bool ossimCodecFactory::decodeJpeg( const std::vector<ossim_uint8>& in,
ossimRefPtr<ossimImageData>& out ) const
{
bool result = false;
// Note: This is public and can be called directly; hence, the signature check
// Check for jpeg signature:
if ( in.size() > 3 )
{
if ( (in[0] == 0xff) &&
(in[1] == 0xd8) &&
(in[2] == 0xff) &&
(in[3] == 0xe0) )
{
/* This struct contains the JPEG decompression parameters and pointers
* to working space (which is allocated as needed by the JPEG library).
*/
jpeg_decompress_struct cinfo;
/* 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.
*/
ossimJpegErrorMgr jerr;
/* Step 1: allocate and initialize JPEG decompression object */
/* We set up the normal JPEG error routines, then override error_exit. */
cinfo.err = jpeg_std_error(&jerr.pub);
jerr.pub.error_exit = ossimJpegErrorExit;
/* Establish the setjmp return context for my_error_exit to use. */
if (setjmp(jerr.setjmp_buffer) == 0)
{
result = true;
/* Now we can initialize the JPEG decompression object. */
jpeg_CreateDecompress(&cinfo, JPEG_LIB_VERSION, sizeof(cinfo));
//---
// Step 2: specify data source. In this case we will uncompress from
// memory so we will use "ossimJpegMemorySrc" in place of " jpeg_stdio_src".
//---
ossimJpegMemorySrc ( &cinfo,
&(in.front()),
(size_t)(in.size()) );
/* Step 3: read file parameters with jpeg_read_header() */
jpeg_read_header(&cinfo, TRUE);
/* Step 4: set parameters for decompression */
/* 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 */
jpeg_start_decompress(&cinfo);
#if 0 /* Please leave for debug. (drb) */
if ( traceDebug() )
{
ossimNotify(ossimNotifyLevel_DEBUG)
<< "jpeg cinfo.output_width: " << cinfo.output_width
<< "\njpeg cinfo.output_height: " << cinfo.output_height
<< "\n";
}
#endif
const ossim_uint32 SAMPLES = cinfo.output_width;
const ossim_uint32 LINES = cinfo.output_height;
const ossim_uint32 BANDS = cinfo.output_components;
if ( out.valid() )
{
// This will resize tile if not correct.
out->setImageRectangleAndBands(
ossimIrect(0,0,(ossim_int32)SAMPLES-1,(ossim_int32)LINES-1), BANDS );
}
else
{
out = new ossimU8ImageData( 0, BANDS, SAMPLES, LINES );
out->initialize();
}
// Get pointers to the cache tile buffers.
std::vector<ossim_uint8*> destinationBuffer(BANDS);
for (ossim_uint32 band = 0; band < BANDS; ++band)
{
destinationBuffer[band] = out->getUcharBuf(band);
}
std::vector<ossim_uint8> lineBuffer(SAMPLES * cinfo.output_components);
JSAMPROW jbuf[1];
jbuf[0] = (JSAMPROW) &(lineBuffer.front());
while (cinfo.output_scanline < LINES)
{
// Read a line from the jpeg file.
jpeg_read_scanlines(&cinfo, jbuf, 1);
//---
// Copy the line which if band interleaved by pixel the the band
// separate buffers.
//---
ossim_uint32 index = 0;
for (ossim_uint32 sample = 0; sample < SAMPLES; ++sample)
{
for (ossim_uint32 band = 0; band < BANDS; ++band)
{
destinationBuffer[band][sample] = lineBuffer[index];
++index;
}
}
for (ossim_uint32 band = 0; band < BANDS; ++band)
{
destinationBuffer[band] += SAMPLES;
}
}
// Set the tile status:
out->validate();
// clean up...
