Overview

The Bar objects have got two main parts: a background which is the object itself and an indicator which shape is similar to the background but its width/height can be adjusted.

The orientation of the bar can be vertical or horizontal according to the width/height ratio. Logically on horizontal bars the indicator width, on vertical bars the indicator height can be changed.

A new value can be set by: lv_bar_set_value(bar, new_value). The value is interpreted in range (minimum and maximum values) which can be modified with: lv_bar_set_range(bar, min, max). The default range is: 1..100.

The setting of a new value can happen with an animation from the current value to the desired. In this case use lv_bar_set_value_anim(bar, new_value, anim_time).

Style usage

  • background is a Base object therefore it uses its style elements. Its default style is: LV_STYLE_PRETTY.
  • indicator is similar to the background. Its styles can be set by: lv_bar_set_style_indic(bar,&style_indic). It uses the hpad and vpad style elements to keep space from the background. Its default style is: LV_STYLE_PRETTY_COLOR.

Notes

  • The indicator is not a real object it is only drawn by the bar
Example of Bar in Littlev Graphics Library

						/*Create a default bar*/
lv_obj_t * bar1 = lv_bar_create(lv_scr_act(), NULL);
lv_obj_set_size(bar1, 200, 30);
lv_obj_align(bar1, NULL, LV_ALIGN_IN_TOP_RIGHT, -20, 30);
lv_bar_set_value(bar1, 70);

/*Create a label right to the bar*/
lv_obj_t * bar1_label = lv_label_create(lv_scr_act(), NULL);
lv_label_set_text(bar1_label, "Default");
lv_obj_align(bar1_label, bar1, LV_ALIGN_OUT_LEFT_MID, -10, 0);

/*Create a bar and an indicator style*/
static lv_style_t style_bar;
static lv_style_t style_indic;

lv_style_copy(&style_bar, &lv_style_pretty);
style_bar.body.main_color = LV_COLOR_BLACK;
style_bar.body.grad_color = LV_COLOR_GRAY;
style_bar.body.radius = LV_RADIUS_CIRCLE;
style_bar.body.border.color = LV_COLOR_WHITE;

lv_style_copy(&style_indic, &lv_style_pretty);
style_indic.body.grad_color =  LV_COLOR_GREEN;
style_indic.body.main_color=  LV_COLOR_LIME;
style_indic.body.radius = LV_RADIUS_CIRCLE;
style_indic.body.shadow.width = 10;
style_indic.body.shadow.color = LV_COLOR_LIME;
style_indic.body.padding.hor = 3;           /*Make the indicator a little bit smaller*/
style_indic.body.padding.ver = 3;

/*Create a second bar*/
lv_obj_t * bar2 = lv_bar_create(lv_scr_act(), bar1);
lv_bar_set_style(bar2, LV_BAR_STYLE_BG, &style_bar);
lv_bar_set_style(bar2, LV_BAR_STYLE_INDIC, &style_indic);
lv_obj_align(bar2, bar1, LV_ALIGN_OUT_BOTTOM_MID, 0, 30); /*Align below 'bar1'*/

/*Create a second label*/
lv_obj_t * bar2_label = lv_label_create(lv_scr_act(), bar1_label);
lv_label_set_text(bar2_label, "Modified");
lv_obj_align(bar2_label, bar2, LV_ALIGN_OUT_LEFT_MID, -10, 0);

lv_obj_t *

lv_bar_create

(lv_obj_t * par, lv_obj_t * copy);

Create a bar objects

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

copy pointer to a bar object, if not NULL then the new object will be copied from it

return pointer to the created bar

void

lv_bar_set_value

(lv_obj_t * bar, int16_t value);

Set a new value on the bar

bar pointer to a bar object

value new value

void

lv_bar_set_value_anim

(lv_obj_t * bar, int16_t value, uint16_t anim_time);

Set a new value with animation on the bar

bar pointer to a bar object

value new value

anim_time animation time in milliseconds

void

lv_bar_set_range

(lv_obj_t * bar, int16_t min, int16_t max);

Set minimum and the maximum values of a bar

bar pointer to the bar object

min minimum value

max maximum value

void

lv_bar_set_style

(lv_obj_t *bar, lv_bar_style_t type, lv_style_t *style);

Set a style of a bar

bar pointer to a bar object

type which style should be set

style pointer to a style

int16_t

lv_bar_get_value

(lv_obj_t * bar);

Get the value of a bar

bar pointer to a bar object

return the value of the bar

int16_t

lv_bar_get_min_value

(lv_obj_t * bar);

Get the minimum value of a bar

bar pointer to a bar object

return the minimum value of the bar

int16_t

lv_bar_get_max_value

(lv_obj_t * bar);

Get the maximum value of a bar

bar pointer to a bar object

return the maximum value of the bar

lv_style_t *

lv_bar_get_style

(lv_obj_t *bar, lv_bar_style_t type);

Get a style of a bar

bar pointer to a bar object

type which style should be get

return style pointer to a style

LittlevGL - Open-source Embedded GUI Library

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The founder of Littlev Graphics Library (LittlevGL) and related software modules is:
Gábor Kiss-Vámosi
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