[Bug 1688] Auto Angle - Incorrectly rotated Labels

[Mark Leslie]

That sounds like a good plan.

So the overview of the problem is that we have an a dataset that
contains short linestrings, each with a single character that we want
displayed.  This was done to work around some limitations in ArcMap, and
the client wants Mapserver to produce a similar image.  Looking at the
desired image as shown by ArcMap
<http://mapserver.gis.umn.edu/bugs/attachment.cgi?id=466&action=view> vs
MapServer
<http://mapserver.gis.umn.edu/bugs/attachment.cgi?id=467&action=view>,
you can see that some of the characters are inverted.  As I oversimplify
it, Mapserver attempts to render text upright with respect to the map,
while in this case, we want the text rendered from left to right along
the linestring.  There is a simple two-line 'fix' for this, but it
changes the expected behaviour of the label rendering.  The real
solution that came from the discussion in the bug tracker, would be to
add a keyword to ANGLE to state which algorithm to use.  It would look
like ANGLE AUTOTRUE for the default, and current, algorithm, or ANGLE
AUTO2 for the new algorithm.
I'm not completely sure of the extent of this change, as I haven't
implemented it yet.  Many of you would know better than I.  I don't
expect to touch much of the code, and there should be no backwards
compatibility issues, but I tend to view anything that touches the lexer
as a significant change.
Any thoughts or concerns?
Mark Leslie

Stephen Woodbridge wrote:
> Hi Mark,
> 
> You might want to just start with an email to the dev list with a brief
> description of the problem (yeah it is described in the bug) and how you
> plan to solve it and any particular testing issues. That will give the
> dev team a better idea of the size and scope and they can suggest email,
> bugtracker, and/or rfc from that.
> 
> -Steve W
> 
> bugzilla-daemon at lists.gis.umn.edu wrote:
>> http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1688
>>
>>
>>
>>
>>
>> ------- Additional Comments From mark at refractions.net  2006-10-19
>> 12:20 -------
>> Well, it looks like I'm taking up this 'bug' and trying to get it
>> resolved.  My
>> first question is, is this large enough to warrent an RFC?  Looking
>> throught
>> RFC1, it doesn't seem to fit the need, but since there is a change to the
>> mapfile, if feels to me that there should be greater visibility than
>> in this
>> bugtracker.  Any thoughts?
>>
>>
>>
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>