将jpeg图片显示在framebuffer上

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1. /**************************************************
2. * example5.c
3. * Author: T-bagwell
4. *
5. * Compile:gcc -Wall example5.c -o example5
6. *************************************************/
7. #include <stdio.h>
8. #include <unistd.h>
9. #include <sys/types.h>
10. #include <sys/stat.h>
11. #include <fcntl.h>
12. #include <linux/fb.h>
13. #include <errno.h>
14. #include <sys/mman.h>
15. #include <stdlib.h>
16. #include <string.h>
17. #include <sys/ioctl.h>
18. #include <jpeglib.h>
19. #include <jerror.h>
22. int print_screen(short *buf,int width,int height);
23. void draw_hline(short *buffer,int x,int y,int maxy,int maxx);
25. char *fb_addr;
26. unsigned int fb_width;
27. unsigned int fb_height;
28. unsigned int fb_depth;
29. unsigned fb_size;
31. unsigned short PIXELRGB888TO565(unsigned char red, unsigned char green, unsigned char blue)
32. {
33.         unsigned short B = (blue >> 3) & 0x001F;
34.         unsigned short G = ((green >> 3) << 5) & 0x07E0;
35.         unsigned short R = ((red >> 3) << 11) & 0xF800;
37.         return (unsigned short) (R | G | B);
38. }
40. int draw_pixel(void *fbmem, int width, int height, int x, int y, unsigned short color)
41. {
42. if ((x > width) || (y > height))
43.                 return -1;
45.         unsigned short *dst = ((unsigned short *) fbmem y * width x);
47. *dst = color;
48.         return (0);
49. }
52. int main(int argc, char *argv[])
53. {
54. int screen_fbd=0;
55.         struct jpeg_decompress_struct cinfo;
56.         struct jpeg_error_mgr jerr;
57.         FILE *infile;
58.         struct fb_fix_screeninfo fb_fix;
59.         struct fb_var_screeninfo fb_var;
60.         char *env=NULL;
61.         unsigned char *buffer;
62.         unsigned char *fbmem;
63.         short *color_white;
64.         unsigned short color;
65.         unsigned int x;
66.         unsigned int y;
67. if ((infile = fopen(argv[1], "rb")) == NULL)
68. {
69.                 fprintf(stderr, "open bbs.chinaffmpeg.com 孙悟空提醒您 %s failedn", argv[1]);
70. exit(-1);
71. }
73. if(!(env = getenv("FRAMEBUFFER")))
74. {
75.                 env = "/dev/fb0";
76. }
78.         screen_fbd = open(env, O_RDWR);
80. if(screen_fbd < 0)
81. {
82.                 return 0;
83. }
85. if(ioctl(screen_fbd, FBIOGET_VSCREENINFO, &fb_var) == -1)
86. {
87.                 close(screen_fbd);
88.                 return 0;
89. }
90.         fb_width = fb_var.xres;
91.         fb_height = fb_var.yres;
92.         fb_depth = fb_var.bits_per_pixel;
94.         cinfo.err = jpeg_std_error(&jerr);
95.         jpeg_create_decompress(&cinfo);
97.         jpeg_stdio_src(&cinfo, infile);
98.         jpeg_read_header(&cinfo, TRUE);
99.         jpeg_start_decompress(&cinfo);
100. if ((cinfo.output_width > fb_width) ||(cinfo.output_height > fb_height))
101. {
102.                 return (-1);
103. }
105.         fbmem = mmap(0, fb_width * fb_height, PROT_READ | PROT_WRITE, MAP_SHARED, screen_fbd, 0);
106.         buffer = (unsigned char *) malloc(cinfo.output_width * cinfo.output_components);
107.         y = 0;
109. while (cinfo.output_scanline < cinfo.output_height)
110. {
111.                 jpeg_read_scanlines(&cinfo, &buffer, 1);
112. if (fb_depth == 16)
113. {
114. for (x = 0; x < cinfo.output_width; x )
115. {
116.                                 color = PIXELRGB888TO565(buffer[x * 3], buffer[x * 3 1], buffer[x * 3 2]);
117.                                 draw_pixel(fbmem, fb_width, fb_height, x, y, color);
118. }
119. }
120.         y ;
121. }
122.         jpeg_finish_decompress(&cinfo);
123.         jpeg_destroy_decompress(&cinfo);
125.         free(buffer);
126.         return 0;
127. }

QQ群里突然有人问了这个问题，希望得到开源的程序，正好以前写过一个，找的挺费劲的，就贴到这里吧 http://bbs.chinaunix.net/forum.php?mod=redirect&goto=findpost&ptid=2021099&pid=14296454&fromuid=11344913