使用CXImage显示jpg的问题

[qqfancia]

不知道有没有朋友经常使用CXImage的，快崩溃拉我。。

我在ximcfg.h里打开了jpg开关。。如下：

#define CXIMAGE_SUPPORT_BMP 0
#define CXIMAGE_SUPPORT_GIF 1
#define CXIMAGE_SUPPORT_JPG 1

然后在load的时候，if ( image.Load(img, CXIMAGE_FORMAT_JPG))//img为图片路径，jpg格式的时候if里面返回false

但是不知道为什么loadGIF格式的时候就正常，返回true；loadJPG格式的时候就返回false。。

跟进去之后发现jpg格式在jpeg_create_decompress(&cinfo)后就返回if (setjmp(jerr.setjmp_buffer))内，return 0，然后就跳出了，为什么这边会return 0 呢？有朋友遇见过这种情况么？


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);

我现在有点晕，GIF打开开关就能用了，JPG为什么这样？？


CXImage的jpg压缩代码如下：（这个不好贴，如果用过的可以看自己的代码）

#include "ximajpg.h"

#if CXIMAGE_SUPPORT_JPG

#include "../jpeg/jmorecfg.h"

#include "ximaiter.h"

#include <setjmp.h>

struct jpg_error_mgr {
struct jpeg_error_mgr pub; /* "public" fields */
jmp_buf setjmp_buffer; /* for return to caller */
char* buffer; /* error message <CSC>*/
};
typedef jpg_error_mgr *jpg_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 */
jpg_error_ptr myerr = (jpg_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);
}
////////////////////////////////////////////////////////////////////////////////
CxImageJPG::CxImageJPG(): CxImage(CXIMAGE_FORMAT_JPG)
{
#if CXIMAGEJPG_SUPPORT_EXIF
m_exif = NULL;
memset(&m_exifinfo, 0, sizeof(EXIFINFO));
#endif
}
////////////////////////////////////////////////////////////////////////////////
CxImageJPG::~CxImageJPG()
{
#if CXIMAGEJPG_SUPPORT_EXIF
if (m_exif) delete m_exif;
#endif
}
////////////////////////////////////////////////////////////////////////////////
#if CXIMAGEJPG_SUPPORT_EXIF
bool CxImageJPG::DecodeExif(CxFile * hFile)
{
m_exif = new CxExifInfo(&m_exifinfo);
if (m_exif){
long pos=hFile->Tell();
m_exif->DecodeExif(hFile);
hFile->Seek(pos,SEEK_SET);
return m_exif->m_exifinfo->IsExif;
} else {
return false;
}
}
#endif //CXIMAGEJPG_SUPPORT_EXIF
////////////////////////////////////////////////////////////////////////////////
#if CXIMAGE_SUPPORT_DECODE
////////////////////////////////////////////////////////////////////////////////
bool CxImageJPG::Decode(CxFile * hFile)
{

bool is_exif = false;
#if CXIMAGEJPG_SUPPORT_EXIF
is_exif = DecodeExif(hFile);
#endif

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. <CSC> */
struct jpg_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); ／／／／／／／／／／／／／／／／／／出错
return 0;
}

/* Now we can initialize the JPEG decompression object. */
jpeg_create_decompress(&cinfo); ／／／／／／／／／／／／／／出错，返回if语句

/* 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);

/* Step 4 <chupeev> handle decoder options*/
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & DECODE_GRAYSCALE) != 0)
cinfo.out_color_space = JCS_GRAYSCALE;
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & DECODE_QUANTIZE) != 0) {
cinfo.quantize_colors = TRUE;
cinfo.desired_number_of_colors = GetJpegQuality();
}
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & DECODE_DITHER) != 0)
cinfo.dither_mode = m_nDither;
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & DECODE_ONEPASS) != 0)
cinfo.two_pass_quantize = FALSE;
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & DECODE_NOSMOOTH) != 0)
cinfo.do_fancy_upsampling = FALSE;

[qqfancia]

//<DP>: 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;
*}
*/ //</DP>

// Set the scale <ignacio>
cinfo.scale_denom = GetJpegScale();

