Imported existing code

indra/llimage/llimagejpeg.cpp

@@ -0,0 +1,654 @@
+/** 
+ * @file llimagejpeg.cpp
+ *
+ * $LicenseInfo:firstyear=2002&license=viewergpl$
+ * 
+ * Copyright (c) 2002-2009, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at
+ * http://secondlifegrid.net/programs/open_source/licensing/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+#include "stdtypes.h"
+
+#include "llimagejpeg.h"
+
+#include "llerror.h"
+
+jmp_buf	LLImageJPEG::sSetjmpBuffer ;
+LLImageJPEG::LLImageJPEG(S32 quality) 
+	:
+	LLImageFormatted(IMG_CODEC_JPEG),
+	mOutputBuffer( NULL ),
+	mOutputBufferSize( 0 ),
+	mEncodeQuality( quality ) // on a scale from 1 to 100
+{
+}
+
+LLImageJPEG::~LLImageJPEG()
+{
+	llassert( !mOutputBuffer ); // Should already be deleted at end of encode.
+	delete[] mOutputBuffer;
+}
+
+BOOL LLImageJPEG::updateData()
+{
+	resetLastError();
+
+	// Check to make sure that this instance has been initialized with data
+	if (!getData() || (0 == getDataSize()))
+	{
+		setLastError("Uninitialized instance of LLImageJPEG");
+		return FALSE;
+	}
+
+	////////////////////////////////////////
+	// Step 1: allocate and initialize JPEG decompression object
+
+	// 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;
+	cinfo.client_data = this;
+
+	struct jpeg_error_mgr jerr;
+	cinfo.err = jpeg_std_error(&jerr);
+	
+	// Customize with our own callbacks
+	jerr.error_exit =		&LLImageJPEG::errorExit;			// Error exit handler: does not return to caller
+	jerr.emit_message =		&LLImageJPEG::errorEmitMessage;		// Conditionally emit a trace or warning message
+	jerr.output_message =	&LLImageJPEG::errorOutputMessage;	// Routine that actually outputs a trace or error message
+	
+	//
+	//try/catch will crash on Mac and Linux if LLImageJPEG::errorExit throws an error
+	//so as instead, we use setjmp/longjmp to avoid this crash, which is the best we can get. --bao 
+	//
+	if(setjmp(sSetjmpBuffer))
+	{
+		jpeg_destroy_decompress(&cinfo);
+		return FALSE;
+	}
+	try
+	{
+		// Now we can initialize the JPEG decompression object.
+		jpeg_create_decompress(&cinfo);
+
+		////////////////////////////////////////
+		// Step 2: specify data source
+		// (Code is modified version of jpeg_stdio_src();
+		if (cinfo.src == NULL)
+		{	
+			cinfo.src = (struct jpeg_source_mgr *)
+				(*cinfo.mem->alloc_small) ((j_common_ptr) &cinfo, JPOOL_PERMANENT,
+				sizeof(struct jpeg_source_mgr));
+		}
+		cinfo.src->init_source	=		&LLImageJPEG::decodeInitSource;
+		cinfo.src->fill_input_buffer =	&LLImageJPEG::decodeFillInputBuffer;
+		cinfo.src->skip_input_data =	&LLImageJPEG::decodeSkipInputData;
+		cinfo.src->resync_to_restart = jpeg_resync_to_restart; // For now, use default method, but we should be able to do better.
