www.pudn.com > CXIMAGE_SRC.ZIP > ximajpg.cpp
/*
* File: ximajpg.cpp
* Purpose: Platform Independent JPEG Image Class Loader and Writer
* 07/Aug/2001
* CxImage version 5.00 23/Aug/2002
*/
#include "ximajpg.h"
#if CXIMAGE_SUPPORT_JPG
#include "ximaiter.h"
#include
struct ima_error_mgr {
struct jpeg_error_mgr pub; /* "public" fields */
jmp_buf setjmp_buffer; /* for return to caller */
char* buffer; /* error message */
};
typedef ima_error_mgr *ima_error_ptr;
////////////////////////////////////////////////////////////////////////////////
// Here's the routine that will replace the standard error_exit method:
////////////////////////////////////////////////////////////////////////////////
static void
ima_jpeg_error_exit (j_common_ptr cinfo)
{
/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
ima_error_ptr myerr = (ima_error_ptr) cinfo->err;
/* Create the message */
myerr->pub.format_message (cinfo, myerr->buffer);
/* Send it to stderr, adding a newline */
/* Return control to the setjmp point */
longjmp(myerr->setjmp_buffer, 1);
}
////////////////////////////////////////////////////////////////////////////////
bool CxImageJPG::Decode(CxFile * hFile)
{
CImageIterator iter(this);
/* 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. */
struct ima_error_mgr jerr;
jerr.buffer=info.szLastError;
/* More stuff */
JSAMPARRAY buffer; /* Output row buffer */
int row_stride; /* physical row width in output buffer */
/* 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 */
/* We set up the normal JPEG error routines, then override error_exit. */
cinfo.err = jpeg_std_error(&jerr.pub);
jerr.pub.error_exit = ima_jpeg_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) */
//jpeg_stdio_src(&cinfo, infile);
CxFileJpg src(hFile);
cinfo.src = &src;
/* Step 3: read file parameters with jpeg_read_header() */
(void) jpeg_read_header(&cinfo, TRUE);
//: Load true color images as RGB (no quantize)
/* Step 4: set parameters for decompression */
/* if (cinfo.jpeg_color_space!=JCS_GRAYSCALE) {
* cinfo.quantize_colors = TRUE;
* cinfo.desired_number_of_colors = 128;
*}
*/ //
/* Step 5: Start decompressor */
jpeg_start_decompress(&cinfo);
/* 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.
*/
Create(cinfo.image_width, cinfo.image_height, 8*cinfo.num_components, CXIMAGE_FORMAT_JPG);
if (cinfo.density_unit==2){
SetXDPI((254*cinfo.X_density)/100);
SetYDPI((254*cinfo.Y_density)/100);
} else {
SetXDPI(cinfo.X_density);
SetYDPI(cinfo.Y_density);
}
if (cinfo.jpeg_color_space==JCS_GRAYSCALE){
SetGrayPalette();
head.biClrUsed =256;
} else {
if (cinfo.quantize_colors==TRUE){
SetPalette(cinfo.actual_number_of_colors, cinfo.colormap[0], cinfo.colormap[1], cinfo.colormap[2]);
head.biClrUsed=cinfo.actual_number_of_colors;
} else {
head.biClrUsed=0;
}
}
/* JSAMPLEs per row in output buffer */
row_stride = cinfo.output_width * cinfo.num_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.
*/
iter.Upset();
while (cinfo.output_scanline < cinfo.output_height) {
if (info.nEscape) longjmp(jerr.setjmp_buffer, 1); // - cancel decoding
(void) jpeg_read_scanlines(&cinfo, buffer, 1);
// info.nProgress = (long)(100*cinfo.output_scanline/cinfo.output_height);
// Step 6a: CMYK->RGB */
if ((cinfo.num_components==4)&&(cinfo.quantize_colors==FALSE)){
BYTE k,*dst,*src;
dst=iter.GetRow();
src=buffer[0];
for(long x3=0,x4=0; x3<(long)info.dwEffWidth && x4 Step 7A: Swap red and blue components */
if ((cinfo.num_components==3)&&(cinfo.quantize_colors==FALSE)){
BYTE *r,*b,t,*r0;
long x,y;
r0=GetBits();
for(y=0;y - cancel decoding
r=r0; b=r+2;
for(x=0;x
#if CXIMAGEJPG_SUPPORT_EXIF
CxExifInfo info(&m_exifinfo);
info.DecodeInfo(cinfo);
#endif //CXIMAGEJPG_SUPPORT_EXIF
/* Step 8: Release JPEG decompression object */
/* This is an important step since it will release a good deal of memory. */
jpeg_destroy_decompress(&cinfo);
/* 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;
}
////////////////////////////////////////////////////////////////////////////////
bool CxImageJPG::Encode(CxFile * hFile)
{
if (head.biClrUsed!=0 && !IsGrayScale()){
strcpy(info.szLastError,"JPEG can save only RGB or GreyScale images");
return false;
}
/* This struct contains the JPEG compression parameters and pointers to
* working space (which is allocated as needed by the JPEG library).
