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Re: Cannot change text rotation centre in SVGs

From: Dirk Schulze <dschulze@adobe.com>
Date: Sat, 30 Mar 2013 20:13:06 -0700
To: "Dr. Olaf Hoffmann" <Dr.O.Hoffmann@gmx.de>
CC: "www-svg@w3.org" <www-svg@w3.org>
Message-ID: <BC1AB872-4179-4F8D-8BF2-49FFAE68DD56@adobe.com>

On Mar 30, 2013, at 9:07 AM, Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de> wrote:

> Dirk Schulze:
>> On Mar 26, 2013, at 7:56 AM, Antonio Roberts <antonio@hellocatfood.com> 
> wrote:
>>> Currently, when you rotate text it rotates using the bottom left of
>>> the text as its centre.
>> 
>> That is not correct. Currently it uses (0,0) of the coordinate space of the 
>> text, which is (if no transform on the ancestor) the top left of the 
>> viewport.
> 
> I think, this is not related to the transform attribute, but the rotate
> attribute for text elements, that can take a list of rotations about the
> current text position, for a list in doubt for every glyph. 
> As Helder already mentioned, there are some limited options
> for authors to have influence on the current text position.
> If nothing of this is applied, indeed such a glyph or glyph group
> is effectively rotated around its bottom left corner.

Ah right. I did not think about the rotate attribute. Thanks for pointing this out.

Greetings,
Dirk

> 
> See: 
> http://www.w3.org/TR/2011/REC-SVG11-20110816/text.html#TextElementRotateAttribute
> 
>> 
>>> Would there ever be the possibility of
>>> allowing the text rotation centre to be either of the corners of the
>>> bounding box or the centre?
>> 
>> With CSS Transforms there will be a 'transform-origin' presentation attribute 
>> that allows you to set the origin. In your case it would be 
>> transform-origin="center center".
> 
> I think, CSS Transforms currently has no property related to the rotate 
> attribute for text elements. Therefore this seems not to be related.
> Respectively one has to set each glyph in a separate element that
> is transformable.
> 
> However due to the efforts to have more properties in SVG representing
> the same as currently attributes, may there will be such a property with
> a list of rotations?
> Could be a good idea to give authors more/simpler options to define the
> center of rotation of every glyph relative to the box of the glyph.
> Currently one has a few horizontal values with text-anchor and maybe
> vertically some control with *baseline* properties (did not check this -
> could be maybe more tricky to get the intended effect, because it
> shifts the glyph as well, therefore presumably one has to use more than
> one glyph.)
> 
> 
> 
> Olaf
> 
Received on Sunday, 31 March 2013 03:13:37 UTC

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