嵌入式在开发板显示bmp图片、jpeg图片

约定不等于承诺〃 2022-05-13 04:56 395阅读 0赞

### **嵌入式 在开发板显示bmp图片、jpeg图片** ###

**一、简述**

**        记--在GEC6818开发板(800W\*480H)显示24位的bmp图片、使用开源的jpeg库显示jpeg图片。**

**        代码：链接: https://pan.baidu.com/s/1G3jzvdncocDMRbwCvsmSlg 密码: gz6m**

**二、效果**

**        执行开始显示bmp图片，回车后显示jpg图片。**

![70][]

**三、工程结构**

![70 1][]

![70 2][]

**四、源代码**

**        display\_bmp.c文件**

**        **

#include <stdio.h>
    #include <stdlib.h>
    #include <sys/mman.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>
    
    #include "lcd.h"
    #include "freetype.h"
    #include "to_wchar.h"
    #include "display_bmp.h"
    
    /*display_bmp:显示bmp图片
     *pathname：图片的路径名
     *lcd_ptr：指向LCD映射首地址
     *x_s，y_s：左上角起始点
     */
    int display_bmp(const char *pathname, unsigned int *lcd_ptr,unsigned int x_s, unsigned int y_s)
    {
    	unsigned int bmp_width,bmp_height;
    	unsigned int x, y, color;
    	unsigned char *pic_buf_ptr, *ptr_save;
    	
    	if( get_bmp_width_and_height( pathname, &bmp_width, &bmp_height) != 0 )//获取图片的宽高
    	{
    		fprintf(stderr, "get bmp width and height failed!\n");
    		return -1;
    	}
    
    	if( get_pic_data_to_buffer(pathname, &pic_buf_ptr) == -1 )//获取图片的像素数据
    	{
    	    fprintf(stderr, "get picture data error\n");
    		return -1;
    	}
    	ptr_save = pic_buf_ptr;
    	
    	for(y=y_s; y<y_s+bmp_height && y< LCD_HEIGHT; y++)
    	{  
    		for(x=x_s; x< x_s+bmp_width ; x++)
    		{  
    			if(x>=0 && x< LCD_WIDTH)
    			{	    
    				//将RGB的3个字节颜色数据装到4字节  RGB：红绿蓝
    				color = (*(pic_buf_ptr+2)<<16) | (*(pic_buf_ptr+1)<<8) | (*pic_buf_ptr);
    				lcd_draw_point(x, LCD_HEIGHT-y-1, color, lcd_ptr);//LCD_HEIGHT-y-1:镜像翻转
    			}
    			pic_buf_ptr += 3;//三个字节一个颜色像素点
    		}
    		
    	}   
    
    	//显示图片路径名	
    	wchar_t *w_pathname = NULL;
    	if( mchars_to_wchars(pathname, &w_pathname) == 0)//将多字节转换为宽字符(汉字未能转换成功)
    	{
    		//显示字体
    		Lcd_Show_FreeType(w_pathname,32,0x00,x_s+10,y_s+50, lcd_ptr);
    		free(w_pathname);
    	}
    	
    	free( ptr_save );
    	return 0;
    }
    
    /*get_pic_data_to_buffer:获取图片的像素数据
     *pathname：图片的路径名
     *pic_buf_ptr：用来指向 存放图片的像素数据缓冲区
     */
    int get_pic_data_to_buffer(const char *pathname, unsigned char **pic_buf_ptr)
    {
        FILE *pic_fp;
    	off_t file_size;
    	struct stat file_info;
            
    	pic_fp = fopen(pathname, "r");
    	if(pic_fp == NULL)
    	{
    		perror("open %s error\n");
    		return -1;
    	}
    
    	if( stat(pathname, &file_info) == -1)
    	{
    		perror("get file info error\n");
    		return -1;
    	}
    	
    	file_size = file_info.st_size;//获取图片大小
    	*pic_buf_ptr = (unsigned char *)malloc(file_size-54);
    
    	fseek(pic_fp, 54,SEEK_SET);//跳过文件头(存在内存对齐，可能是56字节)
    	
    	fread(*pic_buf_ptr, file_size-54, 1, pic_fp);//读取图片颜色数据
    	if(ferror(pic_fp))
    	{
    			perror("read picture data error\n");
    			return -1; 
    	}
    
    	return fclose(pic_fp);
        
