Line meter (lv_lmeter)¶

Overview¶

The Line Meter object consists of some radial lines which draw a scale.

Set value¶

When setting a new value with lv_lmeter_set_value(lmeter, new_value) the proportional part of the scale will be recolored.

Range and Angles¶

The lv_lmeter_set_range(lmeter, min, max) function sets the range of the line meter.

You can set the angle of the scale and the number of the lines by: lv_lmeter_set_scale(lmeter, angle, line_num). The default angle is 240 and the default line number is 21.

Angle offset¶

By default the scale angle is interpreted symmetrically to the y axis. It results in “standing” line meter. With lv_lmeter_set_angle_offset an offset can be added the scale angle. It can used e.g to put a quarter line meter into a corner or a half line meter to the right or left side.

Styles¶

The line meter uses one style which can be set by lv_lmeter_set_style(lmeter, LV_LMETER_STYLE_MAIN, &style). The line meter’s properties are derived from the following style attributes:

line.color “inactive line’s” color which are greater then the current value
body.main_color “active line’s” color at the beginning of the scale
body.grad_color “active line’s” color at the end of the scale (gradient with main color)
body.padding.hor line length
line.width line width

The default style is lv_style_pretty_color.

Events¶

Only the Generic events are sent by the object type.

Learn more about Events.

Keys¶

No Keys are processed by the object type.

Learn more about Keys.

Example¶

C¶

Simple Line meter¶

#include "lvgl/lvgl.h"

void lv_ex_lmeter_1(void)
{
    /*Create a style for the line meter*/
    static lv_style_t style_lmeter;
    lv_style_copy(&style_lmeter, &lv_style_pretty_color);
    style_lmeter.line.width = 2;
    style_lmeter.line.color = LV_COLOR_SILVER;
    style_lmeter.body.main_color = lv_color_hex(0x91bfed);         /*Light blue*/
    style_lmeter.body.grad_color = lv_color_hex(0x04386c);         /*Dark blue*/
    style_lmeter.body.padding.left = 16;                           /*Line length*/

    /*Create a line meter */
    lv_obj_t * lmeter;
    lmeter = lv_lmeter_create(lv_scr_act(), NULL);
    lv_lmeter_set_range(lmeter, 0, 100);                   /*Set the range*/
    lv_lmeter_set_value(lmeter, 80);                       /*Set the current value*/
    lv_lmeter_set_scale(lmeter, 240, 31);                  /*Set the angle and number of lines*/
    lv_lmeter_set_style(lmeter, LV_LMETER_STYLE_MAIN, &style_lmeter);           /*Apply the new style*/
    lv_obj_set_size(lmeter, 150, 150);
    lv_obj_align(lmeter, NULL, LV_ALIGN_CENTER, 0, 0);
}

MicroPython¶

Simple Line meter¶

# Create a style for the line meter
style_lmeter = lv.style_t()
lv.style_copy(style_lmeter, lv.style_pretty_color)
style_lmeter.line.width = 2
style_lmeter.line.color = lv.color_hex(0xc0c0c0)              # Silver
style_lmeter.body.main_color = lv.color_hex(0x91bfed)         # Light blue
style_lmeter.body.grad_color = lv.color_hex(0x04386c)         # Dark blue
style_lmeter.body.padding.left = 16                           # Line length

# Create a line meter
lmeter = lv.lmeter(lv.scr_act())
lmeter.set_range(0, 100)                    # Set the range
lmeter.set_value(80)                        # Set the current value
lmeter.set_scale(240, 31)                   # Set the angle and number of lines
lmeter.set_style(lv.lmeter.STYLE.MAIN, style_lmeter)          # Apply the new style
lmeter.set_size(150, 150)
lmeter.align(None, lv.ALIGN.CENTER, 0, 0)

API¶

Typedefs

typedef uint8_t lv_lmeter_style_t¶

Enums

enum [anonymous]¶

Values:

enumerator LV_LMETER_STYLE_MAIN¶

Functions

lv_obj_t *lv_lmeter_create(lv_obj_t *par, const lv_obj_t *copy)¶

Create a line meter objects

Return

pointer to the created line meter

Parameters

par: pointer to an object, it will be the parent of the new line meter
copy: pointer to a line meter object, if not NULL then the new object will be copied from it

void lv_lmeter_set_value(lv_obj_t *lmeter, int16_t value)¶

Set a new value on the line meter

Parameters

lmeter: pointer to a line meter object
value: new value

void lv_lmeter_set_range(lv_obj_t *lmeter, int16_t min, int16_t max)¶

Set minimum and the maximum values of a line meter

Parameters

lmeter: pointer to he line meter object
min: minimum value
max: maximum value

void lv_lmeter_set_scale(lv_obj_t *lmeter, uint16_t angle, uint16_t line_cnt)¶

Set the scale settings of a line meter

Parameters

lmeter: pointer to a line meter object
angle: angle of the scale (0..360)
line_cnt: number of lines

void lv_lmeter_set_angle_offset(lv_obj_t *lmeter, uint16_t angle)¶

Set the set an offset for the line meter’s angles to rotate it.

Parameters

lmeter: pointer to a line meter object
angle: angle offset (0..360), rotates clockwise

void lv_lmeter_set_style(lv_obj_t *lmeter, lv_lmeter_style_t type, lv_style_t *style)¶

Set the styles of a line meter

Parameters

lmeter: pointer to a line meter object
type: which style should be set (can be only LV_LMETER_STYLE_MAIN)
style: set the style of the line meter

int16_t lv_lmeter_get_value(const lv_obj_t *lmeter)¶

Get the value of a line meter

Return

the value of the line meter

Parameters

lmeter: pointer to a line meter object

int16_t lv_lmeter_get_min_value(const lv_obj_t *lmeter)¶

Get the minimum value of a line meter

Return

the minimum value of the line meter

Parameters

lmeter: pointer to a line meter object

int16_t lv_lmeter_get_max_value(const lv_obj_t *lmeter)¶

Get the maximum value of a line meter

Return

the maximum value of the line meter

Parameters

lmeter: pointer to a line meter object

uint16_t lv_lmeter_get_line_count(const lv_obj_t *lmeter)¶

Get the scale number of a line meter

Return

number of the scale units

Parameters

lmeter: pointer to a line meter object

uint16_t lv_lmeter_get_scale_angle(const lv_obj_t *lmeter)¶

Get the scale angle of a line meter

Return

angle of the scale

Parameters

lmeter: pointer to a line meter object

uint16_t lv_lmeter_get_angle_offset(lv_obj_t *lmeter)¶

get the set an offset for the line meter.

Return

angle offset (0..360)

Parameters

lmeter: pointer to a line meter object

const lv_style_t *lv_lmeter_get_style(const lv_obj_t *lmeter, lv_lmeter_style_t type)¶

Get the style of a line meter

Return

pointer to the line meter’s style

Parameters

lmeter: pointer to a line meter object
type: which style should be get (can be only LV_LMETER_STYLE_MAIN)

struct lv_lmeter_ext_t¶

Public Members

uint16_t scale_angle¶

uint16_t angle_ofs¶

uint16_t line_cnt¶

int16_t cur_value¶

int16_t min_value¶

int16_t max_value¶