Re: Zooming in to a specific part of the page

From: Aditya Mahajan <adityam@umich.edu>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: Zooming in to a specific part of the page
Date: Tue, 16 Nov 2010 20:27:55 -0500 (EST)	[thread overview]
Message-ID: <alpine.LNX.2.01.1011162023520.24166@ybpnyubfg.ybpnyqbznva> (raw)
In-Reply-To: <AANLkTi=oWbfOxw28aKwCXy5C0jnLQYjNyMHuf-bRq6V2@mail.gmail.com>

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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