The 6 Plus is the first iPhone that sports a â€œRetina HDâ€ display â€” the sharpest display Apple has ever made. It forces designers to provide an additional set of image resources to developers to match that sharpness.
We needed only one set of assets for the original iPhone up to iPhone 3GS. And when iPhone 4 came out with the Retina display, we also needed 2x assets â€” images twice as detailed. Now, with the display of the 6 Plus being even more detailed than that of the iPhone 4, we will also need to provide 3x assets. The numbers 1x, 2x and 3x are also called â€œscale factors.â€
Of course, Android developers have always had to deal with many different sets of assets. Still, designers are finding themselves questioning their production workflow. In this article, weâ€™ll focus on iOS, but you could easily extend this approach to Android and the web. We wonâ€™t try to provide a silver bullet, and perhaps other ways might seem easier at first, but this article lays out a solid workflow that scales up for big projects.
First off, your icon sets should be vector-based. The approach described in this article focuses on generating multiple asset versions from a single vector shape in a Photoshop document that contains all of your icons.
A unified icon document has the advantage of keeping everything together in one file, allowing you to see how well your icons and assets harmonize.
If youâ€™re designing for iOS 7 and above, then you might think that 1x versions arenâ€™t needed anymore. However, youâ€™ll still need them for devices such as the original iPad Mini, the iPad 2 and potentially Android and the web.
Reference by :Â http://www.smashingmagazine.com/2014/10/15/create-assets-for-multiple-scale-factors/#more-208648