将GDAL/OGR合并到iOS项目中 - 快速指南

Question

问题在于: GDAL是一个非常棒的开源库,用于管理复杂的GIS数据,包括栅格和矢量.它完全针对Mac OS(由William Kyngesburye提供)和其他平台编译,但不适用于iOS.

浏览网络,您可以找到关于创建iOS库主题的一些(相对较旧的)信息,首先是3年前编写的来自pseudogreen的着名脚本.堆栈溢出上还有一些碎片,例如iPhone上的GDAL/OGR,它们提供了额外的信息.

本文旨在涵盖我采取的所有步骤,这使我在使用iOS6和XCode 4.5.5的简单iOS应用程序中实现GDAL/OGR的全功能集成

Answer 1

注意

这个响应是在不久前编写的,并且mo可以在Xcode 6及更高版本中运行.请检查此链接以获取此问题的最新答案.

介绍

将GDAL合并到您的iOS应用程序中需要5个步骤:

1. 从GDAL网站下载GDAL源代码
2. 运行下面给出的configure/build/install脚本
3. 将生成的静态库与包含文件一起添加到iOS项目中
4. 链接iOS项目中的其他库
5. 开始编码...... GDAL和OGR教程是很好的起点

正在下载GDAL

GDAL是一个C++开源库,可以从www.gdal.org网站下载.在撰写本文时,最新版本是1.9.0.如果可能,您应该下载最新的稳定版本.

运行脚本以编译GDAL for iOS和模拟器

要在iOS项目中使用GDAL,您需要将源代码编译为静态库(.a).使用最新的iOS6支持的体系结构,您应该为以下体系结构创建静态库:

• i386用于模拟器
• armv7 for iPhone 3GS to iPhone 4S
• 适用于iPhone 5的armv7s

用于构建1架构的基本脚本

以下脚本是从pseudogreen改编而来的,它可以为单个架构编译源代码.

将此代码复制粘贴到文本编辑器中,并将其另存为扩展名为.sh的文件:例如build_gdal_ios.sh.

要使用它,请将脚本复制到下载gdal源代码的目录中,并按如下方式运行:

• 要为模拟器构建库:

  `sh build_gdal_ios.sh -p "location where you want to save the resulting files" simulator`
  

• 要为设备构建它:

  `sh build_gdal_ios.sh -p "location where you want to save the resulting files" -a "architecture" device`
  

您也可以输入sh build_gdal_ios.sh -h以获得帮助.

    #!/bin/bash
    ################################################################################
    #
    # Copyright (c) 2008-2009 Christopher J. Stawarz
    #
    # Permission is hereby granted, free of charge, to any person
    # obtaining a copy of this software and associated documentation files
    # (the "Software"), to deal in the Software without restriction,
    # including without limitation the rights to use, copy, modify, merge,
    # publish, distribute, sublicense, and/or sell copies of the Software,
    # and to permit persons to whom the Software is furnished to do so,
    # subject to the following conditions:
    #
    # The above copyright notice and this permission notice shall be
    # included in all copies or substantial portions of the Software.
    #
    # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    # NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
    # BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
    # ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    # SOFTWARE.
    #
    ################################################################################



    # Disallow undefined variables
    set -u


    default_gcc_version=4.2
    default_iphoneos_version=6.0
    default_macos_version=10.8
    default_architecture=armv7
    default_prefix="${HOME}/Documents/iOS_GDAL"

    GCC_VERSION="${GCC_VERSION:-$default_gcc_version}"
    export IPHONEOS_DEPLOYMENT_TARGET="${IPHONEOS_DEPLOYMENT_TARGET:-$default_iphoneos_version}"
    export MACOSX_DEPLOYMENT_TARGET="${MACOSX_DEPLOYMENT_TARGET:-$default_macos_version}"
    DEFAULT_ARCHITECTURE="${DEFAULT_ARCHITECTURE:-$default_architecture}"
    DEFAULT_PREFIX="${HOME}/Documents/iOS_GDAL"

    echo Default architecture: $DEFAULT_ARCHITECTURE

    usage ()
    {
        cat >&2 << EOF
    Usage: ${0##*/} [-ht] [-p prefix] [-a arch] target [configure_args]
        -h  Print help message
        -p  Installation prefix (default: \$HOME/Documents/iOS_GDAL...)
        -t  Use 16-bit Thumb instruction set (instead of 32-bit ARM)
        -a  Architecture target for compilation (default: armv7)

    The target must be "device" or "simulator".  Any additional arguments
    are passed to configure.

    The following environment variables affect the build process:

        GCC_VERSION (default: $default_gcc_version)
        IPHONEOS_DEPLOYMENT_TARGET  (default: $default_iphoneos_version)
        MACOSX_DEPLOYMENT_TARGET    (default: $default_macos_version)
        DEFAULT_PREFIX  (default: $default_prefix)
    EOF
    }

    prefix="${DEFAULT_PREFIX}"

    echo Prefix: $prefix

    while getopts ":hp:a:t" opt; do
        case $opt in
        h  ) usage ; exit 0 ;;
        p  ) prefix="$OPTARG" ;;
        t  ) thumb_opt=thumb ;;
        a  ) DEFAULT_ARCHITECTURE="$OPTARG" ;;
        \? ) usage ; exit 2 ;;
        esac
    done
    shift $(( $OPTIND - 1 ))

    if (( $# < 1 )); then
        usage
        exit 2
    fi

    target=$1
    shift

    case $target in

        device )
        arch="${DEFAULT_ARCHITECTURE}"
        platform=iPhoneOS
        extra_cflags="-m${thumb_opt:-no-thumb} -mthumb-interwork"
        ;;

        simulator )
        arch=i386
        platform=iPhoneSimulator
        extra_cflags="-D__IPHONE_OS_VERSION_MIN_REQUIRED=${IPHONEOS_DEPLOYMENT_TARGET%%.*}0000"
        ;;

