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: Fri, 22 Feb 2019 10:14:15 +0100 [thread overview]
Message-ID: <20190222091414.kehdxqfkhdktdbju@nan> (raw)
In-Reply-To: <20190219094838.rb772tdgj6iiv6cd@nan>
On Tue, Feb 19, 2019 at 10:48:38AM +0100, Bahr Rudolf wrote:
> Hi All,
>
> from an external figure I normally know its width and height in px.
> But I don't know its exact sizes in pt. When newsizing the figure
> in a document (by the same width-to-height-ratio), I'll do that as
> some part of textwidth or textheight, in pt or mm, but not in px,
> i.e. by means of [width=<some pt>].
> Sometimes it would be interesting to know its new height in pt,
> and viceversa.
>
> Is there a variable or something else containing its new size in pt?
>
> Regards,
> Rudolf
Hi All,
up to now Nobody answered to my question, perhaps it might have been
too simple.
Indeed One could normally assume:
picture-width-in-px preset-picture-width-in-pt
-------------------- = --------------------------
picture-height-in-px asked-picture-height-in-pt
And according to Adam Riese One gets:
preset-picture-width-in-pt * picture-height-in-px
asked-picture-height-in-pt = ---------------------------------------------------
picture-width-in-px
-----------------
The picture sizes in px One gets by invoking for instance graphics Magick's identify
in a lua program:
local file = assert ( io.popen ( 'gm identify ' .. picture_name, 'r' ))
local output = file:read ( '*all' )
file:close ()
local words = {}
for w in string.gmatch ( output, "%g+" ) do
words [ #words + 1 ] = w
end
-- Width and height are found in words[3]: i.e. 5407x3544+0+0
local dims = {}
for d in string.gmatch ( words [ 3 ], "%d+" ) do
dims [ #dims + 1 ] = d
end
local px_width = dims [ 1 ]
local px_height = dims [ 2 ]
-----------------
It's a solution at least as long as your Lua supports "io.popen". There might be
shorter solutions.
Cheers, Rudolf
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next prev parent reply other threads:[~2019-02-22 9:14 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 [this message]
2019-02-22 11:59 ` Peter Münster
2019-02-23 10:08 ` Rudolf Bahr
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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