Feature Request: Support for Android 16KB Memory Page Alignment

[shinya-terasaki]

Hello,

Thank you for providing the library. It is helpful so much since Skia supports poor PNG features.

May I ask a thing, do you have any plan to support Android 16KB page alignment?

You may notice that Android requires to update memory page alignment from 4KB to 16KB.

Starting November 1st, 2025, all new apps and updates to existing apps submitted to Google Play and targeting Android 15+ devices must support 16 KB page sizes.

https://developer.android.com/guide/practices/page-sizes

It would be beneficial (particulary for me) to update the android-arm64 binary to ensure compatibility with the new requirements.

Could you please consider adding support for 16KB page alignment in the library as well as in the Hexa.NET.ZLib?

Thank you!

[JunaMeinhold]

Hi, I will do that, but i have a surgery tomorrow and i will probably need a month for recovery and i can't give you a approximate time frame when it's done.

[JunaMeinhold]

Meanwhile, you can try building the Android library yourself with the alignment set

You can find the build process here https://github.com/HexaEngine/Hexa.NET.Libpng/actions/workflows/cmake-android.yml

[shinya-terasaki]

Thank you for your reply. I'm going to try building by myself. Please take care of you.

[shinya-terasaki]

Hello,

I could confirm that the self built binaries are compliant with 16KB paging and worked fine on the actual Android device.

libpng.so
02:39:38       LOAD off    0x0000000000000000 vaddr 0x0000000000000000 paddr 0x0000000000000000 align 2**14
02:39:38       LOAD off    0x0000000000039a90 vaddr 0x000000000003da90 paddr 0x000000000003da90 align 2**14

libz.so
02:39:38       LOAD off    0x0000000000000000 vaddr 0x0000000000000000 paddr 0x0000000000000000 align 2**14
02:39:38       LOAD off    0x0000000000017ca0 vaddr 0x000000000001bca0 paddr 0x000000000001bca0 align 2**14

I've just replaced NDK as r28 default setting is 16KB alignment.
https://developer.android.com/guide/practices/page-sizes#compile-r28

For your reference:

Android SDK

wget https://dl.google.com/android/repository/commandlinetools-linux-13114758_latest.zip -O android-sdk-tools.zip
unzip android-sdk-tools.zip -d tools
mkdir $HOME/android-sdk/
mkdir $HOME/android-sdk/cmdline-tools/
mkdir $HOME/android-sdk/cmdline-tools/latest/
mv ./tools/cmdline-tools/* $HOME/android-sdk/cmdline-tools/latest/
chmod +x $HOME/android-sdk/cmdline-tools/latest/bin/*

yes | $HOME/android-sdk/cmdline-tools/latest/bin/sdkmanager --licenses

yes | $HOME/android-sdk/cmdline-tools/latest/bin/sdkmanager --install "ndk;28.1.13356709"
yes | $HOME/android-sdk/cmdline-tools/latest/bin/sdkmanager --install "build-tools;35.0.0"
yes | $HOME/android-sdk/cmdline-tools/latest/bin/sdkmanager --install "platform-tools"
yes | $HOME/android-sdk/cmdline-tools/latest/bin/sdkmanager --install "platforms;android-35"

export ANDROID_HOME=$HOME/android-sdk
export ANDROID_SDK_ROOT=$HOME/android-sdk
export ANDROID_NDK_HOME=$ANDROID_HOME/ndk/28.1.13356709
export PATH=$PATH:$ANDROID_HOME/ndk/28.1.13356709

libpng

git submodule add git@github.com:pnggroup/libpng.git libpng
pushd libpng
git checkout v1.6.47
popd

cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release -DCMAKE_SYSTEM_NAME=Android -DCMAKE_ANDROID_NDK=$ANDROID_NDK_HOME -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a -DCMAKE_ANDROID_NDK_TOOLCHAIN_VERSION=clang -S libpng -B libpng/build/arm64-v8a -Dlibpng_BUILD_TESTING=OFF -Dlibpng_BUILD_SHARED=ON -Dlibpng_BUILD_STATIC=OFF
cmake --build libpng/build/arm64-v8a --config Release

actual artifact name was libpng16.so

zlib

git submodule add git@github.com:madler/zlib.git zlib
pushd zlib
git checkout v1.3.1
popd

cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release -DCMAKE_SYSTEM_NAME=Android -DCMAKE_ANDROID_NDK=$ANDROID_NDK_HOME -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a -DCMAKE_ANDROID_NDK_TOOLCHAIN_VERSION=clang -S zlib -B zlib/build/arm64-v8a -DZLIB_BUILD_TESTING=OFF -DZLIB_BUILD_SHARED=ON -DZLIB_BUILD_STATIC=OFF
cmake --build zlib/build/arm64-v8a  --config Release

actual artifact name was libz.so