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83 lines
2.3 KiB
ReStructuredText
83 lines
2.3 KiB
ReStructuredText
Bar (lv_bar)
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============
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Overview
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********
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The bar object has a background and an indicator on it. The width of the
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indicator is set according to the current value of the bar.
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Vertical bars can be created if the width of the object is smaller than
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its height.
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Not only the end, but also the start value of the bar can be set, which
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changes the start position of the indicator.
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Parts and Styles
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****************
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- :cpp:enumerator:`LV_PART_MAIN` The background of the bar and it uses the typical
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background style properties. Adding padding makes the indicator
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smaller or larger. The ``anim_time`` style property sets the
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animation time if the values set with :cpp:enumerator:`LV_ANIM_ON`.
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- :cpp:enumerator:`LV_PART_INDICATOR` The indicator itself; also uses all the typical
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background properties.
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Usage
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*****
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Value and range
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---------------
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A new value can be set by
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``lv_bar_set_value(bar, new_value, LV_ANIM_ON/OFF)``. The value is
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interpreted in a range (minimum and maximum values) which can be
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modified with :cpp:expr:`lv_bar_set_range(bar, min, max)`. The default range is
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0..100.
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The new value in :cpp:func:`lv_bar_set_value` can be set with or without an
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animation depending on the last parameter (``LV_ANIM_ON/OFF``).
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Modes
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-----
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The bar can be one of the following modes:
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- :cpp:enumerator:`LV_BAR_MODE_NORMAL` A normal bar as described above
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- :cpp:enumerator:`LV_BAR_MODE_SYMMETRICAL` Draw the indicator from the zero value to current value. Requires a negative
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minimum range and positive maximum range.
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- :cpp:enumerator:`LV_BAR_MODE_RANGE` Allows setting the start value too by
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``lv_bar_set_start_value(bar, new_value, LV_ANIM_ON/OFF)``. The start
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value always has to be smaller than the end value.
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Events
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******
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- :cpp:enumerator:`LV_EVENT_DRAW_PART_BEGIN` and :cpp:enumerator:`LV_EVENT_DRAW_PART_END` are sent
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for the following parts:
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- :cpp:enumerator:`LV_BAR_DRAW_PART_INDICATOR` The indicator of the bar
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- ``part``: :cpp:enumerator:`LV_PART_INDICATOR`
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- ``draw_area``: area of the indicator
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- ``rect_dsc``
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See the events of the `Base object </widgets/obj>`__ too.
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Learn more about :ref:`events`.
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Keys
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****
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No *Keys* are processed by the object type.
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Learn more about :ref:`indev_keys`.
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Example
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*******
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.. include:: ../examples/widgets/bar/index.rst
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API
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***
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