About

Published in Jan 2021, Mapaper might be the first app to utilize the "Set Wallpaper" shortcut action added in iOS 14.3.
With tight integration with Apple's shortcuts app, Mapaper can update your wallpaper with a map whenever it is triggered, let it be a double tap on the back of the phone, a charging notification, a nearby NFC, or just simply a fixed timespan every day. Combined with map styles from Mapbox, Mapaper took the iPhone customization to a whole new level -- mind you, there wasn't an actual 'live wallpaper' app on iOS until Mapaper. This isn't just me bragging, or Apple won't select it as 'Apps We Are Loving Right Now'.

Technical Implementation

Mapaper was built completely with Swift. All the interface was written in SwiftUI.

The app includes a custom Siri Intent for the system shortcuts app to recognize as an image provider -- so that the system shortcut app can consequently set the image as wallpaper.

The hidden restriction of the wallpaper size is that for a square image, its size cannot exceed the half of the longest physical pixel size. That is,

let bounds = UIScreen.nativeBounds
let maxSize = max (bounds.height, bounds.width) / 2.0

Or the system shortcuts app will throw image too large error. Tested on iPhone 12 and iOS 14.3. For more on this please refer to this twitter thread.

Live Demo

This was captured when I was in Singapore, lol. See the background story if you want to know more about the creation of this small app in a tiny hotel of Singapore.

Background Story

Story time! So at the end of 2020, I was in Singapore, trying to get my student visa and fly to the United States from there. Singapore was hot and rainy even in December, so most of the time, I was resting in a tiny hotel in Tanjong Pagar, listening to the rain outside, and trying to get my work done, like student documents, offer letter, etc.

Then I figured, I am in a totally new place, constantly in need of Google Map every day to navigate, then why not build a live map as my iOS wallpaper? And that's why Mapaper was born. It then became a companion app that followed me to travel around Singapore, and later, Pittsburgh.

Again, six months later and I think back, Singapore is still a magical experience. I enjoyed a lot there when I was writing Mapaper.

Spin-offs

Mapaper is actually a shrink-down version of my another app, LiveDesk. Later I lost interest in writing LiveDesk, you know, the common syndrome of being an indie developer. So I took the shortcuts support from LiveDesk and created Mapaper.
LiveDesk is still an interesting idea though that you can get dynamic wallpaper on iOS -- just like what you get on a Mac. It will recognize the format of dynamic wallpapers used on macOS and change it through time and time of the day. In a way, I am trying to replicate the stock feature of macOS on iOS, and I really hope that LiveDesk can be "sherlocked" by Apple.
Some dev screenshots: