openalpr-ios

Xcode Framework for the openalpr library.

Because openalpr requires Tesseract 3.03, and, as of this writing, that version has not been released yet, it means that we cannot yet use the Tesseract CocoaPod. Instead, this module includes a bash script (based on this one) that will compile universal Tesseract 3.03 and Leptonica 1.71 libraries, which can then be used to compile/link openalpr for iOS.

It used to be that getting openalpr working on iOS required that both OpenCV and Tesseract needed to be compiled with libstdc++ instead of libc++. This is no longer the case. OpenCV has more recently begun to be built with libc++, so it is possible to use it across the dependencies and in openalpr. (It does remain a requirement that the same library is used for all dependencies and openalpr.)

The basic steps to getting openalpr configured on XCode are:

• Clone this module, which includes a template XCode project for a openalpr library and Cocoa Touch Framework.
• Run a script to build the dependencies
• Configure your own XCode project that will use the openalpr Cocoa Touch Framework.

Steps in Detail

• Get openalpr source:

  # git clone https://github.com/openalpr/openalpr.git openalpr
  

• Clone this module:

  # git clone git@github.com:twelve17/openalpr-ios.git
  

• From the top level openalpr-ios git folder, run the sync_openalpr_source.sh script, passing the path to whereyou cloned openalpr:

  # ./bin/sync_openalpr_source.sh ~/work/lp/openalpr
  

This script will do the following:

• Copy openalpr sources and headers to openalpr-ios/openalpr-xcode/openalpr, for use by the XCode project.

• Copy openalpr headers (only) to openalpr-ios/work/dependencies/include/openalpr, for use by your own XCode iOS application project.

• Copy openalpr runtime_data folder to openalpr-ios/work/dependencies/share/openalpr, for use by your own XCode iOS application project.

• From the top level openalpr-ios git folder, run the build_dependencies.sh script.

  # ./bin/build_dependencies.sh
  

  This will compile iOS compatible versions of Leptonica and Tesseract to the prefix openalpr-ios/work/dependencies

• The project uses the OpenCV CocoaPod instead of the iOS version from OpenCV site. Install it via the pod command:

  # cd openalpr-xcode
  # pod install
  

  This will install the OpenCV dependency.

• Open the openalpr-ios/openalpr-xcode XCode project as suggested by the CocoaPod docs:

  # open openalpr-xcode.xcworkspace
  

  • As of this writing, the latest openalpr revision was beea8923f6c4671170753b382cc598d76fbf38ff, and it required me to make a couple of manual changes:
    1. Create a file called version.h in the openalpr folder (in same folder main.cpp is in) to set a few variables that are required, like this:

    #define OPENALPR_MAJOR_VERSION "1"
    #define OPENALPR_MINOR_VERSION "2"
    #define OPENALPR_PATCH_VERSION "0"
    

    This module includes a copy you can use. The version numbers may be wrong on this file, so feel free to fix them.

Using the openalpr-xcode Project In Your Own Project

• Go to <Your Project> → Targets → <Project> → Build Settings

  • Under Header Search Paths, add: /<path_to>/openalpr-ios/work/dependencies/include/openalpr

• In your project, create a group called Resources, below the root node.

  • While having the openalpr-xcode project open, browse to Products, then drag the libopenalpr-xcode.a library to your own project, into the Resources group created above. This should cause a few other things to happen, but you should confirm this:
  • Under <Your Project> → Targets → <Project> → Build Settings
    • Library Search Paths should now have an entry that looks something like this: $(USER_LIBRARY_DIR)/Developer/Xcode/DerivedData/openalpr-xcode-ddcvnkuwwembihfiemhmlsqzmnar/Build/Products/Debug-iphoneos
    • Link Binary With Libraries should now have libopenalpr-xcode.a.

Creating the XCode Project From Scratch

• Create Project

  • Framework & Library → Cocoa Touch Static Library
    • Product Name: openalpr-xcode
  • Save under the openalpr-ios folder.
  • Delete openalpr_xcode.h and openalpr_xcode.m (move to trash)

• On the left pane, select the openalpr-xcode group.

• Go to File → Add files to "openalpr-xcode"

  • Browse to /<path_to>/openalpr-ios/openalpr-xcode/openalpr
  • Select all items in that folder (main.cpp, etc.)
    • Uncheck Copy items if needed
    • Under Added folders, select Create groups

• Quit XCode

• Create a Podfile on the openalpr-xcode folder:

platform :ios, '8.1'

source 'https://github.com/CocoaPods/Specs.git'

pod 'OpenCV'

- Install the CocoaPods  

cd openalpr-xcode

pod install

- Re-open XCode as suggested by the CocoaPod docs:

open openalpr-xcode.xcworkspace

- Remove `openalpr-xcodeTests` target by selecting it, then selecting the - at the bottom of the panel.

- Add search path for `openalpr` headers within the Project, as well as 
`tesseract` and `leptonica` headers.
- openalpr-xcode -> Targets -> openalpr-xcode -> Build Settings 
- Search Paths -> Header Search Paths, add: 
  - `$(PROJECT_DIR)/openalpr` (recursive)
  - `$(PROJECT_DIR)/../work/dependencies/include/` (non-recursive)

- Add target for building framework.   Select 'openalpr-xcode' on the navigation panel.  
- Click on the + at the bottom of the right panel to add a new target.
  - Select iOS -> Framework & Library -> Cocoa Touch Framework
    - Product Name: `openalpr`
    - Select `Finish`
- The above framework creates an additional `openalprTests` target.  Remove it by selecting the - at the bottom of the panel.


- Browse to `openalpr-xcode` -> `Targets` -> `openalpr` -> `Build Phases`
- Add libraries to include in the Framework target:
  - `Target Dependencies`, add: `openalpr-xcode` (static library target)
  - `Headers`:  
    - Remove `openalpr.h` by pressing the `-` sign 
    - Add `openalpr/alpr.h` by dragging it from the navigator.
  - `Link Binary With Libraries`
    - `Add Other`.  
    - Browse to `openalpr-ios/work/dependencies/lib`.  
    - Add `libtesseract.a` and `liblept.a`.


- Build library 
- Select the openalpr-xcode Library from the drop down to the right of the "Play" and "Stop" icons on the top toolbar, left side.
- Press command-B to build.  Under Products, the libopenalpr-xcode.a should have turned from red to black.
- Select the openalpr Framework from the drop down to the right of the "Play" and "Stop" icons on the top toolbar, left side.
- Press command-B to build.  Under Products, the libopenalpr-xcode.a should have turned from red to black.

### TODO

TODO: - Add Info.plist file to openalpr (Framework) target.
TODO: - Set installation directory in openalpr (Framework) target.
- from /Library/Frameworks to @loader_path/../Frameworks/ 
- skip install - no?

xxxxx  - openalpr-xcode -> Targets -> openalpr -> Build Phases
- Link Binary With Libraries, add: 
  - `openalpr-xcode.a`
  - `$(PROJECT_DIR)/openalpr` (recursive)
  - `$(PROJECT_DIR)/../work/dependencies/include/` (non-recursive)