How lvgl meter can support range 0.0 ~ 100.0 , data can be float or double ,or major tick label can be customable

Feature request
1

as above, my data range from 0.0~100.0, float or double type
can meter support these data types or custom major tick labels to adjust the display requirement.
thanks

2

This is question?
If yes then try search float here Meter (lv_meter) — LVGL documentation and selfreply.

3

Hi @jianhaozh ,

Here is a code snippet based on lv_example_meter_1() which demonstrates how to modify the labels on the meter to give a float representation. I think this is what you are asking:

static void meter_cb(lv_event_t * e) {

	lv_obj_draw_part_dsc_t	*dsc  = (lv_obj_draw_part_dsc_t *)lv_event_get_param(e);
	double					value;

	if( dsc->text != NULL ) {		// Filter major ticks...
		value = dsc->value / 10;
		snprintf(dsc->text, sizeof(dsc->text), "%5.1f", value);
	}

}

void meter_test( lv_obj_t *parent ) {

    lv_obj_t *meter = lv_meter_create(parent);
    lv_obj_center(meter);
    lv_obj_set_size(meter, 300, 300);

    /*Add a scale first*/
    lv_meter_scale_t * scale = lv_meter_add_scale(meter);
    lv_meter_set_scale_ticks(meter, scale, 41, 2, 10, lv_palette_main(LV_PALETTE_GREY));
    lv_meter_set_scale_major_ticks(meter, scale, 8, 4, 15, lv_color_black(), 10);
    lv_meter_set_scale_range(meter, scale, 0, 1000, 240, 135);
    lv_meter_indicator_t * indic;

    /*Add a blue arc to the start*/
    indic = lv_meter_add_arc(meter, scale, 3, lv_palette_main(LV_PALETTE_BLUE), 0);
    lv_meter_set_indicator_start_value(meter, indic, 0);
    lv_meter_set_indicator_end_value(meter, indic, 200);

    /*Make the tick lines blue at the start of the scale*/
    indic = lv_meter_add_scale_lines(meter, scale, lv_palette_main(LV_PALETTE_BLUE), lv_palette_main(LV_PALETTE_BLUE),
                                     false, 0);
    lv_meter_set_indicator_start_value(meter, indic, 0);
    lv_meter_set_indicator_end_value(meter, indic, 1000);

    /*Add a red arc to the end*/
    indic = lv_meter_add_arc(meter, scale, 3, lv_palette_main(LV_PALETTE_RED), 0);
    lv_meter_set_indicator_start_value(meter, indic, 800);
    lv_meter_set_indicator_end_value(meter, indic, 1000);

    /*Make the tick lines red at the end of the scale*/
    indic = lv_meter_add_scale_lines(meter, scale, lv_palette_main(LV_PALETTE_RED), lv_palette_main(LV_PALETTE_RED), false, 0);
    lv_meter_set_indicator_start_value(meter, indic, 800);
    lv_meter_set_indicator_end_value(meter, indic, 1000);

    /*Add a needle line indicator*/
    indic = lv_meter_add_needle_line(meter, scale, 4, lv_palette_main(LV_PALETTE_GREY), -10);

    /*Add draw callback to override default values*/
    lv_obj_add_event_cb(meter, meter_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);
}

meter
meter1022×790 12.1 KB

This is a scaling by a factor of 10 for 1 decimal place, if you want 2 decimal places you would scale by a factor of 100 and so on.

I hope that helps…

Kind Regards,

Pete

2 Likes
4

great thanks, it helps me a lot !!!

1 Like