[Android]-图片JNI(C++\Java)高斯模糊的实现与比较

泡在网上的日子 / 文 发表于2014-11-15 00:58 次阅读 jni,图像处理

转自:http://blog.csdn.net/qiujuer/article/details/24282047

前几天一直在弄android上的图片模糊效果的实现!

一直找不到方法,看别人说都是调用JNI,但是JNI这个东西我还真不熟悉啊!

只好从零开始了!这里不讲JNI的平台搭建,只讲JNI的关键代码,具体的项目我会共享出来给大家!

对于JNI下使用C++来模糊图片这个我真的没找到,只好自己写C++的来实现了。

在国外的一个项目中找到了一个”堆栈模糊效果“,原型如下:

// Stack Blur v1.0
//
// Author: Mario Klingemann <mario@quasimondo.com>
// http://incubator.quasimondo.com
// created Feburary 29, 2004
// This is a compromise between Gaussian Blur and Box blur
// It creates much better looking blurs than Box Blur, but is
// 7x faster than my Gaussian Blur implementation.
//
// I called it Stack Blur because this describes best how this
// filter works internally: it creates a kind of moving stack
// of colors whilst scanning through the image. Thereby it
// just has to add one new block of color to the right side
// of the stack and remove the leftmost color. The remaining
// colors on the topmost layer of the stack are either added on
// or reduced by one, depending on if they are on the right or
// on the left side of the stack.
//
// If you are using this algorithm in your code please add
// the following line:
//
// Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>
PImage a;
PImage b;
void setup()
{
  a=loadImage("dog.jpg");
  size(a.width, a.height);
  b=new PImage(a.width, a.height);
  fill(255);
  noStroke();
  frameRate(25);
}
void draw()
{
  System.arraycopy(a.pixels,0,b.pixels,0,a.pixels.length);
  fastblur(b,mouseY/4);
  image(b, 0, 0);
}
void fastblur(PImage img,int radius){
  if (radius<1){
    return;
  }
  int[] pix=img.pixels;
  int w=img.width;
  int h=img.height;
  int wm=w-1;
  int hm=h-1;
  int wh=w*h;
  int div=radius+radius+1;
  int r[]=new int[wh];
  int g[]=new int[wh];
  int b[]=new int[wh];
  int rsum,gsum,bsum,x,y,i,p,yp,yi,yw;
  int vmin[] = new int[max(w,h)];
  int divsum=(div+1)>>1;
  divsum*=divsum;
  int dv[]=new int[256*divsum];
  for (i=0;i<256*divsum;i++){
    dv[i]=(i/divsum);
  }
  yw=yi=0;
  int[][] stack=new int[div][3];
  int stackpointer;
  int stackstart;
  int[] sir;
  int rbs;
  int r1=radius+1;
  int routsum,goutsum,boutsum;
  int rinsum,ginsum,binsum;
  for (y=0;y<h;y++){
    rinsum=ginsum=binsum=routsum=goutsum=boutsum=rsum=gsum=bsum=0;
    for(i=-radius;i<=radius;i++){
      p=pix[yi+min(wm,max(i,0))];
      sir=stack[i+radius];
      sir[0]=(p & 0xff0000)>>16;
      sir[1]=(p & 0x00ff00)>>8;
      sir[2]=(p & 0x0000ff);
      rbs=r1-abs(i);
      rsum+=sir[0]*rbs;
      gsum+=sir[1]*rbs;
      bsum+=sir[2]*rbs;
      if (i>0){
        rinsum+=sir[0];
        ginsum+=sir[1];
        binsum+=sir[2];
      } else {
        routsum+=sir[0];
        goutsum+=sir[1];
        boutsum+=sir[2];
      }
    }
    stackpointer=radius;
    for (x=0;x<w;x++){
      r[yi]=dv[rsum];
      g[yi]=dv[gsum];
      b[yi]=dv[bsum];
                                                                                 
      rsum-=routsum;
      gsum-=goutsum;
      bsum-=boutsum;
      stackstart=stackpointer-radius+div;
      sir=stack[stackstart%div];
                                                                                 
      routsum-=sir[0];
      goutsum-=sir[1];
      boutsum-=sir[2];
                                                                                 
      if(y==0){
        vmin[x]=min(x+radius+1,wm);
      }
      p=pix[yw+vmin[x]];
                                                                                 
