專案中Opencv需要顯示中文，由於本身並不支援，所以需要藉助第三方的庫freetype來實現。這個庫雖然android本身也有使用，但並沒有暴露介面給外部使用。

編譯環境

• wsl ubuntu 20.04
• freetype 2.10.4
• ndk-r17c

freetype下載地址，這裡使用最新版本2.10.4

arm64-v8a編譯指令碼

#!/bin/bash
make clean

NDK=/mnt/e/Android/android-ndk-r17c-linux-x86_64/android-ndk-r17c
TOOLCHAIN=$NDK/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64
SYSROOT=$NDK/platforms/android-21/arch-arm64

CPU=armv64-v8a
PREFIX=$(pwd)/android/$CPU

function build
{
./configure \
--host=aarch64-linux-android \
--prefix=$PREFIX \
--enable-shared \
--enable-static \
--with-zlib=no \
--with-bzip2=no \
--with-png=no \
--with-harfbuzz=no \
--with-sysroot=$SYSROOT \

make -j8
make install
}

build
 

編譯過程：

注意別忘了加make install, 否則不會把生成的庫拷貝到Prefix目錄中。

當然也可以同時編譯arm和arm64-v8a, 參考地址

#!/bin/bash
NDK=/mnt/e/Android/android-ndk-r17c-linux-x86_64/android-ndk-r17c
function configure
{   
     CPU=$1
     PREFIX=$(pwd)/android/$CPU
     TOOLCHAIN=""
     SYSROOT=""
     HOST=""
     if [ "$CPU" == "armv7a" ]
     then
         TOOLCHAIN=$NDK/toolchains/arm-linux-android-4.9/prebuilt/linux-x86_64
         SYSROOT=$NDK/platforms/android-21/arch-arm/
         HOST=arm-linux-androideabi
     else
         TOOLCHAIN=$NDK/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64
         SYSROOT=$NDK/platforms/android-21/arch-arm64/
         HOST=aarch64-linux-android
     fi
     export PATH=$TOOLCHAIN:$PATH
     ./configure \
     --with-png=no \
     --with-zlib=no \
     --host=$HOST \
     --prefix=$PREFIX \
     --with-sysroot=$SYSROOT
}


build()
{
     make clean
     cpu=$1
     echo "build $cpu"
    
     configure $cpu
     echo "configure done. CFLAGS:$CFLAGS\n PATH:$PATH"
     echo "start make..."

     make -j8
     echo "make done."
     echo "start make install..."
     make install
     echo "make install done."
}

build arm64
build armv7a
 

編譯生成的目標庫