* It is possible to have several such structures, representing multiple
* compression/decompression processes, in existence at once. We refer
* to any one struct (and its associated working data) as a "JPEG object".
*/
struct jpeg_compress_struct cinfo;
/* This struct represents a JPEG error handler. It is declared separately
* because applications often want to supply a specialized error handler
* (see the second half of this file for an example). But here we just
* take the easy way out and use the standard error handler, which will
* print a message on stderr and call exit() if compression fails.
* Note that this struct must live as long as the main JPEG parameter
* struct, to avoid dangling-pointer problems.
*/
//struct jpeg_error_mgr jerr;
/* We use our private extension JPEG error handler. */
struct ima_error_mgr jerr;
jerr.buffer=info.szLastError;
/* More stuff */
int row_stride; /* physical row width in image buffer */
JSAMPARRAY buffer; /* Output row buffer */
/* Step 1: allocate and initialize JPEG compression object */
/* 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.
*/
//cinfo.err = jpeg_std_error(&jerr);
/* We set up the normal JPEG error routines, then override error_exit. */
cinfo.err = jpeg_std_error(&jerr.pub);
jerr.pub.error_exit = ima_jpeg_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.
*/
strcpy(info.szLastError, jerr.buffer); //
jpeg_destroy_compress(&cinfo);
return 0;
}
/* Now we can initialize the JPEG compression object. */
jpeg_create_compress(&cinfo);
/* Step 2: specify data destination (eg, a file) */
/* Note: steps 2 and 3 can be done in either order. */
/* Here we use the library-supplied code to send compressed data to a
* stdio stream. You can also write your own code to do something else.
* VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
* requires it in order to write binary files.
*/
//jpeg_stdio_dest(&cinfo, outfile);
CxFileJpg dest(hFile);
cinfo.dest = &dest;
/* 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();
if (IsGrayScale()){
cinfo.input_components = 1; // # of color components per pixel
cinfo.in_color_space = JCS_GRAYSCALE; /* colorspace of input image */
} else {
cinfo.input_components = 3; // # of color components per pixel
cinfo.in_color_space = JCS_RGB; /* colorspace of input image */
}
/* 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.
* Here we just illustrate the use of quality (quantization table) scaling:
*/
jpeg_set_quality(&cinfo, info.nQuality, TRUE /* limit to baseline-JPEG values */);
cinfo.density_unit=1;
cinfo.X_density=(unsigned short)GetXDPI();
cinfo.Y_density=(unsigned short)GetYDPI();
/* 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 = info.dwEffWidth; /* JSAMPLEs per row in image_buffer */
// "8+row_stride" fix heap deallocation problem during debug???
buffer = (*cinfo.mem->alloc_sarray)
((j_common_ptr) &cinfo, JPOOL_IMAGE, 8+row_stride, 1);
CImageIterator iter(this);
iter.Upset();
while (cinfo.next_scanline < cinfo.image_height) {
// info.nProgress = (long)(100*cinfo.next_scanline/cinfo.image_height);
iter.GetRow(buffer[0], row_stride);
if (head.biClrUsed==0){ // swap R & B for RGB images
RGBtoBGR(buffer[0], row_stride); // Lance : 1998/09/01 : Bug ID: EXP-2.1.1-9
}
iter.PrevRow();
(void) jpeg_write_scanlines(&cinfo, buffer, 1);
}
/* Step 6: Finish compression */
jpeg_finish_compress(&cinfo);
/* Step 7: release JPEG compression object */
/* This is an important step since it will release a good deal of memory. */
jpeg_destroy_compress(&cinfo);
/* And we're done! */
return true;
}
////////////////////////////////////////////////////////////////////////////////
#endif // CXIMAGE_SUPPORT_JPG