    }
    
    /*get_bmp_width_and_height:获取bmp图片的宽高信息
     *pathname：图片路径名
     *width：图片的宽度
     *height：图片的高度
     */
    int get_bmp_width_and_height(const char *pathname, unsigned int *width, unsigned int *height)
    {
    	FILE *pic_fp;
    	unsigned char file_head[54];
    
    	pic_fp = fopen(pathname, "r");
    	if(pic_fp == NULL)
    	{
    		perror("open %s error\n");
    		return -1;
    	}
    
    	fread( file_head, 54, 1, pic_fp);
    	if( ferror( pic_fp ) )
    	{
    		perror("read picture head error\n");
    		return -1;
    	}
    	fclose(pic_fp);
    	
    	*width = *((int*)&file_head[18]);//宽：18~21共4个字节
    	*height = file_head[22] | file_head[23]<<8;//高：22~23共两个字节
    
    	return 0;
    }

**        display\_jpeg.c文件**

#include <stdio.h>
    #include <stdlib.h>
    #include <setjmp.h>
    #include <jpeglib.h>
    #include <jerror.h>
    
    #include "lcd.h"
    #include "to_wchar.h"
    
    extern JSAMPLE * image_buffer;	/* Points to large array of R,G,B-order data */
    extern int image_height;	/* Number of rows in image */
    extern int image_width;
    
    struct my_error_mgr 
    {
    	struct jpeg_error_mgr pub;	/* "public" fields */
    	jmp_buf setjmp_buffer;	/* for return to caller */
    };
    
    typedef struct my_error_mgr * my_error_ptr;
    
    METHODDEF(void)
    my_error_exit (j_common_ptr cinfo)
    {
    	my_error_ptr myerr = (my_error_ptr) cinfo->err;
    	(*cinfo->err->output_message) (cinfo);
    
    	longjmp(myerr->setjmp_buffer, 1);
    }
    
    /*display_jpeg:显示jpeg图片
     *filename：图片的路径名
     *lcd_ptr：指向LCD映射首地址
     *x_s，y_s：左上角起始点
     */
    int display_jpeg (char * filename, unsigned int *lcd_ptr,unsigned int x_s, unsigned int y_s)
    {
    
    	struct my_error_mgr jerr;
    	struct jpeg_decompress_struct cinfo;
    	int row_stride;		/* physical row width in output buffer */
    	FILE * infile;		/* source file */
    
    	if((infile = fopen(filename, "rb")) == NULL) 
    	{
    		fprintf(stderr, "can't open %s\n", filename);
    		return -1;
    	}
    
    	cinfo.err = jpeg_std_error(&jerr.pub);
    	jerr.pub.error_exit = my_error_exit;
      
    	if(setjmp(jerr.setjmp_buffer)) 
    	{    
    		jpeg_destroy_decompress(&cinfo);
    		fclose(infile);
    		return -1;
    	}
    
    	jpeg_create_decompress(&cinfo);
    
    	jpeg_stdio_src(&cinfo, infile);
    	
    	jpeg_read_header(&cinfo, TRUE);
        
    	jpeg_start_decompress(&cinfo);
      
    	row_stride = cinfo.output_width * cinfo.output_components;
    
    	char *buffer;  
    	buffer = (char*)(*cinfo.mem->alloc_sarray)
    		((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
    
    	unsigned int x, y;
    	unsigned int color;
    	char * ptr_save = buffer; 
    
    	y = y_s;
    	while(cinfo.output_scanline < cinfo.output_height && y < cinfo.output_height) 
    	{    
    		buffer = ptr_save;
    		jpeg_read_scanlines(&cinfo, (JSAMPARRAY)&buffer, 1);
    		
    		for(x=x_s; x< x_s+cinfo.output_width && x<LCD_WIDTH; x++)
    		{
    			color = buffer[2] | buffer[1]<<8 | buffer[0]<<16;
    			lcd_draw_point(x, y, color, lcd_ptr);
    
    			buffer += 3;
    		}
    
    		y++;
    	}
    	
    	//显示图片路径
    	wchar_t *w_pathname = NULL;
    	if( mchars_to_wchars(filename, &w_pathname) == 0)
    	{
    		//显示图片路径
    		Lcd_Show_FreeType(w_pathname,32,0x00,x_s+10,y_s+50, lcd_ptr);
    		free(w_pathname);
    	}
    
    
    	jpeg_finish_decompress(&cinfo);
    	jpeg_destroy_decompress(&cinfo);
    	fclose(infile);
    	return 0;
    }

