戏说 .NET GDI+系列学习教程(二、Graphics类的方法)

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一、DrawBezier 画立体的贝尔塞曲线

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Graphics g = this.CreateGraphics();// e.Graphics; Pen blackPen = new Pen(Color.Red, ); //从第一个点到第四个点绘制贝塞尔曲线。第二个和第三个点是确定曲线的形状的控制点。
Point start = new Point(, );
Point control1 = new Point(, );
Point control2 = new Point(, );
Point end = new Point(, ); //画立体的贝尔塞曲线.
//DrawBezier有多种重载这里就不一一说明了
g.DrawBezier(blackPen, start, control1, control2, end);
}

效果图：

二、DrawArc 画弧

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Graphics g = this.CreateGraphics();// e.Graphics; Pen p = new Pen(Color.Black, ); // 定义矩形，用于确定弧线的边界，顾名思义就是在一个定义好的矩形中画画线
// 现在创建的是一个正方形（正方形画圆，长方形画椭圆）
Rectangle rect = new Rectangle(, , , ); // 从 x 轴到弧线的起始点沿顺时针方向度量的角（以度为单位）
float startAngle = 45.0F;
// 从 startAngle 参数到弧线的结束点沿顺时针方向度量的角（以度为单位）
float sweepAngle = 180.0F;
// 画矩形
g.DrawRectangle(p, rect);
// 画弧.
g.DrawArc(p, rect, startAngle, sweepAngle); p = new Pen(Color.Red, ); // 定义矩形，用于确定弧线的边界，顾名思义就是在一个定义好的矩形中画画线
// 现在创建的是一个长方形（正方形画圆，长方形画椭圆）
rect = new Rectangle(, , , ); // 从 x 轴到弧线的起始点沿顺时针方向度量的角（以度为单位）
startAngle = 45.0F;
// 从 startAngle 参数到弧线的结束点沿顺时针方向度量的角（以度为单位）
sweepAngle = 180.0F;
// 画矩形
g.DrawRectangle(p, rect);
// 画弧.
g.DrawArc(p, rect, startAngle, sweepAngle);
}

效果图：

三、DrawClosedCurve 画闭合曲线

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Graphics g = this.CreateGraphics();// e.Graphics; //DrawClosedCurve 画闭合曲线
Pen redPen = new Pen(Color.Red, );
Pen greenPen = new Pen(Color.Green, ); // 创建七个点来定义一条曲线.
Point point1 = new Point(, );
Point point2 = new Point(, );
Point point3 = new Point(, );
Point point4 = new Point(, );
Point point5 = new Point(, );
Point point6 = new Point(, );
Point point7 = new Point(, );
Point[] curvePoints =
{
point1,
point2,
point3,
point4,
point5,
point6,
point7
}; // 画线.
e.Graphics.DrawLines(redPen, curvePoints); // 画闭合曲线
e.Graphics.DrawClosedCurve(greenPen, curvePoints);
}

效果图：

四、DrawCurve 画曲线

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Graphics g = this.CreateGraphics();// e.Graphics; // Create pens.
Pen redPen = new Pen(Color.Red, );
Pen greenPen = new Pen(Color.Green, ); // Create points that define curve.
Point point1 = new Point(, );
Point point2 = new Point(, );
Point point3 = new Point(, );
Point point4 = new Point(, );
Point point5 = new Point(, );
Point point6 = new Point(, );
Point point7 = new Point(, );
Point[] curvePoints = { point1, point2, point3, point4, point5, point6, point7 }; // Draw lines between original points to screen.
e.Graphics.DrawLines(redPen, curvePoints); // Draw curve to screen.
e.Graphics.DrawCurve(greenPen, curvePoints);
}

效果图：

五、DrawEllipse 画椭圆

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Graphics g = this.CreateGraphics();// e.Graphics; // Create pen.
Pen blackPen = new Pen(Color.Black, ); // 创建矩形，定义椭圆边界值
Rectangle rect = new Rectangle(, , , ); // 绘制椭圆
e.Graphics.DrawEllipse(blackPen, rect);
}

