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Bug 29110 - Incorrect description of order of multiple transform functions
Summary: Incorrect description of order of multiple transform functions
Status: RESOLVED MOVED
Alias: None
Product: CSS
Classification: Unclassified
Component: Transforms (show other bugs)
Version: unspecified
Hardware: All All
: P2 normal
Target Milestone: ---
Assignee: Simon Fraser
QA Contact: public-css-bugzilla
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-09-03 21:04 UTC by rosenau
Modified: 2017-01-13 17:37 UTC (History)
6 users (show)

See Also:


Attachments

Description rosenau 2015-09-03 21:04:00 UTC
http://www.w3.org/TR/2013/WD-css-transforms-1-20131126/#transform-rendering
states in Example 4:


|  transform: translate(80px, 80px) scale(1.5, 1.5) rotate(45deg);
| }
|
| This transform moves the element by 80 pixels in both the X and Y directions,
| then scales the element by 150%, then rotates it 45° clockwise about the Z axis. 

This is technically incorrect. It should read

"This transform rotates the element 45° clockwise about the Z axis, then scales the element by 150%, then moves it by 80 pixels in both the X and Y directions."

And further:

| Note that the scale and rotation operate about the center of the element,
| since the element has the default transform-origin of 50% 50%.

This is very misleading in this context, since it implies that the translation affects the transform-origin too, which it doesn't.


Similar issue in http://www.w3.org/TR/2013/WD-css-transforms-1-20131126/#transform-function-lists :
| [...] a nested set of transforms is equivalent to a single list of transform functions,
| applied from the outside in.

I'm not sure what that even means. Would "applied from the inside out" be more appropriate?
Mathematically, we're talking about the fact that for all x, we have (f o g)(x) == f(g(x)). Now, are we applying f and g "from the inside out" or "from the outside in"? Or is there a better way to put it? I feel like there should be.
Comment 1 Simon Fraser 2017-01-13 17:37:19 UTC
Moved to https://github.com/w3c/csswg-drafts/issues/909