A spangroup is the object that is used to display rich text. Different from the label object, `spangroup` can render text styled with different fonts, colors, and sizes into the spangroup object.
The spangroup object uses span to describe text and text style. so, first we need to create `span` descriptor using `lv_span_t * span = lv_spangroup_new_span(spangroup)`. Then use `lv_span_set_text(span, "text")` to set text. The style of the span is configured as with a normal style object by using its `style` member, eg:`lv_style_set_text_color(&span->style, lv_palette_main(LV_PALETTE_RED))`.
If spangroup object `mode != LV_SPAN_MODE_FIXED` you must call `lv_spangroup_refr_mode()` after you have modified `span` style(eg:set text, changed the font size, del span).
Spangroups store their children differently from normal objects, so normal functions for getting children won't work.
`lv_spangroup_get_child(spangroup, id)` will return a pointer to the child span at index `id`. In addition, `id` can be negative to index from the end of the spangroup where `-1` is the youngest child, `-2` is second youngest, etc.
e.g. `lv_span_t* span = lv_spangroup_get_child(spangroup, 0)` will return the first child of the spangroup. `lv_span_t* span = lv_spangroup_get_child(spangroup, -1)` will return the last (or most recent) child.
### Child Count
Use the function `lv_spangroup_get_child_cnt(spangroup)` to get back the number of spans the group is maintaining.
e.g. `uint32_t size = lv_spangroup_get_child_cnt(spangroup)`
Use `lv_spangroup_set_indent(spangroup, 20)` to set the indent of the first line. all modes support pixel units, in addition to LV_SPAN_MODE_FIXED and LV_SPAN_MODE_BREAK mode supports percentage units too.
