Question

I want to scale images these day and find the following example:

Example #1 of
http://www.codeproject.com/KB/GDI-plus/imageresize.aspx

After several testing, I write the following code:

static System.Drawing.Image Scale(System.Drawing.Image imgPhoto, int v_iPercent)
{
    int destWidth = (int)(imgPhoto.Width * v_iPercent / 100.0);
    int destHeight = (int)(imgPhoto.Height * v_iPercent / 100.0);
    Bitmap bmPhoto = new Bitmap(imgPhoto, destWidth, destHeight);
    return bmPhoto;
}

I am wondering why the example I find needs to use Graphics.DrawImage function to scale the image.

Answer 1

Have you seen what does the Bitmap constructor you are using do:

public Bitmap(Image original, int width, int height) : this(width, height)
{
    using (Graphics graphics = null)
    {
        graphics = Graphics.FromImage(this);
        graphics.Clear(Color.Transparent);
        graphics.DrawImage(original, 0, 0, width, height);
    }
}

It calls DrawImage.