Port Mixxx to iOS - Githubissues

Status

The ios-qt6 branch contains experimental forks of mixxx and vcpkg that support compiling Mixxx and its dependencies for iOS, i.e. for arm64-ios-release. Most changes to Mixxx have been upstreamed, vcpkg upstreaming is still in progress. iOS CI passes.

Documentation and general stuff

[x] Add instructions to README.md
[x] Build dependencies and Mixxx for iOS in CI

Porting the dependencies to iOS

[x] Fix the dependencies (running scripts/install-vcpkg-deps with the arguments given in the aforementioned instructions should pass)
- [x] Fix ffmpeg build by setting --disable-audiotoolbox
- [x] Skip libusb and hidapi for now
- [x] Add patched ports for iOS under vcpkg/overlay/ios
- [x] Fix mp3lame by setting --disable-frontend (otherwise the build would error with missing curses.h headers)
- [x] Fix portaudio by patching in an experimental iOS CoreAudio backend (source)
- [x] Fix portmidi by patching use of legacy Carbon APIs and unavailable CoreAudio APIs (e.g. by replacing the hosttime calls with the mach time APIs as suggested by this Q&A doc)
- [x] Disable rubberband due to licensing issues (GPL + App Store) and build issues
- [x] Patch Qt as needed (it builds but hasn't been tested yet)
  - [x] Disable _debug suffix for libraries (not needed since we already place them in a /debug subfolder, additionally they cause the Mixxx build to fail as Qt5CoreConfig.cmake looks for unsuffixed libraries (e.g. libQt5Core.a instead of the actual libQt5Core_debug.a))
- [x] Update to Qt 6
  - [x] Add gles3 feature to qtbase (otherwise the port is identical to upstream vcpkg)
  - [x] Figure out the right combination of features (Notably opengl, gles2, gles3 and sql-sqlite, but not sql-psql)
- [ ] Figure out if we can link Qt and all non-permissively/non-App Store-clause-licensed libraries dynamically or ideally exclude them/make them optional (this includes Rubberband, xwax, libkeyfinder and potentially others)
  - For libkeyfinder it might be worth asking the rightholders nicely for a relicensing under GPL + App Store clause, given how essential the library has become
- [x] Patch harfbuzz with iOS sdkroot
[x] Support building a patched version of Qt 5 too (as an alternative to Qt 6)
- [ ] Build Mixxx for iOS 12
[x] Add support for targeting iOS simulator
- Requires building for arm64-ios-simulator-release (instead of arm64-ios-release)
- Needed fix to disable PCRE2 JIT

