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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