从PictureBox保存具有透明图像的非透明图像

Question

I have a PictureBox with lots of transparent png's drawn into...

Now I'd like to save the content of this PictureBox to a file, but without the transparency.

How can I do this?

I have already tried to remove transparency from the Image like this, but it didn't work, I still got a transparent image after the save.

...

removeTransparency(pictureBox.Image).Save(saveFileDialog.FileName);

private Bitmap removeTransparency(Image transparentImage)
{
    Bitmap src = new Bitmap(transparentImage);
    Bitmap newImage = new Bitmap(src.Size.Width, src.Size.Height);
    Graphics g = Graphics.FromImage(newImage);
    g.DrawRectangle(new Pen(new SolidBrush(Color.White)), 0, 0, newImage.Width, newImage.Height);
    g.DrawImage(src, 0, 0);

    return newImage;
}

Answer 1

You may cycle through all pixel (please not using GetPixel/SetPixel) to change the color or you may create another bitmap with the same size, create a graphics context from the image, clear the image with your favorite background color and then draw your image on it (so transparent pixels simply will be replaced by the background color).

Example

Did you do something like this?

public static Bitmap Repaint(Bitmap source, Color backgroundColor)
{
 Bitmap result = new Bitmap(source.Width, source.Height, PixelFormat.Format32bppArgb);
 using (Graphics g = Graphics.FromImage(result))
 {
  g.Clear(backgroundColor);
  g.DrawImage(source, new Rectangle(0, 0, source.Width, source.Height));
 }

 return result;
}