Girar libreria java

public static float[][] rotarAngInv(float[][] im1,float ang){

int filas=(int)(im1.length),cols=(int)(im1[0].length);

int xIzq=0,yIzq=filas, xDer=cols, yDer=0;

int xSup=0, ySup=0 ,xInf=cols, yInf=filas;

int nX,nY;

//double cosa=Math.cos(Math.toRadians(ang)),sena=Math.sin(Math.toRadians(ang));

float c=(float)Math.cos(Math.toRadians(ang)), s=(float)Math.sin(Math.toRadians(ang)),

xP=cols/2, yP=filas/2,

r11=c,r12=s,

r21=-s,r22=c,

r31=-xP*c+yP*s+xP,r32=-xP*s-yP*c+yP;

int x1=(int)(xIzq*r11+yIzq*r21+r31);

int x2=(int)(xDer*r11+yDer*r21+r31);

int y1=(int)(xSup*r12+ySup*r22+r32);

int y2=(int)(xInf*r12+yInf*r22+r32);

int ancho=(int)Math.abs(x2-x1);

int alto= (int)Math.abs(y2-y1);

float[][] asal= new float[alto][ancho];

c=(float)Math.cos(Math.toRadians(-ang));

s=(float)Math.sin(Math.toRadians(-ang));

xP=ancho/2; yP=alto/2;

r11=c;r12=s;

r21=-s;r22=c;

r31=-xP*c+yP*s+xP;

r32=-xP*s-yP*c+yP;

for(int i=0;i<alto;i++){

for(int j=0;j<ancho;j++){

nX=(int)(j*r11+i*r21+r31)+x1;

nY=(int)(j*r12+i*r22+r32)+y1;

if((nX >=0 && nX<cols)&&(nY>=0 && nY<filas))

asal[i][j]=im1[nY][nX];

...