c语言gdi绘图_程序设计的基本步骤是

#include <windows.h>
#include <math.h>
#define NUM 1000
#define TWOPI (2*3.14159)

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

int WINAPI WinMain(HINSTANCE hInstance,		//当前实例句柄
	HINSTANCE hPrevInstance, //先前实例句柄
	LPSTR lpCmdLine,			//命令行
	int iCmdShow)			//显示状态
{ 
   
	static TCHAR szAppName[] = TEXT("画图");
	//窗口句柄
	HWND hwnd;
	//消息
	MSG msg;
	//窗口类
	WNDCLASS wndclass;
	//窗口风格：当移动窗口或者改变大小时重绘窗口
	wndclass.style = CS_HREDRAW | CS_VREDRAW;
	//指明回调函数
	wndclass.lpfnWndProc = WndProc;
	//额外的比特用来确认下一个窗口类的位置，暂时不用
	wndclass.cbClsExtra = 0;
	//额外的比特用来确认下一个窗口实例的位置，暂时不用
	wndclass.cbWndExtra = 0;
	//实例句柄
	wndclass.hInstance = hInstance;
	//装载图标
	wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	//装载光标
	wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
	//背景为白色
	wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	//菜单：暂时没有
	wndclass.lpszMenuName = NULL;
	//窗口类名
	wndclass.lpszClassName = szAppName;

	//注册窗口
	if (!RegisterClass(&wndclass))
	{ 
   
		return -1;
	}

	//创建窗口
	hwnd = CreateWindow(
		szAppName,				//窗口类的名称，必须是已经注册的
		TEXT("我的画图"),		//窗口标题
		WS_OVERLAPPEDWINDOW,	//窗口风格
		CW_USEDEFAULT,			//X坐标
		CW_USEDEFAULT,			//Y坐标
		CW_USEDEFAULT,			//宽度
		CW_USEDEFAULT,			//高度
		NULL,					//父窗口句柄
		NULL,					//菜单窗口句柄
		hInstance,				//高级版本的windos忽略
		NULL);

	//显示窗口
	//ShowWindow(hwnd,SW_SHOWNA);
	ShowWindow(hwnd, iCmdShow);

	//更新窗口
	UpdateWindow(hwnd);

	//消息循环
	while (GetMessage(&msg, NULL, 0, 0))
	{ 
   

		TranslateMessage(&msg);
		//将消息给窗口
		DispatchMessage(&msg);

	}

	return msg.wParam;

}


LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{ 
   
	HDC hdc;
	PAINTSTRUCT ps;
	int i, j;
	static int cxClient, cyClient;
	POINT apt[NUM];


	switch (message)
	{ 
   
	case WM_SIZE:
		cxClient = LOWORD(lParam);
		cyClient = HIWORD(lParam);


		return 0;
	case WM_PAINT:
		hdc = BeginPaint(hwnd, &ps);
	
		//画出渐变的颜色
		for(i = 0;i < 500;i++)
		{ 
   
			for(j = 0; j < 26;j++)
			{ 
   
				SetPixel(hdc,200+i,200+j,RGB(i,j*10,0));
			}
		}
		Sleep(5000);

		//划线
	
		//用点划线
		for(i = 0; i < 500;i++)
		{ 
   
			for (int j = 0; j < 500; j++)
			{ 
   
				if (j % 50 == 0)
				{ 
   
					SetPixel(hdc, i, j, RGB(0, 0, 0));
				}
				
			}
		}
		Sleep(5000);

		//用函数划线
		MoveToEx	(hdc,0,			cyClient/2,NULL);
		LineTo		(hdc,cxClient,	cyClient/2);
		for(int i = 0;  i< NUM;i++)
		{ 
   
			//把x轴等分成1000份
			apt[i].x = i * cxClient / NUM;
			apt[i].y = (int) (cyClient / 2 * (1-sin(TWOPI * i /NUM)));
			//LineTo(hdc,apt[i].x,apt[i].y);
		}

		//Polyline绘制，速度快于在for循环内LineTo
		Polyline(hdc,apt,NUM);
		Sleep(5000);

		//绘制矩形
		Rectangle(hdc, cxClient / 8, cyClient / 8,
			7 * cxClient / 8, 7 * cyClient / 8);
		Sleep(5000);

		//绘制对角线
		MoveToEx(hdc, 0, 0, NULL);
		LineTo(hdc, cxClient, cyClient);
		MoveToEx(hdc, 0, cyClient, NULL);
		LineTo(hdc, cxClient, 0);
		Sleep(5000);

		//绘制椭圆
		Ellipse(hdc, cxClient / 8, cyClient / 8,
			7 * cxClient / 8, 7 * cyClient / 8);
		Sleep(5000);

		//绘制圆角矩形
		RoundRect(hdc, cxClient / 4, cyClient / 4,
			3 * cxClient / 4, 3 * cyClient / 4,
			//最后两个参数是圆角矩形的圆角形成的椭圆的长和宽
			cxClient / 4, cyClient / 4);
		Sleep(5000);

		EndPaint(hwnd, &ps);
		return 0;


	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}
	return DefWindowProc(hwnd, message, wParam, lParam);
}