+		cinfo.src->term_source =		&LLImageJPEG::decodeTermSource;
+
+		cinfo.src->bytes_in_buffer =	getDataSize();
+		cinfo.src->next_input_byte =	getData();
+		
+		////////////////////////////////////////
+		// Step 3: read file parameters with jpeg_read_header()
+		jpeg_read_header( &cinfo, TRUE );
+
+		// Data set by jpeg_read_header
+		setSize(cinfo.image_width, cinfo.image_height, 3); // Force to 3 components (RGB)
+
+		/*
+		// More data set by jpeg_read_header
+		cinfo.num_components;
+		cinfo.jpeg_color_space;	// Colorspace of image
+		cinfo.saw_JFIF_marker;		// TRUE if a JFIF APP0 marker was seen
+		cinfo.JFIF_major_version;	// Version information from JFIF marker
+		cinfo.JFIF_minor_version;  //
+		cinfo.density_unit;		// Resolution data from JFIF marker
+		cinfo.X_density;
+		cinfo.Y_density;
+		cinfo.saw_Adobe_marker;	// TRUE if an Adobe APP14 marker was seen
+		cinfo.Adobe_transform;     // Color transform code from Adobe marker
+		*/
+	}
+	catch (int)
+	{
+		jpeg_destroy_decompress(&cinfo);
+
+		return FALSE;
+	}
+	////////////////////////////////////////
+	// Step 4: Release JPEG decompression object 
+	jpeg_destroy_decompress(&cinfo);
+
+	return TRUE;
+}
+
+// Initialize source --- called by jpeg_read_header
+// before any data is actually read.
+void LLImageJPEG::decodeInitSource( j_decompress_ptr cinfo )
+{
+	// no work necessary here
+}
+
+// Fill the input buffer --- called whenever buffer is emptied.
+boolean LLImageJPEG::decodeFillInputBuffer( j_decompress_ptr cinfo )
+{
+//	jpeg_source_mgr* src = cinfo->src;
+//	LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;
+
+	// Should never get here, since we provide the entire buffer up front.
+	ERREXIT(cinfo, JERR_INPUT_EMPTY);
+
+	return TRUE;
+}
+
+// Skip data --- used to skip over a potentially large amount of
+// uninteresting data (such as an APPn marker).
+//
+// Writers of suspendable-input applications must note that skip_input_data
+// is not granted the right to give a suspension return.  If the skip extends
+// beyond the data currently in the buffer, the buffer can be marked empty so
+// that the next read will cause a fill_input_buffer call that can suspend.
+// Arranging for additional bytes to be discarded before reloading the input
+// buffer is the application writer's problem.
+void LLImageJPEG::decodeSkipInputData (j_decompress_ptr cinfo, long num_bytes)
+{
+	jpeg_source_mgr* src = cinfo->src;
+//	LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;
+
+    src->next_input_byte += (size_t) num_bytes;
+    src->bytes_in_buffer -= (size_t) num_bytes;
+}
+
+void LLImageJPEG::decodeTermSource (j_decompress_ptr cinfo)
+{
+  // no work necessary here
+}
+
+
+// Returns true when done, whether or not decode was successful.
+BOOL LLImageJPEG::decode(LLImageRaw* raw_image, F32 decode_time)
+{
+	llassert_always(raw_image);
+	
+	resetLastError();
+	
+	// Check to make sure that this instance has been initialized with data
+	if (!getData() || (0 == getDataSize()))
+	{
+		setLastError("LLImageJPEG trying to decode an image with no data!");
+		return TRUE;  // done
+	}
+	
+	S32 row_stride = 0;
+	U8* raw_image_data = NULL;
+
+	////////////////////////////////////////
+	// Step 1: allocate and initialize JPEG decompression object
+
+	// 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;
+
+	struct jpeg_error_mgr jerr;
+	cinfo.err = jpeg_std_error(&jerr);
+	
+	// Customize with our own callbacks
+	jerr.error_exit =		&LLImageJPEG::errorExit;			// Error exit handler: does not return to caller
+	jerr.emit_message =		&LLImageJPEG::errorEmitMessage;		// Conditionally emit a trace or warning message
+	jerr.output_message =	&LLImageJPEG::errorOutputMessage;	// Routine that actually outputs a trace or error message
+	
+	//
+	//try/catch will crash on Mac and Linux if LLImageJPEG::errorExit throws an error
+	//so as instead, we use setjmp/longjmp to avoid this crash, which is the best we can get. --bao 
+	//
+	if(setjmp(sSetjmpBuffer))
+	{
+		jpeg_destroy_decompress(&cinfo);
+		return TRUE; // done
+	}
+	try
+	{
+		// Now we can initialize the JPEG decompression object.
