Windows绘图—六种映射方式

#include <Windows.h>
#include <tchar.h>

BOOLEAN InitWindowClass(HINSTANCE hInstance, int nCmdShow);
LRESULT	CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow){
	MSG msg;

	if(!InitWindowClass(hInstance, nCmdShow)){
		MessageBox(NULL, L"Failed to Create Windows", L"InFo", NULL);
		return 1;
	}

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

	return 0;
}

BOOLEAN InitWindowClass(HINSTANCE hInstance, int nCmdShow){
	WNDCLASSEX wcex;
	HWND hWnd;
	TCHAR szWindowsClass[] = L"窗口示例";
	TCHAR szTitle[] = L"映射模式及填充示例图";

	wcex.cbClsExtra = 0;
	wcex.cbSize = sizeof(WNDCLASSEX);
	wcex.cbWndExtra = 0;
	wcex.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wcex.hInstance = hInstance;
	wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
	wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
	wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
	wcex.lpfnWndProc = WndProc;
	wcex.lpszClassName = szWindowsClass;
	wcex.lpszMenuName = NULL;
	wcex.style = 0;

	if(!RegisterClassEx(&wcex)){
		return FALSE;
	}

	hWnd = CreateWindow(szWindowsClass, szTitle, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL);
	if(!hWnd){
		return FALSE;
	}

	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);

	return TRUE;
}

LRESULT	CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){
	HDC hDC;							// 标识设备环境句柄
	PAINTSTRUCT PtStr;					// 标识无效区域结构
	HBRUSH hBrush;
	HPEN hPen;
	static int dispMode = -1;			// 按键计数器
	LPCTSTR str;						// Unicode 字符串

	switch(message){
	case WM_LBUTTONDOWN:
		InvalidateRect(hWnd, NULL, TRUE);					// 向指定窗体更新区域添加一个矩形，然后窗口客户区域的这一部分将被重新绘制
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	case WM_PAINT:
		hDC = BeginPaint(hWnd, &PtStr);						// 获取设备环境
		dispMode = (dispMode + 1) % 6;
		switch(dispMode){
		case 0:
			str = _T("映射方式 MM_TEXT: 缺省的映射方式");
			SetMapMode(hDC, MM_TEXT);						// 设置映射模式
			TextOut(hDC, 0, 0, str, _tcsclen(str));
			break;
		case 1:
			str = _T("映射方式 MM_ISOTROPIC: 窗口坐标为 20 * 20，映射为视口尺寸为 10 * 10， 图形缩小1倍");
			SetMapMode(hDC, MM_ISOTROPIC);
			SetWindowExtEx(hDC, 20, 20, NULL);				// 窗口区域定义
			SetViewportExtEx(hDC, 10, 10, NULL);			// 视口区域定义
			TextOut(hDC, 0, 0, str, _tcsclen(str));
			break;
		case 2:
			str = _T("映射方式 MM_ISOTROPIC: 窗口坐标为 10 * 10，映射为视口尺寸为 20 * 20， 图形放大1倍");
			SetMapMode(hDC, MM_ISOTROPIC);
			SetWindowExtEx(hDC, 10, 10, NULL);
			SetViewportExtEx(hDC, 20, 20, NULL);
			TextOut(hDC, 0, 0, str, _tcsclen(str));
			break;
		case 3:
			str = _T("映射方式 MM_ANISOTROPIC: 窗口坐标为 10 * 10，映射为视口尺寸为 20 * 10， 图形横向放大1倍，纵向不变");
			SetMapMode(hDC, MM_ANISOTROPIC);
			SetWindowExtEx(hDC, 10, 10, NULL);
			SetViewportExtEx(hDC, 20, 10, NULL);
			TextOut(hDC, 0, 0, str, _tcsclen(str));
			break;
		case 4:
			str = _T("映射方式 MM_ANISOTROPIC: 窗口坐标为 10 * 10，映射为视口尺寸为 20 * 5， 图形横向放大1倍，纵向缩小1倍");
			SetMapMode(hDC, MM_ANISOTROPIC);
			SetWindowExtEx(hDC, 10, 10, NULL);
			SetViewportExtEx(hDC, 20, 5, NULL);
			TextOut(hDC, 0, 0, str, _tcsclen(str));
			break;
		case 5:
			str = _T("映射方式 MM_ISOTROPIC: 窗口坐标为 10 * 10，映射为视口尺寸为 20 * 5， 图形为了保持原纵横比，系统会调整映射比例");
			SetMapMode(hDC, MM_ISOTROPIC);
			SetWindowExtEx(hDC, 10, 10, NULL);
			SetViewportExtEx(hDC, 20, 5, NULL);
			TextOut(hDC, 0, 0, str, _tcsclen(str));
			break;
		}
		hPen = (HPEN)GetStockObject(BLACK_BRUSH);			// 获取系统画笔、画刷
		hBrush = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
		SelectObject(hDC, hBrush);							// 将画笔、画刷选入设备环境
		SelectObject(hDC, hPen);
		RoundRect(hDC, 50, 120, 100, 200, 15, 15);			// 圆角矩形

		hBrush = (HBRUSH)GetStockObject(LTGRAY_BRUSH);
		SelectObject(hDC, hBrush);
		Ellipse(hDC, 150, 50, 200, 150);					// 椭圆形
		
		hBrush = (HBRUSH)GetStockObject(HOLLOW_BRUSH);
		SelectObject(hDC, hBrush);
		Pie(hDC, 250, 50, 300, 100, 250, 50, 300, 50);		// 饼形

		EndPaint(hWnd, &PtStr);								// 结束绘图
		DeleteObject(hPen);									// 删除画笔、画刷
		DeleteObject(hBrush);
		break;
	default:
		return DefWindowProc(hWnd, message, wParam, lParam);
	}

	return 0;
}