/** =====================================================
 * Copyright © hk. 2022-2025. All rights reserved.
 * File name  : lcd_ctrl_basic.c
 * Author     : 苏木
 * Date       : 2024-09-25
 * Version    : 
 * Description: 
 * ======================================================
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/fb.h>

#define argb8888_to_rgb565(color)   ({ \
                                    unsigned int temp = (color); \
                                    ((temp & 0xF80000UL) >> 8) | \
                                    ((temp & 0xFC00UL) >> 5) | \
                                    ((temp & 0xF8UL) >> 3); \
                                    })

static int width; //LCD X分辨率
static int height; //LCD Y分辨率
static unsigned short *screen_base = NULL; //映射后的显存基地址

/**
 * @brief  lcd_draw_point
 * @note   打点
 * @param [in] x
 * @param [in] y
 * @param [in] color
 * @param [out]
 * @retval 
 */
static void lcd_draw_point(unsigned int x, unsigned int y, unsigned int color)
{
    unsigned short rgb565_color = argb8888_to_rgb565(color);//得到RGB565颜色值

    /* 对传入参数的校验 */
    if (x >= width)
        x = width - 1;
    if (y >= height)
        y = height - 1;

    /* 填充颜色 */
    screen_base[y * width + x] = rgb565_color;
}

/**
 * @brief  lcd_draw_line
 * @note   画线（水平或垂直线）
 * @param [in] x
 * @param [in] y
 * @param [in] dir
 * @param [in] length
 * @param [in] color
 * @param [out]
 * @retval 
 */
static void lcd_draw_line(unsigned int x, unsigned int y, int dir,
            unsigned int length, unsigned int color)
{
    unsigned short rgb565_color = argb8888_to_rgb565(color);//得到RGB565颜色值
    unsigned int end;
    unsigned long temp;

    /* 对传入参数的校验 */
    if (x >= width)
        x = width - 1;
    if (y >= height)
        y = height - 1;

    /* 填充颜色 */
    temp = y * width + x;//定位到起点
    if (dir) 
    {  
        //水平线
        end = x + length - 1;
        if (end >= width)
            end = width - 1;

        for ( ; x <= end; x++, temp++)
        {
            screen_base[temp] = rgb565_color;
        }
    }
    else 
    {  
        //垂直线
        end = y + length - 1;
        if (end >= height)
            end = height - 1;

        for ( ; y <= end; y++, temp += width)
        {
            screen_base[temp] = rgb565_color;
        }
    }
}

/**
 * @brief  lcd_draw_rectangle
 * @note   画矩形
 * @param [in] start_x
 * @param [in] end_x
 * @param [in] start_y
 * @param [in] end_y
 * @param [in] color
 * @param [out]
 * @retval 
 */
static void lcd_draw_rectangle(unsigned int start_x, unsigned int end_x,
            unsigned int start_y, unsigned int end_y,
            unsigned int color)
{
    int x_len = end_x - start_x + 1;
    int y_len = end_y - start_y - 1;

    lcd_draw_line(start_x, start_y, 1, x_len, color);//上边
    lcd_draw_line(start_x, end_y, 1, x_len, color); //下边
    lcd_draw_line(start_x, start_y + 1, 0, y_len, color);//左边
    lcd_draw_line(end_x, start_y + 1, 0, y_len, color);//右边
}

/**
 * @brief  lcd_fill
 * @note   将一个矩形区域填充为参数color所指定的颜色
 * @param [in] start_x
 * @param [in] end_x
 * @param [in] start_y
 * @param [in] end_y
 * @param [in] color
 * @param [out]
 * @retval 
 */
static void lcd_fill(unsigned int start_x, unsigned int end_x,
            unsigned int start_y, unsigned int end_y,
            unsigned int color)
{
    unsigned short rgb565_color = argb8888_to_rgb565(color);//得到RGB565颜色值
    unsigned long temp;
    unsigned int x;

    /* 对传入参数的校验 */
    if (end_x >= width)
        end_x = width - 1;
    if (end_y >= height)
        end_y = height - 1;

    /* 填充颜色 */
    temp = start_y * width; //定位到起点行首
    for ( ; start_y <= end_y; start_y++, temp+=width) 
    {
        for (x = start_x; x <= end_x; x++)
        {
            screen_base[temp + x] = rgb565_color;
        }
    }
}

int main(int argc, char *argv[])
{
    struct fb_fix_screeninfo fb_fix;
    struct fb_var_screeninfo fb_var;
    unsigned int screen_size;
    int fd;

    /* 打开framebuffer设备 */
    if (0 > (fd = open("/dev/fb0", O_RDWR))) 
    {
        perror("open error");
        exit(EXIT_FAILURE);
    }

    /* 获取参数信息 */
    ioctl(fd, FBIOGET_VSCREENINFO, &fb_var);
    ioctl(fd, FBIOGET_FSCREENINFO, &fb_fix);

    screen_size = fb_fix.line_length * fb_var.yres;
    width = fb_var.xres;
    height = fb_var.yres;

    /* 将显示缓冲区映射到进程地址空间 */
    screen_base = mmap(NULL, screen_size, PROT_WRITE, MAP_SHARED, fd, 0);
    if (MAP_FAILED == (void *)screen_base) 
    {
        perror("mmap error");
        close(fd);
        exit(EXIT_FAILURE);
    }

    /* 画正方形方块 */
    int w = height * 0.25;//方块的宽度为1/4屏幕高度
    lcd_fill(0, width-1, 0, height-1, 0x0); //清屏（屏幕显示黑色）
    lcd_fill(0, w, 0, w, 0xFF0000); //红色方块
    lcd_fill(width-w, width-1, 0, w, 0xFF00);   //绿色方块
    lcd_fill(0, w, height-w, height-1, 0xFF);   //蓝色方块
    lcd_fill(width-w, width-1, height-w, height-1, 0xFFFF00);//黄色方块

    /* 画线: 十字交叉线 */
    lcd_draw_line(0, height * 0.5, 1, width, 0xFFFFFF);//白色线
    lcd_draw_line(width * 0.5, 0, 0, height, 0xFFFFFF);//白色线

    /* 画矩形 */
    unsigned int s_x, s_y, e_x, e_y;
    s_x = 0.25 * width;
    s_y = w;
    e_x = width - s_x;
    e_y = height - s_y;

    for ( ; (s_x <= e_x) && (s_y <= e_y); s_x+=5, s_y+=5, e_x-=5, e_y-=5)
    {
        lcd_draw_rectangle(s_x, e_x, s_y, e_y, 0xFFFFFF);
    }
    /* 退出 */
    munmap(screen_base, screen_size);  //取消映射
    close(fd);  //关闭文件
    exit(EXIT_SUCCESS);    //退出进程
}