Dart&Flutter: ตกหลุมขวากกับไลบรารี PROJ แบบเนทีฟบน iOS

# for ALL platforms
export CMTOOLCHAIN=$HOME/dev/3rdParty/ios-cmake-master/ios.toolchain.cmake

# for iOS arm64 device
export PREFIX=$HOME/buildproj4/iphoneos_arm64
export SDKPATH=$(xcrun --sdk iphoneos --show-sdk-path)
export OS=OS64

cd sqlite-amalgamation-master
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DBUILD_SHARED_LIBS=OFF \
    -DSQLITE_ENABLE_RTREE=ON \
    -DSQLITE_ENABLE_COLUMN_METADATA=ON \
    -DSQLITE_OMIT_DECLTYPE=OFF \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

cd proj-9.1.0
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DBUILD_SHARED_LIBS=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DENABLE_TIFF=OFF -DENABLE_CURL=OFF \
    -DBUILD_PROJSYNC=OFF \
    -DSQLITE3_INCLUDE_DIR=$PREFIX/include \
    -DSQLITE3_LIBRARY=$PREFIX/lib/libsqlite3.a \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

# for iOS x86_64 simulator
export PREFIX=$HOME/buildproj4/iphonesimulator_x86_64
export SDKPATH=$(xcrun --sdk iphonesimulator --show-sdk-path)
export OS=SIMULATOR64

cd sqlite-amalgamation-master
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DBUILD_SHARED_LIBS=OFF \
    -DSQLITE_ENABLE_RTREE=ON \
    -DSQLITE_ENABLE_COLUMN_METADATA=ON \
    -DSQLITE_OMIT_DECLTYPE=OFF \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

cd proj-9.1.0
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DBUILD_SHARED_LIBS=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DENABLE_TIFF=OFF -DENABLE_CURL=OFF \
    -DBUILD_PROJSYNC=OFF \
    -DSQLITE3_INCLUDE_DIR=$PREFIX/include \
    -DSQLITE3_LIBRARY=$PREFIX/lib/libsqlite3.a \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..


# for iOS arm64 simulator
export PREFIX=$HOME/buildproj4/iphonesimulator_arm64
export SDKPATH=$(xcrun --sdk iphonesimulator --show-sdk-path)
export OS=SIMULATORARM64

cd sqlite-amalgamation-master
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DBUILD_SHARED_LIBS=OFF \
    -DSQLITE_ENABLE_RTREE=ON \
    -DSQLITE_ENABLE_COLUMN_METADATA=ON \
    -DSQLITE_OMIT_DECLTYPE=OFF \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

cd proj-9.1.0
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DBUILD_SHARED_LIBS=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DENABLE_TIFF=OFF -DENABLE_CURL=OFF \
    -DBUILD_PROJSYNC=OFF \
    -DSQLITE3_INCLUDE_DIR=$PREFIX/include \
    -DSQLITE3_LIBRARY=$PREFIX/lib/libsqlite3.a \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

# for Mac Catalyst x86_64
export PREFIX=$HOME/buildproj4/macos_x86_64
export SDKPATH=$(xcrun --sdk macosx --show-sdk-path)
export OS=MAC_CATALYST

cd sqlite-amalgamation-master
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DBUILD_SHARED_LIBS=OFF \
    -DSQLITE_ENABLE_RTREE=ON \
    -DSQLITE_ENABLE_COLUMN_METADATA=ON \
    -DSQLITE_OMIT_DECLTYPE=OFF \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

cd proj-9.1.0
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DBUILD_SHARED_LIBS=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DENABLE_TIFF=OFF -DENABLE_CURL=OFF \
    -DBUILD_PROJSYNC=OFF \
    -DSQLITE3_INCLUDE_DIR=$PREFIX/include \
    -DSQLITE3_LIBRARY=$PREFIX/lib/libsqlite3.a \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

# for Mac Catalyst arm64
export PREFIX=$HOME/buildproj4/macos_arm64
export SDKPATH=$(xcrun --sdk macosx --show-sdk-path)
export OS=MAC_CATALYST_ARM64

cd sqlite-amalgamation-master
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DBUILD_SHARED_LIBS=OFF \
    -DSQLITE_ENABLE_RTREE=ON \
    -DSQLITE_ENABLE_COLUMN_METADATA=ON \
    -DSQLITE_OMIT_DECLTYPE=OFF \
    -DENABLE_VISIBILITY=ON \
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

cd proj-9.1.0
rm -r build_$OS; mkdir build_$OS; cd build_$OS
cmake -DCMAKE_TOOLCHAIN_FILE=$CMTOOLCHAIN \
    -DPLATFORM=$OS \
    -DENABLE_BITCODE=OFF \
    -DBUILD_SHARED_LIBS=OFF \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DENABLE_TIFF=OFF -DENABLE_CURL=OFF \
    -DBUILD_PROJSYNC=OFF \
    -DSQLITE3_INCLUDE_DIR=$PREFIX/include \
    -DSQLITE3_LIBRARY=$PREFIX/lib/libsqlite3.a \
    -DENABLE_VISIBILITY=ON \    
    ..
cmake --build .
cmake --build . --target install
cd ..
cd ..

