如何在strechmode-c中的圖片框中裁剪和保存圖像＃

Question

我無法在strechmode中的圖片框中裁剪圖像，我嘗試了數週，並且還未獲得解決方案。問題是我的圖像大小是說（1200,750）和圖片大小是說（450,300），但是當我嘗試在strechmode的圖片盒中裁剪它時，圖片的原始大小的座標（1200,750），但我需要使用picturebox（450,300）中顯示的圖像的座標進行裁剪，因此我在裁剪時會出現錯誤的結果。我在C＃winforms中使用visual studio 2013。請給我一個解決方案。先謝謝你。

private void pictureBox1_MouseDown(object sender, MouseEventArgs e) 
    { 
     // Starting point of the selection: 
     if (e.Button == MouseButtons.Left) 
     { 
      _selecting = true; 
      _selection = new Rectangle(new Point(e.X, e.Y), new Size()); 
     } 
    } 

    private void pictureBox1_MouseMove(object sender, MouseEventArgs e) 
    { 
     // Update the actual size of the selection: 
     if (_selecting) 
     { 
      _selection.Width = e.X - _selection.X; 
      _selection.Height = e.Y - _selection.Y; 

      // Redraw the picturebox: 
      pictureBox1.Refresh(); 
     } 
    } 

    private void pictureBox1_MouseUp(object sender, MouseEventArgs e) 
    { 
     // Make a note that we "have the mouse". 
     bHaveMouse = true; 

     // Store the "starting point" for this rubber-band rectangle. 
     ptOriginal.X = e.X; 
     ptOriginal.Y = e.Y; 

     // Special value lets us know that no previous 
     // rectangle needs to be erased. 

     // Display coordinates 
     //lbCordinates.Text = "Coordinates : " + e.X.ToString() + ", " + e.Y.ToString(); 

     //ptLast.X = -1; 
     //ptLast.Y = -1; 

     //rectCropArea = new Rectangle(new Point(e.X, e.Y), new Size()); 
     if (e.Button == MouseButtons.Left && _selecting) 
     { 
      // Create cropped image: 
      Image img = pictureBox1.Image.Crop(_selection); 

      // Fit image to the picturebox: 
      pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage; 
      pictureBox1.Image = img.Fit2PictureBox(pictureBox1); 
      _selecting = false; 
     } 
     button5.Enabled = true; 
    } 

    private void pictureBox1_Paint(object sender, PaintEventArgs e) 
    { 
     if (_selecting) 
     { 
      // Draw a rectangle displaying the current selection 
      Pen pen = Pens.GreenYellow; 
      e.Graphics.DrawRectangle(pen, _selection); 
     } 
    } 

`我使用的命名空間類是如下

namespace gfoidl.Imaging 
{ 

    public static class ImageExtension 
    { 

     public static Image Crop(this Image image, Rectangle selection) 
     { 
      Bitmap bmp = image as Bitmap; 

      // Check if it is a bitmap: 
      if (bmp == null) 
       throw new ArgumentException("Kein gültiges Bild (Bitmap)"); 

      // Crop the image: 
      Bitmap cropBmp = bmp.Clone(selection, bmp.PixelFormat); 

      // Release the resources: 
      image.Dispose(); 

      return cropBmp; 
     } 

     public static Image Fit2PictureBox(this Image image, PictureBox picBox) 
     { 
      Bitmap bmp = null; 
      Graphics g; 

      // Scale: 
      double scaleY = (double)image.Width/picBox.Width; 
      double scaleX = (double)image.Height/picBox.Height; 
      double scale = scaleY < scaleX ? scaleX : scaleY; 

      // Create new bitmap: 
      bmp = new Bitmap(
       (int)((double)image.Width/scale), 
       (int)((double)image.Height/scale)); 

      // Set resolution of the new image: 
      bmp.SetResolution(
       image.HorizontalResolution, 
       image.VerticalResolution); 

      // Create graphics: 
      g = Graphics.FromImage(bmp); 

      // Set interpolation mode: 
      //g.InterpolationMode = InterpolationMode.HighQualityBicubic; 

      // Draw the new image: 

      g.DrawImage(
       image, 
       new Rectangle(   // Ziel 
        0, 0, 
        bmp.Width, bmp.Height), 
       new Rectangle(   // Quelle 
        0, 0, 
        image.Width, image.Height), 
       GraphicsUnit.Pixel); 
      picBox.SizeMode = PictureBoxSizeMode.StretchImage; 

      // Release the resources of the graphics: 
      g.Dispose(); 

      // Release the resources of the origin image: 
      image.Dispose(); 

      return bmp; 
     } 
    } 
} //invoked it in the main program with the header using gfoid1.imaging; 

Answer 1

private Point mouseDown; 

private void pictureBox1_MouseDown(object sender, MouseEventArgs e) 
{ 
    if (e.Button == MouseButtons.Left) 
    { 
     _selecting = true; 

     mouseDown = new Point(e.X, e.Y); 
     _selection = new Rectangle(mouseDown, new Size()); 
    } 
} 

private void pictureBox1_MouseMove(object sender, MouseEventArgs e) 
{ 
    if (_selecting) 
    { 
     Point mousePos = new Point(e.X, e.Y); 

     if(mousePos.X < 0) 
     { 
      mousePos.X = 0; 
     } 

     if(mousePos.X >= pictureBox1.Width) 
     { 
      mousePos.X = pictureBox1.Width - 1; 
     } 

     if(mousePos.Y < 0) 
     { 
      mousePos.Y = 0; 
     } 

     if (mousePos.Y >= pictureBox1.Height) 
     { 
      mousePos.Y = pictureBox1.Height - 1; 
     } 


     _selection.X = Math.Min(mouseDown.X, mousePos.X); 
     _selection.Y = Math.Min(mouseDown.Y, mousePos.Y); 
     _selection.Width = Math.Abs(mousePos.X - mouseDown.X); 
     _selection.Height = Math.Abs(mousePos.Y - mouseDown.Y); 

     // Redraw the picturebox: 
     pictureBox1.Invalidate(); 
    } 
} 

Answer 2

如果你想在所有方向上的正確選擇不留picbox：

private Point mouseDown; 

private void pictureBox1_MouseDown(object sender, MouseEventArgs e) 
    { 
     if (e.Button == MouseButtons.Left) 
     { 
      _selecting = true; 

      mouseDown = new Point(e.X, e.Y); 
      _selection = new Rectangle(mouseDown, new Size()); 
     } 
    } 

private void pictureBox1_MouseMove(object sender, MouseEventArgs e) 
    { 
     if (_selecting) 
     { 
      Point mousePos = new Point(e.X, e.Y); 

      if(mousePos.X < 0) 
      { 
       mousePos.X = 0; 
      } 

      if(mousePos.X >= pictureBox1.Width) 
      { 
       mousePos.X = pictureBox1.Width - 1; 
      } 

      if(mousePos.Y < 0) 
      { 
       mousePos.Y = 0; 
      } 

      if (mousePos.Y >= pictureBox1.Height) 
      { 
       mousePos.Y = pictureBox1.Height - 1; 
      } 


      _selection.X = Math.Min(mouseDown.X, mousePos.X); 
      _selection.Y = Math.Min(mouseDown.Y, mousePos.Y); 
      _selection.Width = Math.Abs(mousePos.X - mouseDown.X); 
      _selection.Height = Math.Abs(mousePos.Y - mouseDown.Y); 

      // Redraw the picturebox: 
      pictureBox1.Invalidate(); 
     } 
    }