+		jpeg_create_decompress(&cinfo);
+
+		////////////////////////////////////////
+		// Step 2: specify data source
+		// (Code is modified version of jpeg_stdio_src();
+		if (cinfo.src == NULL)
+		{	
+			cinfo.src = (struct jpeg_source_mgr *)
+				(*cinfo.mem->alloc_small) ((j_common_ptr) &cinfo, JPOOL_PERMANENT,
+				sizeof(struct jpeg_source_mgr));
+		}
+		cinfo.src->init_source	=		&LLImageJPEG::decodeInitSource;
+		cinfo.src->fill_input_buffer =	&LLImageJPEG::decodeFillInputBuffer;
+		cinfo.src->skip_input_data =	&LLImageJPEG::decodeSkipInputData;
+		cinfo.src->resync_to_restart = jpeg_resync_to_restart; // For now, use default method, but we should be able to do better.
+		cinfo.src->term_source =		&LLImageJPEG::decodeTermSource;
+		cinfo.src->bytes_in_buffer =	getDataSize();
+		cinfo.src->next_input_byte =	getData();
+		
+		////////////////////////////////////////
+		// Step 3: read file parameters with jpeg_read_header()
+		
+		jpeg_read_header(&cinfo, TRUE);
+
+		// We can ignore the return value from jpeg_read_header since
+		//   (a) suspension is not possible with our data source, and
+		//   (b) we passed TRUE to reject a tables-only JPEG file as an error.
+		// See libjpeg.doc for more info.
+
+		setSize(cinfo.image_width, cinfo.image_height, 3); // Force to 3 components (RGB)
+
+		raw_image->resize(getWidth(), getHeight(), getComponents());
+		raw_image_data = raw_image->getData();
+		
+		
+		////////////////////////////////////////
+		// Step 4: set parameters for decompression 
+		cinfo.out_color_components = 3;
+		cinfo.out_color_space = JCS_RGB;
+   
+
+		////////////////////////////////////////
+		// Step 5: Start decompressor 
+		
+		jpeg_start_decompress(&cinfo);
+		// We can ignore the return value since suspension is not possible
+		// with our 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;
+		
+		////////////////////////////////////////
+		// Step 6: while (scan lines remain to be read) 
+		//           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.
+		
+		// Move pointer to last line
+		raw_image_data += row_stride * (cinfo.output_height - 1);
+
+		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.
+			
+			jpeg_read_scanlines(&cinfo, &raw_image_data, 1);
+			raw_image_data -= row_stride;  // move pointer up a line
+		}
+
+		////////////////////////////////////////
+		// Step 7: Finish decompression 
+		jpeg_finish_decompress(&cinfo);
+
+		////////////////////////////////////////
+		// Step 8: Release JPEG decompression object 
+		jpeg_destroy_decompress(&cinfo);
+	}
+
+	catch (int)
+	{
+		jpeg_destroy_decompress(&cinfo);
+		return TRUE; // done
+	}
+
+	// Check to see whether any corrupt-data warnings occurred
+	if( jerr.num_warnings != 0 )
+	{
+		// TODO: extract the warning to find out what went wrong.
+		setLastError( "Unable to decode JPEG image.");
+		return TRUE; // done
+	}
+
+	return TRUE;
+}
+
+
+// Initialize destination --- called by jpeg_start_compress before any data is actually written.
+// static
+void LLImageJPEG::encodeInitDestination ( j_compress_ptr cinfo )
+{
+  LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;
+
+  cinfo->dest->next_output_byte = self->mOutputBuffer;
+  cinfo->dest->free_in_buffer = self->mOutputBufferSize;
+}
+
+
+//  Empty the output buffer --- called whenever buffer fills up.
+// 
+//  In typical applications, this should write the entire output buffer
+//  (ignoring the current state of next_output_byte & free_in_buffer),
+//  reset the pointer & count to the start of the buffer, and return TRUE
+//  indicating that the buffer has been dumped.
