iOS downloadable fonts

[ronaldtse]

On iOS there is something similar to #84 since iOS 6. Apple officially supports apps downloading fonts (https://developer.apple.com/library/archive/samplecode/DownloadFont/Listings/DownloadFont_ViewController_m.html).

This script (https://gist.github.com/liruqi/5309d08e63de0baf3365) pulls fonts from http://mesu.apple.com/assets/com_apple_MobileAsset_Font/com_apple_MobileAsset_Font.xml to find fonts.

This page SteveX Compiled: Downloadable Fonts in iOS 7 gives a good introduction to them and provides list of fonts.

Interestingly, this XML contains Arial Unicode too.

The font licenses here probably follow the iOS license iOS 14 license.

The license contains these lines, so these fonts may only be licensed for iOS/macOS devices:

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2. Permitted License Uses and Restrictions.

(a) Subject to the terms and conditions of this License, you are granted a limited non-exclusive license to use the Apple Software on a single Apple-branded Device. Except as permitted in Section 2(b) below, and unless as provided in a separate agreement between you and Apple, this License does not allow the Apple Software to exist on more than one Apple-branded Device at a time, and you may not distribute or make the Apple Software available over a network where it could be used by multiple Devices at the same time. This License does not grant you any rights to use Apple proprietary interfaces and other intellectual property in the design, development, manufacture, licensing or distribution of third party devices and accessories, or third party software applications, for use with Devices. Some of those rights are available under separate licenses from Apple. For more information on developing third party devices and accessories for Devices, please visit https://developer.apple.com/programs/mfi/. For more information on developing software applications for Devices, please visit https://developer.apple.com.

(b) Subject to the terms and conditions of this License, you are granted a limited non-exclusive license to download Apple Software Updates that may be made available by Apple for your model of the Device to update or restore the software on any such Device that you own or control. This License does not allow you to update or restore any Device that you do not control or own, and you may not distribute or make the Apple Software Updates available over a network where they could be used by multiple Devices or multiple computers at the same time. If you download an Apple Software Update to your computer, you may make one copy of the Apple Software Updates stored on your computer in machine-readable form for backup purposes only, provided that the backup copy must include all copyright or other proprietary notices contained on the original.

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[ronaldtse]

I wonder if this indicates that we should implement a "licensed for OS/platform" flag, e.g. if Fontist is run on macOS then we don't need to ask for agreement on this particular license.