[BUGFIX][Server] In GetPrint, legend as to be fixed when it is not auto update or filter by map

[rldhont]

Description

In release-2_14, a legend is fixed when it is not linked to a map. In
release-2_18, a leganed as to be fixed when it is not auto update or filter
by map.

Actually a legend with no auto update and a layer missing in the request, the
missing layer is repalced by (?)

It's fixed a regression in some.

Checklist

• Commit messages are descriptive and explain the rationale for changes
• I have read the QGIS Coding Standards and this PR complies with them
• This PR passes all existing unit tests (test results will be reported by travis-ci after opening this PR)
• I have run the scripts/prepare-commit.sh script before each commit

[rldhont]

@gioman I think this PR will interested you.

[gioman]

@rldhont thanks! yes, I was vocal about this regression, but I don't think I was the only one affected. To be sure: does this re-introduce a way to select "none" as map object for a specific legend in the map composer? or us fixes the "?" showing when doing the GetPrint requests?

[rldhont]

If you uncheck auto-update, the legend becomes fix like when you select "none" as map.

[gioman]

If you uncheck auto-update, the legend becomes fix like when you select "none" as map.

@rldhont that's the problem: "none" as option has been removed without any previous discussion in one of the first point releases of 2.18

[rldhont]

none is not the problem, because, the legend is only filter by map if check the options. In the other case, the map context is not used.

[gioman]

none is not the problem, because, the legend is only filter by map if check the options. In the other case, the map context is not used.

@rldhont I'm not sure if I'm understanding but I'll give it a try with the patch and let you know. Thanks again.

[rldhont]

I have try the option auto-update and filterByMap and only filterByMap using the linked map. But it's probably an other issue.

[pblottiere]

Hi @rldhont!

Code LGTM but can you add a unit test to highlight the bugfix please?

However, I don't know the underlying mechanism with auto-update or filterByMap, so I leave @gioman judge :).

[gioman]

Trying to compile to test the patch.

[rldhont]

This probably fixed this issue https://issues.qgis.org/issues/16899
Print composer: "none" value for the "map" option of a composer legend is not available anymore in 2.18.10 > no more fixed legends with QGIS Server GetPrint

[gioman]

@rldhont I tested your patch.

I was mistaken when I said (i.e. on Redmine) that the "none" value (for the "map" option in the legend properties of the map composer) was removed sometime at the beginning of the the 2.18 cycle, in fact I compiled also 2.18.0 and the option isn't there.

But compiling 2.18.0 was useful because it allowed me to understand that the problem (or "a" problem) also lies how the project were saved in early 2.18 releases and how they are in later ones.

To make things more clear I used LM to create the GetPrint requests and the Montpellier demo project with only the "Quartiers" and "Buildings" layers active (all the others not active).

All layouts where tested with the "auto-update" option of the legend disabled.

1. if the project is saved and served with 2.18.0 then the GetPrint results are always the expected ones

a) with "filter legend by map content" OFF

b) with "filter legend by map content" ON

c) and even with "filter legend by map content" OFF and map=none, by manually editing the project file as this option is not available anymore in the GUI. This is the "fixed" legend I'm speaking about, and manually editing the project file (to tweak the legend object) is the only way to get again this in GetPrint with QGIS 2.18

2. With the project saved in 2.18.0 and served in 2.18.20 (with the patch) the result for the case

b) with "filter legend by map content" ON

is different from the above one, and it actually seems to show a "fixed legend" behavior, which in my opinion is not correct in this case (if the filter for legend is on it should really show only the layers visible on map):

with results for a) and c) identical to the ones in the first scenario

3. If the project is saved in 2.18.20 and served in 2.18.20 (with the patch or without) the results are only correct for the case b)

while for a) and c) are equals and show the "?" behavior

[rldhont]

Hi @gioman for the review.

Firstly, you need the PR #7250 this one fixed "filter legend by map content" ON.

For the other case, I'll test it and update this PR.

[gioman]

Firstly, you need the PR #7250 this one fixed "filter legend by map content" ON.

@rldhont I also applied this patch, and for a project saved and served with 2.18.20 (with the patches) I don't see any difference from my previous report: with "filter legend by map content" ON result is ok, without the "?" are shown and there no option to select "none" as value for the legend "map" configuration (but even editing the project manually the result is still wrong with the "?").

Thanks for tackling this.

[rldhont]

@gioman I have found why we have (?) in legend. All the layers has to be loaded before, the composer legends are parsed.

I update my commit to fix it.

Now I have to fix the "auto-update" option of the legend enabled. Actually the legend is empty!