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Re: element visibility only within the group, not whole document?

From: Mitch Germansky <mbg@cs.rutgers.edu>
Date: Mon, 24 Mar 2003 21:08:37 -0500
Message-ID: <3E7FBA25.1030303@cs.rutgers.edu>
To: www-svg@w3.org

Steve Schafer wrote:

>On Mon, 24 Mar 2003 11:20:14 -0500, Mitch Germansky <mbg@cs.rutgers.edu>
>wrote:
>
>  
>
>>is it possible to have a white <rect> effect only the objects (e.g. 
>><line>s) of the <g> the <rect> and <line> are contained in?
>>
>>it appears that the <rect> whites out the entire document.  i am looking 
>>for a way to "erase" <line>s only within one of many <g>s in a document.
>>
>>i've written my application to place a <set> hidden visibility animation 
>>for every <line> within the <g> and this works, but it does not perform 
>>as well as a single animated <rect> would do.
>>    
>>
>
>I think you're going to find yourself in a deeper and deeper mess if you
>try to implement "erase" or "undo" functions in this fashion. You've
>only just scratched the surface in terms of the painting complexity, and
>I can tell you from personal experience that it will only get worse. You
>need to implement erase/undo at the "logical" level (i.e., within the
>SVG structure of your document), rather than at the "paint" level (i.e.,
>by dealing with the resulting visual appearance). In other words, if you
>want to erase a set of marks, you have to delete (or otherwise disable)
>the instructions that create those marks from the SVG; you can't paint
>over them.
>
so, you are suggesting that the method i am currently using of changing 
visibility in <set> animations for each <line> is the way to go?

>It's true that performance can be an issue, but you need to address that
>separately. For example, many vector-based drawing programs that allow
>free-form scribbling will convert the scribbles to a relatively small
>number of Bezier curves to improve performance.
>
being new in this arena, can you point me to some resources for doing 
transformations for a set of <line>s to a small number of bezier curves? 
 my platform is java batik.

thanks very much for your insight!
Received on Monday, 24 March 2003 21:08:46 GMT

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