      sir[0]=(p & 0xff0000)>>16;
      sir[1]=(p & 0x00ff00)>>8;
      sir[2]=(p & 0x0000ff);
      rinsum+=sir[0];
      ginsum+=sir[1];
      binsum+=sir[2];
      rsum+=rinsum;
      gsum+=ginsum;
      bsum+=binsum;
                                                                                 
      stackpointer=(stackpointer+1)%div;
      sir=stack[(stackpointer)%div];
                                                                                
      routsum+=sir[0];
      goutsum+=sir[1];
      boutsum+=sir[2];
                                                                                
       rinsum-=sir[0];
      ginsum-=sir[1];
      binsum-=sir[2];
                                                                                
       yi++;
    }
    yw+=w;
  }
  for (x=0;x<w;x++){
    rinsum=ginsum=binsum=routsum=goutsum=boutsum=rsum=gsum=bsum=0;
    yp=-radius*w;
    for(i=-radius;i<=radius;i++){
      yi=max(0,yp)+x;
                                                                                
       sir=stack[i+radius];
                                                                                 
      sir[0]=r[yi];
      sir[1]=g[yi];
      sir[2]=b[yi];
                                                                                
      rbs=r1-abs(i);
                                                                                 
      rsum+=r[yi]*rbs;
      gsum+=g[yi]*rbs;
      bsum+=b[yi]*rbs;
                                                                                
      if (i>0){
        rinsum+=sir[0];
        ginsum+=sir[1];
        binsum+=sir[2];
      } else {
        routsum+=sir[0];
        goutsum+=sir[1];
        boutsum+=sir[2];
      }
                                                                                 
      if(i<hm){
        yp+=w;
      }
    }
    yi=x;
    stackpointer=radius;
    for (y=0;y<h;y++){
      pix[yi]=0xff000000 | (dv[rsum]<<16) | (dv[gsum]<<8) | dv[bsum];
      rsum-=routsum;
      gsum-=goutsum;
      bsum-=boutsum;
      stackstart=stackpointer-radius+div;
      sir=stack[stackstart%div];
                                                                                
      routsum-=sir[0];
      goutsum-=sir[1];
      boutsum-=sir[2];
                                                                                
       if(x==0){
        vmin[y]=min(y+r1,hm)*w;
      }
      p=x+vmin[y];
                                                                                 
      sir[0]=r[p];
      sir[1]=g[p];
      sir[2]=b[p];
                                                                                 
      rinsum+=sir[0];
      ginsum+=sir[1];
      binsum+=sir[2];
      rsum+=rinsum;
      gsum+=ginsum;
      bsum+=binsum;
      stackpointer=(stackpointer+1)%div;
      sir=stack[stackpointer];
                                                                                
      routsum+=sir[0];
      goutsum+=sir[1];
      boutsum+=sir[2];
                                                                                 
      rinsum-=sir[0];
      ginsum-=sir[1];
      binsum-=sir[2];
      yi+=w;
    }
  }
                                                                             
  img.updatePixels();
}

同时找到一个借鉴这个所改进后成为Java的代码,具体如下:

