Panda3D

pnmFileTypeJPGWriter.cxx

00001 // Filename: pnmFileTypeJPGWriter.cxx
00002 // Created by:  mike (19Jun00)
00003 //
00004 ////////////////////////////////////////////////////////////////////
00005 //
00006 // PANDA 3D SOFTWARE
00007 // Copyright (c) Carnegie Mellon University.  All rights reserved.
00008 //
00009 // All use of this software is subject to the terms of the revised BSD
00010 // license.  You should have received a copy of this license along
00011 // with this source code in a file named "LICENSE."
00012 //
00013 ////////////////////////////////////////////////////////////////////
00014 
00015 #include "pnmFileTypeJPG.h"
00016 
00017 #ifdef HAVE_JPEG
00018 
00019 #include "config_pnmimagetypes.h"
00020 
00021 #include "pnmImage.h"
00022 #include "pnmWriter.h"
00023 #include "thread.h"
00024 
00025 
00026 //
00027 // The following bit of code, for setting up jpeg_ostream_src(), was
00028 // lifted from jpeglib, and modified to work with ostream instead of
00029 // stdio.
00030 //
00031 
00032 /*
00033  * jdatadst.c
00034  *
00035  * Copyright (C) 1994-1996, Thomas G. Lane.
00036  * This file is part of the Independent JPEG Group's software.
00037  * For conditions of distribution and use, see the accompanying README file.
00038  *
00039  * This file contains compression data destination routines for the case of
00040  * emitting JPEG data to a file (or any stdio stream).  While these routines
00041  * are sufficient for most applications, some will want to use a different
00042  * destination manager.
00043  * IMPORTANT: we assume that fwrite() will correctly transcribe an array of
00044  * JOCTETs into 8-bit-wide elements on external storage.  If char is wider
00045  * than 8 bits on your machine, you may need to do some tweaking.
00046  */
00047 
00048 /* this is not a core library module, so it doesn't define JPEG_INTERNALS */
00049 extern "C" {
00050 #include <jpeglib.h>
00051 #include <jerror.h>
00052 }
00053 
00054 
00055 /* Expanded data destination object for stdio output */
00056 
00057 typedef struct {
00058   struct jpeg_destination_mgr pub; /* public fields */
00059 
00060   ostream * outfile;            /* target stream */
00061   JOCTET * buffer;              /* start of buffer */
00062 } my_destination_mgr;
00063 
00064 typedef my_destination_mgr * my_dest_ptr;
00065 
00066 #define OUTPUT_BUF_SIZE  4096   /* choose an efficiently fwrite'able size */
00067 
00068 
00069 /*
00070  * Initialize destination --- called by jpeg_start_compress
00071  * before any data is actually written.
00072  */
00073 
00074 METHODDEF(void)
00075 init_destination (j_compress_ptr cinfo)
00076 {
00077   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00078 
00079   /* Allocate the output buffer --- it will be released when done with image */
00080   dest->buffer = (JOCTET *)
00081       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
00082                                   OUTPUT_BUF_SIZE * sizeof(JOCTET));
00083 
00084   dest->pub.next_output_byte = dest->buffer;
00085   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
00086 }
00087 
00088 
00089 /*
00090  * Empty the output buffer --- called whenever buffer fills up.
00091  *
00092  * In typical applications, this should write the entire output buffer
00093  * (ignoring the current state of next_output_byte & free_in_buffer),
00094  * reset the pointer & count to the start of the buffer, and return TRUE
00095  * indicating that the buffer has been dumped.
00096  *
00097  * In applications that need to be able to suspend compression due to output
00098  * overrun, a FALSE return indicates that the buffer cannot be emptied now.
00099  * In this situation, the compressor will return to its caller (possibly with
00100  * an indication that it has not accepted all the supplied scanlines).  The
00101  * application should resume compression after it has made more room in the
00102  * output buffer.  Note that there are substantial restrictions on the use of
00103  * suspension --- see the documentation.
00104  *
00105  * When suspending, the compressor will back up to a convenient restart point
00106  * (typically the start of the current MCU). next_output_byte & free_in_buffer
00107  * indicate where the restart point will be if the current call returns FALSE.
00108  * Data beyond this point will be regenerated after resumption, so do not
00109  * write it out when emptying the buffer externally.
00110  */
00111 
00112 METHODDEF(boolean)
00113 empty_output_buffer (j_compress_ptr cinfo)
00114 {
00115   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00116 
00117   if (!dest->outfile->write((const char *)dest->buffer, OUTPUT_BUF_SIZE))
00118     ERREXIT(cinfo, JERR_FILE_WRITE);
00119 
00120   dest->pub.next_output_byte = dest->buffer;
00121   dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
00122   Thread::consider_yield();
00123 
00124   return TRUE;
00125 }
00126 
00127 
00128 /*
00129  * Terminate destination --- called by jpeg_finish_compress
00130  * after all data has been written.  Usually needs to flush buffer.
