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Re: Changing the Y axis

From: Dean Jackson <dean@w3.org>
Date: Thu, 11 Oct 2001 15:59:57 +1000
To: Ivan Herman <ivan@w3.org>
Cc: "J. David Eisenberg" <catcode@catcode.com>, ronan@roasp.com, albert valls <albert_nexus@hotmail.com>, "Www-Svg@W3. Org" <www-svg@w3.org>
Message-ID: <20011011155957.A17186@grorg.org>

The SVG Working group is considering adding Y-up coordinate
systems into future versions of SVG. This would avoid the
problem that Ivan has just mentioned (text requiring transform).

Dean


On Thu, 11 Oct 2001, Ivan Herman wrote:

> A word of warning (I learned it from my own experience...): if you use the 
> transformation described below, this will also transform characters in a 
> text. Ie, if you put some text in your drawing, it will appear upside down. 
> Ie, you have to apply a local transformation for text elements which turn 
> them upside down first, and then enclose it in the big drawing.
> 
> It is a bit of a pain.
> 
> 
> At 21:30 10-10-01, J. David Eisenberg wrote:
> >On Wed, 10 Oct 2001 ronan@roasp.com wrote:
> >
> >> Hi,
> >>
> >> Unfortunately, SVG works from the top, left hand corner. There are two 
> >ways
> >> to move the axis back to the bottom left hand.
> >>
> >> 1/ translate everyting by defining a transformation and using it in all
> >> objects and use y = -y
> >>
> >> 2/ calculate all the points.
> >>
> >> 3/ create an svg document and embed it at the position you want using the
> >> $svg->image() method. For this case, you just need to use y=-y.
> >>
> >> I use option 2 for the line calculator at
> >> http://roasp.com/svg/lines.html
> >> This is the most reliable and fastest option but the most cumbersome.
> >>
> >> Ronan.
> >>
> >Yet another method:
> >
> >Find the maximum Y value in your drawing. For purposes of this example,
> >say that the maximum Y is 150.
> >
> >Enclose your entire drawing in this:
> >
> > <g transform="translate(0,150) scale(1,-1)">
> >
> >        <!-- your graphics here -->
> > </g>
> >
> >---
> >J. David Eisenberg  http://catcode.com/
> 
> Ivan Herman
> 
> Head of Offices, World Wide Web Consortium
> C/o W3C Dutch Office at CWI,  Kruislaan 413, 1098 SJ Amsterdam
> tel:           +31-20-5924163
> fax:          +31-20-5924312
> mobile:     +33-608872517
> email:       ivan@w3.org
> 
Received on Thursday, 11 October 2001 02:01:05 GMT

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