public static Bitmap doBlur(Bitmap sentBitmap, int radius, boolean canReuseInBitmap) {
    // Stack Blur v1.0 from
    // http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
    //
    // Java Author: Mario Klingemann <mario at quasimondo.com>
    // http://incubator.quasimondo.com
    // created Feburary 29, 2004
    // Android port : Yahel Bouaziz <yahel at kayenko.com>
    // http://www.kayenko.com
    // ported april 5th, 2012
    // This is a compromise between Gaussian Blur and Box blur
    // It creates much better looking blurs than Box Blur, but is
    // 7x faster than my Gaussian Blur implementation.
    //
    // I called it Stack Blur because this describes best how this
    // filter works internally: it creates a kind of moving stack
    // of colors whilst scanning through the image. Thereby it
    // just has to add one new block of color to the right side
    // of the stack and remove the leftmost color. The remaining
    // colors on the topmost layer of the stack are either added on
    // or reduced by one, depending on if they are on the right or
    // on the left side of the stack.
    //
    // If you are using this algorithm in your code please add
    // the following line:
    //
    // Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>
    Bitmap bitmap;
    if (canReuseInBitmap) {
        bitmap = sentBitmap;
    } else {
        bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
    }
    if (radius < 1) {
        return (null);
    }
    int w = bitmap.getWidth();
    int h = bitmap.getHeight();
    int[] pix = new int[w * h];
    bitmap.getPixels(pix, 0, w, 0, 0, w, h);
    int wm = w - 1;
    int hm = h - 1;
    int wh = w * h;
    int div = radius + radius + 1;
    int r[] = new int[wh];
    int g[] = new int[wh];
    int b[] = new int[wh];
    int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
    int vmin[] = new int[Math.max(w, h)];
    int divsum = (div + 1) >> 1;
    divsum *= divsum;
    int dv[] = new int[256 * divsum];
    for (i = 0; i < 256 * divsum; i++) {
        dv[i] = (i / divsum);
    }
    yw = yi = 0;
    int[][] stack = new int[div][3];
    int stackpointer;
    int stackstart;
    int[] sir;
    int rbs;
    int r1 = radius + 1;
    int routsum, goutsum, boutsum;
    int rinsum, ginsum, binsum;
    for (y = 0; y < h; y++) {
        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
        for (i = -radius; i <= radius; i++) {
            p = pix[yi + Math.min(wm, Math.max(i, 0))];
            sir = stack[i + radius];
            sir[0] = (p & 0xff0000) >> 16;
            sir[1] = (p & 0x00ff00) >> 8;
            sir[2] = (p & 0x0000ff);
            rbs = r1 - Math.abs(i);
            rsum += sir[0] * rbs;
            gsum += sir[1] * rbs;
            bsum += sir[2] * rbs;
            if (i > 0) {
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
            } else {
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
            }
        }
        stackpointer = radius;
        for (x = 0; x < w; x++) {
            r[yi] = dv[rsum];
            g[yi] = dv[gsum];
            b[yi] = dv[bsum];
            rsum -= routsum;
            gsum -= goutsum;
            bsum -= boutsum;
            stackstart = stackpointer - radius + div;
            sir = stack[stackstart % div];
            routsum -= sir[0];
            goutsum -= sir[1];
            boutsum -= sir[2];
            if (y == 0) {
                vmin[x] = Math.min(x + radius + 1, wm);
            }
            p = pix[yw + vmin[x]];
            sir[0] = (p & 0xff0000) >> 16;
            sir[1] = (p & 0x00ff00) >> 8;
            sir[2] = (p & 0x0000ff);
            rinsum += sir[0];
            ginsum += sir[1];
            binsum += sir[2];
            rsum += rinsum;
            gsum += ginsum;
            bsum += binsum;
            stackpointer = (stackpointer + 1) % div;
            sir = stack[(stackpointer) % div];
            routsum += sir[0];
            goutsum += sir[1];
            boutsum += sir[2];
            rinsum -= sir[0];
            ginsum -= sir[1];
            binsum -= sir[2];
            yi++;
        }
        yw += w;
    }
    for (x = 0; x < w; x++) {
        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
        yp = -radius * w;
        for (i = -radius; i <= radius; i++) {
            yi = Math.max(0, yp) + x;
            sir = stack[i + radius];
            sir[0] = r[yi];
            sir[1] = g[yi];
            sir[2] = b[yi];
            rbs = r1 - Math.abs(i);
            rsum += r[yi] * rbs;
            gsum += g[yi] * rbs;
            bsum += b[yi] * rbs;
            if (i > 0) {
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
            } else {
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
            }
            if (i < hm) {
                yp += w;
            }
        }
        yi = x;
        stackpointer = radius;
        for (y = 0; y < h; y++) {
            // Preserve alpha channel: ( 0xff000000 & pix[yi] )
            pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];
            rsum -= routsum;
            gsum -= goutsum;
            bsum -= boutsum;
            stackstart = stackpointer - radius + div;
            sir = stack[stackstart % div];
            routsum -= sir[0];
            goutsum -= sir[1];
            boutsum -= sir[2];
            if (x == 0) {
                vmin[y] = Math.min(y + r1, hm) * w;
            }
            p = x + vmin[y];
            sir[0] = r[p];
            sir[1] = g[p];
            sir[2] = b[p];
            rinsum += sir[0];
            ginsum += sir[1];
            binsum += sir[2];
            rsum += rinsum;
            gsum += ginsum;
            bsum += binsum;
            stackpointer = (stackpointer + 1) % div;
            sir = stack[stackpointer];
            routsum += sir[0];
            goutsum += sir[1];
            boutsum += sir[2];
            rinsum -= sir[0];
            ginsum -= sir[1];
            binsum -= sir[2];
            yi += w;
        }
    }
    bitmap.setPixels(pix, 0, w, 0, 0, w, h);
    return (bitmap);
}

