是否有可能获得缩放/翻译的图形对象？

Question

我正在使用WinForms为模拟编写可视化工具。可视化涉及围绕网格移动的各种对象。

到目前为止，我正在使用扩展Panel的自定义控件，并在Paint事件过程中使用Graphics类进行自定义绘图。然而，一个令人烦恼的地方是我经常不得不从grid坐标缩放到control.DisplayRectangle坐标（换句话说，在网格中占用2个单元格的对象将占用2 *（control.DisplayRectangle.Width/horizo​​ntalGridWidth）绘制时的像素）。

我想知道，有没有办法让图形对象为我做这些翻译，以便我可以在网格坐标中表示我的绘图，并让它自动映射到物理坐标？事实证明，Matrix确实是关键（见公认的答案）。下面是使它工作的代码：

public SimulationPanel() { 
    this.DoubleBuffered = true; 
    this.SizeChanged += (o, e) => this.Invalidate(); 
    this.Paint += this.PaintPanel; 
} 

private void Paint(object sender, PaintEventArgs e) { 
       e.Graphics.Clear(Color.Black); 

      var fromRectangle = GetSimulationWorldCoordinates(); 
      var toRectangle = ScaleToFit(fromRectangle, this.DisplayRectangle); 

      using (var matrix = new Matrix(
          fromRectangle, 
          new[] { 
           toRectangle.Location, 
           new Point(toRectangle.Right, toRectangle.Top), 
           new Point(toRectangle.Left, toRectangle.Bottom), 
         })) 
      { 
           // draw the simulation stuff here using simulation coordinates 
       e.Graphics.Transform = matrix; 
       e.Graphics.FillRectangle(Brushes.LightBlue, toRectangle); 
       e.Graphics.DrawLine(Pens.Red, toRectangle.Location, new Point(toRectangle.Right, toRectangle.Bottom)); 
      } 
} 

Answer 1

这段代码如何？

我使用标签而不是网格，因为我无法知道您的网格。

using System.Drawing; 
using System.Drawing.Drawing2D; 
using System.Windows.Forms; 

namespace WindowsFormsApplication1 
{ 
    public partial class Form1 : Form 
    { 
     GraphicsPath path = new GraphicsPath(); 
     RectangleF pathRect; 

     public Form1() 
     { 
      InitializeComponent(); 

      Location = new Point(0, 0); 
      Size = new System.Drawing.Size(500, 500); 

      Label lbl1 = new Label(); 
      lbl1.Location = new Point(100, 100); 
      lbl1.Size = new System.Drawing.Size(200, 100); 
      lbl1.BorderStyle = BorderStyle.FixedSingle; 
      lbl1.Paint += new PaintEventHandler(lbl_Paint); 

      Label lbl2 = new Label(); 
      lbl2.Location = new Point(300, 200); 
      lbl2.Size = new System.Drawing.Size(100, 200); 
      lbl2.BorderStyle = BorderStyle.FixedSingle; 
      lbl2.Paint += new PaintEventHandler(lbl_Paint); 

      Controls.Add(lbl1); 
      Controls.Add(lbl2); 

      path.AddRectangle(new Rectangle(50, 50, 150, 150)); 
      path.AddEllipse(new Rectangle(25, 50, 25, 50)); 
      pathRect = path.GetBounds(); 
     } 

     void lbl_Paint(object sender, PaintEventArgs e) 
     { 
      var rect = ((Control)sender).DisplayRectangle; 

      PointF[] plgpts = new PointF[] { 
       new PointF(rect.Left, rect.Top), 
       new PointF(rect.Right - 1, rect.Top), 
       new PointF(rect.Left, rect.Bottom - 1), 
      }; 

      Graphics g = e.Graphics; 
      g.Clear(SystemColors.Control); 
      using (Matrix matrix = new Matrix(path.GetBounds(), plgpts)) 
      { 
       g.Transform = matrix; 
       g.DrawPath(Pens.Red, path); 
      } 
     } 
    } 
}