If you want to display your map on various devices, you need to consider the types of screens these devices might have. In this article, we’ll shortly explain what are Retina and HiDPI displays and show you how to set a custom Retina scale for map tiles generated with MapTiler Engine.
This option is available only in the Plus and Pro versions of MapTiler Engine. Setting the Retina/HiDPI scale factor is available since MapTiler Engine 11.3.
Retina is a marketing name for HiDPI displays used by Apple. The key property of a HiDPI display is its pixel density, hence the name - HiDPI = High Dots (Pixels) Per Inch. This parameter says how many pixels will fit into one inch of the width or height of the display. With technological progress and the constantly increasing image resolutions, displays naturally need to have a higher pixel density to support higher image resolutions while preserving screen size.
This is not the only reason for the emergence of HiDPI displays though. While the relation between screen size, image resolution, and pixel density is purely technical, this technology is an attempt to improve the experience of looking at the display so that it is practically impossible to make out its single pixels with the naked eye. One of the consequences of this idea is the fact, that in order to keep the same visible image size on the screen, the image dimensions need to be bigger. The scaling factor is specific for particular devices. As an example, its value is 2.0 for iPhone Retina displays, and 3.0 for the ones used in iPads.
This is a pretty good in-depth article explaining the concept of HiDPI and Retina displays.
Retina/HiDPI tiles in MapTiler Engine
MapTiler Engine supports rendering Retina/HiDPI tiles. It is available as one of the options on the Output settings page:
Enabling this setting will, by default, increase the tile size from 256x256px to 512x512px. That will ensure that, despite the effects described in the previous paragraph, your map looks great also on devices with HiDPI/Retina displays such as iPhones, iPad, MacBook Pros, or high-end Android phones/tablets.
Retina scale setting
Starting from MapTiler Engine 11.3, it is possible to set the scaling factor value for Retina/HiDPI tiles. In previous versions, it had a fixed value of 2.0. To change this setting, go to Settings (macOS: Preferences) → Image.
In this article, we have briefly explained the concept of HiDPI/Retina displays and shown you how to use MapTiler Engine to make your maps look great on them as well. By now, you should have a better idea, of how using this setting will impact the look of the rendered map.