Solve the problem that C++ Easyx char and string cannot be converted to LPCTSTR

Table of contents

original code

An error occurred

Solution

char* to TCHAR*

string to TCHAR*

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original code

The pseudocode of the loadimage method in easyx.h in Visual Studio 2022:

// Image related functions
void loadimage(IMAGE *pDstImg, LPCTSTR pImgFile, int nWidth = 0, int nHeight = 0, bool bResize = false);					// Load image from a file (bmp/gif/jpg/png/tif/emf/wmf/ico)
void loadimage(IMAGE *pDstImg, LPCTSTR pResType, LPCTSTR pResName, int nWidth = 0, int nHeight = 0, bool bResize = false);	// Load image from resources (bmp/gif/jpg/png/tif/emf/wmf/ico)

An error occurred

Normally, we would write

IMAGE img;
loadimage(&img, "./resources/abc.png", WIDTH, HEIGHT);

But an error will be reported, so you need to use the _T method for conversion:

IMAGE img;
loadimage(&img, _T("./resources/abc.png"), WIDTH, HEIGHT);

Concatenation of strings also goes wrong

IMAGE img;
loadimage(&img, _T("./resources/"+"abc.png"), WIDTH, HEIGHT);

Including string variables also errors out 

IMAGE img;
string p="./resources/";
loadimage(&img, _T(p+"abc.png"), WIDTH, HEIGHT);

Using string variables directly will also cause errors

IMAGE img;
string p="./resources/abc.png";
loadimage(&img, _T(p), WIDTH, HEIGHT);

Solution

Actually LPCTSTR is TCHAR*

The following BUFFERSIZE can modify the value by itself

char* to TCHAR*

#define BUFFERSIZE 1024

TCHAR* Transform(char c[BUFFERSIZE]) {
	TCHAR result[BUFFERSIZE];
	MultiByteToWideChar(CP_ACP, 0, c, -1, result, BUFFERSIZE);
	return result;
}

string to TCHAR*

#define BUFFERSIZE 1024

TCHAR* Transform(string s) {
	TCHAR result[BUFFERSIZE];
	char c[BUFFERSIZE];
	strcpy_s(c, s.c_str());
	MultiByteToWideChar(CP_ACP, 0, c, -1, result, BUFFERSIZE);
	return result;
}

The main program is changed to:

IMAGE img;
loadimage(&img, Transform(...), WIDTH, HEIGHT); // ...使用char*或string类型即可