**        freetype.c文件**

#include <sys/mman.h>
    #include <stdio.h>
    #include <linux/fb.h>
    #include <string.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>
    #include <wchar.h>
    #include <string.h>
    #include <ft2build.h>
    #include FT_FREETYPE_H
    
    #include <lcd.h>
    
    
    #define	SIM_TTY_PATH	"font/simsun.ttc"
    /*	
    	功能：根据得到的RGB24数据，进行图像任意位置显示
    	（主要是迎合上面的各种转换函数的显示测试）
    	x:显示的x轴起点
    	y:显示的y轴起点
    	w:显示图像宽度。
    	h:显示图像高度。
    	bit_dept:要显示的图像位深 24/32
    	pbmp_data：要进行显示的RGB24_buf
    */
    int Show_FreeType_Bitmap(FT_Bitmap*  bitmap,int start_x,int start_y,int color, unsigned int *lcd_buf_ptr)
    {
    	int  buff_x, buff_y;	//遍历bitmap时使用
    	int  x,y;	//循环遍历使用
    	int  end_x = start_x + bitmap->width;	//图像宽度
    	int  end_y = start_y + bitmap->rows;	//图像高度
    
    	for ( x = start_x, buff_x = 0; x < end_x; buff_x++, x++ )	//y表示起点y，x表示起点x
    	{
    		for ( y = start_y, buff_y = 0; y < end_y; buff_y++, y++ )	//y表示起点y，x表示起点x
    		{
    			//LCD边界处理
    			if ( x < 0 || y < 0 || x >=800   || y >= 480 )
    				continue;
    
    			if(bitmap->buffer[buff_y * bitmap->width + buff_x] )	//判断该位上是不是为1，1则表明需要描点
    				lcd_draw_point(start_x+buff_x , start_y+buff_y ,  color, lcd_buf_ptr);		//在当前x位置加上p的偏移量（p表示buff中列的移动）
    				//在当前y位置加上q的偏移量（q表示buff中行的移动）
    			
    		}
    	}
    } 
    
    void Lcd_Show_FreeType(wchar_t *wtext, int size, int color, int start_x, int start_y, unsigned int *lcd_buf_ptr)
    {
    
    	//1.定义库所需要的变量
    	FT_Library    library;
    	FT_Face       face;
    	FT_GlyphSlot  slot;	//用于指向face中的glyph
    	FT_Vector     pen;                    
    	FT_Error      error;
    
    	int n;
    
    	
    	//2.初始化库
    	error = FT_Init_FreeType( &library );            
    
    	//3.打开一个字体文件，并加载face对象:
    	error = FT_New_Face( library, SIM_TTY_PATH, 0, &face ); 
    	slot = face->glyph;
    	
    	//4.设置字体大小
    	error = FT_Set_Pixel_Sizes(face, size, 0); 
    	
    	//x起点位置：start_x。需要*64
    	pen.x = start_x * 64;	
    	//y起点位置：LCD高度 - start_y。需要*64
    	pen.y = ( 480 - start_y ) * 64;
    	
    	//每次取出显示字符串中的一个字
    	for ( n = 0; n < wcslen( wtext ); n++ )	
    	{
    		//5.设置显示位置和旋转角度，0为不旋转，pen为提前设置好的坐标
    		FT_Set_Transform( face, 0, &pen );
    		
    		
    		//将字形槽的字形图像，转为位图，并存到 face->glyph->bitmap->buffer[]，并且更新bitmap下的其他成员，
    		//	face->glyph->bitmap.rows:图像总高度
    		//	face->glyph->bitmap.width:图像总宽度
    		//	face->glyph->bitmap.pitch:每一行的字节数
    		//	face->glyph->bitmap.pixel_mode：像素模式（1单色 8反走样灰度）
    		//	face->glyph->bitmap.buffer：点阵位图的数据缓冲区
    	
    
    		
    		error = FT_Load_Char( face, wtext[n], FT_LOAD_RENDER );
    			//FT_LOAD_RENDER表示转换RGB888的位图像素数据
    			
    		//出错判断	
    		if ( error )
    		  continue;                
    		
    		
    		Show_FreeType_Bitmap(&slot->bitmap, slot->bitmap_left, 480 - slot->bitmap_top, color, lcd_buf_ptr);
    		
    		//增加笔位
    		pen.x += slot->advance.x;
    		
