Rectangle 27 0

android How to cache bitmaps into native memory?


#include <jni.h>
#include <jni.h>
#include <android/log.h>
#include <stdio.h>
#include <android/bitmap.h>
#include <cstring>
#include <unistd.h>

#define  LOG_TAG    "DEBUG"
#define  LOGD(...)  __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__)
#define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)

extern "C"
  {
  JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniStoreBitmapData(JNIEnv * env, jobject obj, jobject bitmap);
  JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniGetBitmapFromStoredBitmapData(JNIEnv * env, jobject obj, jobject handle);
  JNIEXPORT void JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniFreeBitmapData(JNIEnv * env, jobject obj, jobject handle);
  }

class JniBitmap
  {
  public:
    uint32_t* _storedBitmapPixels;
    AndroidBitmapInfo _bitmapInfo;
    JniBitmap()
      {
      _storedBitmapPixels = NULL;
      }
  };

JNIEXPORT void JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniFreeBitmapData(JNIEnv * env, jobject obj, jobject handle)
  {
  JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
  if (jniBitmap->_storedBitmapPixels == NULL)
    return;
  delete[] jniBitmap->_storedBitmapPixels;
  jniBitmap->_storedBitmapPixels = NULL;
  delete jniBitmap;
  }

JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniGetBitmapFromStoredBitmapData(JNIEnv * env, jobject obj, jobject handle)
  {
  JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
  if (jniBitmap->_storedBitmapPixels == NULL)
    {
    LOGD("no bitmap data was stored. returning null...");
    return NULL;
    }
  //
  //creating a new bitmap to put the pixels into it - using Bitmap Bitmap.createBitmap (int width, int height, Bitmap.Config config) :
  //
  //LOGD("creating new bitmap...");
  jclass bitmapCls = env->FindClass("android/graphics/Bitmap");
  jmethodID createBitmapFunction = env->GetStaticMethodID(bitmapCls, "createBitmap", "(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;");
  jstring configName = env->NewStringUTF("ARGB_8888");
  jclass bitmapConfigClass = env->FindClass("android/graphics/Bitmap$Config");
  jmethodID valueOfBitmapConfigFunction = env->GetStaticMethodID(bitmapConfigClass, "valueOf", "(Ljava/lang/String;)Landroid/graphics/Bitmap$Config;");
  jobject bitmapConfig = env->CallStaticObjectMethod(bitmapConfigClass, valueOfBitmapConfigFunction, configName);
  jobject newBitmap = env->CallStaticObjectMethod(bitmapCls, createBitmapFunction, jniBitmap->_bitmapInfo.height, jniBitmap->_bitmapInfo.width, bitmapConfig);
  //
  // putting the pixels into the new bitmap:
  //
  int ret;
  void* bitmapPixels;
  if ((ret = AndroidBitmap_lockPixels(env, newBitmap, &bitmapPixels)) < 0)
    {
    LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);
    return NULL;
    }
  uint32_t* newBitmapPixels = (uint32_t*) bitmapPixels;
  int pixelsCount = jniBitmap->_bitmapInfo.height * jniBitmap->_bitmapInfo.width;
  memcpy(newBitmapPixels, jniBitmap->_storedBitmapPixels, sizeof(uint32_t) * pixelsCount);
  AndroidBitmap_unlockPixels(env, newBitmap);
  //LOGD("returning the new bitmap");
  return newBitmap;
  }

JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniStoreBitmapData(JNIEnv * env, jobject obj, jobject bitmap)
  {
  AndroidBitmapInfo bitmapInfo;
  uint32_t* storedBitmapPixels = NULL;
  //LOGD("reading bitmap info...");
  int ret;
  if ((ret = AndroidBitmap_getInfo(env, bitmap, &bitmapInfo)) < 0)
    {
    LOGE("AndroidBitmap_getInfo() failed ! error=%d", ret);
    return NULL;
    }
  LOGD("width:%d height:%d stride:%d", bitmapInfo.width, bitmapInfo.height, bitmapInfo.stride);
  if (bitmapInfo.format != ANDROID_BITMAP_FORMAT_RGBA_8888)
    {
    LOGE("Bitmap format is not RGBA_8888!");
    return NULL;
    }
  //
  //read pixels of bitmap into native memory :
  //
  //LOGD("reading bitmap pixels...");
  void* bitmapPixels;
  if ((ret = AndroidBitmap_lockPixels(env, bitmap, &bitmapPixels)) < 0)
    {
    LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);
    return NULL;
    }
  uint32_t* src = (uint32_t*) bitmapPixels;
  storedBitmapPixels = new uint32_t[bitmapInfo.height * bitmapInfo.width];
  int pixelsCount = bitmapInfo.height * bitmapInfo.width;
  memcpy(storedBitmapPixels, src, sizeof(uint32_t) * pixelsCount);
  AndroidBitmap_unlockPixels(env, bitmap);
  JniBitmap *jniBitmap = new JniBitmap();
  jniBitmap->_bitmapInfo = bitmapInfo;
  jniBitmap->_storedBitmapPixels = storedBitmapPixels;
  return env->NewDirectByteBuffer(jniBitmap, 0);
  }
LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := JniBitmapStorageTest
LOCAL_SRC_FILES := JniBitmapStorageTest.cpp
LOCAL_LDLIBS := -llog
LOCAL_LDFLAGS += -ljnigraphics

include $(BUILD_SHARED_LIBRARY)
APP_OPTIM := debug
LOCAL_CFLAGS := -g
package com.example.jnibitmapstoragetest;
...
public class JniBitmapHolder
  {
  ByteBuffer _handler =null;
  static
    {
    System.loadLibrary("JniBitmapStorageTest");
    }

  private native ByteBuffer jniStoreBitmapData(Bitmap bitmap);

  private native Bitmap jniGetBitmapFromStoredBitmapData(ByteBuffer handler);

  private native void jniFreeBitmapData(ByteBuffer handler);

  public JniBitmapHolder()
    {}

  public JniBitmapHolder(final Bitmap bitmap)
    {
    storeBitmap(bitmap);
    }

  public void storeBitmap(final Bitmap bitmap)
    {
    if(_handler!=null)
      freeBitmap();
    _handler=jniStoreBitmapData(bitmap);
    }

  public Bitmap getBitmap()
    {
    if(_handler==null)
      return null;
    return jniGetBitmapFromStoredBitmapData(_handler);
    }

  public Bitmap getBitmapAndFree()
    {
    final Bitmap bitmap=getBitmap();
    freeBitmap();
    return bitmap;
    }

  public void freeBitmap()
    {
    if(_handler==null)
      return;
    jniFreeBitmapData(_handler);
    _handler=null;
    }

  @Override
  protected void finalize() throws Throwable
    {
    super.finalize();
    if(_handler==null)
      return;
    Log.w("DEBUG","JNI bitmap wasn't freed nicely.please rememeber to free the bitmap as soon as you can");
    freeBitmap();
    }
  }

Thanks for reply. What i have to change if i make ur project as library project and include it in my app. like pkg name or path?

Yes, github project working fine. so i want to include it with my project and i tried both ways converted sample project in library and in android tag i included it. it is not showing any error on compile time but on run time ExceptionInInitializerError. I think problem is here System.loadLibrary("JniBitmapOperations"); or may b its packeg name problem. I never used ndk.how to implement it?

You will need to do some research on this. please continue the comments where you started it instead of multiple places. however, you are correct that the package is important, as the code in the C/C++ side assumes about their paths.

as you might guess, the layout has 2 imageViews. i didn't include it in the code since it's quite obvious.

depends on what you do with it (in which package you put it).

is it your first time of importing an android library, or do you have a specific problem with this one in particular? if there is a problem with this one, you can just copy its files to your project, change the packages paths inside all files (especially the C/C++ files) , and it should work fine.

the sample code shows how to store 2 different bitmaps (small ones, but it's just a demo), recycle the original java ones, and later restore them to java instances and use them.

Note
Rectangle 27 0

android How to cache bitmaps into native memory?


