Container (lv_cont)

Overview

The containers are essentially a basic object with layout and automatic sizing features features.

Parts and Styles

The containers has only a main style called LV_CONT_PART_MAIN and it can use all the typicaly bacground properties properties and padding for layout auto sizing.

Usage

Layout

You can apply a layout on the containers to automatically order their children. The layout spacing comes from the style's pad properties. The possible layout options:

  • LV_LAYOUT_OFF - Do not align the children.

  • LV_LAYOUT_CENTER - Align children to the center in column and keep padd_inner space between them.

  • LV_LAYOUT_COLUMN_LEFT - Align children in a left-justified column. Keep padd_left space on the left, pad_top space on the top and pad_inner space between the children.

  • LV_LAYOUT_COLUMN_MID - Align children in centered column. Keep padd_top space on the top and pad_inner space between the children.

  • LV_LAYOUT_COLUMN_RIGHT - Align children in a right-justified column. Keep padd_right space on the right, pad_top space on the top and pad_inner space between the children.

  • LV_LAYOUT_ROW_TOP - Align children in a top justified row. Keep pad_left space on the left, pad_top space on the top and pad_inner space between the children.

  • LV_LAYOUT_ROW_MID - Align children in centered row. Keep pad_left space on the left and pad_inner space between the children.

  • LV_LAYOUT_ROW_BOTTOM - Align children in a bottom justified row. Keep pad_left space on the left, pad_bottom space on the bottom and pad_inner space between the children.

  • LV_LAYOUT_PRETTY_TOP - Put as many objects as possible in a row (with at least pad_inner space and pad_left/right space on the sides). Divide the space in each line equally between the children. If here are children with different height in a row align their top edge.

  • LV_LAYOUT_PRETTY_MID - Same as LV_LAYOUT_PRETTY_TOP but if here are children with different height in a row align their middle line.

  • LV_LAYOUT_PRETTY_BOTTOM - Same as LV_LAYOUT_PRETTY_TOP but if here are children with different height in a row align their bottom line.

  • LV_LAYOUT_GRID - Similar to LV_LAYOUT_PRETTY but not divide horizontal space equally just let pad_left/right on the edges and pad_inner space between the elements.

Autofit

Container have an autofit feature which can automatically change the size of the container according to its children and/or its parent. The following options exist:

  • LV_FIT_NONE - Do not change the size automatically.

  • LV_FIT_TIGHT - Shrink-wrap the container around all of its children, while keeping pad_top/bottom/left/right space on the edges.

  • LV_FIT_PARENT - Set the size to the parent's size minus pad_top/bottom/left/right (from the parent's style) space.

  • LV_FIT_MAX - Use LV_FIT_PARENT while smaller than the parent and LV_FIT_TIGHT when larger. It will ensure that the container is, at minimum, the size of its parent.

To set the auto fit mode for all directions, use lv_cont_set_fit(cont, LV_FIT_...). To use different auto fit horizontally and vertically, use lv_cont_set_fit2(cont, hor_fit_type, ver_fit_type). To use different auto fit in all 4 directions, use lv_cont_set_fit4(cont, left_fit_type, right_fit_type, top_fit_type, bottom_fit_type).

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

Container with auto-fit

code

#include "../../../lv_examples.h"
#if LV_USE_CONT

void lv_ex_cont_1(void)
{
    lv_obj_t * cont;

    cont = lv_cont_create(lv_scr_act(), NULL);
    lv_obj_set_auto_realign(cont, true);                    /*Auto realign when the size changes*/
    lv_obj_align_origo(cont, NULL, LV_ALIGN_CENTER, 0, 0);  /*This parametrs will be sued when realigned*/
    lv_cont_set_fit(cont, LV_FIT_TIGHT);
    lv_cont_set_layout(cont, LV_LAYOUT_COLUMN_MID);

    lv_obj_t * label;
    label = lv_label_create(cont, NULL);
    lv_label_set_text(label, "Short text");

    /*Refresh and pause here for a while to see how `fit` works*/
    uint32_t t;
    lv_refr_now(NULL);
    t = lv_tick_get();
    while(lv_tick_elaps(t) < 500);

    label = lv_label_create(cont, NULL);
    lv_label_set_text(label, "It is a long text");

    /*Wait here too*/
    lv_refr_now(NULL);
    t = lv_tick_get();
    while(lv_tick_elaps(t) < 500);

    label = lv_label_create(cont, NULL);
    lv_label_set_text(label, "Here is an even longer text");
}

#endif

MicroPython

No examples yet.

