Graphic - DrawLine - vẽ đường và di chuyển nó

Question

Trong chương trình .net C# của tôi, tôi vẽ vài dòng bằng cách sử dụng các giá trị từ các hộp văn bản (tôi sử dụng hàm DrawLine). Tôi muốn có thể di chuyển một trong những dòng này bằng cách bấm vào nó và di chuyển dòng này bằng chuột - có thể không?

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<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; 
}