the mesh android,Android drawBitmapMesh扭曲触摸点的图像

Parameters

bitmap Bitmap: The bitmap to draw using the mesh

meshWidth int: The number of columns in the mesh. Nothing is drawn if this is 0

meshHeight int: The number of rows in the mesh. Nothing is drawn if this is 0

verts float: Array of x,y pairs, specifying where the mesh should be drawn. There must be at least (meshWidth+1) * (meshHeight+1) * 2 + vertOffset values in the array

vertOffset int: Number of verts elements to skip before drawing

colors int: May be null. Specifies a color at each vertex, which is interpolated across the cell, and whose values are multiplied by the corresponding bitmap colors. If not null, there must be at least (meshWidth+1) * (meshHeight+1) + colorOffset values in the array.

colorOffset int: Number of color elements to skip before drawing

paint Paint: May be null. The paint used to draw the bitmap

public class MainActivity extends Activity {

private Bitmap bitmap;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(new MyView(MainActivity.this, R.drawable.jinta));

}

private class MyView extends View{

//将图片在横向，纵向划分为20格

private final int WIDTH=20,HEIGHT=20;

//包含441个顶点

private final int COUNT=(WIDTH+1)*(HEIGHT+1);

//保存原坐标

private final float[] verts=new float[COUNT*2];

//保存扭曲后坐标，对图片扭曲关键为修改该数组的值

private final float[] orig=new float[COUNT*2];

public MyView(Context context,int DrawableId) {

super(context);

setFocusable(true);

//加载图片资源

bitmap=BitmapFactory.decodeResource(getResources(), DrawableId);

//获取高，宽

float bitmapWidth=bitmap.getWidth(),

bitmapHeight=bitmap.getHeight();

int index=0;

//对原坐标和扭曲后坐标数组进行初始化操作

for(int y=0;y<=HEIGHT;y++){

float fy=bitmapHeight*y/HEIGHT;

for(int x=0;x<=WIDTH;x++){

float fx=bitmapWidth*x/WIDTH;

orig[index*2+0]=verts[index*2+0]=fx;

orig[index*2+1]=verts[index*2+1]=fy;

index+=1;

}

}

//背景色

setBackgroundColor(Color.WHITE);

}

@Override

protected void onDraw(Canvas canvas) {

canvas.drawBitmapMesh(bitmap,WIDTH,HEIGHT,verts,0,null,0,null);

}

//cx,cy为touch事件发生坐标

private void wrap(float cx,float cy){

for(int i=0;i=1){

//距离近，直接扭曲至事件发生点

verts[i+0]=cx;

verts[i+1]=cy;

}else{

//距离稍远，向事件发生偏移

verts[i+0]=orig[i+0]+dx*pull;

verts[i+1]=orig[i+1]+dy*pull;

}

}

//通知组件调用OnDraw重绘

invalidate();

}

@Override

public boolean onTouchEvent(MotionEvent event) {

//触摸事件发生时调用扭曲方法

wrap(event.getX(),event.getY());

return true;

}

}

}