C++ Win32 API GetTextExtentPoint32 函数演示 - 计算文本字符串的宽度和高度

#include <windows.h> #include <tchar.h> #include 'stdafx.h'

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { static TCHAR szAppName[] = TEXT("GetTextExtentDemo"); HWND hwnd; MSG msg; WNDCLASS wndclass;

wndclass.style = CS_HREDRAW | CS_VREDRAW;
wndclass.lpfnWndProc = WndProc;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hInstance = hInstance;
wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName = NULL;
wndclass.lpszClassName = szAppName;

if (!RegisterClass(&wndclass))
{
	MessageBox(NULL, TEXT("This program requires Windows NT!"),
		szAppName, MB_ICONERROR);
	return 0;
}

hwnd = CreateWindow(szAppName, TEXT("GetTextExtent Demo111"),
	WS_OVERLAPPEDWINDOW,
	CW_USEDEFAULT, CW_USEDEFAULT,
	CW_USEDEFAULT, CW_USEDEFAULT,
	NULL, NULL, hInstance, NULL);

ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);

while (GetMessage(&msg, NULL, 0, 0))
{
	TranslateMessage(&msg);
	DispatchMessage(&msg);
}

return msg.wParam;

}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { static TCHAR szText[] = TEXT('Hello, World!'); static int cxChar, cyChar; HDC hdc; PAINTSTRUCT ps; SIZE size;

HDC hDC;
HDC hMemDC;

HBITMAP hBitmap;

HFONT hFont;

switch (message)
{
case WM_CREATE:
	hdc = GetDC(hwnd);
	SelectObject(hdc, GetStockObject(SYSTEM_FIXED_FONT));
	GetTextExtentPoint32(hdc, TEXT('A'), 1, &size);
	cxChar = size.cx;
	cyChar = size.cy;
	ReleaseDC(hwnd, hdc);
	return 0;

case WM_PAINT:
	hdc = BeginPaint(hwnd, &ps);
	TextOut(hdc, 0, 0, szText, _tcslen(szText));

	// 创建剪贴板的设备上下文
	hDC = GetDC(NULL);
	hMemDC = CreateCompatibleDC(hDC);
	hBitmap = CreateCompatibleBitmap(hDC, 1, 1);
	SelectObject(hMemDC, hBitmap);

	// 计算字符串长度
	hFont = (HFONT)GetStockObject(DEFAULT_GUI_FONT);
	SelectObject(hMemDC, hFont);

	GetTextExtentPoint32(hMemDC, szText, _tcslen(szText), &size);
	TextOut(hdc, 0, cyChar, TEXT('Width: '), 7);
	TextOut(hdc, 7 * cxChar, cyChar, TEXT('Height: '), 8);
	TCHAR szWidth[32], szHeight[32];
	_stprintf_s(szWidth, TEXT('%d'), size.cx);
	_stprintf_s(szHeight, TEXT('%d'), size.cy);
	TextOut(hdc, 14 * cxChar, cyChar, szWidth, _tcslen(szWidth));
	TextOut(hdc, 23 * cxChar, cyChar, szHeight, _tcslen(szHeight));


	//// 创建剪贴板的设备上下文
	//HDC hDC = GetDC(NULL);
	//HDC hMemDC = CreateCompatibleDC(hDC);
	//HBITMAP hBitmap = CreateCompatibleBitmap(hDC, 1, 1);
	//SelectObject(hMemDC, hBitmap);

	//// 计算字符串长度
	//SIZE size;
	//HFONT hFont = (HFONT)GetStockObject(DEFAULT_GUI_FONT);
	//SelectObject(hMemDC, hFont);
	//GetTextExtentPoint32(hMemDC, szText, _tcslen(szText), &size);

	//// 释放资源
	//DeleteObject(hBitmap);
	//DeleteDC(hMemDC);
	//ReleaseDC(NULL, hDC);


	EndPaint(hwnd, &ps);



	return 0;

case WM_DESTROY:
	PostQuitMessage(0);
	return 0;
}

return DefWindowProc(hwnd, message, wParam, lParam);