[Qgis-developer] Multicolumn legends in print composer

Thu Mar 14 02:26:12 PDT 2013

On Thu, Mar 14, 2013 at 10:05 AM, Régis Haubourg
<regis.haubourg at eau-adour-garonne.fr> wrote:
> Hi,
>
> +1 with Radim. Such hacks do produce inconsistencies and bugs not compatible
> with collaborative coding. IMHO, we need clean coding in QGIS.
>
> A feature already asked I remember could solve both issues. Some of us asked
> that for layers having single symbol style, symbol in legend should be drawn
> on the same line as layer’s title (like in Arcgis or mapinfo).

That should be default, it is what most users are expecting, I
believe. This should not be changed in major line, so if we want that,
it must be implemented for 2.0.

> http://hub.qgis.org/issues/6960

He asked for single symbol item labels, I have commented and suggested
single line representation of single symbol layers instead.

Radim

> Using groups will then help reaching Mathieu’s goal?
>
> Opinions?
>
>
>
> I’m ready to put that in a contract if needed
>
> Régis
>
>
>
> De : Radim Blazek-2 [via OSGeo.org] [mailto:ml-node+[hidden email]]
> Envoyé : jeudi 14 mars 2013 09:47
> À : HAUBOURG
> Objet : Re: Multicolumn legends in print composer
>
>
>
> IMO, using empty layer title to achieve grouping of items from
> multiple layers into a single layer (group) is just a workaround. If
> it was working for some reason in previous versions (probably because
> there was no difference between layer and item spacing) it does not
> mean that we must add new and new hacks to the code to support it
> forever.
>
> I am not convinced that removing layer space if the layer title is
> empty
> (http://hub.qgis.org/projects/quantum-gis/repository/revisions/08c8857/diff/src/core/composer/qgscomposerlegend.cpp)
> is good. It is a hack to support your need but it introduces another
> bug and inconsistency because other user may require hidden layer
> titles (if empty) but still keeping layer spacing.
>
> A clean solution could be to add a new group "Road & Railways" with
> roads and railways layers inside and implement something like flatten
> sublayers check box for the group, which would put items of all
> sublayers directly into the group, ignoring layer titles.
>
> Radim
>
>
> On Wed, Mar 13, 2013 at 1:30 PM, Mathieu Pellerin <[hidden email]> wrote:
>
>
>> Radim,
>>
>> Thanks for fixing the width issue.
>>
>> Regarding layers with no titles and the need for treating the space like a
>> layer item, see http://hub.qgis.org/issues/3605. We've discussed this with
>> Marco Hugentobler back then and came up with a nice compromise.
>>
>> Beyond being a regression as it stands (i.e. legends from 1.8 projects
>> will
>> have visible vertical spacing issues), here's a simple scenario in
>> picture:
>> http://hub.qgis.org/attachments/3161/legend-simple-scenario.jpg (the
>> spacing
>> should be equal for all companies, as well as btween roads and railways.
>>
>> Having no layer title is a way to regroup many layers under one layer name
>> (i.e. having 5 shapefile polygons representing different ago-industrial
>> crops might nicely be represented under one layer title even though the
>> items are in five different physical shapefiles).
>>
>> Math
>>
>>
>> On Wed, Mar 13, 2013 at 5:31 PM, Radim Blazek <[hidden email]>
>> wrote:
>>>
>>> On Tue, Feb 19, 2013 at 4:48 AM, Mathieu Pellerin <[hidden email]>
>>> wrote:
>>> > Radim,
>>> >
>>> > Following up on your implementation of the nice legend's multicolumn
>>> > feature. I've noticed two regression (one of which I've filed a bug
>>> > already).
>>> >
>>> > 1) The right-side box spacing is now miscalculated as it fails to add
>>> > the
>>> > icon label space value. Issue 7099 (http://hub.qgis.org/issues/7099)
>>> > has
>>> > been filed with more details and a accompanying screenshot.
>>>
>>> Fixed.
>>>
>>> > 2) There also was a regression in the way vertical spacing is calculate