// Borrowed the idea from GIF implementation <ignacio>
if (info.nEscape == -1) {
// Return output dimensions only
jpeg_calc_output_dimensions(&cinfo);
head.biWidth = cinfo.output_width;
head.biHeight = cinfo.output_height;
info.dwType = CXIMAGE_FORMAT_JPG;
jpeg_destroy_decompress(&cinfo);
return true;
}

/* 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 the image using output dimensions <ignacio>
//Create(cinfo.image_width, cinfo.image_height, 8*cinfo.output_components, CXIMAGE_FORMAT_JPG);
Create(cinfo.output_width, cinfo.output_height, 8*cinfo.output_components, CXIMAGE_FORMAT_JPG);

if (!pDib) longjmp(jerr.setjmp_buffer, 1); //<DP> check if the image has been created

if (is_exif){
#if CXIMAGEJPG_SUPPORT_EXIF
if ((m_exifinfo.Xresolution != 0.0) && (m_exifinfo.ResolutionUnit != 0))
SetXDPI((long)(m_exifinfo.Xresolution/m_exifinfo.ResolutionUnit));
if ((m_exifinfo.Yresolution != 0.0) && (m_exifinfo.ResolutionUnit != 0))
SetYDPI((long)(m_exifinfo.Yresolution/m_exifinfo.ResolutionUnit));
#endif
} else {
switch (cinfo.density_unit) {
case 0: // [andy] fix for aspect ratio...
if((cinfo.Y_density > 0) && (cinfo.X_density > 0)){
SetYDPI((long)(GetXDPI()*(float(cinfo.Y_density)/float(cinfo.X_density))));
}
break;
case 2: // [andy] fix: cinfo.X/Y_density is pixels per centimeter
SetXDPI((long)floor(cinfo.X_density * 2.54 + 0.5));
SetYDPI((long)floor(cinfo.Y_density * 2.54 + 0.5));
break;
default:
SetXDPI(cinfo.X_density);
SetYDPI(cinfo.Y_density);
}
}

if (cinfo.out_color_space==JCS_GRAYSCALE){
SetGrayPalette();
head.biClrUsed =256;
} else {
if (cinfo.quantize_colors){
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.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.
*/
iter.Upset();
while (cinfo.output_scanline < cinfo.output_height) {

if (info.nEscape) longjmp(jerr.setjmp_buffer, 1); // <vho> - cancel decoding

(void) jpeg_read_scanlines(&cinfo, buffer, 1);
// info.nProgress = (long)(100*cinfo.output_scanline/cinfo.output_height);
//<DP> 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<row_stride; x3+=3, x4+=4){
k=src[x4+3];
dst[x3] =(BYTE)((k * src[x4+2])/255);
dst[x3+1]=(BYTE)((k * src[x4+1])/255);
dst[x3+2]=(BYTE)((k * src[x4+0])/255);
}
} else {
/* Assume put_scanline_someplace wants a pointer and sample count. */
iter.SetRow(buffer[0], row_stride);
}
iter.PrevRow();
}

/* 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.
*/

//<DP> Step 7A: Swap red and blue components
// not necessary if swapped red and blue definition in jmorecfg.h;ln322 <W. Morrison>
if ((cinfo.num_components==3)&&(cinfo.quantize_colors==FALSE)){
BYTE* r0=GetBits();
for(long y=0;y<head.biHeight;y++){
if (info.nEscape) longjmp(jerr.setjmp_buffer, 1); // <vho> - cancel decoding
RGBtoBGR(r0,3*head.biWidth);
r0+=info.dwEffWidth;
}
}

/* 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 true;
}


////////////////////////////////////////////////////////////////////////////////
#endif //CXIMAGE_SUPPORT_DECODE
////////////////////////////////////////////////////////////////////////////////
#if CXIMAGE_SUPPORT_ENCODE
////////////////////////////////////////////////////////////////////////////////
bool CxImageJPG::Encode(CxFile * hFile)
{
if (EncodeSafeCheck(hFile)) return false;

if (head.biClrUsed!=0 && !IsGrayScale()){
strcpy(info.szLastError,"JPEG can save only RGB or GreyScale images");
return false;
}

// necessary for EXIF, and for roll backs
long pos=hFile->Tell();

/* 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. <CSC> */
struct jpg_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); <CSC>
/* 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); //<CSC>
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:
*/

[qqfancia]

