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Signature view not working on Android 8 + devices

I am working on an application which captures an applicant's signature and saves it to the phone memory. The class used for the signature view is given below
public class SignatureView extends View {
private static final float STROKE_WIDTH = 5f;
/** Need to track this so the dirty region can accommodate the stroke. **/
private static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;
private Paint paint = new Paint();
private Path path = new Path();
/**
* Optimizes painting by invalidating the smallest possible area.
*/
private float lastTouchX;
private float lastTouchY;
private final RectF dirtyRect = new RectF();
public SignatureView(Context context, AttributeSet attrs) {
super(context, attrs);
paint.setAntiAlias(true);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(STROKE_WIDTH);
}
/**
* Erases the signature.
*/
public void clear() {
path.reset();
// Repaints the entire view.
invalidate();
}
#Override
protected void onDraw(Canvas canvas) {
canvas.drawARGB(255, 233, 255, 255);
canvas.drawPath(path, paint);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(eventX, eventY);
lastTouchX = eventX;
lastTouchY = eventY;
// There is no end point yet, so don't waste cycles invalidating.
return true;
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_UP:
// Start tracking the dirty region.
resetDirtyRect(eventX, eventY);
// When the hardware tracks events faster than they are delivered, the
// event will contain a history of those skipped points.
int historySize = event.getHistorySize();
for (int i = 0; i < historySize; i++) {
float historicalX = event.getHistoricalX(i);
float historicalY = event.getHistoricalY(i);
expandDirtyRect(historicalX, historicalY);
path.lineTo(historicalX, historicalY);
}
// After replaying history, connect the line to the touch point.
path.lineTo(eventX, eventY);
break;
default:
//debug("Ignored touch event: " + event.toString());
return false;
}
// Include half the stroke width to avoid clipping.
invalidate(
(int) (dirtyRect.left - HALF_STROKE_WIDTH),
(int) (dirtyRect.top - HALF_STROKE_WIDTH),
(int) (dirtyRect.right + HALF_STROKE_WIDTH),
(int) (dirtyRect.bottom + HALF_STROKE_WIDTH));
lastTouchX = eventX;
lastTouchY = eventY;
return true;
}
/**
* Called when replaying history to ensure the dirty region includes all
* points.
*/
private void expandDirtyRect(float historicalX, float historicalY) {
if (historicalX < dirtyRect.left) {
dirtyRect.left = historicalX;
} else if (historicalX > dirtyRect.right) {
dirtyRect.right = historicalX;
}
if (historicalY < dirtyRect.top) {
dirtyRect.top = historicalY;
} else if (historicalY > dirtyRect.bottom) {
dirtyRect.bottom = historicalY;
}
}
/**
* Resets the dirty region when the motion event occurs.
*/
private void resetDirtyRect(float eventX, float eventY) {
// The lastTouchX and lastTouchY were set when the ACTION_DOWN
// motion event occurred.
dirtyRect.left = Math.min(lastTouchX, eventX);
dirtyRect.right = Math.max(lastTouchX, eventX);
dirtyRect.top = Math.min(lastTouchY, eventY);
dirtyRect.bottom = Math.max(lastTouchY, eventY);
}
// get drawn image as bitmap
public Bitmap getBitmap() {
this.setDrawingCacheEnabled(true);
this.buildDrawingCache();
Bitmap bmp = Bitmap.createBitmap(this.getDrawingCache());
this.setDrawingCacheEnabled(false);
return bmp;
}
public boolean isDrawn(){
return ! path.isEmpty();
}
}
This class returns the signature bitmap.This view works fine for devices with Android 8.0 and below, but its not working for Android 8.0 plus devices. For Devices above Android 8.0, the method getBitmap() returns a bitmap of the signature, but for Devices above Android 8.0, it returns empty.
Another Solution I tried which did not work either
public class SignatureViewType3 extends View {
private Bitmap _Bitmap;
private Canvas _Canvas;
private Path _Path;
private Paint _BitmapPaint;
private Paint _paint;
private float _mX;
private float _mY;
private float TouchTolerance = 4;
private float LineThickness = 4;
private boolean signatureAdded;
public SignatureViewType3(Context context, AttributeSet attr) {
super(context, attr);
_Path = new Path();
_BitmapPaint = new Paint(Paint.DITHER_FLAG);
_paint = new Paint();
_paint.setAntiAlias(true);
_paint.setDither(true);
_paint.setColor(Color.argb(255, 0, 0, 0));
_paint.setStyle(Paint.Style.STROKE);
_paint.setStrokeJoin(Paint.Join.ROUND);
_paint.setStrokeCap(Paint.Cap.ROUND);
_paint.setStrokeWidth(LineThickness);
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
_Bitmap = Bitmap.createBitmap(w, (h > 0 ? h : ((View) this.getParent()).getHeight()), Bitmap.Config.ARGB_8888);
_Canvas = new Canvas(_Bitmap);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
getParent().requestDisallowInterceptTouchEvent(true);
canvas.drawColor(Color.WHITE);
canvas.drawBitmap(_Bitmap, 0, 0, _BitmapPaint);
canvas.drawPath(_Path, _paint);
}
private void TouchStart(float x, float y) {
_Path.reset();
_Path.moveTo(x, y);
_mX = x;
_mY = y;
}
private void TouchMove(float x, float y) {
float dx = Math.abs(x - _mX);
float dy = Math.abs(y - _mY);
if (dx >= TouchTolerance || dy >= TouchTolerance) {
_Path.quadTo(_mX, _mY, (x + _mX) / 2, (y + _mY) / 2);
_mX = x;
_mY = y;
}
}
private void TouchUp() {
if (!_Path.isEmpty()) {
_Path.lineTo(_mX, _mY);
_Canvas.drawPath(_Path, _paint);
} else {
_Canvas.drawPoint(_mX, _mY, _paint);
}
signatureAdded = true;
_Path.reset();
}
#Override
public boolean onTouchEvent(MotionEvent e) {
super.onTouchEvent(e);
float x = e.getX();
float y = e.getY();
switch (e.getAction()) {
case MotionEvent.ACTION_DOWN:
TouchStart(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
TouchMove(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
TouchUp();
invalidate();
break;
}
return true;
}
public void clear() {
_Canvas.drawColor(Color.WHITE);
invalidate();
}
public byte[] getBytes() {
Bitmap b = getBitmap();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
b.compress(Bitmap.CompressFormat.PNG, 100, baos);
if(signatureAdded)
return baos.toByteArray();
else
return null;
}
public Bitmap getBitmap() {
View v = (View) this.getParent();
Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);
v.layout(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());
v.draw(c);
return b;
}
public boolean isDrawn(){
// return ! _Path.isEmpty();
return true;
}
}

