12089 2011-02-15 17:57:33 +0000 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 2011-08-04 05:03:41 +0000 1 1 1 Unclassified HTML WG LC1 HTML Canvas 2D Context unspecified Other other RESOLVED WONTFIX http://www.whatwg.org/specs/web-apps/current-work/#transformations P3 normal --- 1 contributor ian ayg ian mike public-html-admin public-html-wg-issue-tracking public-html-bugzilla oldest_to_newest 45614 0 contributor 2011-02-15 17:57:33 +0000 Specification: http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html Section: http://www.whatwg.org/specs/web-apps/current-work/complete.html#transformations Comment: 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 operations by a quarter turn, and a rectangle twice as wide as it is tall is then drawn on the canvas, the actual result will be a square. ... This is incorrect. Rotation and scaling are commutative. When a rectangle is rotated a quarter turn by changing the coordinate space, the x-axis is vertical, and scaling up the x direction will not compress the rectangle into a square. Instead, it will make it 4x as tall as it is wide, just as it does if you scale first, then rotate. Posted from: 67.116.239.5 45630 1 Ms2ger 2011-02-15 20:32:47 +0000 *** Bug 12088 has been marked as a duplicate of this bug. *** 45639 2 ayg 2011-02-16 00:49:11 +0000 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. 47894 3 ian 2011-05-03 20:11:17 +0000 EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document: http://dev.w3.org/html5/decision-policy/decision-policy.html Status: Rejected Change Description: no spec change Rationale: see comment 2 52691 4 mike 2011-08-04 05:03:41 +0000 mass-move component to LC1