Re: FW: [office-comment] Orientation problems with angles

From
<>
Date
2012-08-07T14:19:40+00:00
ID
Thread
Re: FW: [office-comment] Orientation problems with angles
For relative rotations (relative to current
placement) all you need to do is specify the amount of rotation and direction
(clockwise versus counter-counterclockwise).  The coordinate system
is irrelevant.

For absolute positioning, e.g., "place
the arrow so it is pointed at +45 degrees" then you need more context.

In any case, I've added this issue to
JIRA (OFFICE-3775) so we can track any proposed resolution there.

-Rob

"Dennis E. Hamilton" <>
wrote on 08/05/2012 11:46:03 AM:

> From: "Dennis E. Hamilton" <>

> To: <>,

> Date: 08/05/2012 11:47 AM

> Subject: FW: [office-comment] Orientation problems
with angles

> 

> [Sorry, sent from an unrecognized address before.]

> 

> -----Original Message-----

> From: Dennis E. Hamilton [mailto:]

> Sent: Saturday, August 04, 2012 23:36

> To: 'Andreas J. Guelzow'; ''

> Subject: RE: [office-comment] Orientation problems with angles

> 

> Help me understand this better,

> 

> From the perspective of the observer that you refer to,

> 

> Where is the origin, and in which directions are +X and +Y from that

> origin?  And from which axis (+X, +Y, -X, -Y) extending from
the 

> origin does this clockwise motion originate that opens the angle 

> with respect to which the gradient vector is oriented?

> 

>  - Dennis

> 

> -----Original Message-----

> From: Andreas J. Guelzow [mailto:]

> Sent: Saturday, August 04, 2012 22:30

> To: 

> Subject: RE: [office-comment] Orientation problems with angles

> 

> On Sat, 2012-08-04 at 21:07 -0600, Dennis E. Hamilton wrote:

> > Are you not assuming the orientation of the +X and +Y axis directions

> > and the placement of the origin from the perspective of the viewer
in

> > making that statement?

> 

> I don't see how the coordinate system has anything to do with

> "clockwise" nor how the placement of the origin is involved
in a

> clockwise rotation. The clocks I know have no coordinate system nor
an

> origin (just a centre of rotation). The meaning of "clockwise"
is

> uniquely determined once we know on which side of the plane the viewer

> is. And in the case of office documents this is always clear. 

> 

> Andreas

> 

> > 

> > -----Original Message-----

> > From: Andreas J. Guelzow [mailto:]

> > Sent: Saturday, August 04, 2012 17:27

> > To: 

> > Subject: Re: [office-comment] Orientation problems with angles

> > 

> > On Sat, 2012-08-04 at 15:04 -0600, Regina Henschel wrote:

> > > Hi members,

> > > 

> > > a lot of places, which use angles, are not exact enough
about the 

> > > direction of the angle. The reason for this problem is,
that the spec 

> > > does not define a coordinate system and therefor terms like
"clockwise"

> > 

> > If we are talking about angles in a plane document with respect
to

> > rotations, what is ambiguous about "clockwise"?

> > 

> > > or "start at 12 o'clock" are ambiguous. Sometimes
a direction is totally 

> > > missing or even a leg of the angle is missing. To get an
angle with 

> > > directions you need an ordered pair of rays.

> > 

> > A rotation in the plane is uniquely determined by its centre,
the

> > measure of the angle and whether angles are measured clockwise
or

> > counterclockwise.

> > 

> > 

> > > 

> > > How to improve the situation?

> > > (1) Do not define own elements or attributes, when well
defined one 

> > > exists in SVG.

> > > (2) Illustrate the definitions, for example as it is done
in SVG for the 

> > > coordinate system 

> > > [http://www.w3.org/TR/SVG/coords.html#InitialCoordinateSystem]

> > > (3) Be careful to define the legs of the angle as ordered
pair of rays 

> > > for every angle.

> > 

> > > (4) Deprecate an attribute, when it has often been implemented
with 

> > > wrong direction, and define an unambiguous solution.

> > 

> > If implementations have bugs, those bugs should be fixed rather
than the

> > standard changed.

> > 

> > Andreas

> > 

> > 

> > -- 

> > Andreas J. Guelzow, PhD, FTICA

> > Concordia University College of Alberta

> > 

> > 

> 

> -- 

> Andreas J. Guelzow, PhD, FTICA

> Concordia University College of Alberta

> 

> 

> -- 

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