ndg/lib/lvgl/docs/widgets/extra/span.md

Span (lv_span)

Overview

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.

Parts and Styles

• LV_PART_MAIN The spangroup has only one part.

Usage

Set text and style

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).

Retrieving a span child

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)

Text align

like label object, the spangroup can be set to one the following modes:

• LV_TEXT_ALIGN_LEFT Align text to left.
• LV_TEXT_ALIGN_CENTER Align text to center.
• LV_TEXT_ALIGN_RIGHT Align text to right.
• LV_TEXT_ALIGN_AUTO Align text auto.

use function lv_spangroup_set_align(spangroup, LV_TEXT_ALIGN_CENTER) to set text align.

Modes

The spangroup can be set to one the following modes:

• LV_SPAN_MODE_FIXED fixes the object size.
• LV_SPAN_MODE_EXPAND Expand the object size to the text size but stay on a single line.
• LV_SPAN_MODE_BREAK Keep width, break the too long lines and auto expand height.

Use lv_spangroup_set_mode(spangroup, LV_SPAN_MODE_BREAK) to set object mode.

Overflow

The spangroup can be set to one the following modes:

• LV_SPAN_OVERFLOW_CLIP truncates the text at the limit of the area.
• LV_SPAN_OVERFLOW_ELLIPSIS will display an ellipsis(...) when text overflows the area.

Use lv_spangroup_set_overflow(spangroup, LV_SPAN_OVERFLOW_CLIP) to set object overflow mode.

first line indent

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.

lines

Use lv_spangroup_set_lines(spangroup, 10) to set the maximum number of lines to be displayed in LV_SPAN_MODE_BREAK mode, negative values indicate no limit.

Events

No special events are sent by this widget.

Learn more about Events.

Keys

No Keys are processed by the object type.

Learn more about Keys.

Example

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

API

.. doxygenfile:: lv_span.h
  :project: lvgl