借鉴于此我弄了一个C的代码,基本上的整体过程都没有变化,只是改变成了C(C++也可已)的而已:

文件名:ImageBlur.c

/*************************************************
Copyright:  Copyright QIUJUER 2013.
Author:     Qiujuer
Date:       2014-04-18
Description:实现图片模糊处理
**************************************************/
#include<malloc.h>
#define ABS(a) ((a)<(0)?(-a):(a))
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
/*************************************************
Function:       StackBlur(堆栈模糊)
Description:    使用堆栈方式进行图片像素模糊处理
Calls:          malloc
Table Accessed: NULL
Table Updated:  NULL
Input:          像素点集合,图片宽,图片高,模糊半径
Output:         返回模糊后的像素点集合
Return:         返回模糊后的像素点集合
Others:         NULL
*************************************************/
static int* StackBlur(int* pix, int w, int h, int radius) {
    int wm = w - 1;
    int hm = h - 1;
    int wh = w * h;
    int div = radius + radius + 1;
    int *r = (int *)malloc(wh * sizeof(int));
    int *g = (int *)malloc(wh * sizeof(int));
    int *b = (int *)malloc(wh * sizeof(int));
    int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
    int *vmin = (int *)malloc(MAX(w,h) * sizeof(int));
    int divsum = (div + 1) >> 1;
    divsum *= divsum;
    int *dv = (int *)malloc(256 * divsum * sizeof(int));
    for (i = 0; i < 256 * divsum; i++) {
        dv[i] = (i / divsum);
    }
    yw = yi = 0;
    int(*stack)[3] = (int(*)[3])malloc(div * 3 * sizeof(int));
    int stackpointer;
    int stackstart;
    int *sir;
    int rbs;
    int r1 = radius + 1;
    int routsum, goutsum, boutsum;
    int rinsum, ginsum, binsum;
    for (y = 0; y < h; y++) {
        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
        for (i = -radius; i <= radius; i++) {
            p = pix[yi + (MIN(wm, MAX(i, 0)))];
            sir = stack[i + radius];
            sir[0] = (p & 0xff0000) >> 16;
            sir[1] = (p & 0x00ff00) >> 8;
            sir[2] = (p & 0x0000ff);
            rbs = r1 - ABS(i);
            rsum += sir[0] * rbs;
            gsum += sir[1] * rbs;
            bsum += sir[2] * rbs;
            if (i > 0) {
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
            }
            else {
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
            }
        }
        stackpointer = radius;
        for (x = 0; x < w; x++) {
            r[yi] = dv[rsum];
            g[yi] = dv[gsum];
            b[yi] = dv[bsum];
            rsum -= routsum;
            gsum -= goutsum;
            bsum -= boutsum;
            stackstart = stackpointer - radius + div;
            sir = stack[stackstart % div];
            routsum -= sir[0];
            goutsum -= sir[1];
            boutsum -= sir[2];
            if (y == 0) {
                vmin[x] = MIN(x + radius + 1, wm);
            }
            p = pix[yw + vmin[x]];
            sir[0] = (p & 0xff0000) >> 16;
            sir[1] = (p & 0x00ff00) >> 8;
            sir[2] = (p & 0x0000ff);
            rinsum += sir[0];
            ginsum += sir[1];
            binsum += sir[2];
            rsum += rinsum;
            gsum += ginsum;
            bsum += binsum;
            stackpointer = (stackpointer + 1) % div;
            sir = stack[(stackpointer) % div];
            routsum += sir[0];
            goutsum += sir[1];
            boutsum += sir[2];
            rinsum -= sir[0];
            ginsum -= sir[1];
            binsum -= sir[2];
            yi++;
        }
        yw += w;
    }
    for (x = 0; x < w; x++) {
        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
        yp = -radius * w;
        for (i = -radius; i <= radius; i++) {
            yi = MAX(0, yp) + x;
            sir = stack[i + radius];
            sir[0] = r[yi];
            sir[1] = g[yi];
            sir[2] = b[yi];
            rbs = r1 - ABS(i);
            rsum += r[yi] * rbs;
            gsum += g[yi] * rbs;
            bsum += b[yi] * rbs;
            if (i > 0) {
                rinsum += sir[0];
                ginsum += sir[1];
                binsum += sir[2];
            }
            else {
                routsum += sir[0];
                goutsum += sir[1];
                boutsum += sir[2];
            }
            if (i < hm) {
                yp += w;
            }
        }
        yi = x;
        stackpointer = radius;
        for (y = 0; y < h; y++) {
            // Preserve alpha channel: ( 0xff000000 & pix[yi] )
            pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];
            rsum -= routsum;
            gsum -= goutsum;
            bsum -= boutsum;
            stackstart = stackpointer - radius + div;
            sir = stack[stackstart % div];
            routsum -= sir[0];
            goutsum -= sir[1];
            boutsum -= sir[2];
            if (x == 0) {
                vmin[y] = MIN(y + r1, hm) * w;
            }
            p = x + vmin[y];
            sir[0] = r[p];
            sir[1] = g[p];
            sir[2] = b[p];
            rinsum += sir[0];
            ginsum += sir[1];
            binsum += sir[2];
            rsum += rinsum;
            gsum += ginsum;
            bsum += binsum;
            stackpointer = (stackpointer + 1) % div;
            sir = stack[stackpointer];
            routsum += sir[0];
            goutsum += sir[1];
            boutsum += sir[2];
            rinsum -= sir[0];
            ginsum -= sir[1];
            binsum -= sir[2];
            yi += w;
        }
    }
    free(r);
    free(g);
    free(b);
    free(vmin);
    free(dv);
    free(stack);
    return(pix);
}

