使用位图叠加

时间:2011-06-21 17:14:05

标签: android image-processing bitmap image-optimization

我有一个应用程序会对位图产生鱼眼失真效果。要创建失真,我必须循环遍历整个位图,检查给定像素是否以圆形边界落下。如果它确实那么我操纵那个像素。这个过程是劳动密集型的,需要50秒。我正在考虑不同的方法,所以我不必循环整个位图来应用效果。 我有一个想法是首先绘制位图并显示它。然后创建第二个只有效果的位图叠加层。然后我可以在第一个位图上覆盖第二个位图。我只是试图想办法,我可以应用这种效果,而无需循环通过尽可能多的像素来加快速度。我将发布失真类。感谢。

class Filters{
    private float xscale;
    private float yscale;
    private float xshift;
    private float yshift;
    private int [] s;
    private int [] scalar;
    private int [] s1;
    private int [] s2;
    private int [] s3;
    private int [] s4;
    private String TAG = "Filters";
    long getRadXStart = 0;
    long getRadXEnd = 0;
    long startSample = 0;
    long endSample = 0;
    public Filters(){

        Log.e(TAG, "***********inside filter constructor");
        s = new int[4];
        scalar = new int[4];
        s1 = new int[4];
        s2 = new int[4];
        s3 = new int[4];
        s4 = new int[4];
    }

    public Bitmap barrel (Bitmap input, float k,float cenx, float ceny){
        //Log.e(TAG, "***********INSIDE BARREL METHOD ");
        Debug.startMethodTracing("barrel");

        //float centerX=input.getWidth()/2; //center of distortion
        //float centerY=input.getHeight()/2;
        float centerX=cenx;
        float centerY=ceny;

        int width = input.getWidth(); //image bounds
        int height = input.getHeight();

        Bitmap dst = Bitmap.createBitmap(width, height,input.getConfig() ); //output pic
       // Log.e(TAG, "***********dst bitmap created ");
          xshift = calc_shift(0,centerX-1,centerX,k);

          float newcenterX = width-centerX;
          float xshift_2 = calc_shift(0,newcenterX-1,newcenterX,k);

          yshift = calc_shift(0,centerY-1,centerY,k);

          float newcenterY = height-centerY;
          float yshift_2 = calc_shift(0,newcenterY-1,newcenterY,k);

          xscale = (width-xshift-xshift_2)/width;
        //  Log.e(TAG, "***********xscale ="+xscale);
          yscale = (height-yshift-yshift_2)/height;
        //  Log.e(TAG, "***********yscale ="+yscale);
        //  Log.e(TAG, "***********filter.barrel() about to loop through bm");
          /*for(int j=0;j<dst.getHeight();j++){
              for(int i=0;i<dst.getWidth();i++){
                float x = getRadialX((float)i,(float)j,centerX,centerY,k);
                float y = getRadialY((float)i,(float)j,centerX,centerY,k);
                sampleImage(input,x,y);
                int color = ((s[1]&0x0ff)<<16)|((s[2]&0x0ff)<<8)|(s[3]&0x0ff);
    //            System.out.print(i+" "+j+" \\");

                dst.setPixel(i, j, color);

              }
            }*/

          int origPixel;
          long startLoop = System.currentTimeMillis();
          for(int j=0;j<dst.getHeight();j++){
              for(int i=0;i<dst.getWidth();i++){
                 origPixel= input.getPixel(i,j);
                 getRadXStart = System.currentTimeMillis();
                float x = getRadialX((float)j,(float)i,centerX,centerY,k);
                getRadXEnd= System.currentTimeMillis();

                float y = getRadialY((float)j,(float)i,centerX,centerY,k);

                sampleImage(input,x,y);

                int color = ((s[1]&0x0ff)<<16)|((s[2]&0x0ff)<<8)|(s[3]&0x0ff);
    //            System.out.print(i+" "+j+" \\");

                //if( Math.sqrt( Math.pow(i - centerX, 2) + ( Math.pow(j - centerY, 2) ) ) <= 150 ){
                if(  Math.pow(i - centerX, 2) + ( Math.pow(j - centerY, 2) )  <= 22500 ){
                dst.setPixel(i, j, color);
                }else{
                    dst.setPixel(i,j,origPixel);
                }
              }
            }
          long endLoop = System.currentTimeMillis();
          long loopDuration = endLoop - startLoop;
          long radXDuration = getRadXEnd - getRadXStart;
          long sampleDur = endSample - startSample;

          Log.e(TAG, "sample method took "+sampleDur+"ms");
          Log.e(TAG, "getRadialX took "+radXDuration+"ms");
          Log.e(TAG, "loop took "+loopDuration+"ms");

        //  Log.e(TAG, "***********filter.barrel()  looped through bm about to return dst bm");
          Debug.stopMethodTracing();
        return dst;

    }

    void sampleImage(Bitmap arr, float idx0, float idx1)
    {
         startSample = System.currentTimeMillis();
       // s = new int [4];
      if(idx0<0 || idx1<0 || idx0>(arr.getHeight()-1) || idx1>(arr.getWidth()-1)){
        s[0]=0;
        s[1]=0;
        s[2]=0;
        s[3]=0;
        return;
      }

      float idx0_fl=(float) Math.floor(idx0);
      float idx0_cl=(float) Math.ceil(idx0);
      float idx1_fl=(float) Math.floor(idx1);
      float idx1_cl=(float) Math.ceil(idx1);

     /* float idx0_fl=idx0;
      float idx0_cl=idx0;
      float idx1_fl=idx1;
      float idx1_cl=idx1;*/

