[C# 学习笔记]运用 GDI+ 的 Matrix 进行显示图形的平移和缩放

C# 学习中，想尝试着做一个工控方面的上位机，可以读取CAD绘制的图形，然后把它显示出来，后面让运动控制器去走CAD里面的轨迹。

一、用netDXF 开源包，对DXF文件进行解析。解析后的直线、圆、圆弧、椭圆、多段线、曲线等图纸，分别用List存起来。

   /// <summary>

        /// 打开DXF文件

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void btn_Open_Click(object sender, EventArgs e)

        {

            using (OpenFileDialog openFile = new OpenFileDialog())

            {

                openFile.Title = "加载DXF文件";

                openFile.Filter = "dxf File(*.dxf)|*.dxf|ALL File(*.*)|*.*";

                if (openFile.ShowDialog() == DialogResult.OK)

                {

                    //获得文件路径

                    file = openFile.FileName;

                    //加载文件

                    dxf = DxfDocument.Load(file);

                    //解析文件

                    ImPort(file);

                    //生成绘制路径

                    BuildPath();

                    //绘制图形

                    this.MainPic.Image = PaintDXF(this.MainPic);

                }

            }

        }

 /// <summary>

        /// 解析DXF文件

        /// </summary>

        /// <param name="fileName">要解析的文件名</param>

        public void ImPort(string fileName)

        {

            lineList.Clear();

            arcList.Clear();

            cirList.Clear();

            polylineList.Clear();

            polylines.Clear();

            // 解析多段线

            foreach (LwPolyline lwPolyline in dxf.LwPolylines)

            {

                bool isHaveArc = false;

                lwPolylineVertices.Clear();

                lwPolylineVertices.AddRange(lwPolyline.Vertexes);

                foreach (LwPolylineVertex lwPolylineVertex in lwPolylineVertices)

                {

                    if (lwPolylineVertex.Bulge != 0)

                    {

                        isHaveArc = true;

                        break;

                    }

                }

                if (isHaveArc)

                {

                    entityObjList.Clear();

                    //将LwPolyline实体炸开

                    entityObjList.AddRange(lwPolyline.Explode());

                    //分解多段线集合

                    foreach (EntityObject entityObject in entityObjList)

                    {

                        //如果是直线，就填加到直线集合

                        Line line_Tmp = entityObject as Line;

                        if (line_Tmp != null)

                        {

                            lineList.Add(line_Tmp);

                        }

                        //如果是圆弧，就填加到圆弧集合

                        Arc arc_Tmp = entityObject as Arc;

                        if (arc_Tmp != null)

                        {

                            arcList.Add(arc_Tmp);

                        }

                    }

                }

                else //多段线中没有圆弧，就把这个多段线添加到多段线List中

                {

                    polylineList.Add(lwPolyline);

                }

            }

            //解析直线

            foreach (Line ln in dxf.Lines)

            {

                lineList.Add(ln);

            }

            //解析圆弧

            foreach (Arc arc in dxf.Arcs)

            {

                arcList.Add(arc);

            }

            //解析圆

            foreach (Circle cir in dxf.Circles)

            {

                cirList.Add(cir);

            }

            //解析椭圆

            foreach (Ellipse elp in dxf.Ellipses)

            {

                //把椭圆转换成多段线

                int precision = GetEllipseToPolylinesPercision(elp, 0.5);

                polylineList.Add(elp.ToPolyline(precision));

            }

            //解析样条曲线

            foreach (Spline spline in dxf.Splines)

            {

                //将样条曲线转换成多段线  (用绘制多段线的方式绘制)

                int precision = GetSplineToPolylinesPrecision(spline, 0.5);

                polylines.Add(spline.ToPolyline(precision));

            }

            //视窗中心坐标

            viewcCenterX = dxf.Viewport.ViewCenter.X;

            viewcCenterY = dxf.Viewport.ViewCenter.Y;

            //视窗高度

            viewcCenterH = dxf.Viewport.ViewHeight;

