Linux C language displays the. BMP Format Image, linux.bmp

Linux C language displays the. BMP Format Image, linux.bmp

1/************************** 2 3 * bmp. h文4 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 // File Header structure 21 typedef struct 22 {23 unsigned char bfType [2]; // file type 24 un Signed long bfSize; // bitmap size 25 unsigned short bfReserved1; // bit 0 26 unsigned short bfReserved2; // bit 027 unsigned long bfOffBits; // to the data offset 28 }__ attribute _ (packed) BitMapFileHeader; // the compiler is not optimized, its size is 14 bytes 29 30 // information header Structure 31 typedef struct 32 {33 unsigned long biSize; // BitMapFileHeader number of bytes 34 long biWidth; // bitmap width 35 long biHeight; // The height of the bitmap, which is positive and vice versa. In the inverted figure 36, unsigned short biPlanes. // the value of this parameter is always set to 137 uns. Igned short biBitCount; // indicates the number of bits/pixels, which are 1, 4, 8, 16, 24, or 32. 38 unsigned long biCompression; // image data compression type without compression type: BI_RGB 39 unsigned long biSizeImage; // The image size, in bytes: 40 long biXPelsPerMeter; // The horizontal resolution is 41 long biYPelsPerMeter. // The vertical resolution is 42 unsigned long biClrUsed. // The number of color indexes in the color table used by the bitmap is 43 unsigned long biClrImportant; // The number of indexes that have an important impact on image display. 0 is important. 44} _ attribute _ (packed) BitMapInfoHeader; 45 46 // pixel structure 47 typedef struct 48 {49 unsigned char Blue; // The Blue weight of the color is 50 unsigned char Green; // The Green weight of the color is 51 unsigned char Red; // The Red weight of the color is 52 unsigned char Reserved; // reserved value (brightness) 53 }__ attribute _ (packed) RgbQuad; 54 55 56 57 int show_photo (const char * fbp, struct fb_var_screeninfo * scrinfo, const char * BMP name); 58 59 60 # endif // _ BMP _h __

 

 

 

1/************************** 2 3 * bmp. c file 4 5 *************************/6 7 # include "bmp. h "8 9 10 11/************************** 12 13 * fbp, ing memory start address 14 15 * scrinfo, screen information struct 16 17 * BMP name.bmp bitmap file name 18 19 ************************/20 int show_photo (const char * fbp, struct fb_var_screeninfo * scrinfo, const char * BMP name) 21 {22 if (NULL = fbp | NULL = scrinfo | NULL = BMP name) 23 return-1; 24 25 int l Ine_x = 0, line_y = 0; 26 unsigned long tmp = 0; 27 int xres = scrinfo-> xres_virtual; // screen width (virtual) 28 int bits_per_pixel = scrinfo-> bits_per_pixel; // screen digits 29 BitMapFileHeader FileHead; 30 BitMapInfoHeader InfoHead; 31 RgbQuad rgb; 32 33 unsigned long location = 0; 34 35 // open .bmp FILE 36 FILE * fb = fopen (BMP name, "rb"); 37 if (fb = NULL) 38 {39 printf ("fopen bmp error \ r \ n"); 40 return-1; 41} 42 43 // read file information 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 // read bitmap information 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 // jump to data zone 66 fseek (fb, FileHead. bfOffBits, SEEK_SET); 67 68 int len = InfoHead. biBitCount/8; // The number of bytes of a pixel in the source image: 69 int bits_len = bits_per_pixel/8; // The number of bytes of a pixel in the screen: // display 70 71 in a loop 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 // calculate the offset of the pixel at the start address of the ing memory 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 file 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 BMP name [20] = {0}; 16 17 // open the device file 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 // obtain screen information 29 30 // ioctl (devfb, FBIOPUT_VSCREENINFO, & scrinfo) 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 // calculate the required ing memory size 50 screensize = scrinfo. xres_virtual * scrinfo. yres_virtual * scrinfo. bits_per_pixel/8; 51 // printf ("screensize = % lu! \ R \ n ", screensize); 52 53 // memory ing 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 ", BMP name); 62 63 // display image 64 show_photo (fbp, & scrinfo, BMP name); 65 66 67 68 // cancel ing, close the file 69 munmap (fbp, screensize); 70 close (devfb); 71 72 return 0; 73}

 

 

 

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

* (I did not advertise this game, but just took a picture)

* Description: 1. The image is a 24-bit or 32-bit bmp image.

2. The screen is a 32-bit screen.

3. Different devices may have different device files.

4. Run the following command under the root user:

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