如何实现触摸平滑的图像橡皮擦在android系统？ [英] How to implement touch smooth image eraser in android?
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问题描述
我已经从API演示看到fingurePaint.java。我想实现触摸平滑的橡皮擦在android的触摸移动擦除部分图像。
I have already seen fingurePaint.java from API demos. I want to implement touch smooth eraser to erase parts of the image by touch move in android.
fingurePaint告诉我要实现这个
fingurePaint told me to implement this
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
但是，这是行不通的删除图像。它正在擦除东西其通过触摸绘制。
But this is not working to erase the image. It is working to erase something which is drawn by touch.
public class SandboxView extends View implements OnTouchListener {
public final Bitmap bitmap;
private final int width;
private final int height;
private Matrix transform = new Matrix();
private Vector2D position = new Vector2D();
private float scale = 1;
private float angle = 0;
public boolean isInitialized = false;
private TouchManager touchManager = new TouchManager(2);
final GestureDetector mGesDetect;
// Debug helpers to draw lines between the two touch points
private Vector2D vca = null;
private Vector2D vcb = null;
private Vector2D vpa = null;
private Vector2D vpb = null;
private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;
private Path mPath;
private Canvas mCanvas;
private Paint mPaint;
private Paint mBitmapPaint;
public SandboxView(Context context, Bitmap bitmap) {
super(context);
this.bitmap = bitmap;
this.width = bitmap.getWidth();
this.height = bitmap.getHeight();
this.mGesDetect = new GestureDetector(context, new DoubleTapGestureDetector());
setOnTouchListener(this);
}
private float getDegreesFromRadians(float angle) {
return (float)(angle * 360.0 / Math.PI);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (!isInitialized) {
Bitmap mBitmap = bitmap.createBitmap(320, 480, Bitmap.Config.ARGB_8888);
mCanvas = new Canvas(mBitmap);
mPaint = new Paint();
mPath = new Path();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(0xFFFF0000);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
mPaint.setAlpha(0);
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
mPaint.setAntiAlias(true);
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
int w = getWidth();
int h = getHeight();
position.set(w / 2, h / 2);
isInitialized = true;
}
if(isEraser==1){
canvas.drawColor(80000000);
canvas.drawBitmap(bitmap, transform, mBitmapPaint);
canvas.drawPath(mPath, mPaint);
}
else{
Paint paint = new Paint();
transform.reset();
transform.postTranslate(-width / 2.0f, -height / 2.0f);
transform.postRotate(getDegreesFromRadians(angle));
transform.postScale(scale, scale);
transform.postTranslate(position.getX(), position.getY());
canvas.drawBitmap(bitmap, transform, paint);
try {
/*paint.setColor(0xFF007F00);
canvas.drawCircle(vca.getX(), vca.getY(), 64, paint);
paint.setColor(0xFF7F0000);
canvas.drawCircle(vcb.getX(), vcb.getY(), 64, paint);
paint.setColor(0xFFFF0000);
canvas.drawLine(vpa.getX(), vpa.getY(), vpb.getX(), vpb.getY(), paint);
paint.setColor(0xFF00FF00);
canvas.drawLine(vca.getX(), vca.getY(), vcb.getX(), vcb.getY(), paint);*/
}
catch(NullPointerException e) {
// Just being lazy here...
}
}
}
private void touch_start(float x, float y) {
mPath.reset();
mPath.moveTo(x, y);
mX = x;
mY = y;
}
private void touch_move(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
mX = x;
mY = y;
}
}
private void touch_up() {
mPath.lineTo(mX, mY);
mCanvas.drawPath(mPath, mPaint);
mPath.reset();
}
@Override
public boolean onTouch(View v, MotionEvent event) {
if(isEraser ==1){
float x = event.getX();
float y = event.getY();
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touch_start(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
touch_move(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
touch_up();
invalidate();
break;
}
return true;
}
else{
vca = null;
vcb = null;
vpa = null;
vpb = null;
mGesDetect.onTouchEvent(event);
try {
touchManager.update(event);
if (touchManager.getPressCount() == 1) {
vca = touchManager.getPoint(0);
vpa = touchManager.getPreviousPoint(0);
position.add(touchManager.moveDelta(0));
}
else {
if (touchManager.getPressCount() == 2) {
vca = touchManager.getPoint(0);
vpa = touchManager.getPreviousPoint(0);
vcb = touchManager.getPoint(1);
vpb = touchManager.getPreviousPoint(1);
Vector2D current = touchManager.getVector(0, 1);
Vector2D previous = touchManager.getPreviousVector(0, 1);
float currentDistance = current.getLength();
float previousDistance = previous.getLength();
if (previousDistance != 0) {
scale *= currentDistance / previousDistance;
}
angle -= Vector2D.getSignedAngleBetween(current, previous);
}
}
invalidate();
}
catch(Throwable t) {
// So lazy...
}
return true;
}
}
class DoubleTapGestureDetector extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onDoubleTap(MotionEvent e) {
colorseekbar.setVisibility(View.INVISIBLE);
opacityseekbar.setVisibility(View.INVISIBLE);
return true;
}
}
}
所以，请帮我用触摸的举动抹去图像的部分。
So please help me to erase the parts of image by using touch move.
先谢谢了。
推荐答案
首先Declar您的油漆在你的构造全部财产。
First Declar your paint with all property in your constructor.
写这个code在的onDraw（）方式
@Override
protected void onDraw(Canvas canvas)
{
System.out.println("come in on draw......");
canvas.drawColor(Color.TRANSPARENT);
canvas.drawBitmap(mBitmap, 0, 0, mPaint);
if(eraser==true)
mPaint.setColor(Color.TRANSPARENT):
else
mPaint.setColor(Color.RED):
canvas.drawPath(mPath, mPaint);
super.dispatchDraw(canvas);
}
第二个解决方案：
拨打下面的方法在 TOUCH_MOVE（）方式
mBitmap.setPixel（X，Y，Color.TRANSPARENT）; 此方法将改变你的位图，你必须通过唯一的 X，Y＆安培; COLOR
mBitmap.setPixel(x, y, Color.TRANSPARENT); This method will change your bitmap you have to pass only X,Y & COLOR
public void changeBitmap(int x, int y, Bitmap mBitmap)
{
Bitmap tempBitmap = Bitmap.createBitmap(mBitmap); //Edited code
tempBitmap.setPixel(x, y, Color.TRANSPARENT);
}
private void touch_move(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
mX = x;
mY = y;
changeBitmap(x, y, your_bitmap)
}
}
这篇关于如何实现触摸平滑的图像橡皮擦在android系统？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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