert -type Bilevel image.jpg image.pcx
$ file image.pcx
image.pcx: PCX ver. 3.0 image data bounding box [0, 0] - [464, 219], 3 planes each of 8-bit colour, 72 x 72 dpi, RLE compressed
This command worked in Ubuntu 12.04 (Imagemagick 6.6.9-7) just fine:
Code: Select all
$ file image_1204.pcx
logo.pcx: PCX ver. 3.0 image data bounding box [0, 0] - [464, 219], 1-bit colour, 72 x 72 dpi, RLE compressed
I've tried with the last version of convert (Imagemagick 6.8.0-7 compiled by myself) and I'm still getting the same issue. I've also tried with "-monochrome", putting parameters before the input file and before the output PCX, but no luck.
Is this a bug? Should I report it?
Regards
Re: Convert to Monochrome PCX doesn't work
Posted: 2012-12-04T11:45:08-07:00
by fmw42
convert -type Bilevel image.jpg image.pcx
I do not know much about PCX, but try the more correct IM6 syntax with the input image before the options
convert image.jpg -type Bilevel image.pcx
convert image.jpg -monochrome image.pcx
This works fine for me on IM 6.8.0.7 Q16 Mac OSX Snow Leopard
convert logo: -monochrome 1tmp1.pcx
identify -verbose 1tmp1.pcx
Image: 1tmp1.pcx
Format: PCX (ZSoft IBM PC Paintbrush)
Class: DirectClass
Geometry: 640x480+0+0
Units: PixelsPerInch
Type: Palette
Endianess: Undefined
Colorspace: sRGB
Depth: 8/1-bit
Channel depth:
red: 1-bit
green: 1-bit
blue: 1-bit
Re: Convert to Monochrome PCX doesn't work
Posted: 2012-12-04T13:49:22-07:00
by mfernandez
Hello!
As I've said before, I've tried both:
Code: Select all
convert -monochrome image.jpg image.pcx
and
Code: Select all
convert image.jpg -monochrome image.pcx
and still doesn't work (-type Bilevel doesn't work either).
Any ideas? Could it be a configure parameter or a system library lacking? I'm using Ubuntu 12.10 x86-64.
Thank you
Re: Convert to Monochrome PCX doesn't work
Posted: 2012-12-04T17:31:43-07:00
by fmw42
Do you get any error messages?
I tried with IM 6.7.7.10 and it works fine for me on my Mac OSX Snow Leopard.
How do you know it is not working? When I display it, it is binary. The -type is palette, however, in both the current and older version of IM. Perhaps PCX does not support a true bilevel type? However, the verbose info shows 1bit for depth:
Depth: 8/1-bit
Channel depth:
red: 1-bit
green: 1-bit
blue: 1-bit
Re: Convert to Monochrome PCX doesn't work
Posted: 2012-12-05T03:09:53-07:00
by mfernandez
fmw42 wrote:Do you get any error messages?
Nope, the command runs fine but the output PCX file under 6.7.x and 6.8.x is different from 6.6 version.
fmw42 wrote:I tried with IM 6.7.7.10 and it works fine for me on my Mac OSX Snow Leopard.
It
seems to work fine, but (I think) the output PCX image is a 24-bit one (dithered and maybe processed like B/W, tough) instead of a 2-bit B/W image.
fmw42 wrote:How do you know it is not working?
This is a "identify -verbose" command output for the PCX file generated with 6.7-6.8 convert (see it has RGB channels and its 20.5 KB in size)):
http://pastebin.com/CyrnFM5v
Now, this is the same input file but converted with Imagemagick 6.6 (it weights only 4.1KB):
http://pastebin.com/z4z1zJqu
Maybe I'm missing something here...
Thanks
Re: Convert to Monochrome PCX doesn't work
Posted: 2012-12-05T11:24:59-07:00
by fmw42
OK, then you have found a difference. This should be reviewed, esp. the verbose info file you have linked, by the IM developers.
Re: Convert to Monochrome PCX doesn't work
Posted: 2012-12-05T11:31:00-07:00
by mfernandez
fmw42 wrote:OK, then you have found a difference. This should be reviewed, esp. the verbose info file you have linked, by the IM developers.
Uhmm... ok, should I file a bug report somewhere?
Thank you
Re: Convert to Monochrome PCX doesn't work
Posted: 2012-12-05T11:56:08-07:00
by fmw42
mfernandez wrote:fmw42 wrote:OK, then you have found a difference. This should be reviewed, esp. the verbose info file you have linked, by the IM developers.
Uhmm... ok, should I file a bug report somewhere?
Thank you
This is the place already. I have just forwarded a message to the IM developers to take a closer look at this. So lets wait until we hear back.
Re: Convert to Monochrome PCX doesn't work
Posted: 2015-01-10T06:01:23-07:00
by ezequielchan
I found this workaround for this bug...
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ezequiel@h5:/tmp/test$ convert example.jpg -type Bilevel -colors 2 good.pcx
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ezequiel@h5:/tmp/test$ convert example.jpg -type Bilevel bad.pcx
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ezequiel@h5:/tmp/test$ file *.pcx
bad.pcx: PCX ver. 3.0 image data bounding box [0, 0] - [464, 239], 3 planes each of 8-bit colour, 72 x 72 dpi, RLE compressed
good.pcx: PCX ver. 3.0 image data bounding box [0, 0] - [464, 239], 1-bit colour, 72 x 72 dpi, RLE compressed
And this is the difference between both images.
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ezequiel@h5:/tmp/test$ identify -verbose good.pcx > good.txt
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ezequiel@h5:/tmp/test$ identify -verbose bad.pcx > bad.txt
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diff good.txt bad.txt > identify.diff
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ezequiel@h5:/tmp/test$ cat identify.diff
1c1
< Image: good.pcx
---
> Image: bad.pcx
3c3
< Class: PseudoClass
---
> Class: DirectClass
50,52d49
< Colormap: 2
< 0: ( 0, 0, 0) #000000 black
< 1: (255,255,255) #FFFFFF white
79c76
< Filesize: 7.04KB
---
> Filesize: 29.9KB
81,83c78,80
< Pixels per second: 11.16MB
< User time: 0.010u
< Elapsed time: 0:01.010
---
> Pixels per second: 0B
> User time: 0.000u
> Elapsed time: 0:01.000