Question

I have scenario, in which I am getting images using Web Service and all images are in different resolution. Now my requirement is that I want resolution of each Images and using that I want to define size of UIImageView so I can prevent my Images from getting blurred

For example image resolution if 326 pixel/inch the imageview should be as size of that image can represent fully without any blur.

Answer 1

To solve this problem, we need to take care of the device’s display resolution..

For example you have an image of resolution 326ppi which is same as of iPhone4, iPhone4S and iPod 4th Gen. So you can simply use solutions suggested by @Nit and @Peko. But for other devices(or for image with different resolution on these devices) you will need to apply maths to calculate size for better display.

Now suppose you have 260ppi(with dimensions W x H) image and you wish to display it on iPhone4S, so as the information contained in it per inches is less than the display resolution of iPhone so we will need to resize it by reducing image size by 326/260 factor. so now the size for imageView that you will use is

imageViewWidth = W*(260/326);

imageViewHeight = H*(260/326);

In general:

resizeFactor = imageResolution/deviceDisplayResolution;
imageViewWidth = W*resizeFactor;
imageViewHeight = H*resizeFactor;

Here I am considering when we set an image in imageView and resize it, it does not removes or adds pixels from image,