-/*
- * Sample routine for JPEG decompression. We assume that the source file name
- * is passed in. We want to return 1 on success, 0 on error.
- */
-
-
-//GLOBAL(int)
-int
-gdcmFile::gdcm_read_JPEG_file12 (void * image_buffer) {
-
-char *pimage;
-
- /* This struct contains the JPEG decompression parameters and pointers to
- * working space (which is allocated as needed by the JPEG library).
- */
-
- struct jpeg_decompress_struct cinfo;
-
- /* -------------- inside, we found :
- JDIMENSION image_width; // input image width
- JDIMENSION image_height; // input image height
- int input_components; // nb of color components in input image
- J_COLOR_SPACE in_color_space; // colorspace of input image
- double input_gamma; // image gamma of input image
- -------------- */
-
- /* We use our private extension JPEG error handler.
- * Note that this struct must live as long as the main JPEG parameter
- * struct, to avoid dangling-pointer problems.
- */
- struct my_error_mgr jerr;
- /* More stuff */
-
- JSAMPARRAY buffer; /* Output row buffer */
-
- // rappel :
- // ------
- // typedef unsigned char JSAMPLE;
- // typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
- // typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
- // typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
-
-
- int row_stride; /* physical row width in output buffer */
-
- if (DEBUG) printf("entree dans gdcmFile::gdcm_read_JPEG_file12, depuis gdcmJpeg\n");
-
-
- /* In this example we want to open the input file before doing anything else,
- * so that the setjmp() error recovery below can assume the file is open.
- * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
- * requires it in order to read binary files.
- */
-
- /* Step 1: allocate and initialize JPEG decompression object */
-
- if (DEBUG)printf("Entree Step 1\n");
-
- /* We set up the normal JPEG error routines, then override error_exit. */
-
- cinfo.err = jpeg_std_error(&jerr.pub);
- jerr.pub.error_exit = my_error_exit;
-
- /* Establish the setjmp return context for my_error_exit to use. */
-
- if (setjmp(jerr.setjmp_buffer)) {
- /* If we get here, the JPEG code has signaled an error.
- * We need to clean up the JPEG object, close the input file, and return.
- */
- jpeg_destroy_decompress(&cinfo);
- return 0;
- }
- /* Now we can initialize the JPEG decompression object. */
- jpeg_create_decompress(&cinfo);
-
- /* Step 2: specify data source (eg, a file) */
-
-if (DEBUG) printf("Entree Step 2\n");
-
- jpeg_stdio_src(&cinfo, fp);
-
- /* Step 3: read file parameters with jpeg_read_header() */
-
- if (DEBUG) printf("Entree Step 3\n");
-
- (void) jpeg_read_header(&cinfo, TRUE);
-
- /* We can ignore the return value from jpeg_read_header since
- * (a) suspension is not possible with the stdio data source, and
- * (b) we passed TRUE to reject a tables-only JPEG file as an error.
- * See libjpeg.doc for more info.
- */
-
-if (DEBUG) {
- printf("--------------Header contents :----------------\n");
- printf("image_width %d image_height %d\n",
- cinfo.image_width , cinfo.image_height);
- printf("bits of precision in image data %d \n",
- cinfo.output_components);
- printf("nb of color components returned %d \n",
- cinfo.data_precision);
-}
-
-
-/*
- JDIMENSION image_width; // input image width
- JDIMENSION image_height; // input image height
- int output_components; // # of color components returned
- J_COLOR_SPACE in_color_space; // colorspace of input image
- double input_gamma; // image gamma of input image
- int data_precision; // bits of precision in image data
-
-*/
-
- /* Step 4: set parameters for decompression */
-
- if (DEBUG) printf("Entree Step 4\n");
-
- /* In this example, we don't need to change any of the defaults set by
- * jpeg_read_header(), so we do nothing here.
- */
-
- /* Step 5: Start decompressor */
-
- if (DEBUG) printf("Entree Step 5\n");
-
- (void) jpeg_start_decompress(&cinfo);
- /* We can ignore the return value since suspension is not possible
- * with the stdio data source.
