43.画线POINT、MoveToEx、LineTo、Polyline、PolylineTo、Arc、ArcTo、SetArcDirection、PolyBezier、PolyBezierTo

POINT点定义如下

typedef struct tagPOINT
{
    LONG  x;
    LONG  y;
} POINT, *PPOINT, NEAR *NPPOINT, FAR *LPPOINT;

MoveToEx移动坐标

__gdi_entry WINGDIAPI BOOL  WINAPI 
MoveToEx( __in HDC hdc, //设备上下文
 __in int x, //X坐标
 __in int y,  //Y坐标
  __out_opt LPPOINT lppt //用于保存上一个点坐标
  );

BOOL为返回值，返回TRUE代表移动成功，FALSE代表失败

LineTo 从MoveToEx的起始点，到LineTo所指的点画一条直线

__gdi_entry WINGDIAPI BOOL WINAPI 
LineTo( 
__in HDC hdc, 
__in int x,
 __in int y
 );

BOOL为返回值，返回TRUE代表画线成功，FALSE代表失败

Polyline多线段

__gdi_entry WINGDIAPI BOOL  WINAPI 
Polyline(
__in HDC hdc, 
__in_ecount(cpt) CONST POINT *apt, //POINT的指针
 __in int cpt //apt中有多少个元素
 );

BOOL为返回值，返回TRUE代表画线成功，FALSE代表失败

Polyline和PolylineTo的区别是PolylineTo把现在的所在的点作为起始点，相当于比Polyline多了一个起始点而已，多画一段线

WINGDIAPI BOOL  WINAPI 
PolylineTo(
__in HDC hdc, 
__in_ecount(cpt) CONST POINT * apt,
__in DWORD cpt
);

Arc画弧线函数

__gdi_entry WINGDIAPI BOOL  WINAPI 
Arc( 
__in HDC hdc, 
__in int x1, __in int y1,  //左上角
__in int x2, __in int y2, //右下角
__in int x3, __in int y3, //切线1
__in int x4, __in int y4  //切线2
);

SetArcDirection函数用于设置时针旋转方向默认是逆时针方向

WINGDIAPI int  WINAPI 
SetArcDirection(
__in HDC hdc,
 __in int dir //时针旋转方向
 // #define AD_COUNTERCLOCKWISE 1 默认参数，逆时针方向旋转
// #define AD_CLOCKWISE        2 顺时针方向旋转
 );

返回值为设置成功后时针旋转方向

PolyBezier 贝塞尔曲线

WINGDIAPI BOOL  WINAPI 
PolyBezier(
__in HDC hdc, 
__in_ecount(cpt) CONST POINT * apt, //POINT结构数组的指针，包括了样条端点和控制点的坐标，其顺序是起点的坐标、起点的控制点的坐标、终点的控制点的坐标和终点的坐标。
 __in DWORD cpt //POINT数组成员个数
 );

例子

#include 
#include "resource.h"

INT_PTR CALLBACK DlgMainProc(HWND hWnd,UINT uMsg,WPARAM wParam,LPARAM lParam)
{
	BOOL bRet = true;
	HDC hdc;
	PAINTSTRUCT ps;
	POINT p1;
	POINT pArrayp2[5] = {{100,100},{400,100},{400,200},{100,200},{100,100}};
	POINT pArrayp3[5] = {{100,100},{400,200},{200,400},{500,400},{400,500}};

	switch(uMsg)
	{
	case WM_PAINT:
		hdc = BeginPaint(hWnd,&ps);
		MoveToEx(hdc,100,100,&p1);
		
		LineTo(hdc,200,200);
		

		PolylineTo(hdc,pArrayp2,5);

		SetArcDirection(hdc,AD_COUNTERCLOCKWISE);
		SetArcDirection(hdc,AD_CLOCKWISE);
		Arc(hdc,100,100,400,300,400,600,100,200);

		PolyBezier(hdc,pArrayp3,4);

		EndPaint(hWnd,&ps);
		break;
	case WM_CLOSE:
		EndDialog(hWnd,0);
		break;
	default:
		bRet = false;
	}


	return bRet;
}

int APIENTRY WinMain(HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	LPSTR lpCmdLine,
	int nCmdShow)
{
	DialogBox(hInstance,MAKEINTRESOURCE(IDD_DIALOG1),NULL,DlgMainProc);
	return 0;
}