为android编译python的图像库pillow

    Pillow是python的图像处理库，可以从github下载。pillow中部分代码使用C编写，如果需要在android环境中使用，则需要编译为android的共享库。编译过程与编译环境相关，这里使用redhat
7.0，已经安装了python 2.7，android的ndk。

 
Pillow使用了jpeg, png, freetype库，首先需要编译它们为静态库.

1.编译jpeg,png,freetype为静态库

    jpeg使用版本jpegsrc.v9b；png使用版本libpng-1.6.26

    a.首先设置交叉编译环境

export ANDROID_NDK="/usr/local/android/android-ndk-r10d"

export PATH="$ANDROID_NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/:$ANDROID_NDK:$ANDROID_NDK/tools:/usr/local/bin:/usr/bin:/bin:$PATH"

export ARCH="armeabi"

export CFLAGS="-DANDROID -mandroid -fomit-frame-pointer --sysroot=$ANDROID_NDK/platforms/android-9/arch-arm"

export CXXFLAGS="$CFLAGS"

export CC="arm-linux-androideabi-gcc $CFLAGS"

export CXX="arm-linux-androideabi-g++ $CXXFLAGS"

export AR="arm-linux-androideabi-ar"

export RANLIB="arm-linux-androideabi-ranlib"

export STRIP="arm-linux-androideabi-strip --strip-unneeded"

export READELF="arm-linux-androideabi-readelf"

export MAKE="make -j4 CROSS_COMPILE_TARGET=yes"

export LAPACK=

    b. 编译jpeg

    解压jpegsrc.v9b.tar.gz

./configure LDFLAGS="-llog -lm" CFLAGS="-mandroid -fomit-frame-pointer -Wno-format" --disable-shared --host=arm-linux --build=i686-pc-linux-gnu --prefix="/usr/local/android/install/jpeg9b.armeabi"
make
make install

    c. 编译png

    解压libpng-1.6.26.tar.gz

./configure LDFLAGS="-llog -lm" CFLAGS="-mandroid -fomit-frame-pointer -Wno-format" --disable-shared --host=arm-linux --build=i686-pc-linux-gnu --prefix="/usr/local/android/install/libpng1626.armeabi"
make
make install

    d. 编译freetype

    解压freetype-2.6.5.tar.gz

./configure LDFLAGS="-llog -lm" LIBPNG_LIBS="-L/usr/local/android/install/libpng1626.armeabi/lib" CFLAGS="-mandroid -fomit-frame-pointer -Wno-format" LIBPNG_CFLAGS="-I/usr/local/android/install/libpng1626.armeabi/include" --disable-shared --host=arm-linux --build=i686-pc-linux-gnu --prefix="/usr/local/android/install/freetype265.armeabi"
make
make install

2. 编译pillow

    从github下载pillow，解压Pillow-master.zip
    打补丁：patch -p0 -i pillow-master.android.patch,

Pillow版本不同可能需要修改补丁，可参照修改
   

diff -ruN ../version/Pillow-master/setup.py Pillow-master/setup.py
--- ../version/Pillow-master/setup.py	2016-11-02 01:10:30.000000000 +0800
+++ Pillow-master/setup.py	2016-11-03 20:27:54.905900300 +0800
@@ -182,6 +182,7 @@
library_dirs = []
include_dirs = []

+        self.compiler.linker_so[0] = os.environ.get('CC')
_add_directory(include_dirs, "libImaging")

#
@@ -380,7 +381,9 @@
# between Python PYD stub libs and real libraries

self.compiler.library_dirs = library_dirs + self.compiler.library_dirs
-        self.compiler.include_dirs = include_dirs + self.compiler.include_dirs
+        self.compiler.include_dirs = include_dirs # + self.compiler.include_dirs
+        self.compiler.include_dirs.remove('/usr/local/include')
+        self.compiler.include_dirs.remove('/usr/include')

#
# look for available libraries
@@ -395,7 +398,8 @@
elif (sys.platform == "win32" and
_find_library_file(self, "zlib")):
feature.zlib = "zlib"  # alternative name
-
+        feature.zlib = "z"  #====================
+
if feature.want('jpeg'):
_dbg('Looking for jpeg')
if _find_include_file(self, "jpeglib.h"):
@@ -559,7 +563,7 @@
exts = [(Extension("PIL._imaging",
files,
libraries=libs,
-                           define_macros=defs))]
+                           define_macros=defs,extra_link_args = ['-Wl,-soname,_imaging.so']))]

