Line (lv_line)

Overview

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

Parts and Styles

LV_PART_MAIN uses the typical background and line style properties.

Usage

Set points

A Line's points have to be stored in an lv_point_precise_t array and passed to the Widget 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() and lv_obj_set_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 Widget. 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 at the bottom of the Widget. y invert is disabled by default.

Events

Only generic events are sent by Line Widgets.

Keys

No Keys are processed by Line Widgets.

Example

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

lv_types.h