     /* int [] s1 = getARGB(arr,(int)idx0_fl,(int)idx1_fl);
      int [] s2 = getARGB(arr,(int)idx0_fl,(int)idx1_cl);
      int [] s3 = getARGB(arr,(int)idx0_cl,(int)idx1_cl);
      int [] s4 = getARGB(arr,(int)idx0_cl,(int)idx1_fl);*/

       s1 = getARGB(arr,(int)idx0_fl,(int)idx1_fl);
       s2 = getARGB(arr,(int)idx0_fl,(int)idx1_cl);
       s3 = getARGB(arr,(int)idx0_cl,(int)idx1_cl);
       s4 = getARGB(arr,(int)idx0_cl,(int)idx1_fl);

      float x = idx0 - idx0_fl;
      float y = idx1 - idx1_fl;

      s[0]= (int) (s1[0]*(1-x)*(1-y) + s2[0]*(1-x)*y + s3[0]*x*y + s4[0]*x*(1-y));
      s[1]= (int) (s1[1]*(1-x)*(1-y) + s2[1]*(1-x)*y + s3[1]*x*y + s4[1]*x*(1-y));
      s[2]= (int) (s1[2]*(1-x)*(1-y) + s2[2]*(1-x)*y + s3[2]*x*y + s4[2]*x*(1-y));
      s[3]= (int) (s1[3]*(1-x)*(1-y) + s2[3]*(1-x)*y + s3[3]*x*y + s4[3]*x*(1-y));

      endSample = System.currentTimeMillis();
    }

    int [] getARGB(Bitmap buf,int x, int y){

        int rgb = buf.getPixel(y, x); // Returns by default ARGB.
       // int [] scalar = new int[4];
        scalar[0] = (rgb >>> 24) & 0xFF;
        scalar[1] = (rgb >>> 16) & 0xFF;
        scalar[2] = (rgb >>> 8) & 0xFF;
        scalar[3] = (rgb >>> 0) & 0xFF;
        return scalar;
    }

    float getRadialX(float x,float y,float cx,float cy,float k){

      x = (x*xscale+xshift);
      y = (y*yscale+yshift);
      float res = x+((x-cx)*k*((x-cx)*(x-cx)+(y-cy)*(y-cy)));
      return res;
    }

    float getRadialY(float x,float y,float cx,float cy,float k){

      x = (x*xscale+xshift);
      y = (y*yscale+yshift);
      float res = y+((y-cy)*k*((x-cx)*(x-cx)+(y-cy)*(y-cy)));
      return res;
    }

    float thresh = 1;

    float calc_shift(float x1,float x2,float cx,float k){

      float x3 = (float)(x1+(x2-x1)*0.5);
      float res1 = x1+((x1-cx)*k*((x1-cx)*(x1-cx)));
      float res3 = x3+((x3-cx)*k*((x3-cx)*(x3-cx)));

      if(res1>-thresh && res1 < thresh)
        return x1;
      if(res3<0){
        return calc_shift(x3,x2,cx,k);
      }
      else{
        return calc_shift(x1,x3,cx,k);
      }
    }



}// end of filters class

[更新] 嗨,我没有看过所有的视频因素我只在加密狗上有这么多的数据限额,所以要等到工作时再观看它。我已将代码修改为下面的代码。这将像素数据存储在int数组中,因此不会调用dst.setPixel。它仍然非常慢(在320万像素摄像头上持续14秒)根本不像你的代码那样几秒钟。你可以分享那些代码,或者告诉我这是不是你的意思。谢谢马特。

int origPixel = 0;
          int []arr = new int[input.getWidth()*input.getHeight()];
          int color = 0;

          int p = 0;
          int i = 0;
          for(int j=0;j<dst.getHeight();j++){
              for( i=0;i<dst.getWidth();i++,p++){
                 origPixel= input.getPixel(i,j);

                float x = getRadialX((float)j,(float)i,centerX,centerY,k);


                float y = getRadialY((float)j,(float)i,centerX,centerY,k);

                sampleImage(input,x,y);

                 color = ((s[1]&0x0ff)<<16)|((s[2]&0x0ff)<<8)|(s[3]&0x0ff);
    //            System.out.print(i+" "+j+" \\");

                //if( Math.sqrt( Math.pow(i - centerX, 2) + ( Math.pow(j - centerY, 2) ) ) <= 150 ){
                if(  Math.pow(i - centerX, 2) + ( Math.pow(j - centerY, 2) )  <= 22500 ){
                //dst.setPixel(i, j, color);
                    arr[p]=color;
                    Log.e(TAG, "***********arr = " +arr[i]+" i = "+i);
                }else{
                    //dst.setPixel(i,j,origPixel);
                    arr[p]=origPixel;

                }
              }
            }



        //  Log.e(TAG, "***********filter.barrel()  looped through bm about to return dst bm");
          Debug.stopMethodTracing();
         Bitmap dst2 = Bitmap.createBitmap(arr,width,height,input.getConfig());
        return dst2;

    }

1 个答案:

答案 0 :(得分:1)

我敢打赌,如果你在内循环中消除了对dst.setPixel的调用,你会大大减少你的执行时间。而不是在循环内的Bitmaps上操作,在循环期间将值填充到整数数组中,并在传入数组的末尾调用setPixels。

我有图像处理代码,可以在几秒钟内循环整个2MP图像。

在较旧的Android api上(我相信早于2.3,但它甚至可能包括2.3),实际的图像数据不会驻留在托管堆中,因此可能会进行一些昂贵的操作来查找位的实际位置'在setPixel的调用中重写。我的信息来源是关于Android内存管理的Google I / O 2011视频。如果您在Android中进行此类工作,则必须注意:

http://www.youtube.com/watch?v=_CruQY55HOk