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99 lines
3.2 KiB
ReStructuredText
99 lines
3.2 KiB
ReStructuredText
.. _lv_scale:
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================
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Scale (lv_scale)
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================
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Overview
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********
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Scale allows you to have a linear scale with ranges and sections with custom styling.
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.. _lv_scale_parts_and_styles:
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Parts and Styles
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****************
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The scale widget is divided in the following three parts:
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- :cpp:enumerator:`LV_PART_MAIN` Main line. See blue line in the example image.
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- :cpp:enumerator:`LV_PART_ITEMS` Minor ticks. See red minor ticks in the example image.
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- :cpp:enumerator:`LV_PART_INDICATOR` Major ticks and its labels (if enabled).
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See pink labels and green major ticks in the example image.
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.. image:: /misc/scale.png
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.. _lv_scale_usage:
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Usage
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*****
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Set ranges
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----------
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The minor and major range (values of each tick) are configured with :cpp:expr:`lv_scale_set_range(scale, minor_range, major_range)`.
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Configure ticks
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---------------
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Set the number of total ticks with :cpp:expr:`lv_scale_set_total_tick_count(scale, total_tick_count)`
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and then configure the major tick being every Nth ticks with :cpp:expr:`lv_scale_set_major_tick_every(scale, nth_tick)`.
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Labels on major ticks can be configured with :cpp:expr:`lv_scale_set_label_show(scale, show_label)`,
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set `show_label` to true if labels should be drawn, :cpp:expr:`false` to hide them.
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If instead of a numerical value in the major ticks a text is required they can be set
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with :cpp:expr:`lv_scale_set_text_src(scale, custom_labels)` using ``NULL`` as the last element,
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i.e. :cpp:expr:`static char * custom_labels[3] = {"One", "Two", NULL};`.
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The length of the ticks can be configured with the length style property on the :cpp:enumerator:`LV_PART_INDICATOR`
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for major ticks and :cpp:enumerator:`LV_PART_ITEMS` for minor ticks, for example with local style:
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:cpp:expr:`lv_obj_set_style_length(scale, 5, LV_PART_INDICATOR);` for major ticks
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and :cpp:expr:`lv_obj_set_style_length(scale, 5, LV_PART_ITEMS);` for minor ticks.
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Sections
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--------
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A section is the space between a minor and a major range. They can be created with :cpp:expr:`lv_scale_add_section(scale)`
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and it handles back an :cpp:type:`lv_scale_section_t` pointer.
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The range of the section is configured with :cpp:expr:`lv_scale_section_set_range(section, minor_range, major_range)`.
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The style of each of the three parts of the scale section can be set with
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:cpp:expr:`lv_scale_section_set_style(section, PART, style_pointer)`, where `PART` can be
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:cpp:enumerator:`LV_PART_MAIN`, :cpp:enumerator:`LV_PART_ITEMS` or :cpp:enumerator:`LV_PART_INDICATOR`,
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:cpp:expr:`style_pointer` should point to a global or static :cpp:type:`lv_style_t` variable.
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For labels the following properties can be configured:
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:cpp:func:`lv_style_set_text_font`, :cpp:func:`lv_style_set_text_color`,
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:cpp:func:`lv_style_set_text_letter_space`, :cpp:func:`lv_style_set_text_opa`.
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For lines (main line, major and minor ticks) the following properties can be configured:
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:cpp:func:`lv_style_set_line_color`, :cpp:func:`lv_style_set_line_width`.
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.. _lv_scale_events:
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Events
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******
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No events supported by this widget.
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.. _lv_scale_keys:
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Keys
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****
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No keys supported by this widget.
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.. _lv_scale_example:
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Example
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*******
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.. include:: ../examples/widgets/scale/index.rst
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.. _lv_scale_api:
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API
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***
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:ref:`lv_scale`
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