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Re: Test for animation of SVGLength values

From: Dirk Schulze <vbs85@gmx.de>
Date: Sat, 26 Feb 2011 12:47:04 +0100
Cc: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>, www-svg@w3.org
Message-Id: <75EC5497-EA80-4ED5-9ABD-0FB0DC766B64@gmx.de>
To: Dirk Schulze <vbs85@gmx.de>
Updated the test according to the annotations of Dr. Hoffmann. The lines are set in inch for animation of the absolute units 'in', 'cm', 'mm' and 'pt'. The other side of the coin is, that the test does not check absolute to relative animations of the form: 'from' in px and 'to' in cm. This should be done in another test as well, since the behavior seems not unique in some viewers. Even so it sound difficult to determine intermediate steps in such an animation without knowledge of the resolution, or how the viewer handles resolution.

Cheers
Dirk



Am 25.02.2011 um 21:04 schrieb Dirk Schulze:

> 
>> - I think the test has a problem with the meaning of some units.
>> The relation between px and absolute units like cm 
>> depend on the resolution of the screen - therefore the
>> gray marker lines should be provided with the same units
>> as the used animation values (or see below with a user
>> dependent calculation of values or positions).
> 
> Yes, like you wrote below, there were long discussions, not only in www-style. I could search the quotes, but I think you know them already since you actively took part on the discussions IIRC. All viewers I know take a fixed resolution. This is from the WebKit source code:
> // We always assume 96 CSS pixels in a CSS inch. This is the cold hard truth of the Web.
> // At high DPI, we may scale a CSS pixel, but the ratio of the CSS pixel to the so-called
> // "absolute" CSS length units like inch and pt is always fixed and never changes.
> 
> The test works on Firefox as well as on Batik and on a local copy of WebKit here. So  
> 
>> 
>> - The description is somehow surprising as well -
>> "Test possible values for 'calcMode="spline"', with both commas, whitespace, 
>> and mixed separators"?
> 
> Thanks, this line needs to be removed. The same for the title. Like I wrote in the comment on the SVG, I took test animate-elem-89-t as reference. This is the clincher :)
> 
>> 
>> - missing unit ex?
> 
> Yes, would be good to test it as well. Now that we use the same fonts on all browsers.
> 
> Cheers,
> Dirk
> 
>> 
>> - Note, that SVG tiny 1.2 and SVG 1.1 depend on CSS2.0 and
>> luckily not on the new CSS2.1 draft with obfuscated absolute units
>> (I sent already an LC-comment to www-style@w3.org
>> about this problem in CSS2.1), therefore such tests are
>> tricky. I have some in my test suite and the results with current
>> viewers are disappointing, not only due to their problems with
>> absolute units, therefore in general it is of course a good idea
>> to have such tests, but I think, for mixes of px and absolute
>> units it has to be interactive (PHP script for example) to allow
>> the tester to provide information about the current resolution
>> (relation between px and mm).
>> 
>> Olaf
>> 
> 
Received on Saturday, 26 February 2011 11:47:42 GMT

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