#include <jni.h>
#include <jni.h>
#include <android/log.h>
#include <stdio.h>
#include <android/bitmap.h>
#include <cstring>
#include <unistd.h>

#define  LOG_TAG    "DEBUG"
#define  LOGD(...)  __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__)
#define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)

extern "C"
  {
  JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniStoreBitmapData(JNIEnv * env, jobject obj, jobject bitmap);
  JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniGetBitmapFromStoredBitmapData(JNIEnv * env, jobject obj, jobject handle);
  JNIEXPORT void JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniFreeBitmapData(JNIEnv * env, jobject obj, jobject handle);
  }

class JniBitmap
  {
  public:
    uint32_t* _storedBitmapPixels;
    AndroidBitmapInfo _bitmapInfo;
    JniBitmap()
      {
      _storedBitmapPixels = NULL;
      }
  };

JNIEXPORT void JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniFreeBitmapData(JNIEnv * env, jobject obj, jobject handle)
  {
  JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
  if (jniBitmap->_storedBitmapPixels == NULL)
    return;
  delete[] jniBitmap->_storedBitmapPixels;
  jniBitmap->_storedBitmapPixels = NULL;
  delete jniBitmap;
  }

JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniGetBitmapFromStoredBitmapData(JNIEnv * env, jobject obj, jobject handle)
  {
  JniBitmap* jniBitmap = (JniBitmap*) env->GetDirectBufferAddress(handle);
  if (jniBitmap->_storedBitmapPixels == NULL)
    {
    LOGD("no bitmap data was stored. returning null...");
    return NULL;
    }
  //
  //creating a new bitmap to put the pixels into it - using Bitmap Bitmap.createBitmap (int width, int height, Bitmap.Config config) :
  //
  //LOGD("creating new bitmap...");
  jclass bitmapCls = env->FindClass("android/graphics/Bitmap");
  jmethodID createBitmapFunction = env->GetStaticMethodID(bitmapCls, "createBitmap", "(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;");
  jstring configName = env->NewStringUTF("ARGB_8888");
  jclass bitmapConfigClass = env->FindClass("android/graphics/Bitmap$Config");
  jmethodID valueOfBitmapConfigFunction = env->GetStaticMethodID(bitmapConfigClass, "valueOf", "(Ljava/lang/String;)Landroid/graphics/Bitmap$Config;");
  jobject bitmapConfig = env->CallStaticObjectMethod(bitmapConfigClass, valueOfBitmapConfigFunction, configName);
  jobject newBitmap = env->CallStaticObjectMethod(bitmapCls, createBitmapFunction, jniBitmap->_bitmapInfo.height, jniBitmap->_bitmapInfo.width, bitmapConfig);
  //
  // putting the pixels into the new bitmap:
  //
  int ret;
  void* bitmapPixels;
  if ((ret = AndroidBitmap_lockPixels(env, newBitmap, &bitmapPixels)) < 0)
    {
    LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);
    return NULL;
    }
  uint32_t* newBitmapPixels = (uint32_t*) bitmapPixels;
  int pixelsCount = jniBitmap->_bitmapInfo.height * jniBitmap->_bitmapInfo.width;
  memcpy(newBitmapPixels, jniBitmap->_storedBitmapPixels, sizeof(uint32_t) * pixelsCount);
  AndroidBitmap_unlockPixels(env, newBitmap);
  //LOGD("returning the new bitmap");
  return newBitmap;
  }

