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RE: Animating length values on gradients

From: Doug Schepers <doug.schepers@vectoreal.com>
Date: Mon, 19 Jun 2006 06:00:38 -0400
To: "'Cameron McCormack'" <cam@mcc.id.au>, <www-svg@w3.org>
Message-Id: <20060619100041.57DD711F363@postalmail-a4.dreamhost.com>

Hi, Cameron-

Cameron McCormack wrote:
| 
| Hi.
| 
| I was wondering what should happen if you try to interpolate between
| percentage values and user unit values on one of a gradient element's
| coordinate attributes.  For example:
| 
|   <svg .>
|     <linearGradient gradientUnits="userSpaceOnUse">
|       <animate attributeName="x1" begin="0s" dur="5s" 
| from="50%" to="150"/>
|     </linearGradient>
|   </svg>
| 
| Since the percentages in these coordinate values are relative to the
| viewport of referencing elements, my guess is that 
| interpolation between 50% and 150 is not possible.
|
| What if the 'linearGradient' element had its 'gradientUnits' attribute
| set to 'objectBoundingBox'?  Should interpolation be possible between
| 50% and 0.75, for example?
| 
| Earlier in the year I asked what should happen when an otherwise
| interpolable attribute is animated between a numeric and a non-numeric
| value, in this thread:
| 
|   http://www.w3.org/mid/20060214212004.GA30064@port.mcc.id.au
| 
| but I haven't received a suitable answer yet.  I guess what should
| happen here for animation between the 50% that cannot be 
| converted to a
| user unit value and the 150 user unit value would be the same for the
| case I asked about before.

Actually, in the case of percentages in the lexical space, there should
always be a computed value in the value space, since there must be a
percentage of some number, be it the viewport's dimensions or the bbox of an
element. Therefore, the UA should interpolate between the computed values.

There's no percentage for you in interpreting it the other way. ;)


Thanks-
Doug, on behalf of the SVG WG 
Received on Monday, 19 June 2006 10:00:51 GMT

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