C# image whitespace

问题

I have an image that is 240x320 (iphone camera image in portrait), and I need to programmatically (in C#) add white "bars" to the sides increasing the full image size to 320x320. I don't want to scale the image because that would mess up the aspect ratio.

I have found a lot of info about how to remove white bars with c#, but nothing about how to add them. I am at a loss. Does anyone have any input that might lead me the correct direction?

Thanks a bunch, Brett

回答1:

using (System.Drawing.Image src = System.Drawing.Image.FromFile("picture.jpg"))
{
       using (Bitmap bmp = new Bitmap(320, 320))
       {
                Graphics g = Graphics.FromImage(bmp);
                g.Clear(Color.White);
                g.DrawImageUnscaled(src, 60, 0, 240, 320);
                bmp.Save("file.jpg", ImageFormat.Jpeg);
       }
}

Remember to dispose the object after use ;)

回答2:

Create a new empty white bitmap of the desired size and blit the smaller image onto it.

回答3:

Basically create a new bitmap with the required dimension, clear it with the color you want and then draw the smaller bitmap so that it is centered vertically.

回答4:

Here's a great link where a more generalized approach is described for resizing images and adding white bars, either at the top or at the bottom (depending of image orientation)c# Image resizing to different size while preserving aspect ratio

来源：https://stackoverflow.com/questions/2555916/c-sharp-image-whitespace