在改为这个的过程中还遇到 了一个很喜剧的问题,我发现我使用这个来进行调用后结果程序内存一直增大,直到500多M,直接卡死。我知道是我写的有内存泄漏了!

然后找了一下,发现果然是。只好进行free了。然后一下就好了,发现内存占用的确比Java的要少,速度也是要快一些!

在JNI中的实现我使用了两种方案,一种是直接传递文件,一直是传递像素点集合进行模糊!分别如下:

/*
 * Class:     com_accumulation_imageblurring_app_jni_ImageBlur
 * Method:    blurIntArray
 * Signature: ([IIII)V
 */
JNIEXPORT void JNICALL Java_com_accumulation_imageblurring_app_jni_ImageBlur_blurIntArray
  (JNIEnv *, jclass, jintArray, jint, jint, jint);
/*
 * Class:     com_accumulation_imageblurring_app_jni_ImageBlur
 * Method:    blurBitMap
 * Signature: (Landroid/graphics/Bitmap;I)V
 */
JNIEXPORT void JNICALL Java_com_accumulation_imageblurring_app_jni_ImageBlur_blurBitMap
  (JNIEnv *, jclass, jobject, jint);

对应的Java调用:

public class ImageBlur {
    public static native void blurIntArray(int[] pImg, int w, int h, int r);
    public static native void blurBitMap(Bitmap bitmap, int r);
    static {
        System.loadLibrary("JNI_ImageBlur");
    }
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

此时我做了3种测试,一种是直接在Java层实现,一种是传递像素点集合模糊,还有就是直接传递图片进行模糊,结果如下:




通过上面的比较我们可以得出这样的结论:

1.Java的确最慢,但是其实也慢不了多少,虚拟机优化好了一样猛。

2.C中直接传递像素集合的速度最快(第一次启动)

3.在我多次切换界面后发现,直接传递像素点集合的耗时会增加,从60多到120多。

4.多次切换后发现,其实直接传递像素点的速度与传递图片过去的速度几乎一样。

5.多次操作后发现传递文件的波动较小,在100~138之间,其次是传递像素点集合的波动较大,java的波动最大!

以上就是我的结论,可能有些不正确,但是在我的机器上的确是这样!

注:勾选选择框“Downscale before blur”会先压缩图片后模糊然后放大图片,这样的情况下,模糊效果会稍微损失一些效果,但是其速度确实无法比拟的。

其耗时在:1~10ms内可运算完成。当然与你要模糊的大小有关系!


最后:项目地址:GitHub


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