复制BMP图片

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <stdlib.h>
/*
 *   复制bmp图片
 *
 *
 */
#pragma pack(1)

// 定义BMP文件头部结构
typedef struct
{
    unsigned short bfType;
    unsigned int bfSize;
    unsigned short bfReserved1;
    unsigned short bfReserved2;
    unsigned int bfOffBits;
} BITMAPFILEHEADER;

typedef struct
{
    unsigned int biSize;
    int biWidth;  // 宽
    int biHeight; // 高
    unsigned short biPlanes;
    unsigned short biBitCount; // 色深
    unsigned int biCompression;
    unsigned int biSizeImage;
    int biXPelsPerMeter;
    int biYPelsPerMeter;
    unsigned int biClrUsed;
    unsigned int biClrImportant;
} BITMAPINFOHEADER;

#pragma pack()

int main(int argc, char const *argv[])
{
    // 1.打开BMP图像
    FILE *bmp_fp = fopen("1.bmp", "rb");
    if (NULL == bmp_fp)
    {
        return -1;
    }
    // 2
    BITMAPFILEHEADER h1; // 文件头    14
    BITMAPINFOHEADER h2; // 信息头    40

    fread(&h1, 1, 14, bmp_fp);
    fread(&h2, 1, 40, bmp_fp);

    // 3每次读一行像素点颜色分量大小
    int line_size = h2.biWidth * 3;
    char *src_pbuf = (char *)calloc(1, line_size);

    // 4打开新图片
    FILE *new_fp = fopen("new.bmp", "wb");
    // 信息写入新图片
    fwrite(&h1, 1, 14, new_fp);
    fwrite(&h2, 1, 40, new_fp);

    // 数据写入新图片
    int line_num = h2.biHeight;
    while (line_num--)
    {
        // 读：空间+1+颜色分量+打开的原图
        fread(src_pbuf, 1, line_size, bmp_fp);
        // 写
        fwrite(src_pbuf, 1, line_size, new_fp);
    }

    return 0;
}

BMP图片显示到显示器

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
/*
 *   把400*240bmp图片展示到800*480的显示屏中
 *
 *
 */
#pragma pack(1)

// 定义BMP文件头部结构
typedef struct{
	unsigned short bfType;
	unsigned int   bfSize;
	unsigned short bfReserved1;
	unsigned short bfReserved2;
	unsigned int   bfOffBits;
}BITMAPFILEHEADER;

typedef struct{
	unsigned int biSize;
	int biWidth;				//宽
	int biHeight;				//高
	unsigned short biPlanes;
	unsigned short biBitCount;	//色深
	unsigned int biCompression;
	unsigned int biSizeImage;
	int biXPelsPerMeter;
	int biYPelsPerMeter;
	unsigned int biClrUsed;
	unsigned int biClrImportant;
}BITMAPINFOHEADER;


#pragma pack()


int main(int argc, char const *argv[])
{
	//1.打开待显示的BMP图像  fopen
	FILE * bmp_fp = fopen("1.bmp","rb");
	if (NULL == bmp_fp)
	{
		return -1;
	}

	//2.读取BMP文件的图像信息，获取BMP的宽和高
	BITMAPINFOHEADER headerinfo;
	fseek(bmp_fp,14,SEEK_SET);
	fread(&headerinfo,1,40,bmp_fp); //读取40字节
	printf("bmp width = %d,height = %d\n",headerinfo.biWidth,headerinfo.biHeight);

	//3.读取BMP图*片的颜色分量  400* 240*3h
	char bmp_buf[400*240*3] = {0};
	fread(bmp_buf,1,400*240*3,bmp_fp);

	//4.关闭BMP
	fclose(bmp_fp);

	//5.打开LCD   open  
	int lcd_fd = open("/dev/fb0",O_RDWR);


	//6.对LCD进行内存映射  mmap
	int * lcd_mp = (int *)mmap(NULL,800*480*4,PROT_READ|PROT_WRITE,MAP_SHARED,lcd_fd,0);

	//7.循环的把BMP图像的颜色分量依次写入到LCD的像素点中 
	int i = 0;
	int data = 0;

	for (int y =  240-1; y >= 0; y--)
	{
		for (int x = 0; x < 400 ; ++x)
		{
			//把BMP图片的一个像素点的颜色分量转换为LCD屏幕的一个像素点的颜色分量格式  ARGB <--- BGR
			data |= bmp_buf[i];			//B
			data |= bmp_buf[i+1]<<8;	//G
			data |= bmp_buf[i+2]<<16;  	//R

			lcd_mp[800*y + x] = data;  //BGR BGR BGR .... 

			i+=3;  
			data = 0;
		}
	}
	
	//8.关闭LCD
	close(lcd_fd);
	munmap(lcd_mp,400*240*4);

	return 0;
}