[Qgis-user] Processing Feature Request(?): 'sticky parameters' AND generic settings....

[Richard Duivenvoorde]

Hi, not sure if I ask something which is already available (then please
let me know how), or else I ask for the following:

I have a model which runs some scripts.
This model takes as input some x,y,value file coming from an external
appliation.
For a given area this external app (actually a real mathamatical
'model') is ran several times given different parameters and the result
is visualized in QGIS by showing the xy values, creating contours and
styling it in some ways.
So the scripts in the processing model for given area has several
'fixed' parameters. Eg the boundaries in the contour script for a given
area are always the same. Or the 'load script' also has some inputs
which are always the same.

So in the different script you have input variables like:

##minval=number 0
##maxval=number 3000

BUT using this script in a model, I do not want to set the values
everytime. In the model it is exactly the same: I can set input values,
but they are not 'remembered' in between following runs.

So my idea (as said: please tell me if it is already there):
Can we have something like


##minval=number 0 sticky
##maxval=number 3000 sticky

My idea is that as soon as this script is ran, the 'default values' are
set to the last used values.
So NO value availabe: use the default one (eg 3000 for maxval), but as
soon as the user has changed this to say 2500, that value is saved in
the QSettings somewhere, and next time the script (or model) is ran, the
default value will be 2500

Idea? Or already available?

Which brings me to the following, which I think is usefull for python
devs, but I think also for cpp code.

Why do we not have some utils class which holds some pretty often used
code. What I now think of:

- save a value in settings with given key
- load a (cast to certain type) value from setting with given key and if
not available provide a default something like (the type part not yet in
it):

    def get_settings_value(self, key, default=''):
        if QSettings().contains(self.SETTINGS_SECTION + key):
            key = self.SETTINGS_SECTION + key
            val = QSettings().value(key)
            return val
        else:
            return default

    def set_settings_value(self, key, value):
        key = self.SETTINGS_SECTION + key
        QSettings().setValue(key, value)

I see know so many places where there this is implemented...


Or another one which I think should be centralized:
- the saving and opening of 'current directory'...
We have a lot of dialogs which open a file manager, but a lot of them
open in pretty weird places (like some directory in the installation
folder).
I think it is better if we come up with some 'reasonable' places like:
- current project folder
- last data folder
And implement those as util methods like to be used as opening places
for the file dialogs.

Opinions and or other ideas?

Regards,

Richard Duivenvoorde