如何将图像裁剪并保存到图片框中-c#中

Question

我无法裁剪图片框中的裸线模式，我尝试了几个星期，并决心得到一个解决方案。问题是，我的图像大小是说(1200,750)，图片大小是(450,300)，但是当我尝试在picturebox中任意裁剪它时，它采用图像原始大小的坐标(1200,750)，但是我需要裁剪图像框(450,300)中显示的图像的坐标，因此在裁剪时会产生错误的结果。我正在使用c# winforms的visual 2013。请给我一个解决办法。提前谢谢你。

    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);
        }
    }

我使用的命名空间类如下所示

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

如果你想在不留下纠察盒的情况下在各个方向做出适当的选择：

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();
        }
    }