Android 手写签名和裁剪

效果图：

主要代码：

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;

@SuppressLint("ClickableViewAccessibility")
public class SignView extends View {

	private Canvas mCanvas;
	private Paint mPaint;
	private Path mPath;
	private Bitmap mBitmap;
	private Paint mBitmapPaint;
	private int mX;
	private int mY;
	private