Implement Layer Filter Concept

[simboss]

This task captures the discussion we have had in the epic about implementing the possibility to implement the concept of Layer Filter.

A Layer Filter acts directly on a layer coming from GeoServer and filter its content upfront. Once a filter is created for a layer:

• the map content for this layer is automatically filtered
• if we issue a GetFeatureInfo, the features we get are automatically filtered using this filter
• if we open the FeatureGrid for this layer, the features we get are automatically filtered using this filter. Any additional filter we define using the Query Builder or the Quick Filters will go in AND with the layer filter.
• if we create a Widget from this layer, the features we get are automatically filtered using this filter. Any additional filter we define using the Query Builder or the Quick Filters will go in AND with the layer filter.
• the filter will be persisted along with the other layer options, inside the map object on map save. If we reload the map once it's saved the filter will be reapplied.

A filter icon shall be shown in the TOC right next to the layer title to notify that the layer is filtered. The Filter Icon should be toggable to temporarily disable the filter from anywhere above.

[simboss]

The way I see the interaction is similar to what I can do with QGIS.

This is in line with this proposal from @kappu72.

Some interaction below.

Toolbar for the Query Builder

• I have 4 icons, Apply (changes)|Save (changes)|Discard (changes)|Reset (filter)
• Apply is the same we have now. It applies changes to the filter as we do them and updates map content immediately.
• Save is new. It persists the changes we do. It enables once we Apply a valid filter or we Reset it to empty. This is new in the toolbar, it is like the one in the layer properties box. It creates a point in filter change history where we can go back if we Discard. Whenever a change is made with Apply|Reset only if we Save we can exit the QB with no message.
• Discard is new. It discards the changes we do and restore the previous saved filter if there is one or an empty filter. It enables everytime we make a change to the filter or we Apply|Reset it and we have a previous filter that was Saved in the QB or when we start with empty (it send us back to empty in this case). It updates map content immediately.
• Reset is the same we have now. It kills the filter and reset the Filtered Layer to be a normal layer. All its content is shown. It enables once we have saved at least once a valid filter, it makes us start from empty filter all over again. It needs Save to exit the QB if we started without an emtpy filter, otherwise discard is enough. It updates map content immediately.

Creating a new filter

• I can open the Query Builder (QB) from the layer directly, no need to go to the FG. I select the layer in the TOC, I click on the filter icon in the TOC toolbar (to be added), the QB opens up and the TOC disappears.
• Once I am in the QB, all icons in the toolbar are disabled. If I click on the upper left exit icon I go back to the TOC, the source layer is selected and nothing happens.

If I stay in the QB, I can start to make a filter.

• As soon as I make changes the Discard icon is enabled. If I discard now I go back to empty.
• Once a valid filter is created the Apply icons is enabled. In order to see it applied on the map I need to click on the Apply Icon in the Toolbar; Once I click on the Apply Icon, the map content should be updated accordingly, no FG is shown. If I do a GetFeatureInfo, the filter I am creating is applied to the content I get, the QB is not closed so that I can keep working. Now I can save or discard.
• Save enables so I can save my work, I click on Save Icon in the QB Toolbar. The filter is persisted but the QB is not closed ( I might want to keep playing). Reset is enabled if I want to clear the filter. I can exit using the upper left arrow but I can keep playing with the filter and make more changes.
• Once I make more changes, to discard changes and go back to previous filter I saved I can click on Discard Icon in the QB Toolbar. The changes since the last save are discarded, the previous filter is restored, the map content is updated immediately, the QB is not closed (I might want to keep playing). I can exit using the upper left arrow but I can keep playing with the filter and make more changes.
• Reset enables after the firt time I save a filter (before that, Discard is enough to back to empty); it kills the saved filter if there is any and enables the Save|Discard button to persist this action. Clicking on the Reset Filter clears immediately the filter and the map content goes back immediately to the full content of the layer right away to give users visual feedback. Save is now enabled and so is Discard; If I save then the layer is not filtered anymore, I can exit using the upper left arrow; if I Discard I go back to the previous saved filter and once again I can exit using the upper left arrow.
• I can close the QB by clicking on the upper left arrow. If any canges were made (transient or through Apply|Reset) but not saved or discarded (i.e. Save|Discard are enabled) we cannot exit and a message should warn the user to ask if he want to save or discard all changes up to the last saved filter or to empty filter if no filter was ever saved.
• Once we exit if a valid filter was saved a new Icon appers on the side of the layer title, close to the eye to mark that this layer is filtered. If no valid filter was saved (no filter save or a final reset was issued) then the layer is not filtered. The TOC shows the source layer higlighted.

I want to remove a filter

• I selected the layer in the TOC, I click on the Filter icon in the TOC toolbar(to be added), the QB opens up and the TOC disappears;
• Reset is enabled (we have a valid filter as a starting point), all the other icons are disabled.
• I click on the Reset icon in the top Toolbar, Save|Discard are enabled, the QB and the map content goes back to the full content of the layer right away to give users immediate feedback.
• If I Save then I reset the filter if I Discard I do nothing and go back to previous saved filter. I can exit using the upper left arrow. The TOC comes back with the source layer highlighted that has no more the filter icon and content is not filtered anymore on the map.
• If I Discard, the previous filter is restored then I can go back to the TOC by clicking on the left arrow in the Top left. The TOC comes back with the source layer highlighted that has still the filter icon and content is filtered on the map

I want to modify a filter

• I selected the layer in the TOC, I click on the Filter icon in the TOC toolbar(to be added), the QB opens up and the TOC disappears;
• Reset is enabled (we have a valid filter as a starting point), all the other icons are disabled. This is the main difference with the first scenario (filter creation)