C#: Warum zoomt das nicht mit der Maus als Mittelpunkt?

Question

Ich versuche eine Leinwand zu erstellen, auf der Sie zoomen und schwenken können. Das Panning funktioniert, aber das Zoomen an der Mausposition funktioniert nicht.

EDIT: Das funktioniert fast. Das Zentrum für Zoom ist leicht aber Offset ...

Dies ist der Code für das Zoomen ist:

public partial class Form1 : Form 
    { 

     PointF mouseDown; 

     float newX; 
     float newY; 
     float zoomFactor = 1.0F; 



     public Form1() 
     { 
      InitializeComponent(); 

      mouseDown = new PointF(0F, 0F); 

      this.panel1.Paint += new PaintEventHandler(panel1_Paint); 
      this.panel1.MouseDown += new System.Windows.Forms.MouseEventHandler(panel1_MouseDown); 
      this.panel1.MouseMove += new System.Windows.Forms.MouseEventHandler(panel1_MouseMove); 

     } 

     private void panel1_Paint(object sender, PaintEventArgs e) 
     { 

      base.OnPaint(e); 

      Graphics dc = e.Graphics; 

      dc.SmoothingMode = SmoothingMode.AntiAlias; 

      dc.TranslateTransform(newX, newY); 
      dc.ScaleTransform(zoomFactor, zoomFactor); 

      Color lineColor = Color.FromArgb(200, 200, 200); 
      Pen linePen = new Pen(lineColor,1*zoomFactor); 

      dc.DrawLine(linePen, 100, 100, 200, 200); 

      textBox1.Text = newX.ToString(); 
      textBox2.Text = newY.ToString(); 
     } 



     private void panel1_MouseDown(object sender, EventArgs e) 
     { 
      MouseEventArgs mouse = e as MouseEventArgs; 

      if (mouse.Button == MouseButtons.Right) 
      { 
       mouseDown = mouse.Location; 

       mouseDown.X = mouseDown.X - newX; 
       mouseDown.Y = mouseDown.Y - newY; 

      } 

     } 

     private void panel1_MouseMove(object sender, EventArgs e) 
     { 
      MouseEventArgs mouse = e as MouseEventArgs; 

      if (mouse.Button == MouseButtons.Right) 
      { 
       Point mousePosNow = mouse.Location; 

       float deltaX = mousePosNow.X - mouseDown.X; 
       float deltaY = mousePosNow.Y - mouseDown.Y; 

       newX = deltaX; 
       newY = deltaY; 

       panel1.Invalidate(); 

      } 
     } 

     protected override void OnMouseWheel(MouseEventArgs e) 
     { 

      MouseEventArgs mouse = e as MouseEventArgs; 

      if (e.Delta > 0) 
      { 
       if (zoomFactor + 0.2 < 10) 
       { 
        zoomFactor += 0.2F; 
       } 
      } 

      else if (e.Delta < 0) 
      { 
       if (zoomFactor - 0.2 > 0.2) 
       { 
        zoomFactor -= 0.2F; 
       } 
      } 

      float x = (mouse.Location.X - newX) * zoomFactor; 
      float y = (mouse.Location.Y - newY) * zoomFactor; 

      newX = mouse.Location.X - x; 
      newY = mouse.Location.Y - y; 

      panel1.Invalidate(); 

     } 
    } 

Answer 1

Ich habe es endlich herausgefunden, also hier ist die Lösung.

public partial class Form1 : Form 
{ 

    PointF mouseDown; 

    float newX; 
    float newY; 
    float zoomFactor = 1.0F; 


    public Form1() 
    { 
     InitializeComponent(); 

     mouseDown = new PointF(0F, 0F); 

     this.panel1.Paint += new PaintEventHandler(panel1_Paint); 
     this.panel1.MouseDown += new System.Windows.Forms.MouseEventHandler(panel1_MouseDown); 
     this.panel1.MouseMove += new System.Windows.Forms.MouseEventHandler(panel1_MouseMove); 

