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Linux C語言解析並顯示.bmp格式圖片,linux.bmp

Linux C語言解析並顯示.bmp格式圖片,linux.bmp

Linux C語言解析並顯示.bmp格式圖片,linux.bmp


 1 /*************************
 2 
 3 *bmp.h文件
 4 
 5 *************************/
 6 
 7 #ifndef __BMP_H__
 8 #define __BMP_H__
 9 
10 #include <unistd.h>
11 #include <stdio.h> 
12 #include <stdlib.h>    
13 #include <fcntl.h>
14 #include <string.h>
15 #include <linux/fb.h>
16 #include <sys/mman.h>
17 #include <sys/ioctl.h>
18 #include <arpa/inet.h>
19 
20 //文件頭結構體
21 typedef struct 
22 { 
23   unsigned char    bfType[2];    //文件類型
24   unsigned long bfSize;     //位圖大小
25   unsigned short bfReserved1;  //位0 
26   unsigned short bfReserved2;  //位0
27   unsigned long bfOffBits;    //到數據偏移量
28 } __attribute__((packed)) BitMapFileHeader;   //使編譯器不優化,其大小為14字節 
29 
30 //信息頭結構體
31 typedef struct 
32 { 
33   unsigned long biSize;          // BitMapFileHeader 字節數
34   long biWidth;                 //位圖寬度 
35   long biHeight;              //位圖高度,正位正向,反之為倒圖 
36   unsigned short biPlanes;        //為目標設備說明位面數,其值將總是被設為1
37   unsigned short biBitCount;        //說明比特數/象素,為1、4、8、16、24、或32。 
38   unsigned long biCompression;       //圖象數據壓縮的類型沒有壓縮的類型:BI_RGB 
39   unsigned long biSizeImage;      //說明圖象的大小,以字節為單位 
40   long biXPelsPerMeter;           //說明水平分辨率 
41   long biYPelsPerMeter;        //說明垂直分辨率 
42   unsigned long biClrUsed;       //說明位圖實際使用的彩色表中的顏色索引數
43   unsigned long biClrImportant;    //對圖象顯示有重要影響的索引數,0都重要。 
44 } __attribute__((packed)) BitMapInfoHeader; 
45 
46 //像素點結構體
47 typedef struct 
48 { 
49   unsigned char Blue;      //該顏色的藍色分量 
50   unsigned char Green;     //該顏色的綠色分量 
51   unsigned char Red;          //該顏色的紅色分量 
52   unsigned char Reserved;    //保留值(亮度)   
53 } __attribute__((packed)) RgbQuad;
54 
55  
56 
57 int show_photo(const char *fbp, struct fb_var_screeninfo *scrinfo, const char *bmpname);
58 
59 
60 #endif //__BMP_H__

 

 

 

