Zooming in to a specific part of the page

Zooming in to a specific part of the page

[Aditya Mahajan]

Hi,

Is it possible to zoom into a specific part of the page? I am thinking of 
the following scenario. Suppose I have the following document

\setuppapersize[S6][S6]
\starttext
\placefigure[right,none]{\externalfigure[dummy][width=0.3\textwidth]}
\input knuth

\page

\input tufte

\stoptext

I want that when I click on the image, the pdf is zoomed in so that the 
image occupies the full screen[1], and when I click on the zoomed in 
image, it zooms out and I get the previous page view.

How do I achieve this? I am guessing that some javascript magic might be 
needed, but I do not understand the interaction code at all. This feature 
will be pretty handy for presentations.

Thanks
Aditya

[1]: I do not know if the pdf reader knows the screen size. Assuming that 
the screen aspect ratio is the same as the page aspect ratio might be a 
good approximation (at least for presentations).
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Re: Zooming in to a specific part of the page

[Mojca Miklavec]

On Wed, Nov 17, 2010 at 01:52, Aditya Mahajan wrote:
> Hi,
>
> Is it possible to zoom into a specific part of the page? I am thinking of
> the following scenario. Suppose I have the following document
>
> \setuppapersize[S6][S6]
> \starttext
> \placefigure[right,none]{\externalfigure[dummy][width=0.3\textwidth]}
> \input knuth
>
> \page
>
> \input tufte
>
> \stoptext
>
> I want that when I click on the image, the pdf is zoomed in so that the
> image occupies the full screen[1], and when I click on the zoomed in image,
> it zooms out and I get the previous page view.
>
> How do I achieve this? I am guessing that some javascript magic might be
> needed, but I do not understand the interaction code at all. This feature
> will be pretty handy for presentations.

You don't need JavaScript. You can use a normal hyperlink:

[page /FitR left bottom right top]

Display the page designated by page, with its contents magnified just
enough to fit the rectangle specified by the coordinates left, bottom,
right, and top entirely within the window both horizontally and
vertically. If the required horizontal and vertical magnification
factors are different, use the smaller of the two, centering the
rectangle within the window in the other dimension.

https://www.adobe.com/devnet/pdf/pdf_reference_archive.html
Section "8.2.1 Destinations" of PDFReference16.pdf

You only need to find a way to transfer the data from nice interface
in ConTeXt into PDF literals.

Mojca

PS: in case that you start hacking with that, please also convince
Hans to fix hyperlinks in formulas/chapters/tables/... (see equation
\in[eq:formulalabel]) to point to specific location on some page, not
to the whole page.
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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________

Re: Zooming in to a specific part of the page

[Aditya Mahajan]

On Wed, 17 Nov 2010, Mojca Miklavec wrote:

> On Wed, Nov 17, 2010 at 01:52, Aditya Mahajan wrote:
>> Hi,
>>
>> Is it possible to zoom into a specific part of the page? I am thinking of
>> the following scenario. Suppose I have the following document
>>
>> \setuppapersize[S6][S6]
>> \starttext
>> \placefigure[right,none]{\externalfigure[dummy][width=0.3\textwidth]}
>> \input knuth
>>
>> \page
>>
>> \input tufte
>>
>> \stoptext
>>
>> I want that when I click on the image, the pdf is zoomed in so that the
>> image occupies the full screen[1], and when I click on the zoomed in image,
>> it zooms out and I get the previous page view.
>>
>> How do I achieve this? I am guessing that some javascript magic might be
>> needed, but I do not understand the interaction code at all. This feature
>> will be pretty handy for presentations.
>
> You don't need JavaScript. You can use a normal hyperlink:
>
> [page /FitR left bottom right top]

I hope that I do not have to write raw PDF literals.

> Display the page designated by page, with its contents magnified just
> enough to fit the rectangle specified by the coordinates left, bottom,
> right, and top entirely within the window both horizontally and
> vertically. If the required horizontal and vertical magnification
> factors are different, use the smaller of the two, centering the
> rectangle within the window in the other dimension.
>
> https://www.adobe.com/devnet/pdf/pdf_reference_archive.html
> Section "8.2.1 Destinations" of PDFReference16.pdf

Thanks.

> You only need to find a way to transfer the data from nice interface
> in ConTeXt into PDF literals.

I don't know if this data is available when a figure is being placed. At 
the very least, I need to know the xy location of one of the corners of 
the figure (and can compute other corners based on height and width)

> PS: in case that you start hacking with that, please also convince
> Hans to fix hyperlinks in formulas/chapters/tables/... (see equation
> \in[eq:formulalabel]) to point to specific location on some page, not
> to the whole page.

I thought that you were the most persuasive person :) This has been around 
for a while. Maybe we should open a tracker item for it.

Aditya
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___________________________________________________________________________________

Re: Zooming in to a specific part of the page

[Hans Hagen]

On 17-11-2010 2:27, Aditya Mahajan wrote:

>> PS: in case that you start hacking with that, please also convince
>> Hans to fix hyperlinks in formulas/chapters/tables/... (see equation
>> \in[eq:formulalabel]) to point to specific location on some page, not
>> to the whole page.
>
> I thought that you were the most persuasive person :) This has been
> around for a while. Maybe we should open a tracker item for it.

For some constructs

\setupinteraction[state=start,focus=width]

will do the job for chapter titles and some more. For others it's work 
in progress. The current setting is carried with the hyperlink so it's 
mostly a matter of dealing with it.

That kind of functionality probably has to be configured on a per 
construct basis (with variants concerning what is the width/height of 
that construct in order to avoid too jumpy behaviour). I don't like to 
hack something that later has to be changed.

Hans

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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@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/
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