[Qgis-user] fill patterns in map printing

[Andreas Neumann]

Hi Markus and Marco,

I think there are two ways of transparency:

* a global layer transparency (still missing as Marco said)
* transparency in the SVG pattern - this is probably what Markus wants.
This should let layers below the SVG pattern layer shine through where
there is no 100% opaque geometry present in the pattern.

The second version is already supported now. Just define your pattern
such, that there is no complete fill across the whole pattern area.

I saw, however, another problem (probably bound to antialiasing problems).
There are some artefacts behind the SVG pattern when the layer below has a
darker fill.

See these two examples:
* http://www.carto.net/neumann/temp/svg_pattern_antialiasing_problem.png
* http://www.carto.net/neumann/temp/svg_patttern_antialiasing_problem_1.png

The first screenshot was made on Windows, the second on Linux.

In the first example you can see some tiny yellow pixels around the black
patterns, in the second example there is some white and yellow halo around
the hatch-lines.

I wonder if the rendering quality could be improved to avoid these
artefacts or halos?

Andreas


On Thu, January 21, 2010 8:40 am, Marco Hugentobler wrote:
> Hi Markus
>
> At the moment, there is no layer transprency setting in the new symbology.
> I'm
> planing to add that soon.
>
> Regards,
> Marco
>
> Am Donnerstag, 21. Januar 2010 05.39:03 schrieb Markus Nater:
>> I was playing around now quite some time with the svgfill feature. it's
>> a great feature! Nevertheless I experience obstacles, making parts of
>> the svg-grafic transparent. The only way I managed to come close to
>> transparency is by drawing an object in inkscape and setting its filling
>> to an opacity-value (alpha-value) of ca. 100. Then, imported to qgis,
>> underlaying layer shine trough.... but unfortunately it's only
>> semi-transparent.
>>
>> cheers
>> markus
>>
>> Marco Hugentobler schrieb:
>> > Hi Markus
>> >
>> >> 2. The new symbology is not yet supported in print composers
>> legend....
>> >> I guess, thats may be coming in a later version?
>> >
>> > Yes. For now, you could add a composer picture and move it over the
>> > legend as a workaround.
>> >
>> > Regards,
>> > Marco
>> >
>> > Am Mittwoch, 20. Januar 2010 13.15:42 schrieb Markus Nater:
>> >> Hi Marco, Hi Andreas
>> >>
>> >> Thanks a lot for your assistance, so nice!
>> >> I am experimenting at the moment with the vector fill patterns.
>> (that's
>> >> exactly what I am looking for).
>> >> There are two problems though I don't know yet how to overcome:
>> >>
>> >> 1. When I create a line in a 16*16 icon in inkscape and want to use
>> with
>> >> SVGFill the background is just white - it would be great to make it
>> >> transparent, so one could see between the lines what layer is
>> >> underneath.
>> >>
>> >> 2. The new symbology is not yet supported in print composers
>> legend....
>> >> I guess, thats may be coming in a later version?
>> >>
>> >> Cheers
>> >> Markus
>> >>
>> >> Andreas Neumann schrieb:
>> >>> Hi Markus,
>> >>>
>> >>> I don't know exactly what pattern you want to apply. Those are
>> >>> fill-patterns not stroke-dashings or stroke-patterns?
>> >>>
>> >>> Do you have access to the latest svn-version.
>> >>>
>> >>> As Marco said, he just implemented vector fill patterns (with the
>> new
>> >>> symbology-engine) - but it was just recently checked in - so it's
>> not
>> >>> part of the QGIS 1.4 release. Because it is new, it also not
>> documented
>> >>> yet - but we can assist you if you need help.
>> >>>
>> >>> You need to compile yourself or install the QGIS-dev version from
>> >>> OSGeo4Win.
>> >>>
>> >>> As Marco said - you cannot print to PDF yet without a workaround.
>> You
>> >>> would need to print to .ps and then convert the .ps to pdf if you
>> use
>> >>> the new vector fills.
>> >>>
>> >>> Hope this helps,
>> >>> Andreas
>> >>>
>> >>> On Wed, January 20, 2010 10:30 am, Markus Nater wrote:
>> >>>> nobody any advice how to print out a map with line fill patterns
>> that
>> >>>> are not too thin? (to visualize two layers that are above each
>> other)
>> >>>> I am desperate, should hand in some maps and can't get over this
>> >>>> obstacle... so I probably will have to rebuild all my projects in
>> >>>> arcview just in order to print out a decent map...!
>> >>>>
>> >>>> cheers
>> >>>> mark
>> >>>>
>> >>>> _______________________________________________
>> >>>> Qgis-user mailing list
>> >>>> Qgis-user at lists.osgeo.org
>> >>>> http://lists.osgeo.org/mailman/listinfo/qgis-user
>>
>
> --
> Dr. Marco Hugentobler
> HUGIS - GIS programming and consulting
> Webereistrasse 66
> CH-8134 Adliswil
> marco at hugis.net
> http://homepage.hispeed.ch/hugis
> Technical Advisor QGIS Project Steering Committee
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>


-- 
Andreas Neumann
http://www.carto.net/neumann/
http://www.svgopen.org/