基于平面格式YUV422的图像缩放

void __fastcall TForm1::N3202401Click(TObject *Sender)
{
        FILE *fp;
        fp = fopen("E://±àÂëÏîÄ¿//YUVË«ÏßÐԱ任//320&240YUV422.yuv", "rb");
        unsigned char *YUV=new unsigned char[320*240*2];
        fread(YUV, sizeof(char), 320*240*2, fp);

        double Y,U,V;

        unsigned short height,width;
        unsigned short heightNew,widthNew;  //ÐÂͼÏñµÄ¸ß¶ÈºÍ¿í¶È

        float k=0.525;
        float widthScale=(float)(1.0/k),heightScale=(float)(1.0/k);
        float xx,yy;
        int a,b;

        width=320;                    //ԭͼÏñ´óС
        height=240;
        widthNew=(int)(width*k);      //µÃµ½ÐÂͼÏñµÄ¸ß¶ÈºÍ¿í¶È
        heightNew =(int)(height*k);
        unsigned char *YUVnew=new unsigned char[widthNew*heightNew*2];

        for(int y=(int)k;y        {
           for(int x=(int)k; x           {
               xx=x*widthScale ;
               yy=y*heightScale ;
               if(xx<=1e-8)
               {
                  xx=0;
               }
               if(xx>width-2)
               {
                  xx=(float)(width-2);
               }
               if(yy<=1e-8)
               {
                  yy=0;
               }
               if(yy>height-2)
               {
                  yy=(float)(height-2);
               }
               a=(int)xx;
               b=(int)yy;

               //·Ö±ðµÃµ½¶ÔÓ¦ÏñËصÄYUVÖµ²¢ÓÃË«ÏßÐÔ²åÖµµÃµ½ÐÂÏñËصÄYUVÖµ
               double y11,y12,y21,y22;
               double u11,u12,u21,u22;
               double v11,v12,v21,v22;
               y11=YUV[b*320+a];
               y12=YUV[b*320+a+1];
               y21=YUV[(b+1)*320+a];
               y22=YUV[(b+1)*320+a+1];
               Y=y11*(a+1-xx)*(b+1-yy)+y12*(a+1-xx)*(yy-b)
                        +y21*(xx-a)*(b+1-yy)+y22*(xx-a)*(yy-b);  //Y
               YUVnew[x+y*widthNew]=(char)Y;

               u11=YUV[320*240+b*320/2+a];
               u12=YUV[320*240+b*320/2+a+1];
               u21=YUV[(b+1)*320/2+320*240+a];
               u22=YUV[(b+1)*320/2+320*240+a+1];
               U=u11*(a+1-xx)*(b+1-yy)+u12*(a+1-xx)*(yy-b)
                        +u21*(xx-a)*(b+1-yy)+u22*(xx-a)*(yy-b);   //U

               v11=YUV[320*240+320*240/2+b*320/2+a];
               v12=YUV[320*240+320*240/2+b*320/2+a+1];
               v21=YUV[(b+1)*320/2+320*240+320*240/2+a];
               v22=YUV[(b+1)*320/2+320*240+320*240/2+a+1];
               V=v11*(a+1-xx)*(b+1-yy)+v12*(a+1-xx)*(yy-b)
                        +v21*(xx-a)*(b+1-yy)+v22*(xx-a)*(yy-b);   //V

               YUVnew[x+y*widthNew]=(char)Y;
               YUVnew[widthNew*heightNew+x+y*widthNew/2]=(char)U;
               YUVnew[widthNew*heightNew+widthNew*heightNew/2+x+y*widthNew/2]=(char)V;
              
           }
        }
        /*Ëõ·ÅºóµÄYUVתRGB²¢ÏÔʾ*/
        int col,row;
        double red,blue,green;
        unsigned char *RGB = new unsigned char [widthNew*heightNew*3];
 for (row=0; row {
  int idx=((heightNew-row-1)*3)*widthNew;
  int rowptr=row*widthNew;
  for (col=0; col  {
   int colhalf=col>>1;
   Y=YUVnew[rowptr+col];
   U=YUVnew[rowptr+colhalf+widthNew*heightNew-row*widthNew/2];
   V=YUVnew[rowptr+colhalf+widthNew*heightNew-row*widthNew/2+widthNew*heightNew/2];

   red=(Y+(U-128)*1.4022)+0.5;
   green=(Y-(U-128)*0.3456-(V-128)*0.7145)+0.5;
   blue=(Y+(V-128)*1.7710)+0.5;

   if (red>255) red=255;
   else if (red<0) red=0;
   if (green>255) green=255;
   else if (green<0) green=0;
   if (blue>255) blue=255;
   else if (blue<0) blue=0;

   RGB[idx++]=(char)red;
   RGB[idx++]=(char)green;
   RGB[idx++]=(char)blue;
  }
 }
        Graphics::TBitmap *pBitNew;
        pBitNew = new Graphics::TBitmap();
        pBitNew->Width=widthNew;
        pBitNew->Height=heightNew;
        Byte *ptr;
        pBitNew->PixelFormat=pf24bit; //¶¨Òå24λµÄλͼ
        for(int i=0; i        {
           ptr= (Byte*)(pBitNew->ScanLine[i]);
           int RGBIndex=3*widthNew*(heightNew-i);
           for(int j=0;j           {
               int B=RGB[RGBIndex+j];
               int G=RGB[RGBIndex+j+1];
               int R=RGB[RGBIndex+j+2];
               *(ptr+j)= B;
               *(ptr+j+1)= G;
               *(ptr+j+2)= R;
           }
        }
        Image2->Picture->Bitmap->Assign(pBitNew);
        delete pBitNew;
}