 1 /*************************
 2 
 3 *bmp.c文件
 4 
 5 *************************/
 6 
 7 #include "bmp.h"
 8 
 9  
10 
11 /*************************
12 
13 *fbp,映射內存起始地址
14 
15 *scrinfo,屏幕信息結構體
16 
17 *bmpname,.bmp位圖文件名
18 
19 *************************/
20 int show_photo(const char *fbp, struct fb_var_screeninfo *scrinfo, const char *bmpname)
21 {
22   if(NULL == fbp || NULL == scrinfo || NULL == bmpname)
23     return -1;
24 
25   int line_x = 0, line_y = 0;
26   unsigned long tmp = 0;
27   int xres = scrinfo->xres_virtual;    //屏幕寬(虛擬)
28   int bits_per_pixel = scrinfo->bits_per_pixel;  //屏幕位數
29   BitMapFileHeader FileHead;
30   BitMapInfoHeader InfoHead;
31   RgbQuad rgb;    
32 
33   unsigned long location = 0;
34 
35   //打開.bmp文件
36   FILE *fb = fopen(bmpname, "rb");
37   if (fb == NULL)
38   {
39     printf("fopen bmp error\r\n");
40     return -1;
41   }
42 
43   //讀文件信息
44   if (1 != fread( &FileHead, sizeof(BitMapFileHeader),1, fb))
45   {
46     printf("read BitMapFileHeader error!\n");
47     fclose(fb);
48     return -1;
49   }
50   if (memcmp(FileHead.bfType, "BM", 2) != 0)
51   {
52     printf("it's not a BMP file\n");
53     fclose(fb);
54     return -1;
55   }
56   
57   //讀位圖信息
58   if (1 != fread( (char *)&InfoHead, sizeof(BitMapInfoHeader),1, fb))
59   {
60     printf("read BitMapInfoHeader error!\n");
61     fclose(fb);
62     return -1;
63   }
64   
65   //跳轉至數據區
66   fseek(fb, FileHead.bfOffBits, SEEK_SET);
67   
68   int len = InfoHead.biBitCount / 8;    //原圖一個像素占幾字節
69   int bits_len = bits_per_pixel / 8;    //屏幕一個像素占幾字節  //循環顯示
70 
71   while(!feof(fb))
72   {
73     tmp = 0;
74     rgb.Reserved = 0xFF;
75   
76     if (len != fread((char *)&rgb, 1, len, fb))
77       break;
78   
79     //計算該像素在映射內存起始地址的偏移量
80     location = line_x * bits_len + (InfoHead.biHeight - line_y - 1) * xres * bits_len;
81   
82     tmp |= rgb.Reserved << 24 | rgb.Red << 16 | rgb.Green << 8 | rgb.Blue;
83   
84     *((unsigned long *)(fbp + location)) = tmp;    
85   
86     line_x++;    
87     if (line_x == InfoHead.biWidth )
88     {
89       line_x = 0;
90       line_y++;
91       if(line_y == InfoHead.biHeight)    
92         break;    
93     }    
94   }
95   
96   fclose(fb);
97 
98   return 0;
99 }

 

 

 1 /*************************
 2 
 3 *main.c文件
 4 
 5 *************************/
 6 
 7 #include "bmp.h"
 8 
 9 int main()
10 {
11   int devfb, filefb;
12   struct fb_var_screeninfo scrinfo;
13   unsigned long screensize;
14   char *fbp ;
15   char bmpname[20] = {0};
16 
17   //打開設備文件
18   devfb = open("/dev/fb0", O_RDWR);
19   if(!devfb)
20   {
21     printf("devfb open error!\r\n");
22     return -1;
23   }
24   //printf("devfb open OK! %d\r\n", devfb);
25 
26  
27 
28   //獲取屏幕信息
29 
30   //若屏幕顯示區域大小不合適,可用ioctl(devfb, FBIOPUT_VSCREENINFO, &scrinfo)設置
31   if(ioctl(devfb, FBIOGET_VSCREENINFO, &scrinfo))
32   {
33     printf("get screen infomation error!\r\n");
34     return -1;
35   }
36 
37   //printf(".xres=%d, .yres=%d, .bit=%d\r\n",scrinfo.xres, scrinfo.yres, scrinfo.bits_per_pixel);
38 
39   //printf(".xres_virtual=%d, .yres_virtual=%d\r\n",scrinfo.xres_virtual, scrinfo.yres_virtual);
40 
41   if(32 != scrinfo.bits_per_pixel)
42   {
43     printf("screen infomation.bits error!\r\n");
44     return -1;
45   }
46 
47  
48 
49   //計算需要的映射內存大小
50   screensize = scrinfo.xres_virtual * scrinfo.yres_virtual * scrinfo.bits_per_pixel / 8;
51   //printf("screensize=%lu!\r\n", screensize);
52   
53   //內存映射
54   fbp = (char *)mmap(NULL, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, devfb, 0);
55   if(-1 == (int)fbp)
56   {
57     printf("mmap error!\r\n");
58     return -1;
59   }
60   
61   scanf("%s", bmpname);
62   
63   //顯示圖片
64   show_photo(fbp, &scrinfo, bmpname);
65 
66  
67 
68   //取消映射,關閉文件
69   munmap(fbp, screensize);
70   close(devfb);
71 
72   return 0;
73 }

 

 

 

/******************************************

*效果圖(我不是給這游戲打廣告,只是隨手拿了一張圖而已)

*說明:1.圖片是24位或32位bmp圖

     2.屏幕是32位屏幕

     3.不同的設備,可能設備文件不同

     4.需要在root用戶下執行

*******************************************/

 

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