[LVGL+Flow] Spinbox specific properties can be expressions/assignable

[fietser28]

Is your feature request related to a problem? Please describe.
I can't dynamically change some of the properties of the spinbox.

Describe the solution you'd like
I would like to have the option to set the specific settings of the spinbox to an expression, not just literal.
These are the settings that the use of the spinbox doesn't change (expression not assignable).

In my case the spinbox properties need to change when I change to a different mode in my application. As an example I've filled in the expressions I need in the literal fields:

Describe alternatives you've considered

1. Create a fixed spinbox for each mode and swap between these.
2. Keep my current manual implementation in flow/native.

Additional context
This has a relation to #229 because spin boxes are mainly useful with encoders (imho).

[fietser28]

I noticed LVGL API is lacking:

• lv_spinbox_get_range_min
• lv_spinbox_get_range_max
• lv_spinbox_get_digit_format_count
• lv_spinbox_get_digit_format_position

So did some digging in lvgl sources. Would this be an option to use (to get min range value) as a temporary(?) workaround:

        lv_spinbox_t *spinbox = (lv_spinbox_t *)objects.obj14;
        int32_t cur_value =  spinbox->range_min;

[fietser28]

I've implemented part of it. Min/max range can be an expression now.
See branch: https://github.com/fietser28/studio/tree/spinbox

Will work on the format count and position options in the same way before creating a merge request.

Feel free to comment on the solution I used.
I might also create an issue in LVGL repo whether they will add the above calls. Probably won't be added backwards to v8.

[fietser28]

is working now on MCU using my branch. The simulator is WIP.

[mvladic]

I flew through the changes a bit and it looks pretty good to me. When you're done, I'll take a closer look. The next release should be by this Monday. If you can finish it by Friday then we can add it to this release.

[mvladic]

I noticed LVGL API is lacking:

• lv_spinbox_get_range_min
• lv_spinbox_get_range_max
• lv_spinbox_get_digit_format_count
• lv_spinbox_get_digit_format_position

So did some digging in lvgl sources. Would this be an option to use (to get min range value) as a temporary(?) workaround:

        lv_spinbox_t *spinbox = (lv_spinbox_t *)objects.obj14;
        int32_t cur_value =  spinbox->range_min;

FYI In version 9.2 you can't access members of lv_spinbox or any other widget directly. Workaround is to include "lvgl/src/lvgl_private.h".

[fietser28]

FYI In version 9.2 you can't access members of lv_spinbox or any other widget directly. Workaround is to include "lvgl/src/lvgl_private.h".

Thanks for the tip.

I don't know if I will have the time to finish this before the end of the week.

[mvladic]

I don't know if I will have the time to finish this before the end of the week.

Never mind, take your time and we will release it when it is ready.

[fietser28]

I've added some updates to the branch (while following master branch). Current status is:

In simulator:

• V9.1 works, except when step is an assignable: Then clicking on a digit with mouse the position flips back.
• V8.3 works until you click on the spinbox: Then simulation freezes. Can't figure out why.
• AFIAK generated code works also in combination with groups on hardware
• using expressions in the expression fields doesn't work reliably. Using variables works fine.

[fietser28]

Here is a test project to explore the different features.
spinboxTest.eez-project.zip

[fietser28]

Also note the last commit I make Commented out unnecesairy callbacks: These are expressions not assignable?
. Is the assumption correct these callbacks are not needed/must not be present when the parameter is an expression?

[mvladic]

I'm not happy how currently adding new LVGL widget works. We have separate definitions for editing and running inside simulator (lvglCreate functions) and for source code generator (lvglBuild functions). So, you need to implemented all these functions:

lvglCreateObj
lvglBuild
lvglBuildTickSpecific

and some more:

getIsAccessibleFromSourceCode
lvglPostBuild

And, even worse, for lvglCreate you need to implement wrapper code for the LVGL (the stuff in studio_api.cpp).

I think, ideally, you should implement only one function that should work for both simulator and source code generator. And you shouldn't need to write wrapper code.

I have some ideas how to do it, so for now I think you should stop working on this since it is possible that very soon I start to refactor all this lvglCreate and lvglBuild code.

[fietser28]

Ok, I agree with you on your analysis. For adding/changing a single widgets parameters I had to touch code in a lot of different places (was not easy to figure it out).

I also changed a few things in expression-property.tsx. Imho these functions will become unmaintainable if more LVGL versions and widgets are added.