C# · 12月 28, 2021

c# – Graphic – DrawLine – 绘制线并移动它

在我的.net c#程序中,我使用文本框中的值绘制几行(我使用DrawLine函数).我想要通过clik移动其中的一条,并用鼠标移动这条线 – 是可能吗?解决方法 public class LineMover : Form{ public LineMover() { this.DoubleBuffered = true; this.Paint += new PaintEventHandler(LineMover_Paint); this.MouseMove += new MouseEventHandler(LineMover_MouseMove); this.MouseDown += new MouseEventHandler(LineMover_MouseDown); this.MouseUp += new MouseEventHandler(LineMover_MouseUp); this.Lines = new List<GraphLine>() { new GraphLine (10,10,100,200),new GraphLine (10,150,120,40),}; } void LineMover_MouseUp(object sender,MouseEventArgs e) { if (Moving != null) { this.Capture = false; Moving = null; } RefreshLineSelection(e.Location); } void LineMover_MouseDown(object sender,MouseEventArgs e) { RefreshLineSelection(e.Location); if (this.SelectedLine != null && Moving == null) { this.Capture = true; Moving = new MoveInfo { Line = this.SelectedLine,StartLinePoint = SelectedLine.StartPoint,EndLinePoint = SelectedLine.EndPoint,StartMoveMousePoint = e.Location }; } RefreshLineSelection(e.Location); } void LineMover_Paint(object sender,PaintEventArgs e) { e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; foreach (var line in Lines) { var color = line == SelectedLine ? Color.Red : Color.Black; var pen = new Pen(color,2); e.Graphics.DrawLine(pen,line.StartPoint,line.EndPoint); } } void LineMover_MouseMove(object sender,MouseEventArgs e) { if (Moving != null) { Moving.Line.StartPoint = new PointF(Moving.StartLinePoint.X + e.X – Moving.StartMoveMousePoint.X,Moving.StartLinePoint.Y + e.Y – Moving.StartMoveMousePoint.Y); Moving.Line.EndPoint = new PointF(Moving.EndLinePoint.X + e.X – Moving.StartMoveMousePoint.X,Moving.EndLinePoint.Y + e.Y – Moving.StartMoveMousePoint.Y); } RefreshLineSelection(e.Location); } private void RefreshLineSelection(Point point) { var selectedLine = FindLineByPoint(Lines,point); if (selectedLine != this.SelectedLine) { this.SelectedLine = selectedLine; this.Invalidate(); } if (Moving != null) this.Invalidate(); this.Cursor = Moving != null ? Cursors.Hand : SelectedLine != null ? Cursors.SizeAll : Cursors.Default; } public List<GraphLine> Lines = new List<GraphLine>(); GraphLine SelectedLine = null; MoveInfo Moving = null; static GraphLine FindLineByPoint(List<GraphLine> lines,Point p) { var size = 10; var buffer = new Bitmap(size * 2,size * 2); foreach (var line in lines) { //draw each line on small region around current point p and check pixel in point p using (var g = Graphics.FromImage(buffer)) { g.Clear(Color.Black); g.DrawLine(new Pen(Color.Green,3),line.StartPoint.X – p.X + size,line.StartPoint.Y – p.Y + size,line.EndPoint.X – p.X + size,line.EndPoint.Y – p.Y + size); } if (buffer.GetPixel(size,size).ToArgb() != Color.Black.ToArgb()) return line; } return null; } public static void Main() { Application.Run(new LineMover()); }}public class MoveInfo{ public GraphLine Line; public PointF StartLinePoint; public PointF EndLinePoint; public Point StartMoveMousePoint;}public class GraphLine{ public GraphLine(float x1,float y1,float x2,float y2) { this.StartPoint = new PointF(x1,y1); this.EndPoint = new PointF(x2,y2); } public PointF StartPoint; public PointF EndPoint;}