win32-move-text.c

#include <windows.h>
#include <wingdi.h>


LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) {
	PAINTSTRUCT ps;
	HDC hdc;
	static int x = 100;
	static int y = 100;
	switch (msg) {
	case WM_TIMER:
		// main loop
		if (GetAsyncKeyState(0x57)) {
			y--;
		}
		if (GetAsyncKeyState(0x53)) {
			y++;
		}
		if (GetAsyncKeyState(0x41)) {
			x--;
		}
		if (GetAsyncKeyState(0x44)) {
			x++;
		}
		InvalidateRect(hWnd, NULL, FALSE);
		return 0;
	case WM_PAINT:
		hdc = BeginPaint(hWnd, &ps);
		SetTextColor(hdc, RGB(255, 0, 0));
		TextOut(hdc, x, y, "Hello, World!", 13);
		EndPaint(hWnd, &ps);
		return 0;
	case WM_CREATE:
		SetTimer(hWnd, 1, 1000 / 60, NULL);
		return 0;
	case WM_DESTROY:
		KillTimer(hWnd, 1);
		PostQuitMessage(0);
		return 0;
	default:
		return DefWindowProc(hWnd, msg, wParam, lParam);
	}
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
	WNDCLASS wc;
	MSG msg;
	ZeroMemory(&wc, sizeof(WNDCLASS));
	wc.lpfnWndProc = WndProc;
	wc.hInstance = hInstance;
	wc.lpszClassName = TEXT("MainWindow");
	wc.hbrBackground = WHITE_BRUSH;
	if (!RegisterClass(&wc)) return 0;
	
	HWND hWnd = CreateWindow(
		wc.lpszClassName,
		TEXT("Main Window"),
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		1280,
		720,
		NULL,
		NULL,
		hInstance,
		NULL
	);
	
	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);
	while (GetMessage(&msg, NULL, 0, 0)) {
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return msg.wParam;
}