[NTG-context] resize and center and clip image

Mikael P. Sundqvist mickep at gmail.com
Thu May 1 17:07:34 CEST 2014


Interesting,

I use ConTeXt  ver: 2014.04.28 23:24 MKIV beta  fmt: 2014.4.29  int:
english/english

and it works. I now defined this with argument:

\startluacode
userdata = userdata or {}
function userdata.lundklippfyllbild(str, bredd, hojd)
if tex.dimen[0] / tex.dimen[2] < tex.dimen[4] / tex.dimen[6] then
      local skalning =
-0.5*(tex.dimen[4]/tex.dimen[0]*tex.dimen[2]-tex.dimen[6])
      context("\\vskip%ssp", skalning)
      context.externalfigure({str},{width=bredd})
      context.sprint("foo")
else
      local skalning =
-0.5*(tex.dimen[6]/tex.dimen[2]*tex.dimen[0]-tex.dimen[4])
      context("\\hskip%ssp", skalning)
      context.externalfigure({str},{height=hojd})
      context.sprint("bar")
end
end
\stopluacode

\unexpanded\def\lundklippfyllbild#1#2#3{%
\startexternalfigurecollection[#1]%
\useexternalfigure[#1][#1]%
\stopexternalfigurecollection%
\clip[
width=#2,
height=#3,
hoffset=0mm,
voffset=0mm,
]{%
\framed[width=#2,height=#3,align={middle,lohi},offset=overlay,frame=off]{%
\dimen0=\externalfigurecollectionminwidth{#1}%
\dimen2=\externalfigurecollectionmaxheight{#1}%
\dimen4=#2%
\dimen6=#3%
{\ctxlua{userdata.lundklippfyllbild([==[#1]==],[==[#2]==],[==[#3]==])}}}}}



and then run


\lundklippfyllbild{k.jpg}{\textwidth}{\textheight}


it works well. Of course you should replace k.jpg with some other image name...

/Mikael

PS And please, if someone has opinions about the code, don't hesitate
to tell me. This is my first time using lua...


On Thu, May 1, 2014 at 4:59 PM, Otared Kavian <otared at gmail.com> wrote:
> Hi Mikael,
>
> Out of curiosity I tried to typeset your example (after adding the usual \starttext, \stoptext), but using
>         ConTeXt  ver: 2014.04.28 23:24 MKIV beta  fmt: 2014.4.29  int: english/english
> I obtained a TeX error:
>
> tex error       > error on line 13 in file /Users/kavian/Context/essais/mkii/figures/resize-and-center.tex: ! Undefined control sequence
>
>
> \startexternalfigurecollection ...igurecollection
>                                                   {#1}\settrue \c_grph_inclu...
> l.13 \clip[width=8cm,height=7cm]
>                               {%
>
>  3     \startexternalfigurecollection[k.jpg]
>  4         \useexternalfigure[k.jpg][k.jpg]
>  5     \stopexternalfigurecollection
>
> I did not understand what is the « Undefined control sequence », since I think \clip is a known control sequence.
>
> Best regards: OK
>
> On 1 mai 2014, at 15:38, Mikael P. Sundqvist <mickep at gmail.com> wrote:
>
>> OK, sorry for the noise. I think I have the solution:
>>
>> \startexternalfigurecollection[k.jpg]
>>     \useexternalfigure[k.jpg][k.jpg]
>> \stopexternalfigurecollection
>>
>>
>> \externalfigurecollectionminwidth{k.jpg}
>> \externalfigurecollectionmaxheight{k.jpg}
>>
>> \clip[width=8cm,height=7cm]{%
>> \framed[width=8cm,height=7cm,align={middle,lohi},offset=overlay]{%
>> \dimen0=\externalfigurecollectionminwidth{k.jpg}
>> \dimen2=\externalfigurecollectionmaxheight{k.jpg}
>> \dimen4=8cm
>> \dimen6=7cm
>> \startluacode
>> if tex.dimen[0] / tex.dimen[2] < tex.dimen[4] / tex.dimen[6] then
>>      local skalning =
>> -0.5*(tex.dimen[4]/tex.dimen[0]*tex.dimen[2]-tex.dimen[6])
>>      context("\\vskip%ssp", skalning)
>>      context.externalfigure({"k.jpg"},{width="8cm"})
>>      context.sprint("foo")
>> else
>>      local skalning =
>> -0.5*(tex.dimen[6]/tex.dimen[2]*tex.dimen[0]-tex.dimen[4])
>>      context("\\hskip%ssp", skalning)
>>      context.externalfigure({"k.jpg"},{height="7cm"})
>>      context.sprint("bar")
>> end
>> \stopluacode
>> }}
>>
>> If there are any bad side effects of this or simplifications, please
>> do not hesitate to tell me :)
>>
>> /Mikael
>>
>> On Thu, May 1, 2014 at 1:50 PM, Mikael P. Sundqvist <mickep at gmail.com> wrote:
>>> Hi!
>>>
>>> Assume that I want to fill in the text area with images, and I want to
>>> clip and scale them according to these rules:
>>>
>>> 1) If the image is "too wide" (in sense of proportions), then scale it
>>> so that the height fits the text area height, center it, and clip it
>>> to the text area. (See the attached image, on top, where the blue area
>>> is supposed to show the text area and the red rectangle the image.)
>>>
>>> 2) If the image is "too high" (in sense of proportions), then scale it
>>> so that the width fits the text area width, center it, and clip it to
>>> the text area. (See the attached image, on bottom.)
>>>
>>> The background why I want to do this is that I'm making a small
>>> template for presentations, and I'd like the users to insert images as
>>> background without really having to think about if their proportions
>>> fit or not.
>>>
>>> Best regards, Mikael
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to the Wiki!
>>
>> maillist : ntg-context at ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
>> webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
>> archive  : http://foundry.supelec.fr/projects/contextrev/
>> wiki     : http://contextgarden.net
>> ___________________________________________________________________________________
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context at ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
> webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
> archive  : http://foundry.supelec.fr/projects/contextrev/
> wiki     : http://contextgarden.net
> ___________________________________________________________________________________


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