ndg/lib/lvgl/docs/widgets/core/bar.md

Bar (lv_bar)

Overview

The bar object has a background and an indicator on it. The width of the indicator is set according to the current value of the bar.

Vertical bars can be created if the width of the object is smaller than its height.

Not only the end, but also the start value of the bar can be set, which changes the start position of the indicator.

Parts and Styles

• LV_PART_MAIN The background of the bar and it uses the typical background style properties. Adding padding makes the indicator smaller or larger. The anim_time style property sets the animation time if the values set with LV_ANIM_ON.
• LV_PART_INDICATOR The indicator itself; also uses all the typical background properties.

Usage

Value and range

A new value can be set by lv_bar_set_value(bar, new_value, LV_ANIM_ON/OFF). The value is interpreted in a range (minimum and maximum values) which can be modified with lv_bar_set_range(bar, min, max). The default range is 0..100.

The new value in lv_bar_set_value can be set with or without an animation depending on the last parameter (LV_ANIM_ON/OFF).

Modes

The bar can be one of the following modes:

• LV_BAR_MODE_NORMAL A normal bar as described above
• LV_BAR_MODE_SYMMETRICAL Draw the indicator from the zero value to current value. Requires a negative minimum range and positive maximum range.
• LV_BAR_MODE_RANGE Allows setting the start value too by lv_bar_set_start_value(bar, new_value, LV_ANIM_ON/OFF). The start value always has to be smaller than the end value.

Events

• LV_EVENT_DRAW_PART_BEGIN and LV_EVENT_DRAW_PART_END are sent for the following parts:
  • LV_BAR_DRAW_PART_INDICATOR The indicator of the bar
    • part: LV_PART_INDICATOR
    • draw_area: area of the indicator
    • rect_dsc

See the events of the Base object too.

Learn more about Events.

Keys

No Keys are processed by the object type.

Learn more about Keys.

Example

.. include:: ../../../examples/widgets/bar/index.rst

API

.. doxygenfile:: lv_bar.h
  :project: lvgl