[QGIS-Developer] Storing a copy of map canvas extent in QgsProject (for server)

[Nyall Dawson]

On Thu, 12 Nov 2020 at 23:53, Alessandro Pasotti <apasotti at gmail.com> wrote:
>
> Hi,
>
> The new landing page server core API module makes use of the canvas
> extent to determine the initial extent of the map being shown in the
> web gis viewer.
>
> If I'm not mistaken, that value is only available in map canvas and
> it's not available in the server context. My current workaround mimics
> what happens in the desktop when QgsProject::readProject is emitted.
>
> This prevents me from using the server's config (project) cache and
> results in an unnecessary additional project read when the server
> landing page API is accessed for the first time.
>
> I was thinking of storing that value directly in QgsProject instances
> as "initialExtent()" by reading it from the "mapcanvas" xml tag, I'm
> not super-happy with that because that would be a duplication but I
> cannot see another way to access that information without re-reading
> the project.
>
> Any idea or comment before I proceed?

I'm in favour. I think there's other good use cases for this too -
e.g. giving a stable api for qfield/input to open projects at the
correct map extents.

Can you put the new settings in QgsProjectViewSettings? That's the
ideal place for things like this to reside...

Nyall