        * )
        echo No target found!!!
        usage
        exit 2

    esac


    platform_dir="/Applications/Xcode.app/Contents/Developer/Platforms/${platform}.platform/Developer"
    platform_bin_dir="${platform_dir}/usr/llvm-gcc-${GCC_VERSION}/bin"
    platform_sdk_dir="${platform_dir}/SDKs/${platform}${IPHONEOS_DEPLOYMENT_TARGET}.sdk"
    prefix="${prefix}/${arch}/${platform}.platform/${platform}${IPHONEOS_DEPLOYMENT_TARGET}.sdk"

    echo library will be exported to $prefix

    export CC="${platform_bin_dir}/llvm-gcc-${GCC_VERSION}"
    export CFLAGS="-arch ${arch} -pipe -Os -gdwarf-2 -isysroot ${platform_sdk_dir} ${extra_cflags}"
    export LDFLAGS="-arch ${arch} -isysroot ${platform_sdk_dir}"
    export CXX="${platform_bin_dir}/llvm-g++-${GCC_VERSION}"
    export CXXFLAGS="${CFLAGS}"
    export CPP="${platform_bin_dir}/llvm-cpp-${GCC_VERSION}"
    export CXXCPP="${CPP}"


    ./configure \
        --prefix="${prefix}" \
        --host="${arch}-apple-darwin" \
        --disable-shared \
        --enable-static \
        --with-unix-stdio-64=no \
        "$@" || exit

    make install || exit

    cat >&2 << EOF

    Build succeeded!  Files were installed in

      $prefix


   EOF

请注意,此脚本有一些默认参数,您可以更改这些参数以反映SDK或LLVM Apple编译器中的首选项或更改:

• default_gcc_version = 4.2
• default_iphoneos_version = 6.0
• default_macos_version = 10.8
• default_architecture = ARMv7的
• default_prefix = "$ {HOME} /文档/ GDALLibrary"

现在正在为多种架构构建

使用前面的脚本(build_gdal_ios.sh)允许您一次构建一个体系结构...您需要编译3,然后将所有这些库集中在一个静态库文件下.

以下脚本只允许(将其保存为另一个名称,如build_gdal_all_ios.sh):

#!/bin/bash
make clean
./build_gdal_ios.sh -p ${HOME}/Documents/GDALLibrary -a armv7 device
make clean
./build_gdal_ios.sh -p ${HOME}/Documents/GDALLibrary -a armv7s device
make clean
./build_gdal_ios.sh -p ${HOME}/Documents/GDALLibrary simulator

运行此脚本后,您的库将保存在子文件夹的$ {HOME}/Documents/GDALLibrary目录中:

• $ {HOME} /Documents/GDALLibrary/i386/iPhoneSimulator.platform/iPhoneSimulator6.0.sdk/lib
• $ {HOME} /Documents/GDALLibrary/armv7/iPhoneOS.platform/iPhoneSimulator6.0.sdk/lib
• $ {HOME} /Documents/GDALLibrary/armv7s/iPhoneOS.platform/iPhoneSimulator6.0.sdk/lib

您现在可以使用可执行脂肪(用于吸脂术)将3个库连接成一个,如下所示:

lipo ${HOME}/Documents/GDALLibrary/i386/iPhoneSimulator.platform/iPhoneSimulator6.0.sdk/lib/libgdal.a ${HOME}/Documents/GDALLibrary/armv7/iPhoneOS.platform/iPhoneSimulator6.0.sdk/lib/libgdal.a ${HOME}/Documents/GDALLibrary/armv7s/iPhoneOS.platform/iPhoneSimulator6.0.sdk/lib/libgdal.a -output ${HOME}/Documents/GDALLibrary/libgdal.a -create

......你做完了......

将静态库添加到XCode项目

这一步非常简单:

1. 在Xcode(4.5)中创建一个新项目或打开要添加GDAL的项目
2. 在文件资源管理器中右键单击并选择"将文件添加到项目"
3. 选择上面创建的libgdal.a以及其中一个include目录中的include文件(3个目录包含相同的文件)
4. 将以下库添加到XCode项目中(从项目框架列表中):
   • 的libstdc ++.6.0.9.dylib
   • libz.dylib
   • libiconv.dylib
   • libsqlite3.dylib
   • libxml2.dylib(如果架构armv7的未定义符号:"_ xmlCatalogResolveSystem"等)

构建代码.所有人都应该顺利编译.

开始编码

这里有一个技巧:您在Objective-C环境中使用C++库(和头文件).如果将一个GDAL头文件包含到.m文件中,XCode会抱怨C++语法.

这里有两个解决方案:

1. 将所有GDAL代码写入.mm文件中,然后Xcode将其识别为Objective-C++文件并进行编译
2. 在Phil Jordan的优秀文章Mixing Objective-C++和C++中描述的Objective-C文件中使用类扩展

有一次,我将发布一些GDAL代码示例...但稍后......