GDI+学习之—— 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，全部代码都是在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
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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
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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);
解说：points数组中的每一个点都是连接线上的转折点，DrawLines会把它们依照顺序一个个连接起来
3、画矩形—–DrawRectangle,仅仅画边框。不画背景色
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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
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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
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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：这里为了比較画曲线与画直线连接线的差别。我用绿色画的曲线，用红色画的直线连接线。同一时候画出了连接点，大家能够比較一下。
6、画闭合曲线
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Pen greenPen(Color::Green, 3);
PointF point1(100.0f, 100.0f);//開始点
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：蓝色点是開始点，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
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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
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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，做为參考
Pen greenPen(Color::Green, 1);
graphics.DrawRectangle(&greenPen,ellipseRect);
9、画扇形—-DrawPie
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Pen blackPen(Color(255, 0, 255, 0), 3);
// 定义椭圆。然后在里面截一部分作为终于的扇形
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解说一下，什么叫startAngle(開始度数)，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函数的解说就会懂了，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，边框相应：DrawClosedCurve
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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：从结果图中也能够看出填充区域（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。边框相应：DrawEllipse
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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，当然也能够不画
Pen borderPen(Color::Green,3);
graphics.DrawEllipse(&borderPen,ellipseRect);
还有类似的几个函数。这里就不一 一解说了
它们是：
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FillPie(Brush* brush, RectF& rect, REAL startAngle, REAL sweepAngle) //填充扇形，相应DrawPie
FillPolygon(Brush* brush, PointF* points, INT count) //填充多边形。相应DrawPolygon
FillRectangle(Brush* brush, RectF& rect) //填充矩形,相应DrawRectangle
FillRectangles(Brush* brush, RectF* rects, INT count) //同一时候填充多个矩形。相应DrawRectangles
还有是关于路径和区域的，先记下，后面再说
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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);
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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。这里是指定写字的開始点
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);
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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);
这样的形式是形式一与形式二的结合，指定写字開始点和字体格式，这里就不举例了。
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