    	}	
    	
    	FT_Done_Face(face);
    	FT_Done_FreeType(library);
    	
    }

**        lcd.c文件**

#include <stdio.h>
    #include <fcntl.h>
    #include <unistd.h>
    #include <sys/mman.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    
    #include "lcd.h"
    
    /*lcd_draw_point:在lcd上画一个点
     *x：x轴坐标   (左上角为原点，x轴分别向右，y轴下递增)
     *y：y轴坐标
     *color：点的颜色
     *lcd_ptr：LCD的操作指针
     */
    void lcd_draw_point(unsigned int x, unsigned int y, unsigned int color, unsigned int *lcd_ptr)
    {
    	if( x>=0 && x<LCD_WIDTH && y>=0 && y<LCD_HEIGHT )
    	{
    		*(lcd_ptr+LCD_WIDTH*y+x) = color;
    	}
    }
    
    /*lcd_draw_full_srceen_single_color:用一种颜色画满整个屏幕
     *color：点的颜色
     *lcd_ptr：LCD的操作指针
     */
    void lcd_draw_full_srceen_single_color(unsigned int color, unsigned int *lcd_ptr)
    {
    	int x, y;
    	for(y=0;y<LCD_HEIGHT;++y)
    	{
    		for(x=0;x<LCD_WIDTH;++x)
    		{
    			lcd_draw_point(x, y, color, lcd_ptr);
    		}
    	}
    }
    
    /*open_lcd_device:打开LCD
     *lcd_ptr：LCD的内存映射首地址
     *返回值：lcd_fd：LCD的描述符
     */
    int open_lcd_device(unsigned int **lcd_ptr)
    {
    
    	int lcd_fd;
    	lcd_fd = open("/dev/fb0", O_RDWR);//打开LCD设备
    	if(lcd_fd == -1)
    	{
    		perror("open lcd device failed\n");
    		return -1;
    	}
    
    	//内存映射
    	*lcd_ptr = mmap( NULL, LCD_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, lcd_fd, 0);
    	if(lcd_ptr == MAP_FAILED)
    	{
    		perror("map lcd_fb error\n");
    		return -1;
    	}
    
    	return lcd_fd;
    }
    
    /*close_lcd_device:关闭LCD
     *lcd_fd：LCD的描述符
     *lcd_ptr：LCD的内存映射首地址
     */
    int close_lcd_device(int lcd_fd, unsigned int *lcd_ptr)
    {
    	munmap(lcd_ptr, LCD_SIZE);
    	return close(lcd_fd);
    }

**        main.c文件**

#include <stdio.h>
    #include <stdlib.h>
    
    #include "lcd.h"
    #include "freetype.h"
    #include "display_bmp.h"
    #include "display_jpeg.h"
    
    int main(int argc, char *argv[])
    {
    	int lcd_fd;
    	int dis_ret;
    	unsigned int *lcd_ptr;
    
    	//打开LCD
    	lcd_fd = open_lcd_device(&lcd_ptr);
    	if(lcd_fd == -1)
    	{
    		return -1;
    	}
    
    	//显示bmp图片
    	dis_ret = display_bmp("pic/test.bmp", lcd_ptr, 0, 0);
    	if(dis_ret != 0)
    	{
    		printf("display bmp error\n");
    	}
    
    	printf("please enter any key continue!\n");
    	getchar();
    
    	//显示jpeg图片
    	dis_ret = display_jpeg("pic/bird.jpg", lcd_ptr, 0, 0);
    	if(dis_ret != 0)
    	{
    		printf("display jpeg error\n");
            }
    	//关闭LCD
    	close_lcd_device(lcd_fd, lcd_ptr);
    
    	return 0;
    }

**       to\_wchar.c文件**

#include <wctype.h>
    #include <locale.h>
    #include <wchar.h>
    #include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
    
    /*mchars_to_wchars:多字节转宽字符
     *mbs_char：多字节字符串
     *w_char：宽字符
     */
    int mchars_to_wchars(const char *mbs_char, wchar_t **w_char)
    {
    	int mbslen = mbstowcs(NULL, mbs_char, 0);
    	if (mbslen == (size_t) -1) 
    	{
    		perror("mbstowcs");
    		return -1;
        }
        *w_char = NULL;
    /*	if (setlocale(LC_CTYPE, "zh_CN.utf8") == NULL) 
    	{
                   perror("setlocale");
    	       return -1;
            }
    */
    	*w_char = calloc(mbslen + 1, sizeof(wchar_t));
    	if(*w_char == NULL )
    	{
    		perror("calloc\n");
    		return -1;
    	}
    	if (mbstowcs(*w_char, mbs_char, mbslen + 1) == (size_t) -1)
    	{
    		perror("mbstowcs");
    		free(*w_char);
    		return -1;
    	}
    	//printf("Wide character string is: %ls (%zu characters)\n", *w_char, mbslen);
    	return 0;
    }

