android drawBitmapMesh

package com.example.and6;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.widget.ImageView;

public class MeshView extends ImageView{
Bitmap bitmap;

//分割成50*50个格
int WIDTH=50;
int HEIGHT=50;
//依次存放每一个点的 x y坐标
float[]origs=new float[ ( (WIDTH+1)*(HEIGHT+1) )*2];
float[]verts=new float[origs.length];

float k;

boolean isStart=false;
public MeshView(Context context) {
super(context);
init();

}
public MeshView(Context context, AttributeSet attrs) {
super(context, attrs);
init();

}
public MeshView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();

}
@SuppressLint("NewApi")
public MeshView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
init();

}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
flagWave();
k+=0.1f;

canvas.drawBitmapMesh(bitmap, WIDTH, HEIGHT, verts, 0, null, 0, null);
if (isStart) {
invalidate();

}

}

public void startAnim() {
isStart=true;
requestLayout();
}

public void stopAnim() {
isStart=false;
}
private void init() {
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pic);

float bitmapHeight=bitmap.getHeight();
float bitmapWidth=bitmap.getHeight();
int index=0;

for (int y = 0; y <= HEIGHT; y++) {
float fy=bitmapHeight*y/HEIGHT;
for (int x = 0; x <= WIDTH; x++) {
float fx=bitmapWidth*x/WIDTH;

origs[index*2+0]=verts[index*2+0]=fx;
origs[index*2+1]=verts[index*2+1]=fy;
index++;
}
}
}
private void flagWave() {
for (int j = 0;j <= HEIGHT; j++) {
for (int i = 0; i <= WIDTH; i++) {
verts[ (j*(WIDTH+1)+i )*2+0 ]+=0;
float offsetY=(float) Math.sin( i*1.0f/WIDTH*2*Math.PI + Math.PI*k);//k 实现周期变化

verts[ (j*(WIDTH+1)+i )*2+1 ]=origs[ ( j*WIDTH+i )*2+1 ]+offsetY*100; //100 振幅

}
}
}

}