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  콘솔에서 프레임버퍼에 색깔을 찍어본 예제입니다. X윈도우상에서도 결과를 보고 싶은데 안되네요.


 

  1. #include <stdio.h>  
  2. #include <stdlib.h>  
  3. #include <string.h>  
  4.     
  5. #include <fcntl.h>  
  6. #include <unistd.h>  
  7. #include <linux/fb.h>  
  8. #include <sys/mman.h>  
  9.     
  10.     
  11. int main( int argc, char* argv[] )  
  12. {  
  13.     int framebuffer_fd = 0;  
  14.     struct fb_var_screeninfo framebuffer_variable_screeninfo;  
  15.     struct fb_fix_screeninfo framebuffer_fixed_screeninfo;  
  16.     
  17.     framebuffer_fd = open( "/dev/fb0", O_RDWR );  
  18.     if ( framebuffer_fd <  0 ){  
  19.         perror( "Error: cannot open framebuffer device\n" );  
  20.         exit(1);  
  21.     }  
  22.     
  23.     
  24.     if ( ioctl(framebuffer_fd, FBIOGET_VSCREENINFO,   
  25.             &framebuffer_variable_screeninfo) )  
  26.     {  
  27.         perror( "Error: reading variable screen infomation\n" );  
  28.         exit(1);  
  29.     }  
  30.     framebuffer_variable_screeninfo.bits_per_pixel=32;  
  31.     
  32.     if ( ioctl(framebuffer_fd, FBIOPUT_VSCREENINFO,   
  33.             &framebuffer_variable_screeninfo) )  
  34.     {  
  35.         perror( "Error: reading variable screen infomation\n" );  
  36.         exit(1);  
  37.     }  
  38.     
  39.     
  40.     
  41.     if ( ioctl(framebuffer_fd, FBIOGET_FSCREENINFO,   
  42.             &framebuffer_fixed_screeninfo) )  
  43.     {  
  44.         perror( "Error: reading fixed screen infomation\n" );  
  45.         exit(1);  
  46.     }  
  47.     
  48.     printf( "framebuffer Display information\n" );  
  49.     printf( " %d x %d  %d bpp\n", framebuffer_variable_screeninfo.xres,  
  50.              framebuffer_variable_screeninfo.yres,   
  51.              framebuffer_variable_screeninfo.bits_per_pixel );  
  52.     
  53.     
  54.     int width  = framebuffer_variable_screeninfo.xres;  
  55.     int height = framebuffer_variable_screeninfo.yres;  
  56.     int bpp = framebuffer_variable_screeninfo.bits_per_pixel/8;  
  57.     int xoffset = framebuffer_variable_screeninfo.xoffset;  
  58.     int yoffset = framebuffer_variable_screeninfo.yoffset;  
  59.     
  60.     
  61.     long int screensize = width*height*bpp;  
  62.     
  63.     
  64.     char *framebuffer_pointer = (char*)mmap( 0, screensize,  
  65.                                         PROT_READ|PROT_WRITE,  
  66.                                         MAP_SHARED,  
  67.                                         framebuffer_fd, 0 );  
  68.     
  69.     if ( framebuffer_pointer == MAP_FAILED )  
  70.     {  
  71.         perror( "Error : mmap\n" );  
  72.         exit(1);  
  73.     }  
  74.     else  
  75.         {  
  76.             int x,y;  
  77.             for ( y=0; y<height; y++)  
  78.             for ( x=0; x<width; x++)  
  79.             {  
  80.                 unsigned int pixel_offset = (y+yoffset)*framebuffer_fixed_screeninfo.line_length*2 +(x+xoffset)*bpp;  
  81.         
  82.     
  83.         if (bpp==4){  
  84.             if ( x<=width*1/3){    
  85.                  framebuffer_pointer[pixel_offset]=255;//B  
  86.                  framebuffer_pointer[pixel_offset+1]=0;//G  
  87.                  framebuffer_pointer[pixel_offset+2]=0;//R  
  88.                  framebuffer_pointer[pixel_offset+3]=0;//A  
  89.             }  
  90.             if ( x>width*1/3 && x<=width*2/3){      
  91.                  framebuffer_pointer[pixel_offset]=0;//B  
  92.                  framebuffer_pointer[pixel_offset+1]=255;//G  
  93.                  framebuffer_pointer[pixel_offset+2]=0;//R  
  94.                  framebuffer_pointer[pixel_offset+3]=0;//A  
  95.             }  
  96.             if ( x>width*2/3){     
  97.                  framebuffer_pointer[pixel_offset]=0;//B  
  98.                  framebuffer_pointer[pixel_offset+1]=0;//G  
  99.                  framebuffer_pointer[pixel_offset+2]=255;//R  
  100.                  framebuffer_pointer[pixel_offset+3]=0;//A  
  101.             }  
  102.         }  
  103.     
  104.          }  
  105.     
  106.     }   
  107.     
  108.     munmap( framebuffer_pointer, screensize );   
  109.     close( framebuffer_fd );  
  110. }  
  111.     
  112.     
  113.     
  114.         


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문제 발생시 지나치지 마시고 댓글 남겨주시면 가능한 빨리 답장드립니다.


제가 쓴 책도 한번 검토해보세요 ^^

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