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[csswg-drafts] [css-transforms] Bunch of bugs in the interpolation algorithms

From: Manish Goregaokar via GitHub <sysbot+gh@w3.org>
Date: Wed, 14 Sep 2016 13:59:50 +0000
To: public-css-archive@w3.org
Message-ID: <issues.opened-176915123-1473861588-sysbot+gh@w3.org>
Manishearth has just created a new issue for 
https://github.com/w3c/csswg-drafts:

== [css-transforms] Bunch of bugs in the interpolation algorithms ==
Found by @canaltinova and me while [implementing in 
Servo](https://github.com/servo/servo/pull/13188)

 - In both interpolation steps, 
([3D](https://drafts.csswg.org/css-transforms/#interpolation-of-decomposed-3d-matrix-values),
 and 
[2D](https://drafts.csswg.org/css-transforms/#interpolation-of-2d-matrices))
 `matrix = multiply(matrix, rotationMatrix)` should be multiplied the 
other way around.
 - [Imterpolation for 
3d](https://drafts.csswg.org/css-transforms/#interpolation-of-decomposed-3d-matrix-values)
 uses `min` and `max` with the wrong numbers; this will 
unconditionally set the product to -1
 - The algorithm needs rotate axes to be normalized, but the spec 
doesn't explicitly say this. We should probably specify that the 
computed value be normalized or at least mention it [with the 
primitives](https://drafts.csswg.org/css-transforms/#transform-primitives)
 - [Recomposing a 3d 
matrix](https://drafts.csswg.org/css-transforms/#recomposing-to-a-3d-matrix)
 should mention that the returned matrix is initialized to an identity
 - [Interpolation for 
3d](https://drafts.csswg.org/css-transforms/#interpolation-of-decomposed-3d-matrix-values)
 uses `dot` as a variable, probably means `product`


cc @dirkschulze 

Please view or discuss this issue at 
https://github.com/w3c/csswg-drafts/issues/483 using your GitHub 
account
Received on Wednesday, 14 September 2016 14:00:02 UTC

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