lv_draw_label.h

API reference for lv_draw_label.h

Summary

Functions

public/draw/lv_draw_label.h:173function

lv_draw_task_get_label_dsc

Try to get a label draw descriptor from a draw task.

lv_draw_label_dsc_t * lv_draw_task_get_label_dsc(lv_draw_task_t *task)

Name	Type	Description
`task`	`lv_draw_task_t *`	draw task

Returns: lv_draw_label_dsc_t * — the task's draw descriptor or NULL if the task is not of type LV_DRAW_TASK_TYPE_LABEL

public/draw/lv_draw_label.h:160function

Name	Type
`dsc`	`lv_draw_letter_dsc_t *`

Name	Type	Description
`dsc`	`lv_draw_label_dsc_t *`	pointer to a draw descriptor

Name	Type	Description
`dsc`	`lv_draw_glyph_dsc_t *`	pointer to a draw descriptor

Name	Type	Description
`layer`	`lv_layer_t *`	pointer to a layer
`dsc`	`const lv_draw_label_dsc_t *`	pointer to draw descriptor
`coords`	`const lv_area_t *`	coordinates of the character

Name	Type	Description
`layer`	`lv_layer_t *`	pointer to a layer
`dsc`	`lv_draw_label_dsc_t *`	pointer to draw descriptor
`point`	`const lv_point_t *`	position of the label
`unicode_letter`	`uint32_t`	the letter to draw

Name	Type	Description
`layer`	`lv_layer_t *`	pointer to a layer
`dsc`	`lv_draw_letter_dsc_t *`	pointer to draw descriptor
`point`	`const lv_point_t *`	position of the label

lv_draw_label_iterate_characters

Should be used during rendering the characters to get the position and other parameters of the characters

void lv_draw_label_iterate_characters(lv_draw_task_t *t, const lv_draw_label_dsc_t *dsc, const lv_area_t *coords, lv_draw_glyph_cb_t cb)

Name	Type	Description
`t`	`lv_draw_task_t *`	pointer to a draw task
`dsc`	`const lv_draw_label_dsc_t *`	pointer to draw descriptor
`coords`	`const lv_area_t *`	coordinates of the label
`cb`	`lv_draw_glyph_cb_t`	a callback to call to draw each glyphs one by one

public/draw/lv_draw_label.h:237function

lv_draw_unit_draw_letter

Draw a single letter using the provided draw unit, glyph descriptor, position, font, and callback.

This function is responsible for rendering a single character from a text string, applying the necessary styling described by the glyph descriptor (dsc). It handles the retrieval of the glyph's description, checks its visibility within the clipping area, and invokes the callback (cb) to render the glyph at the specified position (pos) using the given font (font).

void lv_draw_unit_draw_letter(lv_draw_task_t *t, lv_draw_glyph_dsc_t *dsc, const lv_point_t *pos, const lv_font_t *font, uint32_t letter, lv_draw_glyph_cb_t cb)

Name	Type	Description
`t`	`lv_draw_task_t *`	Pointer to the drawing task.
`dsc`	`lv_draw_glyph_dsc_t *`	Pointer to the descriptor containing styling for the glyph to be drawn.
`pos`	`const lv_point_t *`	Pointer to the point coordinates where the letter should be drawn.
`font`	`const lv_font_t *`	Pointer to the font containing the glyph.
`letter`	`uint32_t`	The Unicode code point of the letter to be drawn.
`cb`	`lv_draw_glyph_cb_t`	Callback function to execute the actual rendering of the glyph.