00131  *
00132  * NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
00133  * application must deal with any cleanup that should happen even
00134  * for error exit.
00135  */
00136 
00137 METHODDEF(void)
00138 term_destination (j_compress_ptr cinfo)
00139 {
00140   my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
00141   size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
00142 
00143   /* Write any data remaining in the buffer */
00144   if (datacount > 0) {
00145     if (!dest->outfile->write((const char *)dest->buffer, datacount))
00146       ERREXIT(cinfo, JERR_FILE_WRITE);
00147   }
00148   dest->outfile->flush();
00149   Thread::consider_yield();
00150   /* Make sure we wrote the output file OK */
00151   if (dest->outfile->fail())
00152     ERREXIT(cinfo, JERR_FILE_WRITE);
00153 }
00154 
00155 
00156 /*
00157  * Prepare for output to a stdio stream.
00158  * The caller must have already opened the stream, and is responsible
00159  * for closing it after finishing compression.
00160  */
00161 
00162 GLOBAL(void)
00163 jpeg_ostream_dest (j_compress_ptr cinfo, ostream * outfile)
00164 {
00165   my_dest_ptr dest;
00166 
00167   /* The destination object is made permanent so that multiple JPEG images
00168    * can be written to the same file without re-executing jpeg_stdio_dest.
00169    * This makes it dangerous to use this manager and a different destination
00170    * manager serially with the same JPEG object, because their private object
00171    * sizes may be different.  Caveat programmer.
00172    */
00173   if (cinfo->dest == NULL) {    /* first time for this JPEG object? */
00174     cinfo->dest = (struct jpeg_destination_mgr *)
00175       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
00176                                   sizeof(my_destination_mgr));
00177   }
00178 
00179   dest = (my_dest_ptr) cinfo->dest;
00180   dest->pub.init_destination = init_destination;
00181   dest->pub.empty_output_buffer = empty_output_buffer;
00182   dest->pub.term_destination = term_destination;
00183   dest->outfile = outfile;
00184 }
00185 
00186 
00187 
00188 //
00189 // The rest of the code in this file is new to Panda.
00190 //
00191 
00192 ////////////////////////////////////////////////////////////////////
00193 //     Function: PNMFileTypeJPG::Writer::Constructor
00194 //       Access: Public
00195 //  Description:
00196 ////////////////////////////////////////////////////////////////////
00197 PNMFileTypeJPG::Writer::
00198 Writer(PNMFileType *type, ostream *file, bool owns_file) :
00199   PNMWriter(type, file, owns_file)
00200 {
00201 }
00202 
00203 ////////////////////////////////////////////////////////////////////
00204 //     Function: PNMFileTypeJPG::Writer::write_data
00205 //       Access: Public, Virtual
00206 //  Description: Writes out an entire image all at once, including the
00207 //               header, based on the image data stored in the given
00208 //               _x_size * _y_size array and alpha pointers.  (If the
00209 //               image type has no alpha channel, alpha is ignored.)
00210 //               Returns the number of rows correctly written.
00211 //
00212 //               It is the user's responsibility to fill in the header
00213 //               data via calls to set_x_size(), set_num_channels(),
00214 //               etc., or copy_header_from(), before calling
00215 //               write_data().
00216 //
00217 //               It is important to delete the PNMWriter class after
00218 //               successfully writing the data.  Failing to do this
00219 //               may result in some data not getting flushed!
00220 //
00221 //               Derived classes need not override this if they
00222 //               instead provide supports_streaming() and write_row(),
00223 //               below.
00224 ////////////////////////////////////////////////////////////////////
00225 int PNMFileTypeJPG::Writer::
00226 write_data(xel *array, xelval *) {
00227   if (_y_size<=0 || _x_size<=0) {
00228     return 0;
00229   }
00230 
00231   /* This struct contains the JPEG compression parameters and pointers to
00232    * working space (which is allocated as needed by the JPEG library).
00233    * It is possible to have several such structures, representing multiple
00234    * compression/decompression processes, in existence at once.  We refer
00235    * to any one struct (and its associated working data) as a "JPEG object".
00236    */
00237   struct jpeg_compress_struct cinfo;
00238   /* This struct represents a JPEG error handler.  It is declared separately
00239    * because applications often want to supply a specialized error handler
00240    * (see the second half of this file for an example).  But here we just
00241    * take the easy way out and use the standard error handler, which will
00242    * print a message on stderr and call exit() if compression fails.
00243    * Note that this struct must live as long as the main JPEG parameter
00244    * struct, to avoid dangling-pointer problems.
