本文实例为大家分享了Android自定义橡皮擦效果，使用贝塞尔曲线处理曲线转折处

public class picFingerToTest extends View {

private Paint paint;

private Bitmap decodeResourceSRC;

private Bitmap createBitmapDST;

// 手指路径，使用贝塞尔路线

private Path path;

private float perX;

private float perY;

public picFingerToTest(Context context, AttributeSet attrs) {

super(context, attrs);

// 1、设置禁用硬件设置

setLayerType(View.LAYER_TYPE_SOFTWARE, null);

// 2、设置手指画笔

paint = new Paint();

paint.setAntiAlias(true);

paint.setColor(Color.RED);

paint.setStyle(Paint.Style.STROKE);

paint.setStrokeWidth(45);

// 3、生成图像手指源目标

// 源

decodeResourceSRC = BitmapFactory.decodeResource(getResources(), R.drawable.welcome, null);

// 目标

createBitmapDST = Bitmap.createBitmap(decodeResourceSRC.getWidth(), decodeResourceSRC.getHeight(),

Config.ARGB_8888);

path = new Path();

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

// 分层绘制

int saveLayer = canvas.saveLayer(0, 0, getWidth(), getHeight(), null,Canvas.ALL_SAVE_FLAG);

// 把手指轨迹划到目标路径上

Canvas canvas2 = new Canvas(createBitmapDST);

canvas2.drawPath(path, paint);

// 把目标图像画到画布上

canvas.drawBitmap(createBitmapDST, 0, 0, paint);

// 计算源图像区域

paint.setXfermode(new PorterDuffXfermode(Mode.SRC_OUT));

canvas.drawBitmap(decodeResourceSRC, 0, 0, paint);

paint.setXfermode(null);

canvas.restoreToCount(saveLayer);

}

//使用贝塞尔曲线，使折线过度圆滑

@Override

public boolean onTouchEvent(MotionEvent event) {

switch (event.getAction()) {

// 记录手指触摸的初始化位置

case MotionEvent.ACTION_DOWN:

path.moveTo(event.getX(), event.getY());

perX = event.getX();

perY = event.getY();

return true;

case MotionEvent.ACTION_MOVE:

float endX = (perX + event.getX()) / 2;

float endY = (perY + event.getY()) / 2;

path.quadTo(perX, perY, endX, endY);

perX = event.getX();

perY = event.getY();

postInvalidate();

break;

case MotionEvent.ACTION_UP:

break;

default:

break;

}

return super.onTouchEvent(event);

}

}

小编再为大家补充一段代码：android橡皮擦擦图片功能

public void onCreate() {

//底边图片

ImageView ivTop = (ImageView) findViewByid(R.id.iv_top);

Options opts = new Options(); //图片加载器，用于配置一些缩放比例，和像素单位

opts.inSampleSize = 2; //制定加载器把原图片的宽高缩放到2/1的效果加载

//获得外层图片,decodeResource方法默认获得的像素单位是RGB(red,green,blue),ARGB(alpha,red,green,blue)

Bitmap topImage = BitmapFactory.decodeResources( getResource(),R.drawable.top, opts);

//创建一张空白图片，并且把图片想读单位指定为:ARGB

Bitmap blank = Bitmap.createBitmap(topImage.getWidth(), topImage.getHeight, Config.ARGB_4444);

//把上边的topImage画到空白图片上

Canvas canvas = new Canvas(blank);

//把topImage画到空白图片上但是像素单位变成ARGB()

canvas.drawBitmap(topImage, 0, 0, null);

ivTop.setImageBitmap(blank);

}

class MyOnTouchListoner implements OnTouchListener {

@Override pulic boolean OnTouch(View v, MotionEvent event) {

//是否是移动的事件

if (event.getAction() == MotionEvent.ACTION_MOVE) {

//获得按下坐标

int x = (int) event.getX();

int y = (int) event.getY();

for (int i = x - 10; i < x + 10; i++) {

for (int j = y - 10; j < y + 10; j++) {

//防止超出边界

if (j >= 0 && blank.getHeight() && i >= 0 && i < blank.getWidth()) {

blank.setPixel(i, j, Color.TRANSPARENT);

}

}

}

//修改后的图片设置给ImageView

ivTop.setImageBitmap(blank);

}

return true; //true 消耗掉这次触摸事件.false 不消耗

}

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。