如何繪製圖形對象中的任何地方

Question

我試圖創建一個繪製不同對象的畫布。我已經使用graphics.scaleTransform和graphics.translateTransform創建了縮放和平移功能，但我不想使用畫布背景（網格）來填充整個窗口，但它不會使用以下代碼：

編輯：我試過在轉換圖形對象中使用座標，但它似乎不會接受負數？？？

編輯：這張圖片說明我的問題：

public partial class Form1 : Form 
     { 

      PointF mouseDown; 

      float newX; 
      float newY; 
      float zoomFactor = 1F; 

      Region _rgn; 
      Graphics _dc; 
      PointF zoomPoint = new PointF(150, 150); 

      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 bg = 

       Graphics dc = e.Graphics; 
       _dc = dc; 

       dc.SmoothingMode = SmoothingMode.AntiAlias; 

Color gridColor = Color.FromArgb(230, 230, 230); 
      Pen gridPen = new Pen(gridColor, 1); 

      for (float i = 0; i < this.Height * (zoomFactor); i = i + 30*zoomFactor) 
      { 
       dc.DrawLine(gridPen, 0, i, this.Width * (zoomFactor), i); 
      } 
      for (float i = 0; i < this.Width * (zoomFactor); i = i + 30*zoomFactor) 
      { 
       dc.DrawLine(gridPen, i, 0, i, this.Height * (zoomFactor)); 
      } 

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



       float XPosition = 10; 
       float YPosition = 10; 
       float CornerRadius = 5; 
       float Width = 50; 
       float Height = 50; 

       Color BoxColor = Color.FromArgb(0, 0, 0); 
       Pen BoxPen = new Pen(BoxColor, 2); 

       GraphicsPath Path = new GraphicsPath(); 

       Path.AddLine(XPosition + CornerRadius, YPosition, XPosition + Width - (CornerRadius * 2), YPosition); 
       Path.AddArc(XPosition + Width - (CornerRadius * 2), YPosition, CornerRadius * 2, CornerRadius * 2, 270, 90); 
       Path.AddLine(XPosition + Width, YPosition + CornerRadius, XPosition + Width, YPosition + Height - (CornerRadius * 2)); 
       Path.AddArc(XPosition + Width - (CornerRadius * 2), YPosition + Height - (CornerRadius * 2), CornerRadius * 2, CornerRadius * 2, 0, 90); 
       Path.AddLine(XPosition + Width - (CornerRadius * 2), YPosition + Height, XPosition + CornerRadius, YPosition + Height); 
       Path.AddArc(XPosition, YPosition + Height - (CornerRadius * 2), CornerRadius * 2, CornerRadius * 2, 90, 90); 
       Path.AddLine(XPosition, YPosition + Height - (CornerRadius * 2), XPosition, YPosition + CornerRadius); 
       Path.AddArc(XPosition, YPosition, CornerRadius * 2, CornerRadius * 2, 180, 90); 

       Path.CloseFigure(); 



       LinearGradientBrush lgb = new LinearGradientBrush(new PointF(XPosition+(Width/2),YPosition), new PointF(XPosition+(Width/2),YPosition + Height), Color.RosyBrown, Color.Red); 

       dc.FillPath(lgb, Path); 


       dc.DrawPath(BoxPen, Path); 

       Matrix transformMatrix = new Matrix(); 
       transformMatrix.Translate(newX, newY); 
       transformMatrix.Scale(zoomFactor, zoomFactor); 

       _rgn = new Region(Path); 

       _rgn.Transform(transformMatrix); 

      } 

      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; 

       } 

       else if (mouse.Button == MouseButtons.Left) 
       { 

        if (_rgn.IsVisible(mouse.Location, _dc)) 
        { 
         MessageBox.Show("tada"); 
        } 


       } 

      } 

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

       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 1

繪製網格之前，把座標系。

如果不能，請使用GetTransform()和ResetTransform()，然後繪製網格，然後使用SetTransform（第一步獲取SetTransform）。

恕我直言：如果你縮放你的圖像'手動'，而不是使用座標轉換會好得多。這樣你就可以有更多的控制，並且不會碰到任何東西。

編輯：

另外：你在你的網格中的錯誤繪製函數：

for (float i = 0; i < this.Height * (zoomFactor); i = i + 30*zoomFactor) 

嘗試在圖片與

for (float i = 0; i < this.Height; i = i + 30*zoomFactor)