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ISSUE-2301: Text on a path layout rules unclear wrt startpoint-on-the-path and text-anchor (svg2) [SVG Core 2.0]

From: SVG Working Group Issue Tracker <sysbot+tracker@w3.org>
Date: Mon, 23 Nov 2009 20:52:07 +0000 (GMT)
To: public-svg-wg@w3.org
Message-Id: <20091123205207.B92E0C1B4@nelson.w3.org>

ISSUE-2301: Text on a path layout rules unclear wrt startpoint-on-the-path and text-anchor (svg2) [SVG Core 2.0]

http://www.w3.org/Graphics/SVG/WG/track/issues/2301

Raised by: Erik Dahlström
On product: SVG Core 2.0

This is duplicated from ISSUE-2299 (for Core2):

Trying to work out the correct behavior for the following testcase:

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
	<path id="tp" d="M50 100c100 400 400 -100 600 200" fill="none" stroke="black"/> 
	<text x="200"><textPath xlink:href="#tp" text-anchor="middle" startOffset="50%">hello world</textPath></text>	
</svg>

I think the spec may be in conflict with itself (from text-on-a-path layout rules):

[[
Before rendering the first glyph, the horizontal component of the startpoint-on-the-path is adjusted to take into account various horizontal alignment text properties and attributes, such as a dx attribute value on a 'tspan' element. (In the picture above, the startpoint-on-the-path is the leftmost dot on the path.)
]]

and furthermore:

[[
When the inline-progression-direction is horizontal, then any x attributes on 'text', 'tspan', 'tref' or 'altGlyph' elements represent new absolute offsets along the path, thus providing explicit new values for startpoint-on-the-path.
]]

Now, should x="200" be the startpoint-on-the-path, or should it be an offset from the startpoint-on-the-path (startOffset=50%), should it be ignored, or should it be handled in some other way?

It seems we have at least three different behaviors in current UA:s.

[1] http://dev.w3.org/SVG/profiles/1.1F2/publish/text.html#TextpathLayoutRules
Received on Monday, 23 November 2009 20:52:12 UTC

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