[嵌入式]【LuatOS-air551G】6.2 修复：画线导致重启

前言

解决画线起点和终点的x或y坐标相同时会出现重启问题。

问题

[2022-02-12 15:21:18.439] I/user.74	23	69	23
[2022-02-12 15:21:18.455] Guru Meditation Error: Core  0 panic'ed (Store access fault). Exception was unhandled.

[2022-02-12 15:28:01.448] I/user.68	64	64	64
[2022-02-12 15:28:01.448] Guru Meditation Error: Core  0 panic'ed (Store access fault). Exception was unhandled.

[2022-02-12 15:30:12.171] I/user.64	64	58	64
[2022-02-12 15:30:12.202] Guru Meditation Error: Core  0 panic'ed (Store access fault). Exception was unhandled.

当使用lcd.drawline()时，如果输入坐标的x或者y相同，会导致重启，这个目前不知道怎么解决

解决

lcd.drawLine(64,64,59,64,0xf000)无法运行
lcd.drawLine(59,64,64,64,0xf000)可以运行
看起来应该是同x或同y的时候只能是从坐标值小的点到大的点。

新增一个函数用于交换两个点的位置就可以了

-- 用于当lcd画线时，横纵坐标相同时从小的点画到大的点
function judge_lcd_xy_same(x1,y1,x2,y2)
    if x1 == x2 then
        if y1>y2 then
            temp = y1
            y1 = y2
            y2 = temp
        end
    end
    if y1 == y2 then
        if x1>x2 then
            temp = x1
            x1 = x2
            x2 = temp
        end
    end
    return x1,y1,x2,y2
    
end

源码

int luat_lcd_draw_line(luat_lcd_conf_t* conf,uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2,uint32_t color){
    uint16_t t;
    uint32_t i = 0;
    int xerr = 0, yerr = 0, delta_x, delta_y, distance;
    int incx, incy, row, col;
    if (x1 == x2 || y1 == y2)
    {
        /* fast draw transverse line */
        luat_lcd_set_address(conf,x1, y1, x2, y2);
        size_t dots = (x2 - x1 + 1) * (y2 - y1 + 1);//点数量
        uint8_t* line_buf = (uint8_t*)luat_heap_malloc(dots * 2);
        for (i = 0; i < dots; i++)
        {
            line_buf[2 * i] = color >> 8;
            line_buf[2 * i + 1] = color;
        }
        luat_gpio_set(conf->pin_dc, Luat_GPIO_HIGH);
        if (conf->port == LUAT_LCD_SPI_DEVICE){
            luat_spi_device_send((luat_spi_device_t*)(conf->userdata),  (const char*)line_buf, dots * 2);
        }else{
            luat_spi_send(conf->port,  (const char*)line_buf, dots * 2);
        }
        luat_heap_free(line_buf);
        return 0;
    }

    delta_x = x2 - x1;
    delta_y = y2 - y1;
    row = x1;
    col = y1;
    if (delta_x > 0)incx = 1;
    else if (delta_x == 0)incx = 0;
    else
    {
        incx = -1;
        delta_x = -delta_x;
    }
    if (delta_y > 0)incy = 1;
    else if (delta_y == 0)incy = 0;
    else
    {
        incy = -1;
        delta_y = -delta_y;
    }
    if (delta_x > delta_y)distance = delta_x;
    else distance = delta_y;
    for (t = 0; t <= distance + 1; t++)
    {
        luat_lcd_draw_point(conf,row, col,color);
        xerr += delta_x ;
        yerr += delta_y ;
        if (xerr > distance)
        {
            xerr -= distance;
            row += incx;
        }
        if (yerr > distance)
        {
            yerr -= distance;
            col += incy;
        }
    }
    return 0;
}