[Qgis-developer] standardisation of the editing map tools: modify behaviour of press-pan-release tools

[Olivier Dalang]

Hello,

Thanks Denis for the initiative ;)

If we are to provide both behaviours, I'm strongly in favour of a user
preference rather than the modifier key. At some point, we'll want to use
modifier keys for other uses (lock orthogonal move, alternate tool mode,
etc.), and this will get very confusing.

To me, the reasons to implement a click-move-click behaviour becomes
evident when you have to edit a lot of features. It's much more effort to
achieve precision while holding the button (tension in the hand), you must
be a finger acrobat to pan/zoom while editing, and you can't answer the
phone neither ;)

Still, I'd suggest once the click-move-click feature is developed, all of
us try it for one week or so, and only then we decide whether we want to
provide both modes or not.


While on the topic of map tools, I was thinking of the following
improvements to the QgsMapTool class:

*1. Implement snapping directly in the QgsMapTool class rather than in each
subclass*
>From what I understand of the source, currently, more or less every
subclass of QgsMapTools provides it's own logic for snapping (or more
generally: for conversion from pixel coordinates click to map coordinates
click). In this context, I don't see how we can achieve cleanly a
cross-tool numerical input system.

*2. Implement pre-click highlighting of features/nodes/edges/rings/...
(depending on what the current tool accepts)*
This type of visual feedback will make editing much more intuitive. Take
the "move node" tool. It's only by mistake that user can learn that it also
acts on edges. Take the move tool : when two features overlap, you have no
idea on which feature you'll act. Etc. This could also be done directly in
QgsMapTool, so that we are sure it's consistent across tools.

Think at how easy it would then be to develop other map tools : almost only
the tool logic, and no boilerplate code at all. What do you think ?


Best regards,

Olivier



On Sep 25, 2014 8:49 AM, "Andreas Neumann" <a.neumann at carto.net> wrote:

> Hi,
>
> I think we should be open-minded towards Denis ideas and not
> categorically reject any changes in curent behaviour. Enabling the CAD
> mode enables a lot of possibilities compared to the current mode.
>
> I am not a CAD expert either, but I am often impressed about how
> efficiently my Autocad colleagues can edit/construct data.
>
> Therefore I would support the option to switch between Graphics/CAD
> mode. There could even be a button in the editing toolbar switching
> between the two modes, though I would expect that people would like to
> stay in one mode most of the time, once they get used to either mode.
>
> From Denis proposals listed below I would prefer option 3 (Provide both
> behaviours and choose which one to use in options). The above suggested
> switch mode button or a modifier key could be added as well, though I
> see it as convenience and not absolutely necessary at the start.
>
> Andreas
>
> Am 25.09.2014 05:46, schrieb Denis Rouzaud:
> > Hi all,
> >
> > I'll try to summarize.
> >
> > *QEP*: I don't mind doing one, but I think it's a bit early since we are
> > still discussing.
> >
> > *Problematic*: Drag'n'drop map tools prevent from enhancing CAD tools in
> > QGIS. For this, it is *required *to add click-click to all map tools.
> >
> > *Other softwares:*
> > CAD softwares use click-click actions while design and GIS (Mapinfo,
> > what about ESRI?) use drag'n'drop.
> > New users or even current users might be afraid of such a change.
> >
> > *Pros of methods:*
> > Advantages of click-clik:
> > * allow other actions to be done in the movement
> > * allow cancelling the action (this was not pointed out yet)
> > Advantages of drag'n'drop
> > * More intuitive (for non-CAD users, which I believe is the majority)
> >
> > I see *3 (and a half) solutions* (thanks to Matthias for pointing some):
> >
> > 1.*Replace current* drag'n'drop to click-click
> > + simplest solution to maintain
> > - need time for new users to get used to this
> >
> > 2.*Enable both* click-clik and drag'n'drop: a short click will free the
> > node/feature while a long click (*) will allow drag'n'drop.
> > + both solutions are here
> > - might be confusing for a "standard" user to make a short click and
> > have a node moving without knowing what to do (although escape would
> > cancel the thing)
> >
> > 3. Provide both behaviours and *choose which one to use in options*
> > (e.g. enable CAD behaviour for map tools).
> > + both solutions are here
> > - behaviour not coherent along the different installations
> >
> > half solution: click-click in map tools, allow drag'n'drop in the main
> > identify tool. Like *Microstation*.
> > - this works only for move features (i.e. not feasible for rotate and
> > node tools)
> >
> > Please comment these solutions, to see if there's a consensus.
> > I'll start and vote for 1. ;)
> >
> >
> > Cheers,
> > Denis
> >
> >
> > * The determination of what should be done is made on the distance in
> > pixels from the press position to the release position. If it's small it
> > is considered as a short. Time might also get into consideration: if you
> > long-click but don't move it could be considered as cancel.
> >
> >
> >
> >
> >
> >
> > On 24.09.2014 10:56, Denis Rouzaud wrote:
> >> Hi all,
> >>
> >> There is somehow an inconsistency in the behaviour of the current
> >> editing map tools.
> >>
> >> Some, like add features, uses the left click to trigger the action.
> >> Others, like the node tool or move feature use press-pan-release mouse
> >> events:
> >> * mouse press to select the node/feature
> >> * mouse mouse to move it
> >> * mouse release sets the position.
> >>
> >> I would propose to standardise this and for the latter tools propose
> >> the following work flow:
> >> * left click enables the move
> >> * left click again to validate at position
> >> * or right click to cancel
> >>
> >> Why changing this?
> >>
> >> If you look at CAD software, they also use the proposed approach. And
> >> there's a reason for doing so, which is valid for QGIS too.
> >>
> >> We are looking at improving the CAD tools in QGIS. In this area, I
> >> recommend trying the fantastic CADinput plugin made by Olivier Dalang.
> >> The plugin works on top of any map tool and enables CAD tools for each
> >> of them.
> >>
> >> The problem with the press-pan-release map tools is that you can't
> >> truly interact while you are actually in the action of the map tool
> >> (holding the click):
> >> * you can't click anymore and this prevents from using intermediate
> >> points (you have to use the tool several times and repeat the
> >> operation as many times as intermediate points you need)
> >> * it is not really user friendly to have to press keys while holing
> >> the click
> >>
> >> This is why, changing the map tools behaviour is requested if we want
> >> to go further with CAD tools in QGIS.
> >>
> >> Regarding the future of CAD tools in QGIS, I am quite sure the plugin
> >> proposed by Olivier would be a good way to go for QGIS, but it still
> >> might be a bit early to integrate it in core. The idea is rather first
> >> to extend the API and propose ready to use methods, so it will be easy
> >> to implement your preferred solution in a plugin.
> >>
> >> But first, we need to standardise the map tools.
> >>
> >> So, the bottom line, any objection to changing the behaviour of:
> >> * edit node tool
> >> * move feature
> >> * rotate feature
> >> * move label
> >> * rotate label
> >> * any other press-pan-release map tool that I am not aware of
> >> ???
> >>
> >> Best wishes,
> >>
> >> Denis
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
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