# [Bug 12089] Under 4.8.11.1.2, Transformations, the specification reads: The transformations must be performed in reverse order. For instance, if a scale transformation that doubles the width is applied, followed by a rotation transformation that rotates drawing opera

From: <bugzilla@jessica.w3.org>
Date: Wed, 16 Feb 2011 00:49:12 +0000

Message-Id: <E1PpVZw-0004Ct-5a@jessica.w3.org>
```http://www.w3.org/Bugs/Public/show_bug.cgi?id=12089

Aryeh Gregor <Simetrical+w3cbug@gmail.com> changed:

----------------------------------------------------------------------------
CC|                            |Simetrical+w3cbug@gmail.com

--- Comment #2 from Aryeh Gregor <Simetrical+w3cbug@gmail.com> 2011-02-16 00:49:11 UTC ---
Rotation and scaling are not commutative.  E.g.,

[ 0 -1 ] [ 2 0 ] = [ 0 -1 ]
[ 1  0 ] [ 0 1 ] = [ 2  0 ],

but

[ 2 0 ] [ 0 -1 ] = [ 0 -2 ]
[ 0 1 ] [ 1  0 ] = [ 1  0 ],

which is different.  One of those matrices is a rotation matrix, and the other
is a "scaling" matrix (meaning diagonal for our purposes, I guess).

In the particular example given, take a rectangle twice as wide as it is tall.
Do a quarter turn, so now it's twice as tall as it is wide.  Double the width,
and it's square.  The spec is correct.

--
Configure bugmail: http://www.w3.org/Bugs/Public/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.
```
Received on Wednesday, 16 February 2011 00:49:13 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 20:01:41 UTC