+// 
+//  In applications that need to be able to suspend compression due to output
+//  overrun, a FALSE return indicates that the buffer cannot be emptied now.
+//  In this situation, the compressor will return to its caller (possibly with
+//  an indication that it has not accepted all the supplied scanlines).  The
+//  application should resume compression after it has made more room in the
+//  output buffer.  Note that there are substantial restrictions on the use of
+//  suspension --- see the documentation.
+// 
+//  When suspending, the compressor will back up to a convenient restart point
+//  (typically the start of the current MCU). next_output_byte & free_in_buffer
+//  indicate where the restart point will be if the current call returns FALSE.
+//  Data beyond this point will be regenerated after resumption, so do not
+//  write it out when emptying the buffer externally.
+
+boolean LLImageJPEG::encodeEmptyOutputBuffer( j_compress_ptr cinfo )
+{
+  LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;
+
+  // Should very rarely happen, since our output buffer is
+  // as large as the input to start out with.
+  
+  // Double the buffer size;
+  S32 new_buffer_size = self->mOutputBufferSize * 2;
+  U8* new_buffer = new U8[ new_buffer_size ];
+  if (!new_buffer)
+  {
+  	llerrs << "Out of memory in LLImageJPEG::encodeEmptyOutputBuffer( j_compress_ptr cinfo )" << llendl;
+  	return FALSE;
+  }
+  memcpy( new_buffer, self->mOutputBuffer, self->mOutputBufferSize );	/* Flawfinder: ignore */
+  delete[] self->mOutputBuffer;
+  self->mOutputBuffer = new_buffer;
+
+  cinfo->dest->next_output_byte = self->mOutputBuffer + self->mOutputBufferSize;
+  cinfo->dest->free_in_buffer = self->mOutputBufferSize;
+  self->mOutputBufferSize = new_buffer_size;
+
+  return TRUE;
+}
+
+//  Terminate destination --- called by jpeg_finish_compress
+//  after all data has been written.  Usually needs to flush buffer.
+// 
+//  NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
+//  application must deal with any cleanup that should happen even
+//  for error exit.
+void LLImageJPEG::encodeTermDestination( j_compress_ptr cinfo )
+{
+	LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;
+
+	S32 file_bytes = (S32)(self->mOutputBufferSize - cinfo->dest->free_in_buffer);
+	self->allocateData(file_bytes);
+
+	memcpy( self->getData(), self->mOutputBuffer, file_bytes );	/* Flawfinder: ignore */
+}
+
+// static 
+void LLImageJPEG::errorExit( j_common_ptr cinfo )	
+{
+	//LLImageJPEG* self = (LLImageJPEG*) cinfo->client_data;
+
+	// Always display the message
+	(*cinfo->err->output_message)(cinfo);
+
+	// Let the memory manager delete any temp files
+	jpeg_destroy(cinfo);
+
+	// Return control to the setjmp point
+	longjmp(sSetjmpBuffer, 1) ;
+}
+
+// Decide whether to emit a trace or warning message.
+// msg_level is one of:
+//   -1: recoverable corrupt-data warning, may want to abort.
+//    0: important advisory messages (always display to user).
+//    1: first level of tracing detail.
+//    2,3,...: successively more detailed tracing messages.
+// An application might override this method if it wanted to abort on warnings
+// or change the policy about which messages to display.
+// static 
+void LLImageJPEG::errorEmitMessage( j_common_ptr cinfo, int msg_level )
+{
+  struct jpeg_error_mgr * err = cinfo->err;
+
+  if (msg_level < 0) 
+  {
+	  // It's a warning message.  Since corrupt files may generate many warnings,
+	  // the policy implemented here is to show only the first warning,
+	  // unless trace_level >= 3.
+	  if (err->num_warnings == 0 || err->trace_level >= 3)
+	  {
+		  (*err->output_message) (cinfo);
+	  }
+	  // Always count warnings in num_warnings.
+	  err->num_warnings++;
+  }
+  else 
+  {
+	  // It's a trace message.  Show it if trace_level >= msg_level.
