Question

我需要绘制一个PictureBox中加载的位图。我一直在寻找这个网站上的方法，但答案不起作用，因为生成的图像位于错误的位置。

private void pbImage_MouseClick(object sender, MouseEventArgs e)
{
    currentImage = pbImage.Image;
    Bitmap imageAux = new Bitmap(currentImage.Width, currentImage.Height);
    using (Graphics g = Graphics.FromImage(imageAux))
    { 
        Brush brush = new SolidBrush(Color.Red);
        Pen pen = new Pen(Color.Black, 10);
        g.DrawImage(currentImage, pbImage.Location);
        g.Flush();
        if (e.Button == MouseButtons.Left)
        {
            Control control = (Control)sender;
            punto = ((Control)sender).PointToScreen(new Point(e.X, e.Y)); ;

            g.DrawRectangle(pen, new Rectangle(punto.X, punto.Y, 50, 50));
            g.FillRectangle(brush, new Rectangle(punto.X, punto.Y, 50, 50));
            g.Flush();
            g.Dispose();
            pbImage.Invalidate();
        }
    }
    pbImage.Refresh();
    currentImage.Save("C:\\prueba3.bmp");
    imageAux.Save("C:\\prueba4.bmp");
    pbImage.Image = (Image)imageAux.Clone();
}

Answer 1

我认为，那是因为g.DrawImage(currentImage, pbImage.Location);将在imageAux上绘制相对于其父级的pbImage的实际位置的图像。请尝试new Point();。

Answer 2

您应该创建其他位图来绘制。

将原件加载到位图中。
创建一个位图以指定图片框。 （副刊）
创建/生成原始位图的灰度版本。

什么时候需要画画：

清除图片框位图
将灰度绘制到
在图片框位图
刷新het picturebox

这是一个示例，将一个图片框添加到表单并用文件名替换文件名。

public partial class Form1 : Form
{
    private Bitmap _originalBitmap;
    private Bitmap _grayScaleBitmap;
    private Bitmap _pictureBoxBitmap;

    //private Brush brush = new SolidBrush(Color.Red);
    private Pen pen = new Pen(Color.Black, 1);
    private Point? _inspectRectStart;

    public Form1()
    {
        InitializeComponent();

        _originalBitmap = (Bitmap)Bitmap.FromFile("lin-png-256x256-Rafael_256x256_png-256x256.png");
        _grayScaleBitmap = MakeGrayscale3(_originalBitmap);

        _pictureBoxBitmap = new Bitmap(_originalBitmap.Width, _originalBitmap.Height);
        DrawImage();

        pictureBox1.Image = _pictureBoxBitmap;
    }

    private static Bitmap MakeGrayscale3(Bitmap original)
    {
        //create a blank bitmap the same size as original
        Bitmap newBitmap = new Bitmap(original.Width, original.Height);

        //get a graphics object from the new image
        Graphics g = Graphics.FromImage(newBitmap);

        //create the grayscale ColorMatrix
        ColorMatrix colorMatrix = new ColorMatrix(
           new float[][]
           {
             new float[] {.3f, .3f, .3f, 0, 0},
             new float[] {.59f, .59f, .59f, 0, 0},
             new float[] {.11f, .11f, .11f, 0, 0},
             new float[] {0, 0, 0, 1, 0},
             new float[] {0, 0, 0, 0, 1}
           });

        //create some image attributes
        ImageAttributes attributes = new ImageAttributes();

        //set the color matrix attribute
        attributes.SetColorMatrix(colorMatrix);

        //draw the original image on the new image
        //using the grayscale color matrix
        g.DrawImage(original, new Rectangle(0, 0, original.Width, original.Height),
           0, 0, original.Width, original.Height, GraphicsUnit.Pixel, attributes);

        //dispose the Graphics object
        g.Dispose();
        return newBitmap;

    }
    private void DrawImage()
    {
        using (Graphics g = Graphics.FromImage(_pictureBoxBitmap))
        {
            g.Clear(Color.White); // if the bitmap has transparent parts

            // draw the grayscale image.
            g.DrawImage(_grayScaleBitmap, new Rectangle(0, 0, _originalBitmap.Width, _originalBitmap.Height), 0, 0, _originalBitmap.Width, _originalBitmap.Height, GraphicsUnit.Pixel);

            // if there is a selection, draw it.
            if (_inspectRectStart.HasValue)
            {
                var rect = new Rectangle(_inspectRectStart.Value, new Size(50, 50));

                // draw the original bitmap in a rectangle.
                g.DrawImage(_originalBitmap, _inspectRectStart.Value.X, _inspectRectStart.Value.Y, rect, GraphicsUnit.Pixel);
                g.DrawRectangle(pen, rect);
            }
        }

        pictureBox1.Refresh();
    }

    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        // move the rectangle position
        _inspectRectStart = e.Location;
        // redraw image.
        DrawImage();
    }

}

绘制在图片框中加载的位图

2 个答案: