init Files

libraries/lvgl/docs/widgets/scale.rst

@@ -0,0 +1,115 @@
+.. _lv_scale:
+
+================
+Scale (lv_scale)
+================
+
+Overview
+********
+
+Scale allows you to have a linear scale with ranges and sections with custom styling.
+
+.. _lv_scale_parts_and_styles:
+
+Parts and Styles
+****************
+
+The scale widget is divided in the following three parts:
+
+- :cpp:enumerator:`LV_PART_MAIN` Main line. See blue line in the example image.
+- :cpp:enumerator:`LV_PART_ITEMS` Minor ticks. See red minor ticks in the example image.
+- :cpp:enumerator:`LV_PART_INDICATOR` Major ticks and its labels (if enabled). 
+  See pink labels and green major ticks in the example image.
+
+.. image:: /misc/scale.png
+
+.. _lv_scale_usage:
+
+Usage
+*****
+
+Set ranges
+----------
+
+The minor and major range (values of each tick) are configured with :cpp:expr:`lv_scale_set_range(scale, minor_range, major_range)`.
+
+Tick drawing order
+------------------
+You can set the drawing of the ticks on top of the main line with :cpp:expr:`lv_scale_set_draw_ticks_on_top(scale, true)`. The default
+drawing order is below the main line.
+
+This is a scale with the ticks being drawn below of the main line (default):
+
+.. image:: /misc/scale_ticks_below.png
+
+This is an scale with the ticks being drawn at the top of the main line:
+
+.. image:: /misc/scale_ticks_on_top.png
+
+Configure ticks
+---------------
+
+Set the number of total ticks with :cpp:expr:`lv_scale_set_total_tick_count(scale, total_tick_count)` 
+and then configure the major tick being every Nth ticks with :cpp:expr:`lv_scale_set_major_tick_every(scale, nth_tick)`.
+
+Labels on major ticks can be configured with :cpp:expr:`lv_scale_set_label_show(scale, show_label)`, 
+set `show_label` to true if labels should be drawn, :cpp:expr:`false` to hide them. 
+If instead of a numerical value in the major ticks a text is required they can be set 
+with :cpp:expr:`lv_scale_set_text_src(scale, custom_labels)` using ``NULL`` as the last element, 
+i.e. :cpp:expr:`static char * custom_labels[3] = {"One", "Two", NULL};`.
+
+<strong> NOTE: </strong> The major tick value is calculated with the :cpp:expr:`lv_map` API (when not setting the custom labels),
+this calculation takes into consideration the total tick number and the scale range, so the label drawn can present rounding errors
+when the calculated value is a float number.
+
+The length of the ticks can be configured with the length style property on the :cpp:enumerator:`LV_PART_INDICATOR` 
+for major ticks and :cpp:enumerator:`LV_PART_ITEMS` for minor ticks, for example with local style: 
+:cpp:expr:`lv_obj_set_style_length(scale, 5, LV_PART_INDICATOR);` for major ticks 
+and :cpp:expr:`lv_obj_set_style_length(scale, 5, LV_PART_ITEMS);` for minor ticks. 
+
+Sections
+--------
+
+A section is the space between a minor and a major range. They can be created with :cpp:expr:`lv_scale_add_section(scale)` 
+and it handles back an :cpp:type:`lv_scale_section_t` pointer.
+
+The range of the section is configured with :cpp:expr:`lv_scale_section_set_range(section, minor_range, major_range)`. 
+The style of each of the three parts of the scale section can be set with 
+:cpp:expr:`lv_scale_section_set_style(section, PART, style_pointer)`, where `PART` can be 
+:cpp:enumerator:`LV_PART_MAIN`, :cpp:enumerator:`LV_PART_ITEMS` or :cpp:enumerator:`LV_PART_INDICATOR`, 
+:cpp:expr:`style_pointer` should point to a global or static :cpp:type:`lv_style_t` variable.
+
+For labels the following properties can be configured:
+:cpp:func:`lv_style_set_text_font`, :cpp:func:`lv_style_set_text_color`, 
+:cpp:func:`lv_style_set_text_letter_space`, :cpp:func:`lv_style_set_text_opa`.
+
+For lines (main line, major and minor ticks) the following properties can be configured:
+:cpp:func:`lv_style_set_line_color`, :cpp:func:`lv_style_set_line_width`.
+
+.. _lv_scale_events:
+
+Events
+******
+
+No events supported by this widget.
+
+.. _lv_scale_keys:
+
+Keys
+****
+
+No keys supported by this widget.
+
+.. _lv_scale_example:
+
+Example
+*******
+
+.. include:: ../examples/widgets/scale/index.rst
+
+.. _lv_scale_api:
+
+API
+***
+
+:ref:`lv_scale`