GDI+学习及代码总结之------画线、区域填充、写字

《精通GDI编程》里的代码，在学习过程中对它加以总结，以防以后用到，所有代码都是在MFC 单文档中实现的，写在View::OnDraw(CDC */*pDC*/)中

画线/边框（Pen）

1、画单线-------DrawLine

	Pen pen(Color(255,0,0,0),3);
	PointF L_PTStart(0,0);
	PointF L_PTEnd(100,10);
	graphics.DrawLine(&pen,L_PTStart,L_PTEnd);

2、连接线--------DrawLines

	Pen blackPen(Color(255, 0, 0, 0), 3);

	PointF point1(10.0f, 10.0f);
	PointF point2(10.0f, 100.0f);
	PointF point3(200.0f, 50.0f);
	PointF point4(250.0f, 80.0f);

	PointF points[4] = {point1, point2, point3, point4};
	PointF* pPoints = points;

	graphics.DrawLines(&blackPen, pPoints, 4);

讲解：points数组中的每个点都是连接线上的转折点，DrawLines会把它们按照顺序一个个连接起来

3、画矩形-----DrawRectangle,只画边框，不画背景色

	Pen blackPen(Color(255,255, 0, 0), 3);
	Rect rect(0, 0, 100, 100);
	graphics.DrawRectangle(&blackPen, rect);

4、一次画多个矩形----DrawRectangles

	Pen blackPen(Color(255, 0, 255, 0), 3);
	// 定义三个矩形
	RectF rect1(0.0f, 0.0f, 50.0f, 60.0f);
	RectF rect2(60.0f, 70.0f, 70.0f, 100.0f);
	RectF rect3(100.0f, 0.0f, 50.0f, 50.0f);
	RectF rects[] = {rect1, rect2, rect3};
	//RectF是对Rect的封装
	graphics.DrawRectangles(&blackPen, rects, 3);

5、画曲线-----DrawCurve

	Pen greenPen(Color::Green, 3);
	PointF point1(100.0f, 100.0f);
	PointF point2(200.0f, 50.0f);
	PointF point3(400.0f, 10.0f);
	PointF point4(500.0f, 100.0f);

	PointF curvePoints[4] = {
		point1,
		point2,
		point3,
		point4};

		PointF* pcurvePoints = curvePoints;

		// 画曲线
		graphics.DrawCurve(&greenPen, curvePoints, 4);

		//画连接点和直线连接线
		SolidBrush redBrush(Color::Red);
		graphics.FillEllipse(&redBrush, Rect(95, 95, 10, 10));//画连接点
		graphics.FillEllipse(&redBrush, Rect(195, 45, 10, 10));
		graphics.FillEllipse(&redBrush, Rect(395, 5, 10, 10));
		graphics.FillEllipse(&redBrush, Rect(495, 95, 10, 10));

		Pen redPen(Color::Red, 2);
		graphics.DrawLines(&redPen,curvePoints,4);//画连接线

注意：这里为了比较画曲线与画直线连接线的区别，我用绿色画的曲线，用红色画的直线连接线，同时画出了连接点，大家可以比较一下。

6、画闭合曲线

	Pen greenPen(Color::Green, 3);
	PointF point1(100.0f, 100.0f);//开始点
	PointF point2(200.0f, 50.0f);
	PointF point3(400.0f, 10.0f);
	PointF point4(500.0f, 100.0f);
	PointF point5(600.0f, 200.0f);
	PointF point6(700.0f, 400.0f);
	PointF point7(500.0f, 500.0f);//结束点

	PointF curvePoints[7] = {
		point1,
		point2,
		point3,
		point4,
		point5,
		point6,
		point7};

		PointF* pcurvePoints = curvePoints;

		//画闭合曲线
		graphics.DrawClosedCurve(&greenPen, curvePoints, 7);

		//画连接点
		SolidBrush redBrush(Color::Red);
		SolidBrush startBrush(Color::Blue);
		SolidBrush endBrush(Color::Black);
		graphics.FillEllipse(&startBrush, Rect(95, 95, 10, 10));
		graphics.FillEllipse(&redBrush, Rect(495, 95, 10, 10));
		graphics.FillEllipse(&redBrush, Rect(195, 45, 10, 10));
		graphics.FillEllipse(&redBrush, Rect(395, 5, 10, 10));
		graphics.FillEllipse(&redBrush, Rect(595, 195, 10, 10));
		graphics.FillEllipse(&redBrush, Rect(695, 395, 10, 10));
		graphics.FillEllipse(&endBrush, Rect(495, 495, 10, 10));

注意：蓝色点是开始点，黑色点是结束点
7、画多边形-----DrawPolygon，既然能画闭合的曲线，肯定也有闭合的直线，当然闭合的直线也就是所谓的多边形

	Pen blackPen(Color(255, 0, 0, 0), 3);
	//创建点数组，DrawPolygon会按这些点的顺序逐个连接起来
	PointF point1(100.0f, 100.0f);
	PointF point2(200.0f, 130.0f);
	PointF point3(150.0f, 200.0f);
	PointF point4(50.0f, 200.0f);
	PointF point5(0.0f, 130.0f);
	PointF points[5] = {point1, point2, point3, point4, point5};
	PointF* pPoints = points;
	// 画多边形，也就是闭合直线
	graphics.DrawPolygon(&blackPen, pPoints, 5);