00245    */
00246   struct jpeg_error_mgr jerr;
00247   /* More stuff */
00248   JSAMPROW row_pointer[1];      /* pointer to JSAMPLE row[s] */
00249   int row_stride;               /* physical row width in image buffer */
00250 
00251   /* Step 1: allocate and initialize JPEG compression object */
00252 
00253   /* We have to set up the error handler first, in case the initialization
00254    * step fails.  (Unlikely, but it could happen if you are out of memory.)
00255    * This routine fills in the contents of struct jerr, and returns jerr's
00256    * address which we place into the link field in cinfo.
00257    */
00258   cinfo.err = jpeg_std_error(&jerr);
00259 
00260   /* Now we can initialize the JPEG compression object. */
00261   jpeg_create_compress(&cinfo);
00262 
00263   /* Step 2: specify data destination (eg, a file) */
00264   /* Note: steps 2 and 3 can be done in either order. */
00265   jpeg_ostream_dest(&cinfo, _file);
00266 
00267   /* Step 3: set parameters for compression */
00268 
00269   /* First we supply a description of the input image.
00270    * Four fields of the cinfo struct must be filled in:
00271    */
00272   cinfo.image_width = _x_size;      /* image width and height, in pixels */
00273   cinfo.image_height = _y_size;
00274   if (is_grayscale()) {
00275     cinfo.input_components = 1;
00276     cinfo.in_color_space = JCS_GRAYSCALE;
00277   } else {
00278     cinfo.input_components = 3;
00279     cinfo.in_color_space = JCS_RGB;
00280   }
00281   /* Now use the library's routine to set default compression parameters.
00282    * (You must set at least cinfo.in_color_space before calling this,
00283    * since the defaults depend on the source color space.)
00284    */
00285   jpeg_set_defaults(&cinfo);
00286   /* Now you can set any non-default parameters you wish to.
00287    * Here we just illustrate the use of quality (quantization table) scaling:
00288    */
00289   jpeg_set_quality(&cinfo, jpeg_quality, TRUE /* limit to baseline-JPEG values */);
00290 
00291   /* Step 4: Start compressor */
00292 
00293   /* TRUE ensures that we will write a complete interchange-JPEG file.
00294    * Pass TRUE unless you are very sure of what you're doing.
00295    */
00296   jpeg_start_compress(&cinfo, TRUE);
00297 
00298   /* Write the user comment, if any */
00299   if (_comment.size()) {
00300     jpeg_write_marker(
00301       &cinfo, JPEG_COM, (JOCTET *)_comment.c_str(), strlen(_comment.c_str()));
00302   }
00303 
00304   /* Step 5: while (scan lines remain to be written) */
00305   /*           jpeg_write_scanlines(...); */
00306 
00307   /* Here we use the library's state variable cinfo.next_scanline as the
00308    * loop counter, so that we don't have to keep track ourselves.
00309    * To keep things simple, we pass one scanline per call; you can pass
00310    * more if you wish, though.
00311    */
00312   row_stride = _x_size * cinfo.input_components; /* JSAMPLEs per row in image_buffer */
00313 
00314   int x = 0;
00315   JSAMPROW row = new JSAMPLE[row_stride];
00316   while (cinfo.next_scanline < cinfo.image_height) {
00317     /* jpeg_write_scanlines expects an array of pointers to scanlines.
00318      * Here the array is only one element long, but you could pass
00319      * more than one scanline at a time if that's more convenient.
00320      */
00321     for (int i = 0; i < row_stride; i += cinfo.input_components) {
00322       if (cinfo.input_components == 1) {
00323         row[i] = (JSAMPLE)(MAXJSAMPLE * PPM_GETB(array[x])/_maxval);
00324       } else {
00325         row[i] = (JSAMPLE)(MAXJSAMPLE * PPM_GETR(array[x])/_maxval);
00326         row[i+1] = (JSAMPLE)(MAXJSAMPLE * PPM_GETG(array[x])/_maxval);
00327         row[i+2] = (JSAMPLE)(MAXJSAMPLE * PPM_GETB(array[x])/_maxval);
00328       }
00329       x++;
00330     }
00331     //row_pointer[0] = & image_buffer[cinfo.next_scanline * row_stride];
00332     //(void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
00333     row_pointer[0] = row;
00334     (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
00335   }
00336   delete row;
00337 
00338   /* Step 6: Finish compression */
00339 
00340   jpeg_finish_compress(&cinfo);
00341 
00342   /* Step 7: release JPEG compression object */
00343 
00344   /* This is an important step since it will release a good deal of memory. */
00345   jpeg_destroy_compress(&cinfo);
00346 
00347   return _y_size;
00348 }
00349 
00350 #endif  // HAVE_JPEG
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