According to a source who spoke to Ars Technica, double-resolution icons were found in “unexpected places” of the Mountain Lion OS. This leads to the speculation of Apple possibly releasing Retina display MacBooks as early as this summer.
One of the double-resolution icons was found in the new Messages application. Some of the icons found were displaying at twice their normal size. Their appearance in the latest build of Mountain Lion Build led the source to suggest the possibility of new MacBooks to be equipped with Retina displays. There is a strong possibility that the display of Retina Display equipped MacBook may coincide with the release of Mac OS X 10.8.
The evidence of Retina display Macs began to arise in February when Apple released OS X 10.7.3 with new HiDPI user interface elements. More specifically, a number of cursors in the operating system were updated to scale to larger sizes on higher resolution screens. Apple added HiDPI modes to OS X Lion last year. However, these modes were only accessible through Xcode. HiDPI is modeled after the User Interface (UI) resolution doubling that Apple does with its Retina display iOS devices.
The rumors of Apple preparing new iterations of its MacBook Pro lineup with double-resolution displays started last year. The resulting display for a 15-inch MacBook Pro would be 2,880 x 1,800 pixels. The support for the higher resolution Macs may possibly come with Intel’s net-generation Ivy Bridge processors. It is said that the Ivy Bridge processors will support up to the 4K resolution, allowing 4,096 x 4,096 pixels per monitor.