Preloader (lv_preload)¶

Overview¶

The preloader object is a spinning arc over a border.

Arc length¶

The length of the arc can be adjusted by lv_preload_set_arc_length(preload, deg).

Spinning speed¶

The speed of the spinning can be adjusted by lv_preload_set_spin_time(preload, time_ms).

Spin types¶

You can choose from more spin types:

LV_PRELOAD_TYPE_SPINNING_ARC spin the arc, slow down on the top
LV_PRELOAD_TYPE_FILLSPIN_ARC spin the arc, slow down on the top but also stretch the arc

To apply one if them use lv_preload_set_type(preload, LV_PRELOAD_TYPE_...)

Spin direction¶

The direction of spinning can be changed with lv_preload_set_dir(preload, LV_PRELOAD_DIR_FORWARD/BACKWARD).

Styles¶

You can set the styles with lv_preload_set_style(btn, LV_PRELOAD_STYLE_MAIN, &style). It describes both the arc and the border style:

arc is described by the line properties
border is described by the body.border properties including body.padding.left/top (the smaller is used) to give a smaller radius for the border.

Events¶

Only the Generic events are sent by the object type.

Keys¶

No Keys are processed by the object type.

Learn more about Keys.

Example¶

C¶

Preloader with custom style¶

#include "lvgl/lvgl.h"

void lv_ex_preload_1(void)
{
    /*Create a style for the Preloader*/
    static lv_style_t style;
    lv_style_copy(&style, &lv_style_plain);
    style.line.width = 10;                         /*10 px thick arc*/
    style.line.color = lv_color_hex3(0x258);       /*Blueish arc color*/

    style.body.border.color = lv_color_hex3(0xBBB); /*Gray background color*/
    style.body.border.width = 10;
    style.body.padding.left = 0;

    /*Create a Preloader object*/
    lv_obj_t * preload = lv_preload_create(lv_scr_act(), NULL);
    lv_obj_set_size(preload, 100, 100);
    lv_obj_align(preload, NULL, LV_ALIGN_CENTER, 0, 0);
    lv_preload_set_style(preload, LV_PRELOAD_STYLE_MAIN, &style);
}

MicroPython¶

Preloader with custom style¶

# Create a style for the Preloader
style = lv.style_t()
lv.style_copy(style, lv.style_plain)
style.line.width = 10                          # 10 px thick arc
style.line.color = lv.color_hex3(0x258)        # Blueish arc color

style.body.border.color = lv.color_hex3(0xBBB) # Gray background color
style.body.border.width = 10
style.body.padding.left = 0

# Create a Preloader object
preload = lv.preload(lv.scr_act())
preload.set_size(100, 100)
preload.align(None, lv.ALIGN.CENTER, 0, 0)
preload.set_style(lv.preload.STYLE.MAIN, style)

MicroPython¶

No examples yet.

API¶

Typedefs

typedef uint8_t lv_preload_type_t¶

typedef uint8_t lv_preload_dir_t¶

typedef uint8_t lv_preload_style_t¶

Enums

enum [anonymous]¶

Type of preloader.

Values:

enumerator LV_PRELOAD_TYPE_SPINNING_ARC¶

enumerator LV_PRELOAD_TYPE_FILLSPIN_ARC¶

enumerator LV_PRELOAD_TYPE_CONSTANT_ARC¶

enum [anonymous]¶

Direction the preloader should spin.

Values:

enumerator LV_PRELOAD_DIR_FORWARD¶

enumerator LV_PRELOAD_DIR_BACKWARD¶

enum [anonymous]¶

Values:

enumerator LV_PRELOAD_STYLE_MAIN¶

Functions

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

Create a pre loader objects

Return

pointer to the created pre loader

Parameters

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

void lv_preload_set_arc_length(lv_obj_t *preload, lv_anim_value_t deg)¶

Set the length of the spinning arc in degrees

Parameters

preload: pointer to a preload object
deg: length of the arc

void lv_preload_set_spin_time(lv_obj_t *preload, uint16_t time)¶

Set the spin time of the arc

Parameters

preload: pointer to a preload object
time: time of one round in milliseconds

void lv_preload_set_style(lv_obj_t *preload, lv_preload_style_t type, const lv_style_t *style)¶

Set a style of a pre loader.

Parameters

preload: pointer to pre loader object
type: which style should be set
style: pointer to a style

void lv_preload_set_type(lv_obj_t *preload, lv_preload_type_t type)¶

Set the animation type of a preloader.

Parameters

preload: pointer to pre loader object
type: animation type of the preload

void lv_preload_set_dir(lv_obj_t *preload, lv_preload_dir_t dir)¶

Set the animation direction of a preloader

Parameters

preload: pointer to pre loader object
direction: animation direction of the preload

lv_anim_value_t lv_preload_get_arc_length(const lv_obj_t *preload)¶

Get the arc length [degree] of the a pre loader

Parameters

preload: pointer to a pre loader object

uint16_t lv_preload_get_spin_time(const lv_obj_t *preload)¶

Get the spin time of the arc

Parameters

preload: pointer to a pre loader object [milliseconds]

const lv_style_t *lv_preload_get_style(const lv_obj_t *preload, lv_preload_style_t type)¶

Get style of a pre loader.

Return

style pointer to the style

Parameters

preload: pointer to pre loader object
type: which style should be get

lv_preload_type_t lv_preload_get_type(lv_obj_t *preload)¶

Get the animation type of a preloader.

Return

animation type

Parameters

preload: pointer to pre loader object

lv_preload_dir_t lv_preload_get_dir(lv_obj_t *preload)¶

Get the animation direction of a preloader

Return

animation direction

Parameters

preload: pointer to pre loader object

void lv_preload_spinner_anim(void *ptr, lv_anim_value_t val)¶

Animator function (exec_cb) to rotate the arc of spinner.

Parameters

ptr: pointer to preloader
val: the current desired value [0..360]

struct lv_preload_ext_t¶

Public Members

lv_arc_ext_t arc¶

lv_anim_value_t arc_length¶

uint16_t time¶

lv_preload_type_t anim_type¶

lv_preload_dir_t anim_dir¶