Porting Mixxx to iOS

[x] Successfully configure mixxx.xcodeproj with the cmake command in the README
[x] Use QIOSIntegrationPlugin
[x] Add option for disabling rubberband (RUBBERBAND)
- [x] Fix build issues (see CI logs, we probably want to test this extensively with the regular desktop macOS build)
- Perhaps we can upstream this?
[x] Figure out potential OpenGL build issues (on iOS we only have OpenGL ES)
[x] Successfully build iOS target in generated Xcode project
[x] Successfully run Mixxx on an actual iOS device
[x] Fix missing precision qualifier in shader
[x] Bundle skins for small screen sizes:
- [x] LateNight Mini: A modified version of @dennisdebel's LateNight skin: https://github.com/dennisdebel/pi_dj
- [x] Pioneered: https://github.com/timewasternl/Pioneered
[x] Successfully load a track from within the sandbox (i.e. Mixxx's documents directory, which the user can access via the files app, e.g. to import music or to export recordings)
[x] Implement screen lock suspension for iOS
[x] Disable tool tips on iOS
[x] Default audio backend to patched PortAudio's "iOS Audio"
- [x] Figure out why we still don't get any sound when using speakers (headphones work, strangely)
- Solution: We needed a playback AVAudioSession
[ ] Investigate how to read files within the iOS sandbox (especially user-picked ones, e.g. via QFileChooser in MixxxMainWindow::slotFileLoadSongPlayer, which is invoked by File > Load Track to Deck ...)
- Perhaps "import" files by always copying them to the sandbox/documents folder when loading them to a deck?
- This would probably be required anyway to (permanently) add them to the library
[ ] Investigate how much of the macOS sandboxing logic we can reuse
- Bookmarking seems to be possible, but in a slightly different fashion, see
- https://github.com/fwcd/mixxx/commit/8e0a652546798c75e259e017f3a7293dba874d9b
- https://bugreports.qt.io/browse/QTBUG-67522
[ ] Set dragMode to scrolling on scrollable views (library, preferences etc.)
[ ] Make preferences (and other modals such as "about"?) full-screen
- Ideally, these modals should probably be a sheet-presented view controllers, but it is unclear whether Qt supports this natively
[x] Use MediaPlayer (instead of iTunesLibrary) framework to access music library on iOS
- [x] Figure out how we can make the sandbox play these tracks (the same issue as for files outside the sandbox)
- Solution: We copy these tracks for now
[x] Tapping track in library brings up keyboard, even if the text field seems to be non-editable, it would be nice if we could find a fix or workaround for this
- Solution: https://github.com/mixxxdj/mixxx/pull/13494 (for now)
[x] Investigate why the app doesn't layout properly on iPadOS.
- Updating Qt from 6.5 to 6.7 seems to fix these issues
- Interestingly, iOS window management seems to be undergoing a larger rewrite upstream: https://bugreports.qt.io/browse/QTBUG-121781
[x] Figure out how to deal with absolute paths into the iOS file system which are unstable across updates/reinstalls
- See https://aplus.rs/2013/never-save-absolute-file-paths-in-your-ios-app/ for details
- Solution: https://github.com/mixxxdj/mixxx/pull/13493
[ ] Figure out why waveforms do not initialize immediately (first upon resizing)
[ ] Figure out why multi-touch doesn't work
[ ] Investigate whether we would want to add a dispatch timeout to track loading in the iOS iTunes importer

Packaging Mixxx for iOS

[x] Bundle resources with iOS app
[x] Update qResourcePath logic to handle iOS app bundles (which use a flatter file structure than macOS bundles)
[x] Add iOS app icon (custom SVG, derived from the macOS icon without rounded corners + script for rendering it)
[x] Add custom Info.plist (including the permission for users to access Mixxx's documents directory via the Files app)
[x] Customize LaunchScreen to use Mixxx logo
[x] Investigate why the IOS variable is not automatically set by CMake when setting CMAKE_SYSTEM_NAME to iOS
- This variable is first set on the project call. We check the vcpkg triplet instead now and set CMAKE_SYSTEM_NAME automatically as needed.

Upstreaming the Mixxx patches

TBD:

Disable features (RUBBERBAND, HID, BATTERY, QTKEYCHAIN) for iOS in upstream CMakeLists and remove them from our README (and user presets as needed)
- rubberband and qtkeychain-qt6 have been fixed, so we could investigate reenabling them
The LateNight Mini skin
- Should be discussed on Zulip first, though a general purpose "small screen" skin would probably be useful for other use cases too (e.g. Raspberry Pis)

Upstreaming the vcpkg patches

to `microsoft/vcpkg`

to `mixxxdj/vcpkg`

TBD:

Update Qt to 6.7 (or higher) upstream
Upstream our updated vcpkg.json manifest
Figure out a solution to the SDKROOT workarounds

to upstream projects

TBD:

Find a way to get rid of the workaround of explicitly setting an SDKROOT for some ports

Ideas for future work

Investigate replacing the native (deprecated) OpenGL ES framework with ANGLE, which runs on top of Metal
Hot reloading for skins over the network

fwcd / m1xxx

Port Mixxx to iOS #16

Status

Documentation and general stuff

Porting the dependencies to iOS

Porting Mixxx to iOS

Packaging Mixxx for iOS

Upstreaming the Mixxx patches

Upstreaming the vcpkg patches

to `microsoft/vcpkg`

to `mixxxdj/vcpkg`

to upstream projects

Ideas for future work

fwcd / m1xxx

Port Mixxx to iOS #16

Status

Documentation and general stuff

Porting the dependencies to iOS

Porting Mixxx to iOS

Packaging Mixxx for iOS

Upstreaming the Mixxx patches

Upstreaming the vcpkg patches

to microsoft/vcpkg

to mixxxdj/vcpkg

to upstream projects

Ideas for future work

to `microsoft/vcpkg`

to `mixxxdj/vcpkg`