效果图：

六、DrawImage 画图像

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Color.Red);
// 创建Image对象
Image newImage = Image.FromFile(@"E:\Test\Test\GDI_Demo\images\DrawBackgroundImage.png"); // 创建图像左上角的坐标
float x = 100.0F;
float y = 100.0F; // 定义矩形的位置（这个和Graphics对象的方法有关）和大小
// public RectangleF (float x, float y, float width, float height);
// x,y 矩形左上角坐标
RectangleF srcRect = new RectangleF(50.0F, 50.0F, 150.0F, 150.0F);
// 单位：像素
GraphicsUnit units = GraphicsUnit.Pixel; // 矩形左上角坐标，是参照Form窗体的
e.Graphics.DrawRectangle(p, 50.0F, 50.0F, 150.0F, 150.0F);
// 将图像绘制到屏幕上
// 矩形左上角坐标，是参照Image对象的
e.Graphics.DrawImage(newImage, x, y, srcRect, units);
}

效果图：

说明：

七、DrawLine 画线

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Color.Red);
//起点坐标
Point point1 = new Point(, );
//终点坐标
Point point2 = new Point(, ); // 绘制直线
e.Graphics.DrawLine(p, point1, point2);
}

效果图：

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Color.Red);
Point[] points =
{
new Point(, ),
new Point(, ),
new Point(, ),
new Point(, )
}; //Draw lines to screen.
e.Graphics.DrawLines(p, points);
}

效果图：

八、DrawPath 通过路径画线和曲线

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Color.Red);
// 创建图形路径对象，并向它添加一个椭圆
GraphicsPath graphPath = new GraphicsPath();
graphPath.AddEllipse(, , , );
// 绘制图形路径
e.Graphics.DrawPath(p, graphPath);
}

效果图：

九、DrawPie 画饼形

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Color.Red);
// 绘制一个扇形，该形状由一个坐标对、宽度、高度以及两条射线所指定的椭圆定义
float x = 0.0F;
float y = 0.0F;
float width = 200.0F;
float height = 100.0F; // Create start and sweep angles.
float startAngle = 0.0F;
float sweepAngle = 90.0F; // Draw pie to screen.
e.Graphics.DrawPie(p, x, y, width, height, startAngle, sweepAngle);
}

效果图	说明图

十、DrawPolygon 画多边形

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Color.Red,);
// Create points that define polygon.
PointF point1 = new PointF(50.0F, 50.0F);
PointF point2 = new PointF(100.0F, 25.0F);
PointF point3 = new PointF(200.0F, 5.0F);
PointF point4 = new PointF(250.0F, 50.0F);
PointF point5 = new PointF(300.0F, 100.0F);
PointF point6 = new PointF(350.0F, 200.0F);
PointF point7 = new PointF(250.0F, 250.0F);
PointF[] curvePoints =
{
point1,
point2,
point3,
point4,
point5,
point6,
point7
}; // Draw polygon curve to screen.
e.Graphics.DrawPolygon(p, curvePoints);
}

效果图：

十一、DrawRectangle 画矩形

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
Pen p = new Pen(Color.Red,);
// Create rectangle.
Rectangle rect = new Rectangle(, , , ); // Draw rectangle to screen.
e.Graphics.DrawRectangle(p, rect);
}

效果图：

十二、DrawString 绘制文字

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
// 定义绘制文字
String drawString = "Sample Text"; // 定义字体
Font drawFont = new Font("Arial", );
// 定义单色画笔，墨要使用刷子（可以理解为毛笔）才能作画
// 所以刷子就有以下几种
// SolidBrush ：单色画笔
// TextureBrush ：纹理画笔（使用图像来填充形状的内部）
// HatchBrush ：用阴影样式、前景色和背景色定义矩形画笔
// LinearGradientBrush ：线性渐变
// PathGradientBrush ：通过渐变填充 GraphicsPath 对象
SolidBrush drawBrush = new SolidBrush(Color.Black); // Create point for upper-left corner of drawing.
float x = 150.0F;
float y = 50.0F; // 绘制文本的格式化特性（如行距和对齐方式）
StringFormat drawFormat = new StringFormat();
drawFormat.FormatFlags = StringFormatFlags.DirectionVertical; // Draw string to screen.
e.Graphics.DrawString(drawString, drawFont, drawBrush, x, y, drawFormat);
}

