[NTG-context] resize and center and clip image

Otared Kavian otared at gmail.com
Thu May 1 16:59:50 CEST 2014


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
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