+	  if (err->trace_level >= msg_level)
+	  {
+		  (*err->output_message) (cinfo);
+	  }
+  }
+}
+
+// static 
+void LLImageJPEG::errorOutputMessage( j_common_ptr cinfo )
+{
+	// Create the message
+	char buffer[JMSG_LENGTH_MAX];	/* Flawfinder: ignore */
+	(*cinfo->err->format_message) (cinfo, buffer);
+
+	std::string error = buffer ;
+	LLImage::setLastError(error);
+
+	BOOL is_decode = (cinfo->is_decompressor != 0);
+	llwarns << "LLImageJPEG " << (is_decode ? "decode " : "encode ") << " failed: " << buffer << llendl;
+}
+
+BOOL LLImageJPEG::encode( const LLImageRaw* raw_image, F32 encode_time )
+{
+	llassert_always(raw_image);
+	
+	resetLastError();
+
+	switch( raw_image->getComponents() )
+	{
+	case 1:
+	case 3:
+		break;
+	default:
+		setLastError("Unable to encode a JPEG image that doesn't have 1 or 3 components.");
+		return FALSE;
+	}
+
+	setSize(raw_image->getWidth(), raw_image->getHeight(), raw_image->getComponents());
+
+	// Allocate a temporary buffer big enough to hold the entire compressed image (and then some)
+	// (Note: we make it bigger in emptyOutputBuffer() if we need to)
+	delete[] mOutputBuffer;
+	mOutputBufferSize = getWidth() * getHeight() * getComponents() + 1024;
+	mOutputBuffer = new U8[ mOutputBufferSize ];
+
+	const U8* raw_image_data = NULL;
+	S32 row_stride = 0;
+
+	////////////////////////////////////////
+	// Step 1: allocate and initialize JPEG compression object
+
+	// This struct contains the JPEG compression parameters and pointers to
+	// working space (which is allocated as needed by the JPEG library).
+	struct jpeg_compress_struct cinfo;
+	cinfo.client_data = this;
+
+	// We have to set up the error handler first, in case the initialization
+	// step fails.  (Unlikely, but it could happen if you are out of memory.)
+	// This routine fills in the contents of struct jerr, and returns jerr's
+	// address which we place into the link field in cinfo.
+	struct jpeg_error_mgr jerr;
+	cinfo.err = jpeg_std_error(&jerr);
+
+	// Customize with our own callbacks
+	jerr.error_exit =		&LLImageJPEG::errorExit;			// Error exit handler: does not return to caller
+	jerr.emit_message =		&LLImageJPEG::errorEmitMessage;		// Conditionally emit a trace or warning message
+	jerr.output_message =	&LLImageJPEG::errorOutputMessage;	// Routine that actually outputs a trace or error message
+
+	//
+	//try/catch will crash on Mac and Linux if LLImageJPEG::errorExit throws an error
+	//so as instead, we use setjmp/longjmp to avoid this crash, which is the best we can get. --bao 
+	//
+	if( setjmp(sSetjmpBuffer) ) 
+	{
+		// 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_compress(&cinfo);
+		delete[] mOutputBuffer;
+		mOutputBuffer = NULL;
+		mOutputBufferSize = 0;
+		return FALSE;
+	}
+
+	try
+	{
+
+		// Now we can initialize the JPEG compression object.
+		jpeg_create_compress(&cinfo);
+
+		////////////////////////////////////////
+		// Step 2: specify data destination
+		// (code is a modified form of jpeg_stdio_dest() )
+		if( cinfo.dest == NULL)
+		{	
+			cinfo.dest = (struct jpeg_destination_mgr *)
+				(*cinfo.mem->alloc_small) ((j_common_ptr) &cinfo, JPOOL_PERMANENT,
+				sizeof(struct jpeg_destination_mgr));
+		}
+		cinfo.dest->next_output_byte =		mOutputBuffer;		// => next byte to write in buffer
+		cinfo.dest->free_in_buffer =		mOutputBufferSize;	// # of byte spaces remaining in buffer
+		cinfo.dest->init_destination =		&LLImageJPEG::encodeInitDestination;
+		cinfo.dest->empty_output_buffer =	&LLImageJPEG::encodeEmptyOutputBuffer;
+		cinfo.dest->term_destination =		&LLImageJPEG::encodeTermDestination;
+
+		////////////////////////////////////////
+		// Step 3: set parameters for compression 
+		//
+		// First we supply a description of the input image.
