[mapserver-dev] Letterspacing is different for polyline labels

[Daniel Morissette]

Ah! And Ben (the original contributor) is no longer around to comment I 
guess.

For anyone interested, that contribution was in ticket #1620:
   https://github.com/mapserver/mapserver/issues/1620

No objection here for the change.

Daniel


On 12-07-30 1:41 PM, thomas bonfort wrote:
> Just checked, it dates from the initial patch that was provided to the
> project in 2006.
>
> --
> thomas
>
> On Mon, Jul 30, 2012 at 7:38 PM, Daniel Morissette
> <dmorissette at mapgears.com> wrote:
>> Do we know when the 1.25 factor was introduced and by who? My only concern
>> would be to not undo something that may have been done for a good reason,
>> otherwise I have no objection.
>>
>> Daniel
>>
>>
>> On 12-07-30 12:50 PM, thomas bonfort wrote:
>>>
>>> Any objection in pushing this into 6.2 ? From all my tests, there were
>>> no more or no less inter-character collisions when reducing the
>>> letterspacing, and it has the added advantage of a consistent output
>>> between ANGLE AUTO and ANGLE FOLLOW labels (follow labels fall back to
>>> "auto" mode when the line has only two vertices).
>>>
>>> regards,
>>> thomas
>>>
>>> On Tue, Jul 24, 2012 at 10:46 PM, Lime, Steve D (DNR)
>>> <Steve.Lime at state.mn.us> wrote:
>>>>
>>>> +1 on the change (it'll bust a few regression tests...)
>>>>
>>>> Steve
>>>>
>>>> -----Original Message-----
>>>> From: mapserver-dev-bounces at lists.osgeo.org
>>>> [mailto:mapserver-dev-bounces at lists.osgeo.org] On Behalf Of Oliver Tonnhofer
>>>> Sent: Tuesday, July 24, 2012 9:34 AM
>>>> To: mapserver-dev at lists.osgeo.org
>>>> Subject: [mapserver-dev] Letterspacing is different for polyline labels
>>>>
>>>> Hi,
>>>>
>>>> while comparing the rendering of Mapnik and Mapserver I found out that
>>>> the letter spacing of line labels is much larger with  Mapserver.
>>>>
>>>> After diving into the source code, I found out that labels on a straight
>>>> line are rendered differently than on curved lines. As mentioned in #4026,
>>>> the inter-character spacing is defined in the font itself, but that spacing
>>>> is multiplied by 1.25 when a label is rendered on a polyline.
>>>> See:
>>>> https://github.com/mapserver/mapserver/blob/master/mapprimitive.c#L1818
>>>>
>>>>
>>>> Here you can see how "Alter Wall" and "Neuer Wall" are rendered with
>>>> different spacing. "Alter Wall" is on a straight line, while "Neuer Wall" is
>>>> on a curved line.
>>>> https://dl.dropbox.com/u/2633201/issues/mapserver/letterspacing-125.png
>>>>
>>>> Changing the letterspacing to 1.0 in mapprimitive.c makes the rendering
>>>> more similar:
>>>> https://dl.dropbox.com/u/2633201/issues/mapserver/letterspacing-100.png
>>>>
>>>> The output is now also quite similar to the output of Mapnik (after
>>>> adapting the fontsize).
>>>>
>>>> I've created a ticket for that issue:
>>>> https://github.com/mapserver/mapserver/issues/4404
>>>>
>>>> Regards,
>>>> Oliver
>>>>
>>>> --
>>>> Oliver Tonnhofer    | Omniscale GmbH & Co KG    | http://omniscale.de
>>>> http://mapproxy.org | https://github.com/olt | @oltonn
>>>>
>>>>
>>>>
>>>>
>>>>
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>>>>
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>>
>>
>> --
>> Daniel Morissette
>> http://www.mapgears.com/
>> Provider of Professional MapServer Support since 2000
>>
>>
>>
>>
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-- 
Daniel Morissette
http://www.mapgears.com/
Provider of Professional MapServer Support since 2000