Use Pngquant Lib (libimagequant) In Android Ndk

I am trying to use the png quantization library at pngquant.org/lib in my Android project using the NDK r10 (64bit) on OS X. I am making progress in compiling the library. The prob

Solution 1:

I don't have enough information to directly solve your specific problem, are you trying to use the standalone toolchain ?

When building for Android, since you have more than one architecture to target and the toolchain is a bit complex, it's better to use the ndk-build script from the NDK.

I've made a project here that you can integrate to your Android project directory: https://github.com/android-native-libraries/pngquant-android

The original library is using configure script but instead of extending these I've rewritten NDK Makefiles to directly compile all the lib sources, with the same cflags (openmp, sse...)

Android.mk:

LOCAL_PATH := $(call my-dir)

SRC_PATH := pngquant/lib

include$(CLEAR_VARS)
LOCAL_MODULE := imagequant
LOCAL_SRC_FILES := \
    $(SRC_PATH)/blur.c \
    $(SRC_PATH)/libimagequant.c \
    $(SRC_PATH)/mediancut.c \
    $(SRC_PATH)/mempool.c \
    $(SRC_PATH)/nearest.c \
    $(SRC_PATH)/pam.c \
    $(SRC_PATH)/viter.c 

LOCAL_C_INCLUDES := pngquant/lib

LOCAL_CFLAGS += -O3 -fno-math-errno -funroll-loops -fomit-frame-pointer -Wall -std=c99 -fopenmp
LOCAL_LDFLAGS += -fopenmp

ifeq ($(TARGET_ARCH_ABI),x86)
    LOCAL_CFLAGS += -mtune=atom -msse -mfpmath=sse -mssse3 -DUSE_SSE=1
endifinclude$(BUILD_SHARED_LIBRARY)

You can extend this Android.mk file to add your own native library with your sources, that are using libimagequant: include $(CLEAR_VARS) LOCAL_MODULE := yourlib LOCAL_SRC_FILES := yoursources.c LOCAL_C_INCLUDES := pngquant/lib LOCAL_SHARED_LIBRARIES := imagequant

LOCAL_CFLAGS += -O3 -fno-math-errno -funroll-loops -fomit-frame-pointer -Wall -std=c99 -fopenmp
LOCAL_LDFLAGS += -fopenmp

ifeq ($(TARGET_ARCH_ABI),x86)
    LOCAL_CFLAGS += -mtune=atom -msse -mfpmath=sse -mssse3 -DUSE_SSE=1
endifinclude$(BUILD_SHARED_LIBRARY)

Solution 2:

If you just want to use this library with default settings, I've made a simple Android library that may suit your purposes.

In your build.gradle:

dependencies {
    compile'com.ndahlquist:pngquant-android:0.2'
}

In your Android app:

FileinputPngFile= getYourPng();
FileoutputPngFile= getOutputFile()
newLibPngQuant().pngQuantFile(inputFile, outputFile);