[mapserver-dev] RFC 54: MapServer Rendering API

[Steve Lime]

Comments inline. - Steve

>>> On 4/20/2009 at 4:13 AM, in message
<2922382e0904200213j29e1fd66v1efaf3062a2e0b27 at mail.gmail.com>, Thomas Bonfort
<thomas.bonfort at camptocamp.com> wrote:
> Steve,
> 
> I'd also favor a rapid merge, to cut down on the branch maintainance
> and get more testers to iron out bugs.
>
> However before going that way I was hoping for some feedback on the
> sanity of the proposed approach, and more specifically:
>
> * does the API seem usable from the OpenGL implementation point of view ?
> * is the raster layer handling ok, and will we manage to get some time
> and/or funding to implement the change  ?

Toby and Frank will have to comment on the "saneness" of what you've proposed. Hopefully
soon. Do you have a feel for how the raster code would have to be changed? Seems like it
would have to be able to write to a GD buffer and rasterBufferObj. I guess that's why you
reference time and/or $'s for that change.

> As for the instability of the current code, we worked things out with
> Tamas yesterday and begun arriving to some reasonable results
> (embedded legends and scalebars were wrecking havock in the internal
> structures). This in any case should not be a major show stopper, as
> the new code is isolated from the current mapserver API and should not
> be activated unless explicitely activated in configure, and selected
> from a mapfile outputformat.
> 
>>
>>  - how should renderer options be encoded in an output format (presumably 
> not
>> as a format option, perhaps a new renderer option (hash?))
> formatoptions aren't ideal, but these options would mostly be specific
> to each renderer. What are you thinking of when talking of a hash ?

I was thinking of this, in mapfile syntax:

OUTPUTFORMAT
  ...
  RENDEREROPTIONS
    'key' 'value'
    ...
  END
END 

>>  -  what will the make-up of the more specific rendering objects such as 
> line styles
>> look like?
> Not sure I understand your question here. What do you mean by "make-up" ?

The RFC references objects like 'strokeStyleObj' and 'symbolStyleObj', what will
those look like?

>>  - reference maps are still necessary but I think we could attack them by  turning a
>> request for one into an internal mapfile and handing it off to the renderer.
>
> The scale, legend and overview will be needing some major refactoring
> anyways, but this will be probably be done in a second phase once the
> rest of the api has stabilized.

The legend and scalebar will be hard since they have significant layout tasks
associated with them. Reference/overview maps should be easier since they are
just maps. 

> Best regards,
> 
> thomas
> 
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