fix(arc): arc pressing bounds detection

[liamHowatt]

Description of the feature or fix

Fixes #5870

1

Fix an issue where the start and end angle of the arc are not processed correctly if the start angle is smaller than the end angle (and the end angle was <=360 when it was set with the setter).

This is the whole fix

diff --git a/src/widgets/arc/lv_arc.c b/src/widgets/arc/lv_arc.c
index 6d4383971..aa9349a56 100644
--- a/src/widgets/arc/lv_arc.c
+++ b/src/widgets/arc/lv_arc.c
@@ -937,12 +937,12 @@ static bool lv_arc_angle_within_bg_bounds(lv_obj_t * obj, const lv_value_precise
     lv_value_precise_t smaller_angle = 0;
     lv_value_precise_t bigger_angle = 0;
 
     /* Determine which background angle is smaller and bigger */
     if(arc->bg_angle_start < arc->bg_angle_end) {
-        bigger_angle = arc->bg_angle_end;
-        smaller_angle = arc->bg_angle_start;
+        bigger_angle = arc->bg_angle_end - arc->bg_angle_start;
+        smaller_angle = 0;
     }
     else {
         bigger_angle = (360 - arc->bg_angle_start) + arc->bg_angle_end;
         smaller_angle = 0;
     }

It works because the angle parameter in that function is relative to arc->bg_angle_start. The else branch already did the correct thing. I think the else was casually fixed by 84c8cf8

2

I simplified the rest of the function given that smaller_angle is always 0 and all the parameters are non-negative.

@C47D if you can catch anything I oversimplified please comment.

3

I fixed the "big jump prevention logic" which seemed to be misbehaving in master.

Notes

• Update the Documentation if needed.
• Add Examples if relevant.
• Add Tests if applicable.
• If you added new options to lv_conf_template.h run lv_conf_internal_gen.py and update Kconfig.
• Run scripts/code-format.py (astyle version v3.4.12 needs to be installed) and follow the Code Conventions.
• Mark the Pull request as Draft while you are working on the first version, and mark is as Ready when it's ready for review.
• When changes were requested, re-request review to notify the maintainers.
• Help us to review this Pull Request! Anyone can approve or request changes.

[C47D]

Hi @liamHowatt , thanks for taking care of this while I was away.

It's also good to remove complex logic, all looks good to me.

[kisvegabor]

Fantastic, thank you Liam!

[W-Mai]

I think there may still be some minor problems here. In this case, it will be expected that the knob will get stuck at the boundary instead of going back.

void lv_example_arc_1(void)
{
    lv_obj_t * label = lv_label_create(lv_screen_active());

    /*Create an Arc*/
    lv_obj_t * arc = lv_arc_create(lv_screen_active());
    lv_obj_set_size(arc, 150, 150);
    lv_arc_set_rotation(arc, 135);
    lv_arc_set_bg_angles(arc, 0, 359);
    lv_arc_set_value(arc, 10);
    lv_obj_center(arc);
    lv_obj_add_event_cb(arc, value_changed_event_cb, LV_EVENT_VALUE_CHANGED, label);

    /*Manually update the label for the first time*/
    lv_obj_send_event(arc, LV_EVENT_VALUE_CHANGED, NULL);
}

[liamHowatt]

Thanks for trying it @W-Mai! Yup! I was able to fix the problem you found but not without affecting other good behavior. Let me see.

No one merge this yet.

[kisvegabor]

No one merge this yet.

Ups, please open a new PR if you find a good solution. 😅