jpeg_finish_decompress(&cinfo);
} // Matches: if (setjmp(jerr.setjmp_buffer) == 0)
jpeg_destroy_decompress(&cinfo);
} // Matches: if ( (in[0] == 0xff) ... )
} // Matches: if ( in.size() > 3 )
return result;
}
bool ossimCodecFactory::encodeJpeg( ossim_uint32 quality,
const ossimRefPtr<ossimImageData>& in,
std::vector<ossim_uint8>& out ) const
{
bool result = false;
if ( in.valid() && (in->getDataObjectStatus() != OSSIM_NULL) )
{
if ( in->getScalarType() == OSSIM_UINT8 )
{
// Open a memory stream up to put the jpeg image in memory:
std::stringstream jpegStreamBuf;
//---
// Initialize JPEG compression library:
// NOTE: JDIMENSION is an "unsigned int"
//---
struct jpeg_compress_struct cinfo;
struct jpeg_error_mgr jerr;
cinfo.err = jpeg_std_error( &jerr );
jpeg_create_compress(&cinfo);
// Define a custom stream destination manager for jpeglib to write compressed block:
jpeg_cpp_stream_dest(&cinfo, jpegStreamBuf);
/* Setting the parameters of the output file here */
cinfo.image_width = in->getWidth();
cinfo.image_height = in->getHeight();
// Bands must be one or three for this writer.
const ossim_uint32 INPUT_BANDS = in->getNumberOfBands();
if ( (INPUT_BANDS == 1) || (INPUT_BANDS == 3) )
{
cinfo.input_components = INPUT_BANDS;
}
else
{
if ( INPUT_BANDS < 3 )
{
cinfo.input_components = 1; // Use first band.
}
else
{
cinfo.input_components = 3; // Use the first 3 bands.
}
}
// colorspace of input image
if ( cinfo.input_components == 3)
{
cinfo.in_color_space = JCS_RGB;
}
else
{
cinfo.in_color_space = JCS_GRAYSCALE;
}
// Default compression parameters, we shouldn't be worried about these.
jpeg_set_defaults( &cinfo );
jpeg_set_quality(&cinfo, quality, TRUE); //limit to baseline-JPEG values
// Now do the compression...
jpeg_start_compress( &cinfo, TRUE );
// Line buffer:
ossim_uint32 buf_size = cinfo.input_components*cinfo.image_width;
std::vector<ossim_uint8> buf(buf_size);
// Compress the tile on line at a time:
JSAMPROW row_pointer[1]; // Pointer to a single row.
row_pointer[0] = (JSAMPLE*)&buf.front();
// Get pointers to the input data:
std::vector<const ossim_uint8*> inBuf(cinfo.input_components);
for ( ossim_int32 band = 0; band < cinfo.input_components; ++band )
{
inBuf[band] = in->getUcharBuf(band);
}
ossim_uint32 inIdx = 0;
for (ossim_uint32 line=0; line< cinfo.image_height; ++line)
{
// Convert from band sequential to band interleaved by pixel.
ossim_uint32 outIdx = 0;
for ( ossim_uint32 p = 0; p < cinfo.image_width; ++p )
{
for ( ossim_int32 band = 0; band < cinfo.input_components; ++band )
{
buf[outIdx++] = inBuf[band][inIdx];
}
++inIdx;
}
// Write it...
jpeg_write_scanlines( &cinfo, row_pointer, 1 );
}
// Similar to read file, clean up after we're done compressing.
jpeg_finish_compress( &cinfo );
jpeg_destroy_compress( &cinfo );
// Copy the memory stream to output vector.
out.resize(jpegStreamBuf.str().size());
jpegStreamBuf.seekg(0, std::ios_base::beg);
jpegStreamBuf.read((char*)&out.front(), jpegStreamBuf.str().size());
result = true;
}
else // Scalar type check...
{
ossimNotify(ossimNotifyLevel_WARN)
<< "ossimCodecFactory::encodeJpeg ERROR:"
<< "\nPassing non-eight bit data to eight bit encoder!" << std::endl;
}
} // Matches: if ( in.valid() ... )
return result;
}
