GOEXIF读取和写入EXIF信息

/*
 * File:	gexif.h
 * Purpose:	cpp EXIF reader
 * 3/2/2017 <jsxyhelu@foxmail.com>
 * 基于GDI+的EXIF读写类
 */
//2017年2月3日 jsxyhelu 在原有cexif的基础上重构
#pragma once


#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <stdio.h>
#include <math.h>
#include <windows.h>
#include <gdiplus.h>
#include <stdio.h>
#pragma comment(lib, "gdiplus.lib")   

class Gexif
{
public:
	Gexif(void);
	~Gexif(void);
	int GetEncoderClsid(const WCHAR* format, CLSID* pClsid);
	Gdiplus::Bitmap* LoadBitmapFromMemory(const void* memory, DWORD size);
	Gdiplus::Bitmap* LoadBitmapFromFile(const TCHAR* file_name);
	int WriteExif2Image(CString strFileName, int PropertyTag, CString propertyValue);
	CString ReadExifFromImage(CString strFileName, int PropertyTag);
	float GetXresoutionFromImage(CString strFileName);
};

/*
 * File:	gexif.h
 * Purpose:	cpp EXIF reader
 * 3/2/2017 <jsxyhelu@foxmail.com>
 * 基于GDI+的EXIF读写类
 */

#include "stdafx.h"
#include "Gexif.h"
using namespace Gdiplus;

Gexif::Gexif(void)
{
}


Gexif::~Gexif(void)
{
}


int Gexif::GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
	return 0;
}

// 从内存加载图片，失败返回NULL
Gdiplus::Bitmap* Gexif::LoadBitmapFromMemory(const void* memory, DWORD size)
{
	Bitmap* bmp = NULL;
	IStream* stream = NULL;
	if (CreateStreamOnHGlobal(NULL, TRUE, &stream) == S_OK)
	{
		ULARGE_INTEGER uli;
		uli.QuadPart = size;
		stream->SetSize(uli);
		if (stream->Write(memory, size, NULL) == S_OK)
			bmp = new Bitmap(stream);
		stream->Release();
	}
	return bmp;
}

// 从文件加载图片，不独占文件，失败返回NULL
Gdiplus::Bitmap* Gexif::LoadBitmapFromFile(const TCHAR* file_name)
{
	Bitmap* bmp = NULL;
	HANDLE file_handle = CreateFile(file_name, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
	if (file_handle != INVALID_HANDLE_VALUE)
	{
		DWORD temp = 0;
		DWORD file_size = GetFileSize(file_handle, &temp);
		if (file_size && !temp)  // 不处理大于4G的文件
		{
			// 将图片文件读到内存后，再从内存创建Bitmap
			unsigned char* buffer = new unsigned char[file_size];
			if (ReadFile(file_handle, buffer, file_size, &temp, NULL))
				bmp = LoadBitmapFromMemory(buffer, temp);
			delete [] buffer;
		}
		CloseHandle(file_handle);
	}
	return bmp;
}

//写入exif信息到图片中去,目前只支持jpeg格式
//返回 0为正常 -1为异常
//各种tchar wchar cstring的转换，技巧较多.
int Gexif::WriteExif2Image(CString strFileName, int PropertyTag, CString pValue)
{
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
	Status stat;
	CLSID  clsid;

	char* propertyValue = (char*)pValue.GetBuffer(pValue.GetLength());
	Bitmap* bitmap = LoadBitmapFromFile(strFileName);
	PropertyItem* propertyItem = new PropertyItem;
	GetEncoderClsid(L"image/jpeg", &clsid);

	propertyItem->id = PropertyTag;//给Tag赋值
	propertyItem->length = 255;  
	propertyItem->type = PropertyTagTypeASCII; 
	propertyItem->value = propertyValue;
	bitmap->SetPropertyItem(propertyItem);


	WCHAR wcharbuf[100];
	CStringW strWide = CT2W(strFileName);
	wcscpy(wcharbuf,strWide);
	stat = bitmap->Save(wcharbuf, &clsid, NULL);

	if(stat != Ok)
		return -1;
	delete propertyItem;
	delete bitmap;
	GdiplusShutdown(gdiplusToken);
	return 0;
}

//使用基于GDI+,获取Exif信息
//这里种类很多的，目前只是实现了copytright
CString Gexif::ReadExifFromImage(CString strFileName, int PropertyTag)
{
	CString strRet;//用于返回的str

	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
	Status stat;
	CLSID  clsid;

	//打开图片
	Bitmap* bitmap = LoadBitmapFromFile(strFileName);
	int icount = bitmap->GetPropertyCount();
	PROPID* propIDs = new PROPID[icount];
	bitmap->GetPropertyIdList(icount,propIDs);
	UINT size=0;
	UINT type = 0;
	Gdiplus::PropertyItem* propertyItem = NULL;
	//定位到这个PropertyTag
	/*
	#define PropertyTagTypeByte        1
	#define PropertyTagTypeASCII       2
	#define PropertyTagTypeShort       3
	#define PropertyTagTypeLong        4
	#define PropertyTagTypeRational    5
	#define PropertyTagTypeUndefined   7
	#define PropertyTagTypeSLONG       9
	#define PropertyTagTypeSRational  10
	*/
	for(UINT j=0;j < icount; ++j)
	{
		 if (PropertyTag == propIDs[j])
		 {
			 size= bitmap->GetPropertyItemSize(propIDs[j]);
			 propertyItem= (Gdiplus::PropertyItem*)malloc(size);
			 bitmap->GetPropertyItem(propIDs[j], size, propertyItem);
			 type = propertyItem->type;
			 char cbuf[255];
			 switch (type)
			 {
			 case  PropertyTagTypeASCII  :
				 strcpy(cbuf,(char*)propertyItem->value);
				 strRet = cbuf;
				 return strRet;
			 default:
				 return _T("empty");
				 break;
			 }
			
		 }
	} 
	
}

//获得x方向的分辨率
float Gexif::GetXresoutionFromImage(CString strFileName)
{
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
	Status stat;
	CLSID  clsid;
	Bitmap* bitmap = LoadBitmapFromFile(strFileName);
	float fret = bitmap->GetHorizontalResolution();
	return fret;
}