1. 窗口的本质：GUI GDI

2. GDI 图形设备接口(Graphics Device Interface)

<1> 设备对象(HWND)

<2> DC(设备上下文,Device Contexts)

<3> 图形对象

3. 画一个最简单的窗口

c

# include "stdafx.h"
# include <windows.h>


int main(int argc, char* argv[])
{
	HWND hwnd;
    HDC hdc;
    HPEN hpen;
    HBRUSH hBrush;
    //1. 设备对象，画在哪
    //hwnd = (HWND)0x00180126;
    hwnd = (HWND)NULL;  //如果是NULL就是桌面
    //2. 获取设备的上下文对象
    hdc = GetDC(hwnd);
    //3. 创建画笔 设置线条的属性
    hpen = CreatePen(PS_SOLID,5,RGB(0xFF,00,00));
    hBrush = (HBRUSH)GetStockObject(BLACK_BRUSH);
    //4. 关联
    SelectObject(hdc,hpen);
//     //5. 开始画线
//     MoveToEx(hdc,0,400,NULL);
//     LineTo(hdc,400,400);    //gdi32.dll
    SelectObject(hdc,hBrush);
    Rectangle(hdc,0,0,400,400);
    //6. 释放资源
    DeleteObject(hpen);
    DeleteObject(hBrush);
    ReleaseDC(hwnd,hdc);

	return 0;
}