做過jpeg解壓的大俠幫個(gè)忙啊

sumland

1.   FILE * infile;        /* source file */
   
2.   JSAMPARRAY buffer;        /* Output row buffer，typedef unsigned char **  JSAMPARRAY   */
   
3.   int row_stride;        /* physical row width in output buffer */
   
4. 
   
5. row_stride = cinfo.output_width * cinfo.output_components;
   
6.   /* Make a one-row-high sample array that will go away when done with image */
   
7.   buffer = (*cinfo.mem->alloc_sarray)
   
8.         ((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
   
9. 
   
10.   /* Step 6: while (scan lines remain to be read) */
    
11.   /*           jpeg_read_scanlines(...); */
    
12. 
    
13.   /* Here we use the library's state variable cinfo.output_scanline as the
    
14.    * loop counter, so that we don't have to keep track ourselves.
    
15.    */
    
16.   while (cinfo.output_scanline < cinfo.output_height) {
    
17.     /* jpeg_read_scanlines expects an array of pointers to scanlines.
    
18.      * Here the array is only one element long, but you could ask for
    
19.      * more than one scanline at a time if that's more convenient.
    
20.      */
    
21.     (void) jpeg_read_scanlines(&cinfo, buffer, 1);
    
22.     /* Assume put_scanline_someplace wants a pointer and sample count. */
    
23.     put_scanline_someplace(buffer[0], row_stride);
    
24.   }
    

復(fù)制代碼

請(qǐng)問如何輸出代碼中buffer的內(nèi)容呢？

林漢邦

//put_scanline_someplace(buffer[0], row_stride);

write(1,buffer[0], row_stride);