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).

Retreiving 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.

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

Span with custom styles

C code  

 GitHub
#include "../../lv_examples.h"
#if LV_USE_SPAN && LV_BUILD_EXAMPLES

/**
 * Create span.
 */
void lv_example_span_1(void)
{
    static lv_style_t style;
    lv_style_init(&style);
    lv_style_set_border_width(&style, 1);
    lv_style_set_border_color(&style, lv_palette_main(LV_PALETTE_ORANGE));
    lv_style_set_pad_all(&style, 2);

    lv_obj_t * spans = lv_spangroup_create(lv_scr_act());
    lv_obj_set_width(spans, 300);
    lv_obj_set_height(spans,300);
    lv_obj_center(spans);
    lv_obj_add_style(spans, &style, 0);

    lv_spangroup_set_align(spans, LV_TEXT_ALIGN_LEFT);
    lv_spangroup_set_overflow(spans, LV_SPAN_OVERFLOW_CLIP);
    lv_spangroup_set_indent(spans, 20);
    lv_spangroup_set_mode(spans, LV_SPAN_MODE_BREAK);

    lv_span_t * span = lv_spangroup_new_span(spans);
    lv_span_set_text(span, "china is a beautiful country.");
    lv_style_set_text_color(&span->style, lv_palette_main(LV_PALETTE_RED));
    lv_style_set_text_decor(&span->style, LV_TEXT_DECOR_STRIKETHROUGH | LV_TEXT_DECOR_UNDERLINE);
    lv_style_set_text_opa(&span->style, LV_OPA_30);

    span = lv_spangroup_new_span(spans);
    lv_span_set_text_static(span, "good good study, day day up.");
#if LV_FONT_MONTSERRAT_24
    lv_style_set_text_font(&span->style,  &lv_font_montserrat_24);
#endif
    lv_style_set_text_color(&span->style, lv_palette_main(LV_PALETTE_GREEN));

    span = lv_spangroup_new_span(spans);
    lv_span_set_text_static(span, "LVGL is an open-source graphics library.");
    lv_style_set_text_color(&span->style, lv_palette_main(LV_PALETTE_BLUE));

    span = lv_spangroup_new_span(spans);
    lv_span_set_text_static(span, "the boy no name.");
    lv_style_set_text_color(&span->style, lv_palette_main(LV_PALETTE_GREEN));
#if LV_FONT_MONTSERRAT_20
    lv_style_set_text_font(&span->style, &lv_font_montserrat_20);
#endif
    lv_style_set_text_decor(&span->style, LV_TEXT_DECOR_UNDERLINE);

    span = lv_spangroup_new_span(spans);
    lv_span_set_text(span, "I have a dream that hope to come true.");

    lv_spangroup_refr_mode(spans);
}

#endif

MicroPython code  

 GitHub Simulator
#
# Create span
#
style = lv.style_t()
style.init()
style.set_border_width(1)
style.set_border_color(lv.palette_main(lv.PALETTE.ORANGE))
style.set_pad_all(2)

spans = lv.spangroup(lv.scr_act())
spans.set_width(300)
spans.set_height(300)
spans.center()
spans.add_style(style, 0)

spans.set_align(lv.TEXT_ALIGN.LEFT)
spans.set_overflow(lv.SPAN_OVERFLOW.CLIP)
spans.set_indent(20)
spans.set_mode(lv.SPAN_MODE.BREAK)

span = spans.new_span()
span.set_text("china is a beautiful country.")
span.style.set_text_color(lv.palette_main(lv.PALETTE.RED))
span.style.set_text_decor(lv.TEXT_DECOR.STRIKETHROUGH | lv.TEXT_DECOR.UNDERLINE)
span.style.set_text_opa(lv.OPA._30)

span = spans.new_span()
span.set_text_static("good good study, day day up.");
#if LV_FONT_MONTSERRAT_24
#    lv_style_set_text_font(&span->style,  &lv_font_montserrat_24);
#endif
span.style.set_text_color(lv.palette_main(lv.PALETTE.GREEN))

span = spans.new_span()
span.set_text_static("LVGL is an open-source graphics library.")
span.style.set_text_color(lv.palette_main(lv.PALETTE.BLUE))

span = spans.new_span()
span.set_text_static("the boy no name.")
span.style.set_text_color(lv.palette_main(lv.PALETTE.GREEN))
#if LV_FONT_MONTSERRAT_20
#    lv_style_set_text_font(&span->style, &lv_font_montserrat_20);
#endif
span.style.set_text_decor(lv.TEXT_DECOR.UNDERLINE)

span = spans.new_span()
span.set_text("I have a dream that hope to come true.")

spans.refr_mode()

# lv_span_del(spans, span);
# lv_obj_del(spans);


API

Typedefs

typedef uint8_t lv_span_overflow_t
typedef uint8_t lv_span_mode_t

Enums

enum [anonymous]

Values:

enumerator LV_SPAN_OVERFLOW_CLIP
enumerator LV_SPAN_OVERFLOW_ELLIPSIS
enum [anonymous]

Values:

enumerator LV_SPAN_MODE_FIXED

fixed the obj size

enumerator LV_SPAN_MODE_EXPAND

Expand the object size to the text size

enumerator LV_SPAN_MODE_BREAK

Keep width, break the too long lines and expand height

Functions

lv_obj_t *lv_spangroup_create(lv_obj_t *par)

Create a spangroup object

Parameters

par -- pointer to an object, it will be the parent of the new spangroup

Returns

pointer to the created spangroup

lv_span_t *lv_spangroup_new_span(lv_obj_t *obj)

Create a span string descriptor and add to spangroup.

