title: How can I crop original image in a pictureBox that shows image in Stretch mode?
body: <p>How can I crop an image in a pictureBox that shows in Stretch mode?</p>
  
  <p>I draw a rectangle in pictureBox :</p>
  
  <pre><code>void pictureBox1_MouseUp(object sender, MouseEventArgs e)
      {
  
          //pictureBox1.Image.Clone();
          xUp = e.X;
          yUp = e.Y;
          Rectangle rec = new Rectangle(xDown, yDown, Math.Abs(xUp - xDown), Math.Abs(yUp - yDown));
          using (Pen pen = new Pen(Color.YellowGreen, 3))
          {
  
              pictureBox1.CreateGraphics().DrawRectangle(pen, rec);
          }
          rectCropArea = rec;
      }
  
      void pictureBox1_MouseDown(object sender, MouseEventArgs e)
      {
          pictureBox1.Invalidate();
  
          xDown = e.X;
          yDown = e.Y;
      }
  </code></pre>
  
  <p>and crop the selected part with :</p>
  
  <pre><code>private void btnCrop_Click(object sender, EventArgs e)
      {
          try
          {
              pictureBox3.Refresh();
              //Prepare a new Bitmap on which the cropped image will be drawn
              Bitmap sourceBitmap = new Bitmap(pictureBox1.Image, pictureBox1.Width, pictureBox1.Height);
              Graphics g = pictureBox3.CreateGraphics();
  
              //Draw the image on the Graphics object with the new dimesions
              g.DrawImage(sourceBitmap, new Rectangle(0, 0, pictureBox3.Width, pictureBox3.Height), rectCropArea, GraphicsUnit.Pixel);
              sourceBitmap.Dispose();
          }
          catch (Exception ex)
          {
  
          }
      }
  </code></pre>
  
  <p>but the quality of the cropped image is very low because it cropped the stretch Image not the original image. How can I crop the original image with size of rectangle that User drawing in pictureBox?</p>