import Flutter
import UIKit

public class SwiftProj4Plugin: NSObject, FlutterPlugin {
  public static func register(with registrar: FlutterPluginRegistrar) {
    let channel = FlutterMethodChannel(name: "proj4", binaryMessenger: registrar.messenger())
    let instance = SwiftProj4Plugin()
    registrar.addMethodCallDelegate(instance, channel: channel)
  }

  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    result("iOS " + UIDevice.current.systemVersion)
  }
    public func dummyMethodToEnforceBundling() {
      // This will never be executed
      proj_context_create();
    }
    public func dummyMethodToEnforceBundling2() {
      //This will never be executed
      sqlite3_memory_used();
    }
}

Pod::Spec.new do |s|
  s.name             = 'proj4'
  s.version          = '1.0.0'
  s.summary          = 'PROJ.4 is a catographic projections library.'
  s.description      = <<-DESC
  PROJ.4 is in active use by  GRASS GIS,  MapServer,  PostGIS,  Thuban,  OGDI,  Mapnik,  TopoCad, and  OGRCoordinateTransformation as well as various other projects.\n\nSince work started on the PROJ.4.4.x series of releases, various bug fixes have been incorporated, and the build system has been overhauled to use autoconf/libtool. Support has also been added for 3 and 7 parameter datum shifts, the PJ* structure now also carries datum information and PJ* can be considered a full coordinate system (geographic coordinate systems are also now supported with the +proj=latlong pseudo-projection). The new cs2cs program performs a similar function to the proj program, but transforming from any one coordinate system to another. The new pj_transform() is used to access the extended coordinate system to coordinate system transformation with datum shifting. Work is underway to improve ThreadSafety.\n\nA mapping file (epsg) has also been introduced mapping most EPSG ( http://www.epsg.org/) coordinate systems to PROJ.4 format.\n\nAs of May 2008 PROJ.4 has become part of the  MetaCRS project, a confederation of coordinate systems related projects and it is hoped MetaCRS will enter incubation as an  OSGeo project.
                       DESC
  s.homepage         = 'http://example.com'
  s.license          = { :file => '../LICENSE' }
  s.author           = { 'Your Company' => 'email@example.com' }
  s.source           = { :path => '.' }
  s.public_header_files = 'Classes**/*.h'
  s.source_files = 'Classes/**/*'
  s.static_framework = true
  s.ios.vendored_libraries = 'libs/libproj.a', 'libs/libsqlite3.a'
  s.xcconfig = { 
    'OTHER_LDFLAGS' => '-lproj -lsqlite3 -lc++ -lstdc++ ', # ต้องมี -lc++ -lstdc++
  }
  s.dependency  'Flutter'
  s.platform = :ios, '12.0'
  s.pod_target_xcconfig = { 'DEFINES_MODULE' => 'YES', 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'i386' }
  s.swift_version = '5.0'
end

...
/* Geodesic distance (in meter) between two points with angular 2D coordinates */
extern "C" __attribute__((visibility("default"))) __attribute__((used))
double proj_lp_dist (const PJ *P, PJ_COORD a, PJ_COORD b) {
    double s12, azi1, azi2;
    /* Note: the geodesic code takes arguments in degrees */
    if( !P->geod ) {
        return HUGE_VAL;
    }
    geod_inverse (P->geod,
        PJ_TODEG(a.lpz.phi), PJ_TODEG(a.lpz.lam),
        PJ_TODEG(b.lpz.phi), PJ_TODEG(b.lpz.lam),
        &s12, &azi1, &azi2
    );
    return s12;
}

/* The geodesic distance AND the vertical offset */
extern "C" __attribute__((visibility("default"))) __attribute__((used))
double proj_lpz_dist (const PJ *P, PJ_COORD a, PJ_COORD b) {
    if (HUGE_VAL==a.lpz.lam || HUGE_VAL==b.lpz.lam)
        return HUGE_VAL;
    return hypot (proj_lp_dist (P, a, b), a.lpz.z - b.lpz.z);
}

/* Euclidean distance between two points with linear 2D coordinates */
extern "C" __attribute__((visibility("default"))) __attribute__((used))
double proj_xy_dist (PJ_COORD a, PJ_COORD b) {
    return hypot (a.xy.x - b.xy.x, a.xy.y - b.xy.y);
}
...