[中文]

Line (lv_line)

Overview

The Line object is capable of drawing straight lines between a set of points.

Parts and Styles

  • LV_PART_MAIN uses all the typical background properties and line style properties.

Usage

Set points

The points have to be stored in an lv_point_precise_t array and passed to the object by the lv_line_set_points(lines, point_array, point_cnt) function.

Their coordinates can either be specified as raw pixel coordinates (e.g. {5, 10}), or as a percentage of the line's bounding box using lv_pct(x). In the latter case, the line's width/height may need to be set explicitly using lv_obj_set_width/height, as percentage values do not automatically expand the bounding box.

Auto-size

By default, the Line's width and height are set to LV_SIZE_CONTENT. This means it will automatically set its size to fit all the points. If the size is set explicitly, parts on the line may not be visible.

Invert y

By default, the y == 0 point is in the top of the object. It might be counter-intuitive in some cases so the y coordinates can be inverted with lv_line_set_y_invert(line, true). In this case, y == 0 will be the bottom of the object. y invert is disabled by default.

Events

Only the Generic events are sent by the object type.

See the events of the Base object too.

Learn more about Events.

Keys

No Keys are processed by the object type.

Learn more about Keys.

Example

[中文]

Simple Line

#include "../../lv_examples.h"
#if LV_USE_LINE && LV_BUILD_EXAMPLES

void lv_example_line_1(void)
{
    /*Create an array for the points of the line*/
    static lv_point_precise_t line_points[] = { {5, 5}, {70, 70}, {120, 10}, {180, 60}, {240, 10} };

    /*Create style*/
    static lv_style_t style_line;
    lv_style_init(&style_line);
    lv_style_set_line_width(&style_line, 8);
    lv_style_set_line_color(&style_line, lv_palette_main(LV_PALETTE_BLUE));
    lv_style_set_line_rounded(&style_line, true);

    /*Create a line and apply the new style*/
    lv_obj_t * line1;
    line1 = lv_line_create(lv_screen_active());
    lv_line_set_points(line1, line_points, 5);     /*Set the points*/
    lv_obj_add_style(line1, &style_line, 0);
    lv_obj_center(line1);
}

#endif

API

lv_line.h