JNIEXPORT jobject JNICALL Java_com_example_jnibitmapstoragetest_JniBitmapHolder_jniStoreBitmapData(JNIEnv * env, jobject obj, jobject bitmap)
  {
  AndroidBitmapInfo bitmapInfo;
  uint32_t* storedBitmapPixels = NULL;
  //LOGD("reading bitmap info...");
  int ret;
  if ((ret = AndroidBitmap_getInfo(env, bitmap, &bitmapInfo)) < 0)
    {
    LOGE("AndroidBitmap_getInfo() failed ! error=%d", ret);
    return NULL;
    }
  LOGD("width:%d height:%d stride:%d", bitmapInfo.width, bitmapInfo.height, bitmapInfo.stride);
  if (bitmapInfo.format != ANDROID_BITMAP_FORMAT_RGBA_8888)
    {
    LOGE("Bitmap format is not RGBA_8888!");
    return NULL;
    }
  //
  //read pixels of bitmap into native memory :
  //
  //LOGD("reading bitmap pixels...");
  void* bitmapPixels;
  if ((ret = AndroidBitmap_lockPixels(env, bitmap, &bitmapPixels)) < 0)
    {
    LOGE("AndroidBitmap_lockPixels() failed ! error=%d", ret);
    return NULL;
    }
  uint32_t* src = (uint32_t*) bitmapPixels;
  storedBitmapPixels = new uint32_t[bitmapInfo.height * bitmapInfo.width];
  int pixelsCount = bitmapInfo.height * bitmapInfo.width;
  memcpy(storedBitmapPixels, src, sizeof(uint32_t) * pixelsCount);
  AndroidBitmap_unlockPixels(env, bitmap);
  JniBitmap *jniBitmap = new JniBitmap();
  jniBitmap->_bitmapInfo = bitmapInfo;
  jniBitmap->_storedBitmapPixels = storedBitmapPixels;
  return env->NewDirectByteBuffer(jniBitmap, 0);
  }
LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := JniBitmapStorageTest
LOCAL_SRC_FILES := JniBitmapStorageTest.cpp
LOCAL_LDLIBS := -llog
LOCAL_LDFLAGS += -ljnigraphics

include $(BUILD_SHARED_LIBRARY)
APP_OPTIM := debug
LOCAL_CFLAGS := -g
package com.example.jnibitmapstoragetest;
...
public class JniBitmapHolder
  {
  ByteBuffer _handler =null;
  static
    {
    System.loadLibrary("JniBitmapStorageTest");
    }

  private native ByteBuffer jniStoreBitmapData(Bitmap bitmap);

  private native Bitmap jniGetBitmapFromStoredBitmapData(ByteBuffer handler);

  private native void jniFreeBitmapData(ByteBuffer handler);

  public JniBitmapHolder()
    {}

  public JniBitmapHolder(final Bitmap bitmap)
    {
    storeBitmap(bitmap);
    }

  public void storeBitmap(final Bitmap bitmap)
    {
    if(_handler!=null)
      freeBitmap();
    _handler=jniStoreBitmapData(bitmap);
    }

  public Bitmap getBitmap()
    {
    if(_handler==null)
      return null;
    return jniGetBitmapFromStoredBitmapData(_handler);
    }

  public Bitmap getBitmapAndFree()
    {
    final Bitmap bitmap=getBitmap();
    freeBitmap();
    return bitmap;
    }

  public void freeBitmap()
    {
    if(_handler==null)
      return;
    jniFreeBitmapData(_handler);
    _handler=null;
    }

  @Override
  protected void finalize() throws Throwable
    {
    super.finalize();
    if(_handler==null)
      return;
    Log.w("DEBUG","JNI bitmap wasn't freed nicely.please rememeber to free the bitmap as soon as you can");
    freeBitmap();
    }
  }

Thanks for reply. What i have to change if i make ur project as library project and include it in my app. like pkg name or path?

Yes, github project working fine. so i want to include it with my project and i tried both ways converted sample project in library and in android tag i included it. it is not showing any error on compile time but on run time ExceptionInInitializerError. I think problem is here System.loadLibrary("JniBitmapOperations"); or may b its packeg name problem. I never used ndk.how to implement it?

You will need to do some research on this. please continue the comments where you started it instead of multiple places. however, you are correct that the package is important, as the code in the C/C++ side assumes about their paths.

as you might guess, the layout has 2 imageViews. i didn't include it in the code since it's quite obvious.

depends on what you do with it (in which package you put it).

is it your first time of importing an android library, or do you have a specific problem with this one in particular? if there is a problem with this one, you can just copy its files to your project, change the packages paths inside all files (especially the C/C++ files) , and it should work fine.

the sample code shows how to store 2 different bitmaps (small ones, but it's just a demo), recycle the original java ones, and later restore them to java instances and use them.

Note