Bug 2757

Summary: Row vectors vs. column vectors
Product: cairo Reporter: Owen Taylor <otaylor>
Component: generalAssignee: Carl Worth <cworth>
Status: RESOLVED FIXED QA Contact: cairo-bugs mailing list <cairo-bugs>
Severity: normal    
Priority: high CC: jwatt
Version: 0.9.3   
Hardware: x86 (IA32)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description Owen Taylor 2005-03-17 11:29:57 UTC 
We need to decide on a row vector vs. column vector convention;
while we can largely dodge this in documentation, that can
get pretty convoluted and doesn't make things easier for users.

This has an API effect ... the ordering of the arguments for
cairo_matrix_t is right for row vectors and wrong for column
vectors.

(My personal preference is for column vectors
 
 M*x = T*S*x

Correspnds to M(x) = T(S(x))

While x*M = x*S*T doesn't. The column vector convention I think
is also more common in math and marginally more common in 
computer graphics.)
Comment 1 Owen Taylor 2005-08-19 09:00:36 UTC 
The decision was row vectors, and the API was validated for that. While 
there is a remaining work item to improve the docs for describing 
transformations, this bug can be closed.
Comment 2 Carl Worth 2005-08-22 17:14:09 UTC 
Move bugs against "cvs" version to "0.9.3" so we can remove the "cvs" version.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.