效果图：

十三、FillEllipse 填充椭圆

效果图：

十四、FillPath 填充路径

效果图：

十五、FillPie 填充饼图

效果图：

十六、FillPolygon 填充多边形

效果图：

十七、FillRectangle 填充矩形

效果图：

十八、FillRectangles 填充矩形组

效果图：

十九、FillRegion 填充区域

private void frmGraphics_Paint(object sender, PaintEventArgs e)
{
// 定义单色画笔，墨要使用刷子（可以理解为毛笔）才能作画
// 所以刷子就有以下几种
// SolidBrush ：单色画笔
// TextureBrush ：纹理画笔（使用图像来填充形状的内部）
// HatchBrush ：用阴影样式、前景色和背景色定义矩形画笔
// LinearGradientBrush ：线性渐变
// PathGradientBrush ：通过渐变填充 GraphicsPath 对象 Graphics g = e.Graphics;
// 创建矩形，为定义Region对象的填充区域
Rectangle regionRect = new Rectangle(, , , );
Pen pen1 = new Pen(Color.Black);
//为看出效果
g.DrawRectangle(pen1, regionRect); // 创建第二个矩形，主要用于区域交集填充
RectangleF unionRect = new RectangleF(, , , );//第2个矩形
pen1.Color = Color.Red;
//为看出效果
g.DrawEllipse(pen1, unionRect);//画椭圆 GraphicsPath myPath = new GraphicsPath();
myPath.AddEllipse(unionRect); // 创建Region对象的填充区域
Region myRegion = new Region(regionRect); //两个区域的交集被填充
myRegion.Intersect(myPath); SolidBrush blueBrush = new SolidBrush(Color.Blue);
// 填充
e.Graphics.FillRegion(blueBrush, myRegion); //=================Complement==================
regionRect = new Rectangle(, , , );
pen1 = new Pen(Color.Black);
//为看出效果
g.DrawRectangle(pen1, regionRect); // 创建第二个矩形
unionRect = new RectangleF(, , , );
pen1.Color = Color.Red;
g.DrawEllipse(pen1, unionRect);//画椭圆 myPath = new GraphicsPath();
myPath.AddEllipse(unionRect); myRegion = new Region(regionRect);
// myPath 无交集的区域被填充
myRegion.Complement(myPath); // 填充
e.Graphics.FillRegion(blueBrush, myRegion); //=================Exclude================== regionRect = new Rectangle(, , , );
pen1 = new Pen(Color.Black);
//为看出效果
g.DrawRectangle(pen1, regionRect); // 创建第二个矩形
unionRect = new RectangleF(, , , );
pen1.Color = Color.Red;
g.DrawEllipse(pen1, unionRect);//画椭圆 myPath = new GraphicsPath();
myPath.AddEllipse(unionRect); myRegion = new Region(regionRect); // myRegion 无交集的区域被填充
myRegion.Exclude(myPath); // 填充
e.Graphics.FillRegion(blueBrush, myRegion); //=================Union================== regionRect = new Rectangle(, , , );
pen1 = new Pen(Color.Black);
//为看出效果
g.DrawRectangle(pen1, regionRect); // 创建第二个矩形
unionRect = new RectangleF(, , , );
pen1.Color = Color.Red;
g.DrawEllipse(pen1, unionRect);//画椭圆 myPath = new GraphicsPath();
myPath.AddEllipse(unionRect); myRegion = new Region(regionRect); // 两个区域被填充
myRegion.Union(myPath); // 填充
e.Graphics.FillRegion(blueBrush, myRegion); //=================Xor================== regionRect = new Rectangle(, , , );
pen1 = new Pen(Color.Black);
//为看出效果
g.DrawRectangle(pen1, regionRect); // 创建第二个矩形
unionRect = new RectangleF(, , , );
pen1.Color = Color.Red;
g.DrawEllipse(pen1, unionRect);//画椭圆 myPath = new GraphicsPath();
myPath.AddEllipse(unionRect); myRegion = new Region(regionRect); // 交集以外区域被填充
myRegion.Xor(myPath); // 填充
e.Graphics.FillRegion(blueBrush, myRegion);
}