API

Typedefs

typedef uint8_t lv_layout_t
typedef uint8_t lv_fit_t

Enums

enum [anonymous]

Container layout options

Values:

enumerator LV_LAYOUT_OFF = 0

No layout

enumerator LV_LAYOUT_CENTER

Center objects

enumerator LV_LAYOUT_COLUMN_LEFT

COULMN:

  • Place the object below each other

  • Keep pad_top space on the top

  • Keep pad_inner space between the objectsColumn left align

enumerator LV_LAYOUT_COLUMN_MID

Column middle align

enumerator LV_LAYOUT_COLUMN_RIGHT

Column right align

enumerator LV_LAYOUT_ROW_TOP

ROW:

  • Place the object next to each other

  • Keep pad_left space on the left

  • Keep pad_inner space between the objects

  • If the object which applies the layout has base_dir == LV_BIDI_DIR_RTL the row will start from the right applying pad.right spaceRow top align

enumerator LV_LAYOUT_ROW_MID

Row middle align

enumerator LV_LAYOUT_ROW_BOTTOM

Row bottom align

enumerator LV_LAYOUT_PRETTY_TOP

PRETTY:

  • Place the object next to each other

  • If there is no more space start a new row

  • Respect pad_left and pad_right when determining the available space in a row

  • Keep pad_inner space between the objects in the same row

  • Keep pad_inner space between the objects in rows

  • Divide the remaining horizontal space equallyRow top align

enumerator LV_LAYOUT_PRETTY_MID

Row middle align

enumerator LV_LAYOUT_PRETTY_BOTTOM

Row bottom align

enumerator LV_LAYOUT_GRID

GRID

  • Place the object next to each other

  • If there is no more space start a new row

  • Respect pad_left and pad_right when determining the available space in a row

  • Keep pad_inner space between the objects in the same row

  • Keep pad_inner space between the objects in rows

  • Unlike PRETTY, GRID always keep pad_inner space horizontally between objects so it doesn't divide the remaining horizontal space equallyAlign same-sized object into a grid

enumerator _LV_LAYOUT_LAST
enum [anonymous]

How to resize the container around the children.

Values:

enumerator LV_FIT_NONE

Do not change the size automatically

enumerator LV_FIT_TIGHT

Shrink wrap around the children

enumerator LV_FIT_PARENT

Align the size to the parent's edge

enumerator LV_FIT_MAX

Align the size to the parent's edge first but if there is an object out of it then get larger

enumerator _LV_FIT_LAST
enum [anonymous]

Values:

enumerator LV_CONT_PART_MAIN = LV_OBJ_PART_MAIN
enumerator _LV_CONT_PART_VIRTUAL_LAST = _LV_OBJ_PART_VIRTUAL_LAST
enumerator _LV_CONT_PART_REAL_LAST = _LV_OBJ_PART_REAL_LAST

Functions

lv_obj_t *lv_cont_create(lv_obj_t *par, const lv_obj_t *copy)

Create a container objects

Return

pointer to the created container

Parameters
  • par: pointer to an object, it will be the parent of the new container

  • copy: pointer to a container object, if not NULL then the new object will be copied from it

void lv_cont_set_layout(lv_obj_t *cont, lv_layout_t layout)

Set a layout on a container

Parameters
  • cont: pointer to a container object

  • layout: a layout from 'lv_cont_layout_t'

void lv_cont_set_fit4(lv_obj_t *cont, lv_fit_t left, lv_fit_t right, lv_fit_t top, lv_fit_t bottom)

Set the fit policy in all 4 directions separately. It tell how to change the container's size automatically.

Parameters
  • cont: pointer to a container object

  • left: left fit policy from lv_fit_t

  • right: right fit policy from lv_fit_t

  • top: top fit policy from lv_fit_t

  • bottom: bottom fit policy from lv_fit_t

void lv_cont_set_fit2(lv_obj_t *cont, lv_fit_t hor, lv_fit_t ver)

Set the fit policy horizontally and vertically separately. It tells how to change the container's size automatically.

Parameters
  • cont: pointer to a container object

  • hor: horizontal fit policy from lv_fit_t

  • ver: vertical fit policy from lv_fit_t

void lv_cont_set_fit(lv_obj_t *cont, lv_fit_t fit)

Set the fit policy in all 4 direction at once. It tells how to change the container's size automatically.

Parameters
  • cont: pointer to a container object

  • fit: fit policy from lv_fit_t

lv_layout_t lv_cont_get_layout(const lv_obj_t *cont)

Get the layout of a container

Return

the layout from 'lv_cont_layout_t'

Parameters
  • cont: pointer to container object

lv_fit_t lv_cont_get_fit_left(const lv_obj_t *cont)

Get left fit mode of a container

Return

an element of lv_fit_t

Parameters
  • cont: pointer to a container object

lv_fit_t lv_cont_get_fit_right(const lv_obj_t *cont)

Get right fit mode of a container

Return

an element of lv_fit_t

Parameters
  • cont: pointer to a container object

lv_fit_t lv_cont_get_fit_top(const lv_obj_t *cont)

Get top fit mode of a container

Return

an element of lv_fit_t

Parameters
  • cont: pointer to a container object

lv_fit_t lv_cont_get_fit_bottom(const lv_obj_t *cont)

Get bottom fit mode of a container

Return

an element of lv_fit_t

Parameters
  • cont: pointer to a container object

struct lv_cont_ext_t

Public Members

lv_layout_t layout
lv_fit_t fit_left
lv_fit_t fit_right
lv_fit_t fit_top
lv_fit_t fit_bottom