    } 

    private void panel1_Paint(object sender, PaintEventArgs e) 
    { 

     base.OnPaint(e); 

     Graphics dc = e.Graphics; 

     dc.SmoothingMode = SmoothingMode.AntiAlias; 

     dc.TranslateTransform(newX, newY); 

     dc.ScaleTransform(zoomFactor, zoomFactor, MatrixOrder.Prepend); 

     Color lineColor = Color.FromArgb(200, 200, 200); 
     Pen linePen = new Pen(lineColor,1*zoomFactor); 

     dc.DrawLine(linePen, 100, 100, 200, 100); 
     dc.DrawLine(linePen, 200, 100, 200, 200); 
     dc.DrawLine(linePen, 200, 200, 100, 200); 
     dc.DrawLine(linePen, 100, 200, 100, 100); 
     dc.DrawLine(linePen, 100, 100, 200, 200); 
     dc.DrawLine(linePen, 200, 100, 100, 200); 

    } 

    private void panel1_MouseDown(object sender, EventArgs e) 
    { 
     MouseEventArgs mouse = e as MouseEventArgs; 

     if (mouse.Button == MouseButtons.Right) 
     { 
      mouseDown = mouse.Location; 

      mouseDown.X = mouseDown.X - newX; 
      mouseDown.Y = mouseDown.Y - newY; 

     } 

    } 

    private void panel1_MouseMove(object sender, EventArgs e) 
    { 
     MouseEventArgs mouse = e as MouseEventArgs; 

     if (mouse.Button == MouseButtons.Right) 
     { 
      PointF mousePosNow = mouse.Location; 

      float deltaX = mousePosNow.X - mouseDown.X; 
      float deltaY = mousePosNow.Y - mouseDown.Y; 

      newX = deltaX; 
      newY = deltaY; 

      panel1.Invalidate(); 

     } 


    } 

    protected override void OnMouseWheel(MouseEventArgs e) 
    { 

     MouseEventArgs mouse = e as MouseEventArgs; 

     PointF mP = mouse.Location; 

     if (e.Delta > 0) 
     { 
      if (zoomFactor >= 1 && zoomFactor <= 10) 
      { 
       zoomFactor += 1F; 

       newX = newX - ((mP.X - newX)/(zoomFactor - 1)); 
       newY = newY - ((mP.Y - newY)/(zoomFactor - 1)); 
      } 
      else if (zoomFactor == 0.5) 
      { 
       zoomFactor = zoomFactor * 2; 
       newX = newX - ((mP.X - newX)); 
       newY = newY - ((mP.Y - newY)); 
      } 
      else if (zoomFactor < 0.5) 
      { 
       zoomFactor = zoomFactor * 2; 
       newX = newX - ((mP.X - newX)); 
       newY = newY - ((mP.Y - newY)); 
      } 
     } 

     else if (e.Delta < 0) 
     { 
      if (zoomFactor >2) 
      { 
       zoomFactor -= 1F; 
       newX = newX + (((mP.X - newX))/(zoomFactor+1)); 
       newY = newY + (((mP.Y - newY))/(zoomFactor+1)); 
      } 
      else if (zoomFactor == 2) { 
       zoomFactor -= 1F; 

       newX = newX + ((mP.X - newX)/2); 
       newY = newY + ((mP.Y - newY)/2); 
      }else if(zoomFactor <= 1 && zoomFactor > 0.2) 
      { 
       zoomFactor = zoomFactor/2; 

       newX = newX + ((mP.X - newX)/2); 
       newY = newY + ((mP.Y - newY)/2); 

      } 


     } 

     panel1.Invalidate(); 

    } 
} 

Answer 2

Vielleicht ist Ihr MousePosition unterscheidet sich von PanelPosition? Ich meine auf ist relativ zur Kontrolle und eine relativ zum Bildschirm?

Control.PointToScreen ist dein Freund!