从 Picturebox 保存图像

Question

我正在将图像绘制到图片框。我根据宽度和高度调整图片框中的图像大小，以使其正确适合 picutrebox。之后我想保存它，在保存它的同时我也想在保存的文件中保存非图像绘制部分。请看截图，在截图中我有 2 个白色部分标记为 'X'。当我将图像保存在图片框中时，我也想将空白部分（用红色标记）保存为透明 .png 或纯白色 .jpg。

实际上我从google复制了部分代码并进行了修改。如果有人请逐行解释，那将非常有用。

这是我目前所知道的，

private void button1_Click(object sender, EventArgs e)
    {
        OpenFileDialog open = new OpenFileDialog();
        open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp;  *.png)|*.jpg; *.jpeg; *.gif; *.bmp; *.png";
        if (open.ShowDialog() == DialogResult.OK)
        {               
            Image original = Bitmap.FromFile(open.FileName);
            pictureBox1.Image = new Bitmap(ScaleImage(original));

            pictureBox1.Padding = new Padding((pictureBox1.Width - ScaleImage(original).Width) / 2, (pictureBox1.Height - ScaleImage(original).Height) / 2, 0, 0);
        }
    }

    private Bitmap ScaleImage(Image oldImage)
    {
        double resizeFactor = 1;

        if (oldImage.Width > 300 || oldImage.Height > 300)
        {
            double widthFactor = Convert.ToDouble(oldImage.Width) / 300;
            double heightFactor = Convert.ToDouble(oldImage.Height) / 125;
            resizeFactor = Math.Max(widthFactor, heightFactor);
        }

        int width = Convert.ToInt32(oldImage.Width / resizeFactor);
        int height = Convert.ToInt32(oldImage.Height / resizeFactor);
        Bitmap newImage = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

        newImage.MakeTransparent(Color.White);

        Graphics g = Graphics.FromImage(newImage);

        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
        g.DrawImage(oldImage, 0, 0, newImage.Width, newImage.Height);
        return newImage;
    }
    private void button2_Click(object sender, EventArgs e)
    {
        pictureBox1.BackColor = Color.White;
        pictureBox1.Image.Save("D:\temp.png", ImageFormat.Png);
    }

Answer 1

希望对您有所帮助。尝试使用它来保存调整大小的图像（我猜是 button2_Click）。

using (Bitmap bitmap = new Bitmap(pictureBox1.Width, pictureBox1.Height))
{
    using (Graphics graphics = Graphics.FromImage(bitmap))
    {
        graphics.Clear(Color.Transparent);
        graphics.DrawImage(pictureBox1.Image, (bitmap.Width - pictureBox1.Image.Width) / 2, (bitmap.Height - pictureBox1.Image.Height) / 2);
    }

    bitmap.Save(@"D:\tmpMod.png", ImageFormat.Png);
}

从 Picturebox 保存图像

Saving Image From Picturebox

c#

picturebox