* parameters of (setup)externalfigure, conversions etc.
@ 2022-08-11 13:51 Henning Hraban Ramm via ntg-context
2022-08-12 11:07 ` Henning Hraban Ramm via ntg-context
0 siblings, 1 reply; 2+ messages in thread
From: Henning Hraban Ramm via ntg-context @ 2022-08-11 13:51 UTC (permalink / raw)
To: mailing list for ConTeXt users, Hans Hagen; +Cc: Henning Hraban Ramm
Hi Hans,
yesterday you told me about the image conversions in grph-con.lua, and I
tried to find out how to use them. Up to know I only knew "mp" for SVG
images.
I found I can use "gray.pdf" or "cmyk.pdf" to convert an image (JPG or
PNG) to grayscale/CMYK, but the resolution isn’t used for downsampling
(of course, it’s not mentioned in the command template):
\externalfigure[hacker][conversion={gray.pdf},resolution=72]
I tried to write my own downsampling converter, but don’t understand how
I can hook it into the list of converters:
"""
local downsample = sandbox.registerrunner {
name = "downsample",
program = "gm",
template = [[convert -compress Zip -sampling-factor 1x1 -density
%resolution%x%resolution% -resample %resolution%x%resolution% %oldname%
%newname%]],
checkers = checkers,
defaults = defaults,
}
programs.downsample = { runner = downsample }
"""
(I’m not sure if I must calculate the desired pixel size beforehand.)
-*-*-
Apart from converters, there are several parameters of \externalfigure
that I don’t understand and thus can’t document in the Wiki; a few are
even not yet documented in the interface files:
* equalwidth/equalheight
* s/sx/sy
* xmax/ymax
* prefix, label, comment
* bodyfont
* mask
* frames (≠ frame)
* interaction, crossreference
* resources
* display
* order
* crop, transform
* controls, preview: only related to video and thus obsolete?
* hfactor/wfactor: When do these make sense? (I know factor)
I accidentally learned that I can use parameters of \framed, but the
inheritance from \setupframed is not explicit – some are mentioned, like
backgroundcolor, others not, even if they work, like corner (but they
don’t affect the image).
Hraban
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: parameters of (setup)externalfigure, conversions etc.
2022-08-11 13:51 parameters of (setup)externalfigure, conversions etc Henning Hraban Ramm via ntg-context
@ 2022-08-12 11:07 ` Henning Hraban Ramm via ntg-context
0 siblings, 0 replies; 2+ messages in thread
From: Henning Hraban Ramm via ntg-context @ 2022-08-12 11:07 UTC (permalink / raw)
To: ntg-context; +Cc: Henning Hraban Ramm
Am 11.08.22 um 15:51 schrieb Henning Hraban Ramm via ntg-context:
> Hi Hans,
>
> yesterday you told me about the image conversions in grph-con.lua, and I
> tried to find out how to use them. Up to know I only knew "mp" for SVG
> images.
>
> I found I can use "gray.pdf" or "cmyk.pdf" to convert an image (JPG or
> PNG) to grayscale/CMYK, but the resolution isn’t used for downsampling
> (of course, it’s not mentioned in the command template):
>
> \externalfigure[hacker][conversion={gray.pdf},resolution=72]
>
> I tried to write my own downsampling converter, but don’t understand how
> I can hook it into the list of converters:
>
> """
>
> local downsample = sandbox.registerrunner {
> name = "downsample",
> program = "gm",
> template = [[convert -compress Zip -sampling-factor 1x1 -density
> %resolution%x%resolution% -resample %resolution%x%resolution% %oldname%
> %newname%]],
> checkers = checkers,
> defaults = defaults,
> }
>
> programs.downsample = { runner = downsample }
I found the solution in
https://wiki.contextgarden.net/Using_Graphics#Image_Conversion, but
that’s not as elegant as those in grph-inc.lua
(And I learned that ImageMagick’s convert works differently than
GraphicsMagick’s WRT -density; i.e. you must use "gm convert".)
Peter Münster’s grph-downsample.lua was better, it calculated the actual
pixel size necessary, but that doesn’t work any more.
> """
>
> (I’m not sure if I must calculate the desired pixel size beforehand.)
>
> -*-*-
>
> Apart from converters, there are several parameters of \externalfigure
> that I don’t understand and thus can’t document in the Wiki; a few are
> even not yet documented in the interface files:
>
> * equalwidth/equalheight
> * s/sx/sy
> * xmax/ymax
> * prefix, label, comment
> * bodyfont
> * mask
> * frames (≠ frame)
> * interaction (PDF inclusion; found)crossreference
> * resources
> * display (alternative source? multimedia only?)
> * order (of extensions; found)
> * crop, transform
> * controls, preview: only related to video and thus obsolete?
> * hfactor/wfactor: When do these make sense? (I know factor)
Also, orientation seems to be missing in the interface (auto-syntax
doesn’t pick it up).
Hraban
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
webpage : https://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : https://contextgarden.net
___________________________________________________________________________________
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