8、画弧线----DrawArc

	Pen redPen(Color::Red, 3);
	RectF ellipseRect(0, 0, 200, 100);
	REAL startAngle = 0.0f;//起始度数
	REAL sweepAngle = 90.0f;//结尾时的度数
	// 画弧线
	graphics.DrawArc(&redPen, ellipseRect, startAngle, sweepAngle);
	//画出边框，做为参考
	Pen greenPen(Color::Green, 1);
	graphics.DrawRectangle(&greenPen,ellipseRect);

9、画扇形----DrawPie

	Pen blackPen(Color(255, 0, 255, 0), 3);

	// 定义椭圆，然后在里面截一部分作为最终的扇形
	RectF ellipseRect(0, 0, 200, 100);
	REAL startAngle = 40.0f;
	REAL sweepAngle = 100.0f;

	//画扇形
	graphics.DrawPie(&blackPen, ellipseRect, startAngle, sweepAngle);

先出效果图：

这里要对它两上名词讲解一下，什么叫startAngle(开始度数)，什么叫sweepAngle(范围度数也能叫扫过度数，我译的，嘿嘿)

看下MSDN里对DrawPie函数的讲解就会懂了，里面有这个图，给大家看一下

填充区域（SolidBrush）

1、填充闭合区域----FillClosedCurve，边框对应：DrawClosedCurve

	SolidBrush blackBrush(Color(255, 0, 0, 0));

	PointF point1(100.0f, 100.0f);
	PointF point2(200.0f, 50.0f);
	PointF point3(250.0f, 200.0f);
	PointF point4(50.0f, 150.0f);
	PointF points[4] = {point1, point2, point3, point4};

	//填充闭合区域
	graphics.FillClosedCurve(&blackBrush, points, 4);
	//为闭合区域画边框
	Pen curPen(Color::Green,3);
	graphics.DrawClosedCurve(&curPen,points,4);

注意：从结果图中也可以看出填充区域（背景）和边框是分离的，用FillClosedCurve来填充背景色，用DrawClosedCurve来画边框

2、填充椭圆---FillEllipse，边框对应：DrawEllipse

	SolidBrush blackBrush(Color(255, 0, 0, 0));
	RectF ellipseRect(0.0f, 0.6f, 200.8f, 100.9f);
	//填充椭圆
	graphics.FillEllipse(&blackBrush, ellipseRect);
	//画边框，当然也可以不画
	Pen borderPen(Color::Green,3);
	graphics.DrawEllipse(&borderPen,ellipseRect);

还有类似的几个函数，这里就不一 一讲解了

它们是：

FillPie(Brush* brush, RectF& rect, REAL startAngle, REAL sweepAngle)    //填充扇形，对应DrawPie

FillPolygon(Brush* brush, PointF* points, INT count)                       //填充多边形，对应DrawPolygon

FillRectangle(Brush* brush, RectF& rect)                                          //填充矩形,对应DrawRectangle

FillRectangles(Brush* brush, RectF* rects, INT count)                   //同时填充多个矩形，对应DrawRectangles

还有是关于路径和区域的，先记下，后面再说

Status FillPath( const Brush* brush, const GraphicsPath*path);

Status FillRegion( const Brush* brush, const Region*region);

写字（SolidBrush）

形式一：Status DrawString( const WCHAR*string, INTlength, const Font* font, const PointF&origin, const Brush*brush);

	Graphics graphics(this->GetDC()->m_hDC);

	SolidBrush brush(Color(255,0,0,255));

	FontFamily fontfamily(L"宋体");
	Font font(&fontfamily,24,FontStyleRegular,UnitPixel);

	PointF  pointf(0,0);//PointF类对点进行了封装，这里是指定写字的开始点

	graphics.DrawString(L"GDI写字",-1,&font,pointf,&brush);
	//DrawString还有另外两个重载形式，能实现更强大的功能

形式二：Status DrawString( const WCHAR*string, INT length, const Font*font, const RectF&layoutRect, const StringFormat*stringFormat, const Brush*brush);

	WCHAR string[256];
	wcscpy(string, L"Sample Text");

	// Initialize arguments.
	Font myFont(L"Arial", 16);//字体
	RectF layoutRect(0.0f, 0.0f, 200.0f, 50.0f);//矩形

	//设定字体格式
	StringFormat format;
	format.SetAlignment(StringAlignmentCenter); //水平方向的对齐方式，这里设置为水平居中
	format.SetLineAlignment(StringAlignmentFar);//垂直方向的对齐方式，这里设置为垂直居下
	SolidBrush blackBrush(Color(255, 0, 0, 0));

	//画矩形边框
	graphics.DrawRectangle(&Pen(Color::Green, 3), layoutRect);
	//填充矩形背景
	graphics.FillRectangle(&SolidBrush(Color(255,255,0,0)),layoutRect);
	//DrawString，一定要先画背景再写字，要不然，字会被背景覆盖
	graphics.DrawString(
		string,
		wcslen(string),
		&myFont,
		layoutRect,
		&format,
		&blackBrush);

形式三：Status DrawString( const WCHAR*string, INTlength, const Font* font, const PointF&origin, const StringFormat* stringFormat, const Brush* brush);

这种形式是形式一与形式二的结合，指定写字开始点和字体格式，这里就不举例了。