- */
-
- /* We may need to do some setup of our own at this point before reading
- * the data. After jpeg_start_decompress() we have the correct scaled
- * output image dimensions available, as well as the output colormap
- * if we asked for color quantization.
- * In this example, we need to make an output work buffer of the right size.
- */
-
- /* JSAMPLEs per row in output buffer */
- row_stride = cinfo.output_width * cinfo.output_components;
-
- if (DEBUG) printf ("cinfo.output_width %d cinfo.output_components %d row_stride %d\n",
- cinfo.output_width, cinfo.output_components,row_stride);
-
- /* Make a one-row-high sample array that will go away when done with image */
- buffer = (*cinfo.mem->alloc_sarray)
- ((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
-
- /* Step 6: while (scan lines remain to be read) */
-
- if (DEBUG) printf("Entree Step 6\n");
-
- /* jpeg_read_scanlines(...); */
-
- /* Here we use the library's state variable cinfo.output_scanline as the
- * loop counter, so that we don't have to keep track ourselves.
- */
-
- if (DEBUG) printf ("cinfo.output_height %d cinfo.output_width %d\n",
- cinfo.output_height,cinfo.output_width);
-
- pimage=(char *)image_buffer;
-
- while (cinfo.output_scanline < cinfo.output_height) {
- /* jpeg_read_scanlines expects an array of pointers to scanlines.
- * Here the array is only one element long, but you could ask for
- * more than one scanline at a time if that's more convenient.
- */
-
- (void) jpeg_read_scanlines(&cinfo, buffer, 1);
-
- if ( BITS_IN_JSAMPLE == 8) {
- memcpy( pimage, buffer[0],row_stride);
- pimage+=row_stride;
- } else {
- memcpy( pimage, buffer[0],row_stride*2 ); // FIXME : *2 car 16 bits?!?
- pimage+=row_stride*2; // FIXME : *2 car 16 bits?!?
- }
- }
-
- /* Step 7: Finish decompression */
-
-if (DEBUG) printf("Entree Step 7\n");
-
- (void) jpeg_finish_decompress(&cinfo);
- /* We can ignore the return value since suspension is not possible
- * with the stdio data source.
- */
-
- /* Step 8: Release JPEG decompression object */
-
-if (DEBUG) printf("Entree Step 8\n");
-
- /* This is an important step since it will release a good deal of memory. */
-
- jpeg_destroy_decompress(&cinfo);
-
- /* After finish_decompress, we can close the input file.
- * Here we postpone it until after no more JPEG errors are possible,
- * so as to simplify the setjmp error logic above. (Actually, I don't
- * think that jpeg_destroy can do an error exit, but why assume anything...)
- */
-
- /* At this point you may want to check to see whether any corrupt-data
- * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
- */
-
- /* And we're done! */
-
- return 1;
-}
-
-/*
- * SOME FINE POINTS:
- *
- * In the above code, we ignored the return value of jpeg_read_scanlines,
- * which is the number of scanlines actually read. We could get away with
- * this because we asked for only one line at a time and we weren't using
- * a suspending data source. See libjpeg.doc for more info.
- *
- * We cheated a bit by calling alloc_sarray() after jpeg_start_decompress();
- * we should have done it beforehand to ensure that the space would be
- * counted against the JPEG max_memory setting. In some systems the above
- * code would risk an out-of-memory error. However, in general we don't
- * know the output image dimensions before jpeg_start_decompress(), unless we
- * call jpeg_calc_output_dimensions(). See libjpeg.doc for more about this.
- *
- * Scanlines are returned in the same order as they appear in the JPEG file,
- * which is standardly top-to-bottom. If you must emit data bottom-to-top,
- * you can use one of the virtual arrays provided by the JPEG memory manager
- * to invert the data. See wrbmp.c for an example.
- *
- * As with compression, some operating modes may require temporary files.
- * On some systems you may need to set up a signal handler to ensure that
- * temporary files are deleted if the program is interrupted. See libjpeg.doc.
- */
-
-
-
-
-
-