MOOC清华《VC++面向对象与可视化程序设计》第2章：Windows绘图-例（2）映像模式的使用（一）

#include <windows.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

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

int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInst,LPSTR lpszCmdLine,int nCmdShow)
{
HWND hwnd ;
MSG Msg ;
WNDCLASS wndclass ;
char lpszClassName[] = "映射模式";
char lpszTitle[]= "My_Map_Mode";
wndclass.style = 0;
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 = lpszClassName ;
if( !RegisterClass( &wndclass))
{
MessageBeep(0) ;
return FALSE ;
}

hwnd = CreateWindow
(
lpszClassName,
lpszTitle,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInstance,
NULL
);

ShowWindow( hwnd, nCmdShow) ;				//显示窗口
UpdateWindow(hwnd);							//绘制用户区
while( GetMessage(&Msg, NULL, 0, 0))		//消息循环
{
TranslateMessage( &Msg) ;
DispatchMessage( &Msg) ;
}
return Msg.wParam;						//消息循环结束时将信息返回系统
}

LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM  wParam,LPARAM  lParam)

{
HDC hdc;
PAINTSTRUCT ps;
HBRUSH hB1,hB2;
switch(message)
{
case WM_LBUTTONDOWN:					//单击鼠标左键的消息
nMode=MM_ISOTROPIC;				//更改映射模式为MM_ISOTROPIC
InvalidateRect(hwnd,NULL,1);		//刷新用户区
break;

case WM_RBUTTONDOWN:					//单击鼠标右键消息
nMode=MM_ANISOTROPIC;			//更改显示模式为MM_ANISOTROPIC
InvalidateRect(hwnd,NULL,1);		//刷新用户区
break;

case WM_PAINT:
hdc=BeginPaint(hwnd,&ps);			//取得设备环境句柄
SetMapMode(hdc,nMode);				//设置映射模式
SetWindowExtEx(hdc,150,150,NULL); 	//设置窗口区域
SetViewportExtEx(hdc,150,100,NULL); 	//设置视口区域
SetViewportOrgEx(hdc,150,60,NULL); 	//设置视口原点
hB1=(HBRUSH)GetStockObject(WHITE_BRUSH);		//定义白色画刷
hB2=(HBRUSH)GetStockObject(BLACK_BRUSH);		//定义黑色画刷
SelectObject(hdc,hB1);				//将黑白刷选入设备环境
RoundRect(hdc,0,0,150,150,30,30);	//绘制圆角矩形并填充
SelectObject(hdc,hB2);				//更改当前画刷为黑色画刷
Ellipse(hdc,0,10,150,140);			//绘制椭圆并填充
EndPaint(hwnd,&ps);					//释放设备环境句柄
DeleteObject(hB1);					//删除画刷句柄
DeleteObject(hB2);
break;

case WM_DESTROY:
PostQuitMessage(0);
break;

default:
return  DefWindowProc(hwnd,message,wParam,lParam);
}
return 0;
}