How to zoom an image in&out in C#?

问题

I want to implement zoom for an image. I don't want to resize the PictureBox, but the image itself.

How do I do this?

回答1:

One solution is:

1. Create new image of the desired size (for example 200% or 50% of original image size)
2. Draw original image to new image using Graphics.DrawImage(Image, Rectangle);, which draws the given image to the new image at the given position with the given size
3. Set new image as source for the PictureBox

Another way is to simple create a new bitmap instance like that:

Size newSize = new Size((int)(originalBitmap.Width * zoomFactor), (int)(originalBitmap.Height * zoomFactor));
Bitmap bmp = new Bitmap(originalBitmap, newSize);

回答2:

I used a web browser to achieve this.

//loads the image
myWebBrowser.Navigate(@"C:\myimage.png");

From there I used SendKeys to zoom in and out

myWebBrowser.Select(); //Selects browser.
SendKeys.Send("^{+}"); //Sends the control + key combo, causing the browser to zoom in. Replace the "+" with a "-" to zoom out.

It's a bit of a weird method, but it worked really well for me. I hope you find this helpful!

来源：https://stackoverflow.com/questions/10915958/how-to-zoom-an-image-inout-in-c