Bug#413954: incompatibilities between graphicsmagick-imagemagick-compat and imagemagick

2021-01-22 Thread Mattia Rizzolo 
On Fri, Oct 02, 2009 at 11:31:05AM -0400, Daniel Kahn Gillmor wrote:
> A few more things that are missing (i just ran into this while trying to
> convert some private scripts from imagemagick to
> graphicsmagick-imagemagick-compat:

And today I stumbled upon this, as a system that was supposed to have
"impagemagick" installed couldn't find the `compare` program, which has
been part of imagemagick since… whatever long, but apparently is not
provided by this graphicsmagick-imagemagick-compat package.


After all these years, if graphicsmagick can't keep up the interface of
imagemagick, please consider dropping this Provides, as it's really
just annoying and it clearly isn't serving its porpuses well enough.

-- 
regards,
Mattia Rizzolo

GPG Key: 66AE 2B4A FCCF 3F52 DA18  4D18 4B04 3FCD B944 4540  .''`.
More about me:  https://mapreri.org : :'  :
Launchpad user: https://launchpad.net/~mapreri  `. `'`
Debian QA page: https://qa.debian.org/developer.php?login=mattia  `-


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Bug#413954: incompatibilities between graphicsmagick-imagemagick-compat and imagemagick

2010-04-23 Thread Ben Finney 
On 02-Oct-2009, Daniel Kahn Gillmor wrote:
 A few more things that are missing (i just ran into this while
 trying to convert some private scripts from imagemagick to
 graphicsmagick-imagemagick-compat:

I ran into this also, in trying to package a software work that uses
some ImageMagick commands. I assumed that, since I have
‘graphicsmagick-imagemagick-compat’ installed, that would suffice. Not
so.

  graphicsmagick-imagemagick-compat does not know about the Alpha
  channel -- it knows about Opacity, but the convert wrapper
  apparently isn't smart enough to translate between the synonyms.
  (or is alpha actually 1-opacity? i'm not sure)

According to the ImageMagick documentation:

Note that the channel names 'Alpha' ('A'), 'Opacity' ('O'), and
'Matte', are also aliases for the -channel setting referring to
the images transparency information. It does not matter that an
'alpha' channel is the inverse of a 'matte' channel, it still
refers to the same channel, and produces the same result.

Whether the data in that channel is acted upon a 'alpha' channel
data or as a 'matte' channel data, depend of the operator. Low
level channel operators like -threshold work on the raw 'matte'
data of the channel in memory. However most higher level operators
like -fx and -composite treat that data as representing
'alpha' data, for operation purposes.

URL:http://www.imagemagick.org/Usage/channels/

 This means i've had to revert to imagemagick, after a fair amount of
 debugging and searching for the promised compatibility.

Likewise.

 Perhaps the long description of the package should indicate that it is
 not fully-compatible, and the specifics of the known incompatibilities
 could be dropped into
 /usr/share/doc/graphicsmagick-imagemagick-compat/incompatibilities.txt

Ideally, of course there would be enough interest in graphicsmagick as
a replacement to implement the features compatibly and submit changes
upstream :-)

-- 
 \  “Only the educated are free.” —Epictetus, _Discourses_ |
  `\   |
_o__)  |
Ben Finney b...@benfinney.id.au


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Bug#413954: incompatibilities between graphicsmagick-imagemagick-compat and imagemagick

2009-10-02 Thread Daniel Kahn Gillmor 
A few more things that are missing (i just ran into this while trying to
convert some private scripts from imagemagick to
graphicsmagick-imagemagick-compat:

 graphicsmagick-imagemagick-compat does not know about the Alpha channel
-- it knows about Opacity, but the convert wrapper apparently isn't
smart enough to translate between the synonyms.  (or is alpha actually
1-opacity? i'm not sure)

 graphicsmagick-imagemagick-compat lacks the -fx functionality.
-operator provides a less flexible alternative, but it is not capable of
matching the full power of -fx, afaict.  i see no other equivalent
replacement.

This means i've had to revert to imagemagick, after a fair amount of
debugging and searching for the promised compatibility.

Perhaps the long description of the package should indicate that it is
not fully-compatible, and the specifics of the known incompatibilities
could be dropped into
/usr/share/doc/graphicsmagick-imagemagick-compat/incompatibilities.txt

thanks,

--dkg



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