#
# additional libraries
@@ -567,7 +571,7 @@
if feature.freetype:
exts.append(Extension("PIL._imagingft",
["_imagingft.c"],
-                                  libraries=["freetype"]))
+                                  libraries=["freetype","png"],extra_link_args = ['-Wl,-soname,_imagingft.so']))

if feature.lcms:
extra = []
@@ -575,7 +579,7 @@
extra.extend(["user32", "gdi32"])
exts.append(Extension("PIL._imagingcms",
["_imagingcms.c"],
-                                  libraries=[feature.lcms] + extra))
+                                  libraries=[feature.lcms] + extra,extra_link_args = ['-Wl,-soname,_imagingcms.so']))

if feature.webp:
libs = [feature.webp]
@@ -589,7 +593,7 @@
exts.append(Extension("PIL._webp",
["_webp.c"],
libraries=libs,
-                                  define_macros=defs))
+                                  define_macros=defs,extra_link_args = ['-Wl,-soname,_webp.so']))

tk_libs = ['psapi'] if sys.platform == 'win32' else []
exts.append(Extension("PIL._imagingtk",
@@ -597,8 +601,8 @@
include_dirs=['Tk'],
libraries=tk_libs))

-        exts.append(Extension("PIL._imagingmath", ["_imagingmath.c"]))
-        exts.append(Extension("PIL._imagingmorph", ["_imagingmorph.c"]))
+        exts.append(Extension("PIL._imagingmath", ["_imagingmath.c"],extra_link_args = ['-Wl,-soname,_imagingmath.so']))
+        exts.append(Extension("PIL._imagingmorph", ["_imagingmorph.c"],extra_link_args = ['-Wl,-soname,_imagingmorph.so']))

self.extensions[:] = exts

    编译需要python头文件,下载starcore_for_android,解压到pillow同级目录
   


    使用python2.7编译，首先设置交叉编译环境

export ANDROID_NDK="/usr/local/android/android-ndk-r10d"

export PATH="$ANDROID_NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin/:$ANDROID_NDK:$ANDROID_NDK/tools:/usr/local/bin:/usr/bin:/bin:$PATH"

export ARCH="armeabi"

export CFLAGS="-DANDROID -mandroid -fomit-frame-pointer --sysroot=$ANDROID_NDK/platforms/android-9/arch-arm -I../starcore_for_android.2.5.1/python.files/python-2.7/armeabi/include/python2.7 -I/usr/local/android/install/jpeg9b.armeabi/include  -I/usr/local/android/install/freetype265.armeabi/include"

export CXXFLAGS="$CFLAGS"

export CC="arm-linux-androideabi-gcc"

export LDFLAGS="-lm -L../starcore_for_android.2.5.1/python.files/python-2.7/armeabi  -L/usr/local/android/install/jpeg9b.armeabi/lib -L/usr/local/android/install/freetype265.armeabi/lib  -L/usr/local/android/install/libpng1626.armeabi/lib"

export CXX="arm-linux-androideabi-g++"

export AR="arm-linux-androideabi-ar"

export RANLIB="arm-linux-androideabi-ranlib"

export STRIP="arm-linux-androideabi-strip --strip-unneeded"

export READELF="arm-linux-androideabi-readelf"

export MAKE="make -j4 CROSS_COMPILE_TARGET=yes"

export LAPACK=

     运行python setup.py build
    编译结果在
Pillow-master/build/lib.linux-x86_64-2.7
    将PIL打包成zip，既可以在android应用中使用

3.测试pillow

   测试使用eclipse开发，可以导入到android
studio
   将PIL.zip放到assets目录，在app中将其解压到"/data/data/"+getPackageName()+"/files"。
   在assets中创建test.py，在app中将test.py拷贝到"/data/data/"+getPackageName()+"/files"。
   

import os, sys
import traceback
try:
from PIL import Image
print(Image)
print(AppPath)

im=Image.open(AppPath+"/dir.jpg")
print(im.size)
print(im.mode)
print("===end===")

except Exception,e:
traceback.print_exc()

    加载test.py

python._Set("AppPath", "/data/data/"+getPackageName()+"/files");
Service._DoFile("python", "/data/data/"+getPackageName()+"/files/test.py", "");

    关于android中使用python，请参考之前的文章
    示例下载