>>> > between layer items and layers. An old issue, 3605, highlighted a
>>> > similar
>>> > visual problem which was fixed in revision 08c88575
>>> >
>>> >
>>> > (http://hub.qgis.org/projects/quantum-gis/repository/revisions/08c885759bd280339605ea07a221ab20f7dfdb75/diff/).
>>> > Long story short, layers with no titles are often used as part of a
>>> > group of
>>> > layer items. As such, the solution found in the cited revision was to
>>> > take
>>> > into account the layer item vertical spacing to the layer vertical
>>> > spacing.
>>> > The multicolumn appear to have regressed this. I can open an issue with
>>> > screenshots if necessary.
>>>
>>> Layers with no titles? Is it a hack to avoid the layer title to be
>>> drawn in the legend for single symbol layers? Wouldn't it be better to
>>> modify composer legend so that single symbol layers will be drawn
>>> without separated layer title above symbol and the layer title text
>>> will be used as the symbol label?
>>>
>>> Radim
>>>
>>> > Mathieu
>>> >
>>> >
>>> > On Sun, Nov 18, 2012 at 12:10 AM, Radim Blazek <[hidden email]>
>>> > wrote:
>>> >>
>>> >> On Wed, Nov 14, 2012 at 11:11 AM, Andreas Neumann <[hidden email]>
>>> >> wrote:
>>> >> > Hi,
>>> >> >
>>> >> > Thanks to Radim we now have multi-column legends in print composer.
>>> >>
>>> >> Thanks to Régis and Agence de l'eau Adour as it was already mentioned
>>> >> by
>>> >> others.
>>> >>
>>> >> > This
>>> >> > was one of my long-time feature requests - but it never got to the
>>> >> > top
>>> >> > of my requests so that we could pay for the work.
>>> >> >
>>> >> > Generally it works great, but I noticed two strange behaviors:
>>> >> >
>>> >> > * when having only one column (default) - the background rectangle
>>> >> > is
>>> >> > way too small, not covering the full bouding box of the legend
>>> >>
>>> >> Width? Fixed.
>>> >>
>>> >> > * when going beyong 4 columns, QGIS gets really slow, hangs or
>>> >> > crashes.
>>> >>
>>> >> Splitting of layers into columns is not that easy as it seems to be.
>>> >> It is a special sort of bin packing problem (NP-hard). Maybe it has
>>> >> its own name? I have used brute force because:
>>> >>  - I thought that the number of layer will never be too big
>>> >>  - implementaion of heuristic algorithm for such a marginal feature
>>> >> seemed to be overkill
>>> >>  - suboptimal solution could look quite bad
>>> >>
>>> >> You proved immediately that I was wrong. How many layers do you have?
>>> >> 70 I have read somewhere? My original idea was to calculate number of
>>> >> possibilities first and decide if heuristic should be used. Now it
>>> >> seems a necessity.
>>> >>
>>> >> Maybe I am wrong and there is a simple solution? Well, I did not know
>>> >> at the beginning that I am going to solve combinatorial exercises.
>>> >>
>>> >> Regarding the crash, I was quite careful, using value() where there
>>> >> was minimum suspicion that it could run out of range. Many
>>> >> combinations should not mean allocation of a lot of memory, just more
>>> >> computational time. Only one combination is always evaluated at time.
>>> >> Does it seem to be a memory allocation problem or out of list bounds?
>>> >> Could you send me backtrace off list?
>>> >>
>>> >> Please follow/comment http://hub.qgis.org/issues/1841
>>> >>
>>> >> Radim
>>> >>
>>> >> > Did other test the new multicolumn legends?
>>> >> >
>>> >> > Thanks Radim for your work!
>>> >> >
>>> >> > Andreas
>>> >> > _______________________________________________
>>> >> > Qgis-developer mailing list
>>> >> > [hidden email]
>>> >> > http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>> >> _______________________________________________
>>> >> Qgis-developer mailing list
>>> >> [hidden email]
>>> >> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>> >
>>> >
>>
>>
>
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