Structs

struct

lv_draw_label_dsc_t

Member	Type	Description
`base`	`lv_draw_dsc_base_t`
`text`	`const char *`	The text to draw
`text_size`	`lv_point_t`	The size of the text
`font`	`const lv_font_t *`	The font to use. Fallback fonts are also handled.
`color`	`lv_color_t`	Color of the text
`line_space`	`int32_t`	Extra space between the lines
`letter_space`	`int32_t`	Extra space between the characters
`ofs_x`	`int32_t`	Offset the text with this value horizontally
`ofs_y`	`int32_t`	Offset the text with this value vertically
`rotation`	`int32_t`	Rotation of the letters in 0.1 degree unit
`sel_start`	`uint32_t`	The first characters index for selection (not byte index). `LV_DRAW_LABEL_NO_TXT_SEL` for no selection
`sel_end`	`uint32_t`	The last characters's index for selection (not byte index). `LV_DRAW_LABEL_NO_TXT_SEL` for no selection
`sel_color`	`lv_color_t`	Color of the selected characters
`sel_bg_color`	`lv_color_t`	Background color of the selected characters
`text_length`	`uint32_t`	The number of characters to render. 0: means render until reaching the `\0` termination.
`align`	`lv_text_align_t`	The alignment of the text `LV_TEXT_ALIGN_LEFT/RIGHT/CENTER`
`bidi_dir`	`lv_base_dir_t`	The base direction. Used when type setting Right-to-left (e.g. Arabic) texts
`opa`	`lv_opa_t`	Opacity of the text in 0...255 range. LV_OPA_TRANSP, LV_OPA_10, LV_OPA_20, .. LV_OPA_COVER can be used as well
`outline_stroke_opa`	`lv_opa_t`	Letter outline stroke opacity
`decor`	`lv_text_decor_t`	Text decoration, e.g. underline
`flag`	`lv_text_flag_t`	Some flags to control type setting
`text_local`	`uint8_t`	1: malloc a buffer and copy `text` there. 0: `text` will be valid during rendering.
`text_static`	`uint8_t`	Indicate that the text is constant and its pointer can be safely saved e.g. in a cache.
`has_bided`	`uint8_t`	1: already executed lv_bidi_process_paragraph. 0: has not been executed lv_bidi_process_paragraph.
`hint`	`lv_draw_label_hint_t *`	Pointer to an externally stored struct where some data can be cached to speed up rendering
`outline_stroke_color`	`lv_color_t`
`outline_stroke_width`	`int32_t`

Used by 12 functions

lv_obj_init_draw_label_dsc — param draw_dsc
lv_draw_label_dsc_init — param dsc
lv_draw_label — param dsc
lv_draw_character — param dsc
lv_draw_label_iterate_characters — param dsc
lv_draw_eve_label — param dsc
lv_draw_nanovg_label — param dsc
lv_draw_nema_gfx_label — param dsc
lv_draw_dave2d_label — param dsc
lv_draw_sdl_label — param dsc
lv_draw_sw_label — param dsc
lv_draw_vg_lite_label — param dsc

struct

lv_draw_letter_dsc_t

Member	Type	Description
`base`	`lv_draw_dsc_base_t`
`unicode`	`uint32_t`
`font`	`const lv_font_t *`
`color`	`lv_color_t`
`rotation`	`int32_t`
`scale_x`	`int32_t`
`scale_y`	`int32_t`
`skew_x`	`int32_t`
`skew_y`	`int32_t`
`pivot`	`lv_point_t`
`opa`	`lv_opa_t`
`decor`	`lv_text_decor_t`
`blend_mode`	`lv_blend_mode_t`
`outline_stroke_opa`	`lv_opa_t`
`outline_stroke_width`	`int32_t`
`outline_stroke_color`	`lv_color_t`

Used by 5 functions

lv_draw_letter_dsc_init — param dsc
lv_draw_letter — param dsc
lv_draw_nanovg_letter — param dsc
lv_draw_sw_letter — param dsc
lv_draw_vg_lite_letter — param dsc

Typedefs

public/draw/lv_draw_label.h:153typedef

lv_draw_glyph_cb_t

typedef void(* lv_draw_glyph_cb_t) (lv_draw_task_t *t, lv_draw_glyph_dsc_t *dsc, lv_draw_fill_dsc_t *fill_dsc, const lv_area_t *fill_area)

Passed as a parameter to lv_draw_label_iterate_characters to draw the characters one by one

Used by 3 functions

lv_draw_label_iterate_characters — param cb
lv_draw_unit_draw_letter — param cb
lv_draw_unit_draw_letter_internal — param cb

Macros

public/draw/lv_draw_label.h:26macro

LV_DRAW_LABEL_NO_TXT_SEL

#define LV_DRAW_LABEL_NO_TXT_SEL (0xFFFF)

lv_draw_label.h

Functions

lv_draw_task_get_label_dsc

lv_draw_letter_dsc_init

lv_draw_label_dsc_init

lv_draw_glyph_dsc_init

lv_draw_label

lv_draw_character

lv_draw_letter