Parameters

obj -- pointer to a spangroup object.

Returns

pointer to the created span.

void lv_spangroup_del_span(lv_obj_t *obj, lv_span_t *span)

Remove the span from the spangroup and free memory.

Parameters
  • obj -- pointer to a spangroup object.

  • span -- pointer to a span.

void lv_span_set_text(lv_span_t *span, const char *text)

Set a new text for a span. Memory will be allocated to store the text by the span.

Parameters
  • span -- pointer to a span.

  • text -- pointer to a text.

void lv_span_set_text_static(lv_span_t *span, const char *text)

Set a static text. It will not be saved by the span so the 'text' variable has to be 'alive' while the span exist.

Parameters
  • span -- pointer to a span.

  • text -- pointer to a text.

void lv_spangroup_set_align(lv_obj_t *obj, lv_text_align_t align)

Set the align of the spangroup.

Parameters
  • obj -- pointer to a spangroup object.

  • align -- see lv_text_align_t for details.

void lv_spangroup_set_overflow(lv_obj_t *obj, lv_span_overflow_t overflow)

Set the overflow of the spangroup.

Parameters
  • obj -- pointer to a spangroup object.

  • overflow -- see lv_span_overflow_t for details.

void lv_spangroup_set_indent(lv_obj_t *obj, lv_coord_t indent)

Set the indent of the spangroup.

Parameters
  • obj -- pointer to a spangroup object.

  • indent -- The first line indentation

void lv_spangroup_set_mode(lv_obj_t *obj, lv_span_mode_t mode)

Set the mode of the spangroup.

Parameters
  • obj -- pointer to a spangroup object.

  • mode -- see lv_span_mode_t for details.

lv_span_t *lv_spangroup_get_child(const lv_obj_t *obj, int32_t id)

Get a spangroup child by its index.

Parameters
  • obj -- The spangroup object

  • id -- the index of the child. 0: the oldest (firstly created) child 1: the second oldest child count-1: the youngest -1: the youngest -2: the second youngest

Returns

The child span at index id, or NULL if the ID does not exist

uint32_t lv_spangroup_get_child_cnt(const lv_obj_t *obj)
Parameters

obj -- The spangroup object to get the child count of.

Returns

The span count of the spangroup.

lv_text_align_t lv_spangroup_get_align(lv_obj_t *obj)

get the align of the spangroup.

Parameters

obj -- pointer to a spangroup object.

Returns

the align value.

lv_span_overflow_t lv_spangroup_get_overflow(lv_obj_t *obj)

get the overflow of the spangroup.

Parameters

obj -- pointer to a spangroup object.

Returns

the overflow value.

lv_coord_t lv_spangroup_get_indent(lv_obj_t *obj)

get the indent of the spangroup.

Parameters

obj -- pointer to a spangroup object.

Returns

the indent value.

lv_span_mode_t lv_spangroup_get_mode(lv_obj_t *obj)

get the mode of the spangroup.

Parameters

obj -- pointer to a spangroup object.

lv_coord_t lv_spangroup_get_max_line_h(lv_obj_t *obj)

get max line height of all span in the spangroup.

Parameters

obj -- pointer to a spangroup object.

lv_coord_t lv_spangroup_get_expand_width(lv_obj_t *obj)

get the width when all span of spangroup on a line. include spangroup pad.

Parameters

obj -- pointer to a spangroup object.

lv_coord_t lv_spangroup_get_expand_height(lv_obj_t *obj, lv_coord_t width)

get the height with width fixed. the height include spangroup pad.

Parameters

obj -- pointer to a spangroup object.

void lv_spangroup_refr_mode(lv_obj_t *obj)

update the mode of the spangroup.

Parameters

obj -- pointer to a spangroup object.

Variables

const lv_obj_class_t lv_spangroup_class
struct lv_span_t

Public Members

char *txt
lv_obj_t *spangroup
lv_style_t style
uint8_t static_flag
struct lv_spangroup_t
#include <lv_span.h>

Data of label

Public Members

lv_obj_t obj
lv_coord_t indent
lv_coord_t cache_w
lv_coord_t cache_h
lv_ll_t child_ll
uint8_t mode
uint8_t overflow
uint8_t refresh