How to Crop an Image

I am using an ImageBox, and it is displaying an image. I need to be able to show only a portion of the image.

My original image:



Now I want it to look like this:



What would be the easiest way of doing this? Thanks.

imageBox->setImageCoord(MyGUI::IntCoord(0, 0, imageWidth / 2, imageHeight));

Awesome, thank you!