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）。 我希望能够通过clik移动其中一条线并用鼠标移动这条线 – 这可能吗？

Answer 1

 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() { 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 + eX - Moving.StartMoveMousePoint.X, Moving.StartLinePoint.Y + eY - Moving.StartMoveMousePoint.Y); Moving.Line.EndPoint = new PointF(Moving.EndLinePoint.X + eX - Moving.StartMoveMousePoint.X, Moving.EndLinePoint.Y + eY - 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 Lines = new List(); GraphLine SelectedLine = null; MoveInfo Moving = null; static GraphLine FindLineByPoint(List 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 - pX + size, line.StartPoint.Y - pY + size, line.EndPoint.X - pX + size, line.EndPoint.Y - pY + 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; }