Makefile文件

make:
    	arm-linux-gcc src/*.c -o lcd -I include -I include/freetype2 -L lib -ljpeg -lfreetype

**五、待添加功能**

**       1、图片根据显示屏的大小自适应(缩放操作："偷工减料"； 复制周边)**

**       2、百叶窗式显示图片**

**       3、从左到右滚动**

4、扇形显示图片

=================================以下 回复 qq\_37261494 ==================

百叶窗式显示图片测试

主要思路：将图片数据分为几个部分显示，每个部分交由子线程同时显示/隐藏。

测试代码：

#include <stdio.h>
    #include <stdlib.h>
    #include <sys/mman.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <string.h>
    #include <unistd.h>
    
    #define LCD_HEIGHT        480
    #define LCD_WIDTH        800
    #define LCD_SIZE        ((LCD_WIDTH)*(LCD_HEIGHT)*4)
    #define ON 1
    #define OFF 0
    #define BLIND 5
    
    int open_lcd_device(unsigned int **lcd_ptr);
    void lcd_draw_point(unsigned int x, unsigned int y, unsigned int color, unsigned int *lcd_ptr);
    int get_pic_data_to_buffer(const char *pathname, unsigned char **pic_buffer);
    void blind_window(int lcd, unsigned char *image, int flag);
    
    //打包数据给子线程使用
    struct argument
    {
    	unsigned int *lcd_ptr;//LCD显示屏的显示内存空间指针
    	unsigned char *pic_buf_ptr;;//图片数据
    	int offset;//每叶的像素数据的偏移量（距离全部数据的起始位置）起始就是用来记录每叶的起始行
    	int flag;//用来控制类似开窗关窗
    };
    
    int main(int argc, char *argv[])
    {
    	int lcd_fd;
    	int ret;
    	unsigned int *lcd_ptr;
    	if(argc !=2)
    	{
    		printf("argc !=2\n");
    		return -1;
    	}
    	
    	//打开LCD
    	lcd_fd = open_lcd_device(&lcd_ptr);
    	if(lcd_fd == -1)
    	{
    		return -1;
    	}
    	
    	//获取图片的像素数据
    	unsigned char *pic_ptr;
    	ret = get_pic_data_to_buffer(argv[1], &pic_ptr);
    	if(ret == -1)
    	{
    		printf("get_pic_data_to_buffer erro\n");
    	}   
    	
    	//百叶窗显示
    	blind_window(lcd_fd, pic_ptr, ON);//关窗
    	blind_window(lcd_fd, pic_ptr, OFF);//开窗
    	
    	munmap(lcd_ptr, LCD_SIZE);//接触映射
    	close(lcd_fd);//关闭LCD设备
    	return 0;
    }
    
    void *routine(void *_arg)//子线程执行的动作---显示1叶图片数据
    {
    	struct argument *arg = (struct argument *)_arg;
    
    	unsigned int color;
    	int x,y;
    
    	if(arg->flag == ON)
    	{
    		arg->pic_buf_ptr += (4*(LCD_HEIGHT/BLIND)-arg->offset) * LCD_WIDTH * 3;
    		for(y=arg->offset+LCD_HEIGHT/BLIND-1; y>=arg->offset; y--)//显示每叶数据-从下往上，有HEIGHT/BLIN行
    		{
    			for(x=0; x<LCD_WIDTH; x++)
    			{
    				color = (arg->pic_buf_ptr[2]<<16) | (arg->pic_buf_ptr[1]<<8) | arg->pic_buf_ptr[0];
    				lcd_draw_point(x, y, color, arg->lcd_ptr);
    				arg->pic_buf_ptr += 3;
    			}
    			
    			usleep(10000);
    		}
    	}
    	else if(arg->flag == OFF)//清除每叶数据-从上往下，有HEIGHT/BLIN行
    	{
    		for(y=arg->offset; y<arg->offset+LCD_HEIGHT/BLIND; y++)
    		{
    			for(x=0; x<LCD_WIDTH; x++)
    			{
    				lcd_draw_point(x, y, 0, arg->lcd_ptr);
    			}
    			usleep(10000);
    		}
    	}
    	
