Calculate the standard proportion of the image height with fixed image width in iPhone?

I have taken the image from the iPhone 4G and post those images to the server, after that i fetched those images and displayed in the table view cell. I want to display the correct aspect ratio of the image, when change the image height.

In my calculation,

  CGSize imageSize = image.size;

 CGFloat imageWidth = imageSize.width; (620) (In retina from iPhone 4G)

 CGFloat imageHeight = imageSize.height; (620)  (In 开发者_如何学运维retina from iPhone 4G)

 CGFloat aspectRatio = imageSize.width / imageSize.height; (620 / 620 = 1).

 CGFloat newImageWidth = 300.0f; (Fixed Width). 

 // Calculate new Image Height.

CGFloat newImageHeight = newImageWidth / aspectRatio; (300 / 1 = 300)

So, new image width / height.(300, 300).

And, Should i need to check the image is retina or not?

I don't know, whether the calculation is correct or not, so please guide me to achieve this. I want to know, standard procedure to find the height of the image with the fixed image width(Set the correct aspect ratio).

Please help me out.

Thanks!

Why don't you just put it into a UIImageView and set its contentMode to UIViewContentModeScaleAspectFit?