From: Rudolf Bahr <quasi@quasi.de>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: When newsizing an external figure bei [width=<some pt>], what will be its height in pt and viceversa?
Date: Sat, 23 Feb 2019 11:08:18 +0100 [thread overview]
Message-ID: <20190223100818.t5azu6c2hgaps6pe@nan> (raw)
In-Reply-To: <874l8wm3t0.fsf@a16n.net>
On Fri, Feb 22, 2019 at 12:59:55PM +0100, Peter Münster wrote:
> On Fri, Feb 22 2019, Rudolf Bahr wrote:
>
> > The picture sizes in px One gets by invoking for instance graphics Magick's identify
> > in a lua program:
>
> Or just img.scan():
>
> \startluacode
> local image = img.scan{filename = "my-image.jpg"}
> logs.report("xsize", image.xsize)
> logs.report("ysize", image.ysize)
> \stopluacode
>
> --
> Peter
Hi Peter,
thank you for pointing to img.scan{}! It's indeed shorter than to invoke Graphics Magick
in Lua. Remains the conversion of image sizes into pt. There is an example in the chapter
"Calculations in Lua" in "https://wiki.contextgarden.net/Image_Placement" (a work in
progress). According to there it's necessary to know the resolution in order to convert
image sizes from px to pt which at least I don't know. Mostly I can preset one size of
a picture (say the width in pt) to be able to place it on a page and assuming
x-resolution = y-resolution and keeping width-to-height ratio I calculate the missing
size (here the height in pt) in Lua by
picture-height-in-px
asked-picture-height-in-pt = preset-picture-width-in-pt * --------------------
picture-width-in-px
This is simple and normally it suffices for me.
Rudolf
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next prev parent reply other threads:[~2019-02-23 10:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 9:48 Rudolf Bahr
2019-02-22 9:14 ` Rudolf Bahr
2019-02-22 11:59 ` Peter Münster
2019-02-23 10:08 ` Rudolf Bahr [this message]
2019-02-23 10:56 ` Hans Hagen
2019-02-23 11:37 ` Rudolf Bahr
2019-02-23 11:48 ` Hans Hagen
[not found] <mailman.727.1550955497.1205.ntg-context@ntg.nl>
2019-02-23 22:38 ` Jeong Dal
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