www.pudn.com > RSImageManger.rar > JPEGFILE.CPP
////////////////////////////////////////////////////////////
// JpegFile - A C++ class to allow reading and writing of
// RGB and Grayscale JPEG images.
// It is based on the IJG V.6 code.
//
// This class Copyright 1997, Chris Losinger
// This is free to use and modify provided my name is
// included.
//
// See jpegfile.h for usage.
//
////////////////////////////////////////////////////////////
#include "stdafx.h"
#include "JpegFile.h"
#include
#ifdef __cplusplus
extern "C" {
#endif // __cplusplus
#include "jpeglib.h"
#ifdef __cplusplus
}
#endif // __cplusplus
//
//
//
/*
* is used for the optional error recovery mechanism shown in
* the second part of the example.
*/
#include
// error handler, to avoid those pesky exit(0)'s
struct my_error_mgr {
struct jpeg_error_mgr pub; /* "public" fields */
jmp_buf setjmp_buffer; /* for return to caller */
};
typedef struct my_error_mgr * my_error_ptr;
//
//
//
METHODDEF(void) my_error_exit (j_common_ptr cinfo);
//
// to handle fatal errors.
// the original JPEG code will just exit(0). can't really
// do that in Windows....
//
METHODDEF(void) my_error_exit (j_common_ptr cinfo)
{
/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
my_error_ptr myerr = (my_error_ptr) cinfo->err;
char buffer[JMSG_LENGTH_MAX];
/* Create the message */
(*cinfo->err->format_message) (cinfo, buffer);
/* Always display the message. */
MessageBox(NULL,buffer,"JPEG Fatal Error",MB_ICONSTOP);
/* Return control to the setjmp point */
longjmp(myerr->setjmp_buffer, 1);
}
// store a scanline to our data buffer
void j_putRGBScanline(BYTE *jpegline,
int widthPix,
BYTE *outBuf,
int row);
void j_putGrayScanlineToRGB(BYTE *jpegline,
int widthPix,
BYTE *outBuf,
int row);
//
// constructor doesn't do much - there's no real class here...
//
JpegFile::JpegFile()
{
}
//
//
//
JpegFile::~JpegFile()
{
}
//
// read a JPEG file
//
BYTE * JpegFile::JpegFileToRGB(CString fileName,
UINT *width,
UINT *height,int *color)
{
// basic code from IJG Jpeg Code v6 example.c
*width=0;
*height=0;
/* 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;
/* 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 */
FILE * infile=NULL; /* source file */
JSAMPARRAY buffer; /* Output row buffer */
int row_stride; /* physical row width in output buffer */
char buf[250];
/* 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.
*/
if ((infile = fopen(fileName, "rb")) == NULL) {
sprintf(buf, "JPEG :\nCan't open %s\n", fileName);
AfxMessageBox(buf);
return NULL;
}
/* 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 = 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);
if (infile!=NULL)
fclose(infile);
return NULL;
}
/* Now we can initialize the JPEG decompression object. */
jpeg_create_decompress(&cinfo);
/* Step 2: specify data source (eg, a file) */
jpeg_stdio_src(&cinfo, infile);
/* Step 3: read file parameters with jpeg_read_header() */
(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.
*/
/* 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 */
(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.
*/
// get our buffer set to hold data
BYTE *dataBuf;
////////////////////////////////////////////////////////////
// alloc and open our new buffer
dataBuf=(BYTE *)new BYTE[cinfo.output_width * 3 * cinfo.output_height];
if (dataBuf==NULL) {
AfxMessageBox("JpegFile :\nOut of memory",MB_ICONSTOP);
jpeg_destroy_decompress(&cinfo);
fclose(infile);
return NULL;
}
// how big is this thing gonna be?
*width = cinfo.output_width;
*height = cinfo.output_height;
/* JSAMPLEs per row in output buffer */
row_stride = cinfo.output_width * cinfo.output_components;
/* 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) */
/* 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.
*/
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);
/* Assume put_scanline_someplace wants a pointer and sample count. */
// asuumer all 3-components are RGBs
if (cinfo.out_color_components==3) {
*color=1;
j_putRGBScanline(buffer[0],
*width,
dataBuf,
cinfo.output_scanline-1);
} else if (cinfo.out_color_components==1) {
// assume all single component images are grayscale
*color=0;
j_putGrayScanlineToRGB(buffer[0],
*width,
dataBuf,
cinfo.output_scanline-1);
}
}
/* Step 7: Finish decompression */
(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 */
/* 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...)
*/
fclose(infile);
/* At this point you may want to check to see whether any corrupt-data
* warnings occurred (test whether jerr.pub.num_warnings is nonzero).
*/
return dataBuf;
}
BOOL JpegFile::GetJPGDimensions(CString fileName,
UINT *width,
UINT *height)
{
// basic code from IJG Jpeg Code v6 example.c
/* 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;
/* 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 */
FILE * infile=NULL; /* source file */
char buf[250];
/* 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.
*/
if ((infile = fopen(fileName, "rb")) == NULL) {
sprintf(buf, "JPEG :\nCan't open %s\n", fileName);
AfxMessageBox(buf);
return FALSE;
}
/* 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 = 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);
if (infile!=NULL)
fclose(infile);
return FALSE;
}
/* Now we can initialize the JPEG decompression object. */
jpeg_create_decompress(&cinfo);
/* Step 2: specify data source (eg, a file) */
jpeg_stdio_src(&cinfo, infile);
/* Step 3: read file parameters with jpeg_read_header() */
(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.
*/
// how big is this thing ?
*width = cinfo.image_width;
*height = cinfo.image_height;
/* Step 8: Release JPEG decompression object */
/* 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...)
*/
fclose(infile);
/* At this point you may want to check to see whether any corrupt-data
* warnings occurred (test whether jerr.pub.num_warnings is nonzero).
*/
return TRUE;
}
//
//
//
BYTE *JpegFile::RGBFromDWORDAligned(BYTE *inBuf,
UINT widthPix,
UINT widthBytes,
UINT height)
{
if (inBuf==NULL)
return NULL;
BYTE *tmp;
tmp=(BYTE *)new BYTE[height * widthPix * 3];
if (tmp==NULL)
return NULL;
UINT row;
for (row=0;row