Hi all,
Thank you Martin and Jürgen for your explanation. Sounds logical to me.
As a longer time QGIS user I remember that I had the problem of shifted
columns in the field widgets (this was fixed by Jürgen quite some time
ago) and that I had troubles with the shifted columns in data-defined
labeling and data-defined symbology in the past, partially also because
my table design changed after the QGIS project was created. I would
assume that I am not the only one who changes table design during the
life cycle of a project.
So a big +1 to change to a name-based index instead of a numerical
based index for data-defined columns.
Andreas
On Mon, 28 Jan 2013 11:00:09 +0100, Martin Dobias wrote:
Hi Andreas
On Mon, Jan 28, 2013 at 10:30 AM, Andreas Neumann
<[email protected]> wrote:
Hi,
In some of my projects data-defined values for labeling (like
font-color,
rotation fields) are now failing - the order of the column
assignments are
shifted by one column. Perhaps the new Vector API is the cause? My
data
comes from the Postgis data provider. I am testing in the version
74ace4ad21
from January 27.
I checked with an older version from last week (the version starting
with
298f0c000e from January 25) and the labeling is still working ok.
Martin or Marco - could either one of you please have a look what
may be
causing this problem?
I have briefly looked into the code and it seems that new labeling
stores data-defined attributes by index instead of name. If so,
that's
the source of the problem and it should be changed to read/write
names
so that if the order of fields change, the projects work correctly.
Old labeling should not have this problem as it always saves field
names.
The source of the problem is that before, it was possible to have
"holes" in attribute field indices: e.g. three attributes with
indices
0,2,3. Whether such holes appeared depended on the provider being
used. The support for holes has been removed for performance and
simplicity - many developers were not even aware of this thing.
As a quick fix I think you'll need to update your project file. The
proper fix should change writing of attributes as names in
data-defined properties (for new labeling).
Regards
Martin
--
--
Andreas Neumann
Böschacherstrasse 10A
8624 Grüt (Gossau ZH)
Switzerland
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