将jpeg圖檔顯示在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>
20. int print_screen(short *buf,int width,int height);
21. void draw_hline(short *buffer,int x,int y,int maxy,int maxx);
22. char *fb_addr;
23. unsigned int fb_width;
24. unsigned int fb_height;
25. unsigned int fb_depth;
26. unsigned fb_size;
27. unsigned short PIXELRGB888TO565(unsigned char red, unsigned char green, unsigned char blue)
28. {
29.         unsigned short B = (blue >> 3) & 0x001F;
30.         unsigned short G = ((green >> 3) << 5) & 0x07E0;
31.         unsigned short R = ((red >> 3) << 11) & 0xF800;
32.         return (unsigned short) (R | G | B);
33. }
34. int draw_pixel(void *fbmem, int width, int height, int x, int y, unsigned short color)
35. {
36. if ((x > width) || (y > height))
37.                 return -1;
38.         unsigned short *dst = ((unsigned short *) fbmem + y * width + x);
39. *dst = color;
40.         return (0);
41. }
42. int main(int argc, char *argv[])
43. {
44. int screen_fbd=0;
45.         struct jpeg_decompress_struct cinfo;
46.         struct jpeg_error_mgr jerr;
47.         FILE *infile;
48.         struct fb_fix_screeninfo fb_fix;
49.         struct fb_var_screeninfo fb_var;
50.         char *env=NULL;
51.         unsigned char *buffer;
52.         unsigned char *fbmem;
53.         short *color_white;
54.         unsigned short color;
55.         unsigned int x;
56.         unsigned int y;
57. if ((infile = fopen(argv[1], "rb")) == NULL)
58. {
59.                 fprintf(stderr, "open bbs.chinaffmpeg.com 孫悟空提醒您 %s failed\n", argv[1]);
60. exit(-1);
61. }
62. if(!(env = getenv("FRAMEBUFFER")))
63. {
64.                 env = "/dev/fb0";
65. }
66.         screen_fbd = open(env, O_RDWR);
67. if(screen_fbd < 0)
68. {
69.                 return 0;
70. }
71. if(ioctl(screen_fbd, FBIOGET_VSCREENINFO, &fb_var) == -1)
72. {
73.                 close(screen_fbd);
74.                 return 0;
75. }
76.         fb_width = fb_var.xres;
77.         fb_height = fb_var.yres;
78.         fb_depth = fb_var.bits_per_pixel;
79.         cinfo.err = jpeg_std_error(&jerr);
80.         jpeg_create_decompress(&cinfo);
81.         jpeg_stdio_src(&cinfo, infile);
82.         jpeg_read_header(&cinfo, TRUE);
83.         jpeg_start_decompress(&cinfo);
84. if ((cinfo.output_width > fb_width) ||(cinfo.output_height > fb_height))
85. {
86.                 return (-1);
87. }
88.         fbmem = mmap(0, fb_width * fb_height, PROT_READ | PROT_WRITE, MAP_SHARED, screen_fbd, 0);
89.         buffer = (unsigned char *) malloc(cinfo.output_width * cinfo.output_components);
90.         y = 0;
91. while (cinfo.output_scanline < cinfo.output_height)
92. {
93.                 jpeg_read_scanlines(&cinfo, &buffer, 1);
94. if (fb_depth == 16)
95. {
96. for (x = 0; x < cinfo.output_width; x++)
97. {
98.                                 color = PIXELRGB888TO565(buffer[x * 3], buffer[x * 3 + 1], buffer[x * 3 + 2]);
99.                                 draw_pixel(fbmem, fb_width, fb_height, x, y, color);
100. }
101. }
102.         y++;
103. }
104.         jpeg_finish_decompress(&cinfo);
105.         jpeg_destroy_decompress(&cinfo);
106.         free(buffer);
107.         return 0;
108. }

QQ群裡突然有人問了這個問題，希望得到開源的程式，正好以前寫過一個，找的挺費勁的，就貼到這裡吧

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