[Mapserver-users] pointObj method 'draw'

Manfred Meier m.meier at spiekermann.de
Tue May 18 00:12:25 EDT 2004


Thank you Sean,

for your explanations. Sometimes some background information is 
necessary to understand why an api does this and not that.

 > In my opinion, pointObj::draw and shapeObj::draw are
 > elements of bad design and we shouldn't increase bad design with a
 > lineObj::draw

Can you give me one cue why it is bad design?

Thanks
Manfred

Sean Gillies schrieb:

> Manfred,
> 
> Why the difference?
> 
> First, it must be understood that the development of the MapServer software
> is primarily driven by advances in the mapserv program, and that the
> mapscript module has been developed by wrapping structures and functions
> used in mapserv.  I don't think that the mapscript module has been through
> much design, rather it grows by judicious accretion of features from
> mapserv.
> 
> In mapserv, lines are only drawn within the context of layer features or
> within the context of a legend, hence there is no drawing of lines only,
> only the function that we wrap to use with shapeObj::draw.
> Because of the need for annotation, there are functions to draw points
> outside of the layer feature context and this is the basis for 
> pointObj::draw.
> 
> You are right that the mapscript API implies that there may exist a
> lineObj::draw, and I agree that such a function could be useful.  However,
> I am not in favor of extending the general drawing features of mapscript
> in the current API.  In my opinion, pointObj::draw and shapeObj::draw are
> elements of bad design and we shouldn't increase bad design with a
> lineObj::draw.
> 
> Hope this explains, cheers,
> Sean
> 
> On May 16, 2004, at 10:30 PM, Manfred Meier wrote:
> 
>> Thank you for your answer, Daniel,
>>
>> I knew that, and I would like to know, why there is this difference. 
>> But it's not so very important.
>>
>> Mapserver and mapscript are very helpful for me. I'm trying to display 
>> the location of busses with information about delays.
>>
>> Manfred
>>
> -- 
> Sean Gillies
> sgillies at frii dot com
> http://users.frii.com/sgillies
> 
> 




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