Resizing custom component to fill Grid layout

How-to
,
1

Hi Everyone,
I’m trying to make custom widget in LVGL. I’ve created simple component based on lv_objx_template.c/h. My widget will be a composition of few standard widget including scale and few labels. For sake of this example I simplified my widget to following code:

#include "gc_guage.h"
#include "../LVGL/src/core/lv_obj_private.h"
#include "../LVGL/src/core/lv_obj_class_private.h"

#define MY_CLASS &gc_guage_class

static void gc_guage_constructor(const lv_obj_class_t * class_p, lv_obj_t * obj);

const lv_obj_class_t gc_guage_class  = {
    .constructor_cb = gc_guage_constructor,
    .group_def = LV_OBJ_CLASS_GROUP_DEF_TRUE,
    .base_class = &lv_obj_class,
    .width_def = LV_DPI_DEF,
    .height_def = LV_DPI_DEF,
    .instance_size = sizeof(gc_guage_t),
    .name = "gc_guage",
};

lv_obj_t* gc_guage_create(lv_obj_t *parent) {
    LV_LOG_INFO("begin");
    lv_obj_t * obj = lv_obj_class_create_obj(MY_CLASS, parent);
    lv_obj_class_init_obj(obj);

    gc_guage_t *_guage = (gc_guage_t *)obj;
    LV_ASSERT_MALLOC(obj);
    if (obj == NULL) return NULL;

    lv_obj_t *container = lv_obj_create(obj);

    return obj;
}

Everything seems to work so far.

The issue is when I’m trying to insert my widget into GRID layout with:

lv_obj_set_grid_cell(my_widget, LV_GRID_ALIGN_STRETCH, 0, 1, LV_GRID_ALIGN_STRETCH, 0, 1);

The widget doesn’t fill entire space of grid cell. Every other lvgl built-in widget I put into grid this way is stretching to fill entire grid cell but mine stays small in the corner of grid’s cell.

Im suspecting this part of code:

[...]
    .width_def = LV_DPI_DEF,
    .height_def = LV_DPI_DEF,
[...]

but my widget seems to not respond to any changes for this values.
I’ve also try to experiment with events like LV_EVENT_SIZE_CHANGED but with no success.

What is missing in my widget?
Also if you know any source of knowledge in custom widget subject let me know.