实现lvgl的点画线

在LVGL（Light and Versatile Graphics Library）中实现点画线功能，可以通过自定义绘制回调函数来实现。以下是一个实现点画线功能的步骤和示例代码：

1. **定义点画线样式**：首先，需要定义点画线的样式，包括线宽、颜色和点画模式。
2. **实现绘制回调函数**：在绘制回调函数中，根据点画模式绘制线段。

#include "lvgl.h"

static void draw_dashed_line(lv_obj_t * obj, const lv_area_t * mask, const lv_point_t * p1, const lv_point_t * p2, lv_color_t color, lv_coord_t width, lv_opa_t opa)
{
    lv_coord_t dx = p2->x - p1->x;
    lv_coord_t dy = p2->y - p1->y;
    lv_coord_t abs_dx = LV_ABS(dx);
    lv_coord_t abs_dy = LV_ABS(dy);
    lv_coord_t x = p1->x;
    lv_coord_t y = p1->y;
    lv_coord_t err = abs_dx - abs_dy;

    while (1)
    {
        lv_draw_rect_dsc_t rect_dsc;
        lv_draw_rect_dsc_init(&rect_dsc);
        rect_dsc.bg_color = color;
        rect_dsc.radius = 0;
        rect_dsc.border_width = 0;
        rect_dsc.bg_opa = opa;

        lv_area_t rect_area;
        rect_area.x1 = x;
        rect_area.y1 = y;
        rect_area.x2 = x + width - 1;
        rect_area.y2 = y + width - 1;

        lv_draw_rect(mask, &rect_dsc, &rect_area);

        if (x == p2->x && y == p2->y)
            break;

        lv_coord_t e2 = 2 * err;
        if (e2 > -abs_dy)
        {
            err -= abs_dy;
            x += (dx > 0) ? 1 : -1;
        }
        if (e2 < abs_dx)
        {
            err += abs_dx;
            y += (dy > 0) ? 1 : -1;
        }
    }
}

static void custom_dashed_line(lv_obj_t * obj, const lv_area_t * mask, const lv_point_t * p1, const lv_point_t * p2, lv_color_t color, lv_coord_t width, lv_opa_t opa)
{
    // Implement dashed line logic here
    draw_dashed_line(obj, mask, p1, p2, color, width, opa);
}

void my_dashed_line(lv_obj_t * parent, lv_point_t p1, lv_point_t p2, lv_color_t color, lv_coord_t width, lv_opa_t opa)
{
    lv_obj_t * line = lv_line_create(parent, NULL);
    lv_line_set_points(line, &p1, &p2);
    lv_obj_set_style_local_line_dash_width(line, LV_LINE_PART_MAIN, LV_STATE_DEFAULT, width);
    lv_obj_set_style_local_line_color(line, LV_LINE_PART_MAIN, LV_STATE_DEFAULT, color);
    lv_obj_set_style_local_line_width(line, LV_LINE_PART_MAIN, LV_STATE_DEFAULT, width);
    lv_obj_set_style_local_line_opa(line, LV_LINE_PART_MAIN, LV_STATE_DEFAULT, opa);
}

int main()
{
    lv_init();
    // Initialize your display and input devices here

    lv_obj_t * scr = lv_cont_create(NULL, NULL);
    lv_disp_load_scr(scr);

    lv_point_t p1 = {10, 10};
    lv_point_t p2 = {100, 100};
    lv_color_t color = LV_COLOR_BLUE;
    lv_coord_t width = 2;
    lv_opa_t opa = LV_OPA_COVER;

    my_dashed_line(scr, p1, p2, color, width, opa);

    // Run the main loop
    while (1)
    {
        lv_task_handler();
        // Add a delay here
    }

    return 0;
}

在上述代码中，`draw_dashed_line` 函数实现了点画线的绘制逻辑，`custom_dashed_line` 函数可以进一步扩展以实现不同的点画模式。`my_dashed_line` 函数是一个辅助函数，用于在指定的父对象上绘制点画线。