    	sleep(1);
    	pthread_exit(NULL);
    }
    
    //百叶窗式显示图片
    void blind_window(int lcd_fd, unsigned char *image, int flag)
    {
    	unsigned int *p = mmap( NULL, LCD_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, lcd_fd, 0);//内存映射，将LCD显示屏显示空间映射为内存空间，方便操作，这样给内存赋值为像素数据就是显示图片了
    	int i;
    	pthread_t tid[BLIND];
    	for(i=0; i<BLIND; i++)//每１叶交由一条子线程显示
    	{
    		struct argument *arg = malloc(sizeof(struct argument));
    		arg->lcd_ptr = p;
    		arg->pic_buf_ptr = image;
    		arg->offset = i*(LCD_HEIGHT/BLIND);//设置偏移量
    		arg->flag = flag;
    		//printf("offset=%d\n", arg->offset);
    		pthread_create(&tid[i], NULL, routine, (void *)arg);//创建线程
    	}
    
    	for(i=0; i<BLIND; i++)
    	{
    		pthread_join(tid[i], NULL);//等待子线程结束
    	}
    }
    
    
    /*lcd_draw_point:在lcd上画一个点
     *x：x轴坐标   (左上角为原点，x轴分别向右，y轴下递增)
     *y：y轴坐标
     *color：点的颜色
     *lcd_ptr：LCD的操作指针
     */
    void lcd_draw_point(unsigned int x, unsigned int y, unsigned int color, unsigned int *lcd_ptr)
    {
    	if( x>=0 && x<LCD_WIDTH && y>=0 && y<LCD_HEIGHT )
    	{
    		*(lcd_ptr+LCD_WIDTH*y+x) = color;
    	}
    }
    
    /*open_lcd_device:打开LCD
     *lcd_ptr：LCD的内存映射首地址
     *返回值：lcd_fd：LCD的描述符
     */
    int open_lcd_device(unsigned int **lcd_ptr)
    {
    
    	int lcd_fd;
    	lcd_fd = open("/dev/fb0", O_RDWR);//打开LCD设备
    	if(lcd_fd == -1)
    	{
    		perror("open lcd device failed\n");
    		return -1;
    	}
    
    	//内存映射
    	*lcd_ptr = mmap( NULL, LCD_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, lcd_fd, 0);
    	if(lcd_ptr == MAP_FAILED)
    	{
    		perror("map lcd_fb error\n");
    		return -1;
    	}
    
    	return lcd_fd;
    }
    
    
    /*get_pic_data_to_buffer:获取图片的像素数据
     *pathname：图片的路径名
     *pic_buf_ptr：用来指向 存放图片的像素数据缓冲区
     */
    int get_pic_data_to_buffer(const char *pathname, unsigned char **pic_buf_ptr)
    {
        FILE *pic_fp;
    	off_t file_size;
    	struct stat file_info;
            
    	pic_fp = fopen(pathname, "r");
    	if(pic_fp == NULL)
    	{
    		perror("open %s error\n");
    		return -1;
    	}
    
    	if( stat(pathname, &file_info) == -1)
    	{
    		perror("get file info error\n");
    		return -1;
    	}
    	
    	file_size = file_info.st_size;//获取图片大小
    	*pic_buf_ptr = (unsigned char *)malloc(file_size-54);
    
    	fseek(pic_fp, 54,SEEK_SET);//跳过文件头(存在内存对齐，可能是56字节)
    	
    	fread(*pic_buf_ptr, file_size-54, 1, pic_fp);//读取图片颜色数据
    	if(ferror(pic_fp))
    	{
    			perror("read picture data error\n");
    			return -1; 
    	}
    	
    	return fclose(pic_fp);
        
    }

测试结果：

![20190417220237364.gif][]

完整版：链接:https://pan.baidu.com/s/1cRO5tSMAnZdFeTii-qnYZA 提取码:9xfh

[70]: /images/20220513/03b79abec31b4abeb8154dfd004fac56.png
[70 1]: /images/20220513/45a083810c2d4647a93eb4128b95c239.png
[70 2]: /images/20220513/de22198862764fbfaaa900ca364dadf2.png
[20190417220237364.gif]: /images/20220513/331077e9427a48e0bd78a43d022f5bcd.png