By Richard Mallion
The display of Apple’s retina MacBook is a stunning piece of engineering. After spending a week with it here is an article that covers how it works and some of the problems you may face.
The Physical Screen
The display itself is Apple’s first retina display on a non iOS device. Its extremely high resolution, offering a native resolution of 2880 x 1800 pixels. Compared to Apple’s 27-inch Thunderbolt Display it offers 44% pixels and to the old 30-inch display 26%. With a resolution of 220 pixels per inch its the highest density consumer notebook on the market today. However this is considerably less than the iPhone 4S with has 326 pixels per inch.
The other thing you will notice is that Apple has done away with the traditional cover glass we have seen on all of Apple’s recent laptops. So now you have two pieces of glass but the outermost piece now integrates the bezel. This has an advantage that you are less likely to see trapped dust particles between the layers of glass but if you scratch the display you will now be scratching the lcd panel itself. If you need to replace the screen the unit including the bezel is now one piece. This might be the machine you consider adding Appe Care to.
Mac OS X / Software
When it comes to how Mac OS X and applications drive the display, its very similar to how iOS works. On traditional, non retina displays, we have a one to one relationship between pixels and points. So one point would be represented by one pixel where as on the retina display we now have 1 point being represented by 4 pixels, offering a much higher resolution, sharper image. As an example, which is shown below, on an old display if you drew a square 10 points by 10 points, the actual image drawn would be 10 pixels by 10 pixels. On the retina display this square would now be 20 pixels by 20 pixels, offering more pixels for more detail.
When an application draws to the screen it can set a backing scale factor, either 1.0 or 2.0. When set to 1.0 you get the traditional one to one point to pixel mapping. When set to 2.0 you get the retina mode where each point is represented by 4 pixels. Whats interesting about this backing scale is that it is not a global setting for the entire screen. Different regions of the screen can have different backing scales. Which means you can set the UI elements of an application to one and the actual content its displaying to another.
Apple have made sure that their key modern API’s will make best use of the retina display, thus saving developers a lot of time which also means some apps will automatically make use of the retina display. Notice I say some apps, more on this later. For instance if an app uses vector based graphics or displays text using Apple’s API’s then all should be good. Apps that use standard menus, standard open/save dialogs, standard toolbars should all look crisp on the new display. An example of an open dialog not looking great on this display are the ones found in the Adobe programs. Adobe have modified these dialogs, adding there own functionality, so on the retina they will not make sure of the extra pixels so look slightly ‘fuzzy’.
When it comes to bitmapped images, the OS will scales these up to fit the extra pixels unless the developer has supplied a higher resolution version which in that case the OS will substitute for that. This is how iOS works, for every graphic two versions are supplied. A lower resolution version and a @2x version for the retina display. The OS decides which version to display based on the display.
The Display Preference Pane
One aspect of Mac OS X that has changed is the Display preference pane. Rather than being presented with a list of resolutions you instead get a list of scaling options as shown below.
In the display preferences pane, Apple has given you 5 options from “Larger Text” to “Best” (Retina) to “More Space”. These options give you an indication on how the screen would look on a similar resolution on a non retina screen as listed below.
- 1920 by 1200 – More Space
- 1680 by 1050
- 1440 by 900 – Best (Retina)
- 1280 by 800
- 1024 by 640 – Larger Text
So when selecting “Best” this puts the screen into retina mode. In this mode , the screen would the look the equivalent to the size of a 1440 by 900 display. However everything is scaled up by a factor of @2x to make use of the 2880 by 1800 pixels.
All the other modes are non retina. They give you a choice of changing the apparent size of the screen from 1024 by 640 to 1920 by 1200. Again when displayed all assets are scaled up by a factor of @2x but because they don’t scale to the magic 2880 by 1800 they are not retina optimised so the quality of the image may degrade slightly.
So Apple have updated most of their apps to support retina. These applications include Mail, Safari, iCal, Address Book, iChat, FaceTime, Photo Booth, and TextEdit. Additionally, iPhoto, iMovie, iTunes, Aperture, Final Cut Pro X, and Motion all support the Retina display. The exception is iWorks, this suite of apps are quite old now. They look the worse for ware on a retina screen. Once assumes an update is close by.
As mentioned any app using modern API’s (Cocoa API’s) should be ok. The exception comes when the developers of these apps have taken some short cuts. Fort instance with the Twitter app, the detail pane for a tweet looks very very good, however the table that lists your tweets looks slightly blurred, one assumes because they haven’t exactly followed Apple’s way of doing things.
If you perform a “Get Info” on an application you will notice a new option “Open In Low Res”
Depending on the application this option may be clickable.
On apps that have native retina support this will be switch off. On Cocoa apps that are not optimised this option will most likely be ticked. If its not then you may notice visual issue with the apps. If you do just check. On carbon apps like Microsoft Office this option will be grey out, unelectable. For these apps you will have to accept they won’t look great until an updated version is made available.