//#ifdef C_ARITH_CODING_SUPPORTED
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_ARITHMETIC) != 0)
cinfo.arith_code = TRUE;
//#endif

//#ifdef ENTROPY_OPT_SUPPORTED
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_OPTIMIZE) != 0)
cinfo.optimize_coding = TRUE;
//#endif

if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_GRAYSCALE) != 0)
jpeg_set_colorspace(&cinfo, JCS_GRAYSCALE);

if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_SMOOTHING) != 0)
cinfo.smoothing_factor = m_nSmoothing;

jpeg_set_quality(&cinfo, GetJpegQuality(), (GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_BASELINE) != 0);

//#ifdef C_PROGRESSIVE_SUPPORTED
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_PROGRESSIVE) != 0)
jpeg_simple_progression(&cinfo);
//#endif

#ifdef C_LOSSLESS_SUPPORTED
if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_LOSSLESS) != 0)
jpeg_simple_lossless(&cinfo, m_nPredictor, m_nPointTransform);
#endif

//SetCodecOption(ENCODE_SUBSAMPLE_444 | GetCodecOption(CXIMAGE_FORMAT_JPG),CXIMAGE_FORMAT_JPG);

// 2x2, 1x1, 1x1 (4:1:1) : High (default sub sampling)
cinfo.comp_info[0].h_samp_factor = 2;
cinfo.comp_info[0].v_samp_factor = 2;
cinfo.comp_info[1].h_samp_factor = 1;
cinfo.comp_info[1].v_samp_factor = 1;
cinfo.comp_info[2].h_samp_factor = 1;
cinfo.comp_info[2].v_samp_factor = 1;

if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_SUBSAMPLE_422) != 0){
// 2x1, 1x1, 1x1 (4:2:2) : Medium
cinfo.comp_info[0].h_samp_factor = 2;
cinfo.comp_info[0].v_samp_factor = 1;
cinfo.comp_info[1].h_samp_factor = 1;
cinfo.comp_info[1].v_samp_factor = 1;
cinfo.comp_info[2].h_samp_factor = 1;
cinfo.comp_info[2].v_samp_factor = 1;
}

if ((GetCodecOption(CXIMAGE_FORMAT_JPG) & ENCODE_SUBSAMPLE_444) != 0){
// 1x1 1x1 1x1 (4:4:4) : None
cinfo.comp_info[0].h_samp_factor = 1;
cinfo.comp_info[0].v_samp_factor = 1;
cinfo.comp_info[1].h_samp_factor = 1;
cinfo.comp_info[1].v_samp_factor = 1;
cinfo.comp_info[2].h_samp_factor = 1;
cinfo.comp_info[2].v_samp_factor = 1;
}

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 */

//<DP> "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);
// not necessary if swapped red and blue definition in jmorecfg.h;ln322 <W. Morrison>
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);


#if CXIMAGEJPG_SUPPORT_EXIF
if (m_exif && m_exif->m_exifinfo->IsExif){
// discard useless sections (if any) read from original image
m_exif->DiscardAllButExif();
// read new created image, to split the sections
hFile->Seek(pos,SEEK_SET);
m_exif->DecodeExif(hFile,EXIF_READ_IMAGE);
// save back the image, adding EXIF section
hFile->Seek(pos,SEEK_SET);
m_exif->EncodeExif(hFile);
}
#endif


/* And we're done! */
return true;
}
////////////////////////////////////////////////////////////////////////////////
#endif // CXIMAGE_SUPPORT_ENCODE
////////////////////////////////////////////////////////////////////////////////
#endif // CXIMAGE_SUPPORT_JPG

[kvkvmedoly]

没有遇到过!

[fandh]

首先你jpg文件路径是否正确？还有，换一个jpg文件试试！

[harry330]

我用过很多次CxImage来显示图片，从没出现过这种问题。觉得有几种可能。
第一：你的jpg文件有问题。换几个试试。
第二：是否你没有编译jpg的库，或者某些地方设置有问题。我好像没有在ximcfg.h中改过东西。直接就可用的。

[quweijun218]

ximcfg.h里面的开关是在编译库文件(*.lib)时才有效的。如果你库文件已经编译好了，在程序中使用的时候ximcfg.h已经不起作用了。

[小生我怕怕]

还费那个劲干啥啊~~直接用CImage不就行了吗？