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RE: [css3-transform] definition of skewing

From: Rik Cabanier <cabanier@adobe.com>
Date: Mon, 17 Jan 2011 17:13:11 -0800
To: Simon Fraser <smfr@me.com>
CC: Chris Marrin <cmarrin@apple.com>, "www-style@w3.org" <www-style@w3.org>
Message-ID: <8A13F0222395BD428969E5BA529EFA747767253691@NAMBX01.corp.adobe.com>
I've attached an example.
It simply rotates a symbol 360 degrees around one of the axis.

Let me know if the attachment doesn't make it and I'll post it online.


From: Simon Fraser [mailto:smfr@me.com]
Sent: Monday, January 17, 2011 5:00 PM
To: Rik Cabanier
Cc: Chris Marrin; www-style@w3.org
Subject: Re: [css3-transform] definition of skewing

Can you point us to a Flash example that uses rotate(a, b)? I'd like to see what it looks like.


On Jan 17, 2011, at 4:50 PM, Rik Cabanier wrote:

Hi Chris,

>  I don't see a reason to have such a function. If an author wants to do such transformations, he can use matrix().
Having no rotate(a, b) means that we can't use a transition or animation.

Ie if you have an object that rotates into view you want to transition from rotate(0, -90) to rotate(0, 0)
There is no way to do this operation with the current rotate/skew/translate primitives.
Doing it through matrix(...) doesn't work because the transition just interpolates the matrix values (which btw is pretty useless).

>  Again, that's what matrix() is for. A skew(x,y) primitive would always have the issue of ordering between x and y. I think the current primitives are plenty for allowing authors to construct matrices.
The issue is also with transitions/animations.

Also, why would skew(x, y) have an issue of ordering? The matrix would be:
| 1        tan(x)   0 |
| tan(y) 1          0 |
| 0        0         1 |

It doesn't seem necessary to have a separate skewx/skewy since there is usually no need to concatenate skews...

Received on Tuesday, 18 January 2011 01:13:44 UTC

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