+		// Four fields of the cinfo struct must be filled in:
+		
+		cinfo.image_width = getWidth(); 	// image width and height, in pixels 
+		cinfo.image_height = getHeight();
+
+		switch( getComponents() )
+		{
+		case 1:
+			cinfo.input_components = 1;		// # of color components per pixel
+			cinfo.in_color_space = JCS_GRAYSCALE; // colorspace of input image
+			break;
+		case 3:
+			cinfo.input_components = 3;		// # of color components per pixel
+			cinfo.in_color_space = JCS_RGB; // colorspace of input image
+			break;
+		default:
+			setLastError("Unable to encode a JPEG image that doesn't have 1 or 3 components.");
+			return FALSE;
+		}
+
+		// Now use the library's routine to set default compression parameters.
+		// (You must set at least cinfo.in_color_space before calling this,
+		// since the defaults depend on the source color space.)
+		jpeg_set_defaults(&cinfo);
+
+		// Now you can set any non-default parameters you wish to.
+		jpeg_set_quality(&cinfo, mEncodeQuality, TRUE );  // limit to baseline-JPEG values
+
+		////////////////////////////////////////
+		// Step 4: Start compressor 
+		//
+		// TRUE ensures that we will write a complete interchange-JPEG file.
+		// Pass TRUE unless you are very sure of what you're doing.
+   
+		jpeg_start_compress(&cinfo, TRUE);
+
+		////////////////////////////////////////
+		// Step 5: while (scan lines remain to be written) 
+		//            jpeg_write_scanlines(...); 
+
+		// Here we use the library's state variable cinfo.next_scanline as the
+		// loop counter, so that we don't have to keep track ourselves.
+		// To keep things simple, we pass one scanline per call; you can pass
+		// more if you wish, though.
+   
+		row_stride = getWidth() * getComponents();	// JSAMPLEs per row in image_buffer
+
+		// NOTE: For compatibility with LLImage, we need to invert the rows.
+		raw_image_data = raw_image->getData();
+		
+		const U8* last_row_data = raw_image_data + (getHeight()-1) * row_stride;
+
+		JSAMPROW row_pointer[1];				// pointer to JSAMPLE row[s]
+		while (cinfo.next_scanline < cinfo.image_height) 
+		{
+			// jpeg_write_scanlines expects an array of pointers to scanlines.
+			// Here the array is only one element long, but you could pass
+			// more than one scanline at a time if that's more convenient.
+
+			//Ugly const uncast here (jpeg_write_scanlines should take a const* but doesn't)
+			//row_pointer[0] = (JSAMPROW)(raw_image_data + (cinfo.next_scanline * row_stride));
+			row_pointer[0] = (JSAMPROW)(last_row_data - (cinfo.next_scanline * row_stride));
+
+			jpeg_write_scanlines(&cinfo, row_pointer, 1);
+		}
+
+		////////////////////////////////////////
+		//   Step 6: Finish compression 
+		jpeg_finish_compress(&cinfo);
+
+		// After finish_compress, we can release the temp output buffer. 
+		delete[] mOutputBuffer;
+		mOutputBuffer = NULL;
+		mOutputBufferSize = 0;
+
+		////////////////////////////////////////
+		//   Step 7: release JPEG compression object 
+		jpeg_destroy_compress(&cinfo);
+	}
+
+	catch(int)
+	{
+		jpeg_destroy_compress(&cinfo);
+		delete[] mOutputBuffer;
+		mOutputBuffer = NULL;
+		mOutputBufferSize = 0;
+		return FALSE;
+	}
+
+	return TRUE;
+}