//プロジェクト名overlayjpeg001 C++ソースファイルoverlayjpeg001.cpp
#include <stdio.h>
#include <setjmp.h>
#include <windows.h>
#include <jpeglib.h>
#pragma comment(lib, "libjpeg.lib")
static char documentation[] = "this software is based in part on the work of the Independent JPEG Group";
extern "C" {
__declspec(dllexport) void overlayjpeg( HDC hdc, int by1, int bx1, int by2, int bx2, char * string01);
struct my_error_mgr
{
	struct jpeg_error_mgr pub;
	jmp_buf setjmp_buffer;
};
typedef struct my_error_mgr * my_error_ptr;
METHODDEF(void) my_error_exit (j_common_ptr cinfo)
{
	my_error_ptr myerr = (my_error_ptr) cinfo->err;
	(*cinfo->err->output_message) (cinfo);
	longjmp(myerr->setjmp_buffer, 1);
}
void overlayjpeg( HDC hdc, int by1, int bx1, int by2, int bx2, char * string01)
{
	if (strstr( string01, ".jpg") == 0)
		if (strstr( string01, ".JPG") == 0)
			if (strstr( string01, ".jpeg") == 0)
				if (strstr( string01, ".JPEG") == 0)
					return;	
	FILE * fp01 = NULL;
	if((fp01=fopen(string01,"rb"))==NULL)
	{
		return;
	}
	SetGraphicsMode( hdc,GM_ADVANCED);
	SetBkMode( hdc,TRANSPARENT);
	SetStretchBltMode( hdc, COLORONCOLOR);
	int dpix=GetDeviceCaps( hdc,LOGPIXELSX);
	int dpiy=GetDeviceCaps( hdc,LOGPIXELSY);
	struct jpeg_decompress_struct cinfo;
//	struct jpeg_error_mgr jerr;
	struct my_error_mgr jerr;
	JSAMPARRAY buffer;
	int row_stride;
	int image_width;
	int image_height;
	char * dib = NULL;
	unsigned char * bmp_image;
	int bmp_row;
	int bmp_row_bytes;
	int bmp_image_size;
//	cinfo.err = jpeg_std_error(&jerr);
	cinfo.err = jpeg_std_error(&jerr.pub);
	jerr.pub.error_exit = my_error_exit;
	if (setjmp(jerr.setjmp_buffer))
	{
		jpeg_destroy_decompress(&cinfo);
		if (fp01 != NULL)
			fclose(fp01);
		if (dib != NULL)
			free(dib);
		return;
	}
	jpeg_create_decompress(&cinfo);
	jpeg_stdio_src(&cinfo, fp01);
	jpeg_read_header(&cinfo, TRUE);
	jpeg_start_decompress(&cinfo);
	row_stride = cinfo.output_width * cinfo.output_components;
	buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
	if( !buffer)
	{
		jpeg_destroy_decompress(&cinfo);
		if (fp01 != NULL)
			fclose(fp01);
		if (dib != NULL)
			free(dib);
		return;
	}
	image_width  = cinfo.image_width;
	image_height = cinfo.image_height;
	bmp_row_bytes = (( ( image_width * 3 ) + 3 ) / 4) * 4;
	bmp_image_size = bmp_row_bytes * image_height;
	dib = (char *)malloc( 40 + bmp_image_size );
	if( !dib)
	{
		jpeg_destroy_decompress(&cinfo);
		if (fp01 != NULL)
			fclose(fp01);
		if (dib != NULL)
			free(dib);
		return;
	}
	bmp_image = (unsigned char *)(dib + 40);
	bmp_row = image_height - 1;
	while (cinfo.output_scanline < cinfo.output_height) {
		int i;
		unsigned char * src, * dest;
		(void) jpeg_read_scanlines(&cinfo, buffer, 1);
		src = buffer[0];
		dest = &bmp_image[ bmp_row_bytes * bmp_row-- ];
		for( i = 0; i < row_stride; i+=3 ) {
		   * dest++ = src[i+2];
		   * dest++ = src[i+1];
		   * dest++ = src[i];
		}
		for( i = 0; i < bmp_row_bytes - image_width * 3; i++ ) * dest++ = 0;
	}
	(void) jpeg_finish_decompress(&cinfo);
	jpeg_destroy_decompress(&cinfo);
	fclose(fp01);
	memset( dib, 0, 40 );
	* (long *)(dib+0)  = 40;
	* (long *)(dib+4)  = image_width;
	* (long *)(dib+8)  = image_height;
	* (short *)(dib+12) = 1;
	* (short *)(dib+14) = 24;
	* (long *)(dib+20) = bmp_image_size;
	BITMAPINFO * info = (BITMAPINFO *)dib;
	BYTE * bitmap = bmp_image;
	StretchDIBits( hdc, (int)((dpix * bx1)/254), (int)((dpix * by1)/254), (int)((dpix * (bx2-bx1))/254),
	(int)((dpix * (by2-by1))/254), 0, 0,	info->bmiHeader.biWidth, info->bmiHeader.biHeight, bitmap, info, DIB_RGB_COLORS, SRCCOPY);
	free(dib);
	return;
}
}