            //根据视窗高度和显示框高度调整图形显示比例

            m_fratio = (float)(MainPic.Size.Height / viewcCenterH);

            //显示数据

            this.uiDataGridView1.DataSource = lineList;

            this.dataGridView2.DataSource = arcList;

            this.dataGridView3.DataSource = cirList;

            this.dataGridView4.DataSource = polylines;

        }

二、把所有需要绘制图形(直线、圆弧、圆、椭圆、多段线、曲线、等)都添加到GraphicsPath 对象里面去

/// <summary>

        /// 生成绘制路径

        /// </summary>

        private void BuildPath()

        {

            //清空之前存在的路径轨迹

            graphicsPath.Reset();

            // 直线 添加到绘制路径中

            foreach (Line line in lineList)

            {

                PointF tf = Vector2PointF(line.StartPoint);

                PointF tf2 = Vector2PointF(line.EndPoint);

                //将线段添加到绘制路径对象

                graphicsPath_tmp.AddLine(tf, tf2);

                graphicsPath.AddPath(graphicsPath_tmp, false);

                graphicsPath_tmp.Reset();

            }

            // 圆弧 添加到绘制路径中

            foreach (Arc arc in arcList)

            {

                RectangleF ef3 = new RectangleF();

                //半径

                float r = Convert.ToSingle(arc.Radius);//* m_fratio;

                //圆心坐标转换

                PointF pf = Vector2PointF(arc.Center);

                ef3.X = pf.X - r;

                ef3.Y = pf.Y - r;

                ef3.Width = 2f * r;

                ef3.Height = 2f * r;

                //起始角度

                starAg = Convert.ToSingle(arc.StartAngle);

                //扫描角度

                sweepAg = Convert.ToSingle((360 - arc.StartAngle + arc.EndAngle) % 360);

                graphicsPath_tmp.AddArc(ef3, starAg, sweepAg);

                graphicsPath.AddPath(graphicsPath_tmp, false);

                graphicsPath_tmp.Reset();

            }

            // 圆  添加到绘制路径中

            foreach (Circle circle in cirList)

            {

                RectangleF rect = new RectangleF();

                float r = Convert.ToSingle(circle.Radius);

                //显示坐标转换

                PointF pf = Vector2PointF(circle.Center);

                rect.X = pf.X - r;

                rect.Y = pf.Y - r;

                rect.Width = 2f * r;

                rect.Height = 2f * r;

                graphicsPath_tmp.AddEllipse(rect);

                graphicsPath.AddPath(graphicsPath_tmp, false);

                graphicsPath_tmp.Reset();

            }

            //  样条曲线转成的多段线添加到绘制路径中

            foreach (Polyline polyline in polylines)

            {

                pointFs.Clear();

                foreach (PolylineVertex vertex in polyline.Vertexes)

                {

                    PointF pf = Vector2PointF(vertex.Position);

                    pointFs.Add(pf);

                }

                PointF[] potFs = pointFs.ToArray();

                graphicsPath_tmp.AddLines(potFs);

                if (polyline.IsClosed)

                {

                    graphicsPath_tmp.CloseFigure();

                }

                graphicsPath.AddPath(graphicsPath_tmp, false);

                graphicsPath_tmp.Reset();

            }

            //  轻量多段线 添加到绘制路径中

            foreach (LwPolyline lwPolyline in polylineList)

            {

                pointFs.Clear();

                foreach (LwPolylineVertex vertex in lwPolyline.Vertexes)

                {

                    PointF pf = Vector2PointF(vertex.Position);

                    pointFs.Add(pf);

                }

                PointF[] potFs = pointFs.ToArray();

                graphicsPath_tmp.AddLines(potFs);

                if (lwPolyline.IsClosed)

                {

                    graphicsPath_tmp.CloseFigure();

                }

                graphicsPath.AddPath(graphicsPath_tmp, false);

                graphicsPath_tmp.Reset();

            }

            //定义一个矩阵，把纵坐标翻转

            Matrix matrix = new Matrix(1, 0, 0, -1, 0, 0);

            //定义矩阵的缩放向量

            matrix.Scale(m_fratio, m_fratio);

            //定义矩阵偏移向量 dxf文件的视窗中心放到显示的中心

            matrix.Translate((float)viewcCenterX * -1, (float)viewcCenterY * -1);

            //对路径进行矩阵转换

            graphicsPath.Transform(matrix);

        }

三、绘制路径（显示图形）

 //新一个Matrix矩阵对象

        Matrix translateMatrix = new Matrix();

        /// <summary>

        /// 图形绘制

        /// </summary>

        /// <param name="picture">绘制图形的控件</param>

        /// <returns>返回图形绘制完成的图片</returns>

        public Bitmap PaintDXF(PictureBox myPicBox)

        {

            //定义一个GDI+对象

            using (Graphics graphics = Graphics.FromImage(image))

            {

                ////设GDI对象的单位

                //graphics.PageUnit = GraphicsUnit.Pixel;

                // 设置为可剪辑区域

                graphics.SetClip(displayRectangle);

                //定义一个刷子 设置为黑色

                SolidBrush brush = new SolidBrush(Color.Black);

                //用上面定义的刷子填充整个图形

                graphics.FillRectangle(brush, displayRectangle);

                //定义绘制直线和曲线的笔 并设置为它的颜色和宽度(宽度为浮点数)

                Pen pen1 = new Pen(Color.Blue, 2f);

                Pen pen2 = new Pen(Color.FromArgb(50, 50, 50), 1f);

                //画横格

                for (int i = 1, rh = displayRectangle.Height; i < rh; i += 40)

                {

                    graphics.DrawLine(pen2, 0, i, displayRectangle.Width, i);

                }

                //画竖格

                for (int i = 1, rw = displayRectangle.Width; i < rw; i += 40)

                {

                    graphics.DrawLine(pen2, i, 0, i, displayRectangle.Height);

                }

                //设置图形显示区中心为坐标原点

                graphics.TranslateTransform(displayRectangle.Width / 2, displayRectangle.Height / 2);

                //对绘制路径用定义的矩阵进行矩阵变换

                graphicsPath.Transform(translateMatrix);

                //绘制图象

                graphics.DrawPath(pen1, graphicsPath);

            }

            return image;

        }

四、图形平移

   /// <summary>

        /// 鼠标按下

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void MainPic_MouseDown(object sender, MouseEventArgs e)

        {

            if (e.Button == MouseButtons.Left)

                isLeftButton = true;

            xStrat = e.X;

            yStart = e.Y;

        }

   /// <summary>

        /// 鼠标拖动

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void MainPic_MouseMove(object sender, MouseEventArgs e)

        {

            if (isLeftButton == true)

            {

                xEnd = e.X;

                yEnd = e.Y;

                m13 = xEnd - xStrat;

                m23 = yEnd - yStart;

                //重置矩阵

                translateMatrix.Reset();

                // 定义矩阵平移向量。

                translateMatrix.Translate(m13, m23);

                MainPic.Image = PaintDXF(this.MainPic);

                m13 = m23 = 0;

                xStrat = xEnd;

                yStart = yEnd;

            }

        }

五、图形缩放

/// <summary>

        /// 滚轮滚动

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void MainPic_MouseWheel(object sender, MouseEventArgs e)

        {

            float fratio = 1f;

            if (e.Delta < 0)

            {

                m_fratio *= 1f-0.05f;

                fratio -= 0.05f;

            }

            else

            {

                m_fratio *= 1f+0.05f;

                fratio += 0.05f;

            }

            if (m_fratio >= 10f)

            {

                m_fratio = 10f;

                fratio = 1f;

            }

            if (m_fratio <= 0.1f)

            {

                m_fratio = 0.1f;

                fratio = 1f;

            }

            //重置矩阵

            translateMatrix.Reset();

            //定义矩阵缩放向量

            translateMatrix.Scale(fratio, fratio);

            MainPic.Image = PaintDXF(this.MainPic);

        }

巴特西

[C# 学习笔记]运用 GDI+ 的 Matrix 进行显示图形的平移和缩放

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