getDrawingCache() is deprecated in Android API 28, so you should use Canvas like in this answer of Ashvin solanki
RelativeLayout view = (RelativeLayout)findViewById(R.id.relativelayout);
Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Drawable bgDrawable = view.getBackground();
if (bgDrawable != null) {
bgDrawable.draw(canvas);
} else {
canvas.drawColor(Color.WHITE);
}
view.draw(canvas);
or PixelCopy like in that article of Shivesh Karan Mehta:
// for api level 28
fun getScreenShotFromView(view: View, activity: Activity, callback: (Bitmap) -> Unit) {
activity.window?.let { window ->
val bitmap = Bitmap.createBitmap(view.width, view.height, Bitmap.Config.ARGB_8888)
val locationOfViewInWindow = IntArray(2)
view.getLocationInWindow(locationOfViewInWindow)
try {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
PixelCopy.request(
window,
Rect(
locationOfViewInWindow[0],
locationOfViewInWindow[1],
locationOfViewInWindow[0] + view.width,
locationOfViewInWindow[1] + view.height
), bitmap, { copyResult ->
if (copyResult == PixelCopy.SUCCESS) {
callback(bitmap) }
else {
}
// possible to handle other result codes ...
},
Handler()
)
}
} catch (e: IllegalArgumentException) {
// PixelCopy may throw IllegalArgumentException, make sure to handle it
e.printStackTrace()
}
}
}

Remove the last color form bitmap Undo

Please I need the help regarding Undo method , I tried to implement it like the code below but it is not remove the last color,
Kindly help me to resolve it.
awaiting your kind response.
Thanks in Advance.
MainActivity
public class MainActivity extends AppCompatActivity implements
View.OnTouchListener {
Button red, blue, yellow, undo;
Paint paint;
private RelativeLayout drawingLayout;
private MyView myView;
private ArrayList<Path> paths = new ArrayList<Path>();
private ArrayList<Path> undonePaths = new ArrayList<Path>();
/**
* Called when the activity is first created.
*/
/*
*
* private ImageView imageView; private Canvas cv; private Bitmap mask,
* original, colored; private int r,g,b; private int sG, sR, sB;
*/
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myView = new MyView(this);
drawingLayout = (RelativeLayout) findViewById(R.id.relative_layout);
drawingLayout.addView(myView);
red = (Button) findViewById(R.id.btn_red);
blue = (Button) findViewById(R.id.btn_blue);
yellow = (Button) findViewById(R.id.btn_yellow);
undo = (Button) findViewById(R.id.undo);
red.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
paint.setColor(Color.RED);
}
});
yellow.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
paint.setColor(Color.YELLOW);
}
});
blue.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
paint.setColor(Color.BLUE);
}
});
undo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myView.onClickUndo();
}
});
}
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
return false;
}
// flood fill
public class MyView extends View {
final Point p1 = new Point();
Bitmap mBitmap;
ProgressDialog pd;
Canvas canvas;
private Path path;
// Bitmap mutableBitmap ;
public MyView(Context context) {
super(context);
paint = new Paint();
paint.setAntiAlias(true);
pd = new ProgressDialog(context);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(5f);
mBitmap = BitmapFactory.decodeResource(getResources(),
R.drawable.gp1_1).copy(Bitmap.Config.ARGB_8888, true);
this.path = new Path();
}
public void onClickUndo() {
if (paths.size() > 0) {
undonePaths.add(paths.remove(paths.size() - 1));
invalidate();
} else {
Toast.makeText(getContext(), getString(R.string.nomore), Toast.LENGTH_SHORT).show();
}
}
#Override
protected void onDraw(Canvas canvas) {
this.canvas = canvas;
paint.setColor(Color.GREEN);
// int width = drawingLayout.getWidth();
// int height = drawingLayout.getHeight();
// float centerX = (width - mBitmap.getWidth()) * 0.5f;
//float centerY = (height - mBitmap.getHeight()) * 0.5f;
canvas.drawBitmap(mBitmap, 0, 0, paint);
///////////////////////////////
for (Path p : paths) {
canvas.drawPath(p, paint);
//////////////////////////
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
p1.x = (int) x;
p1.y = (int) y;
final int sourceColor = mBitmap.getPixel((int) x, (int) y);
final int targetColor = paint.getColor();
new TheTask(mBitmap, p1, sourceColor, targetColor).execute();
paths.add(path);
invalidate();
}
return true;
}
public void clear() {
path.reset();
invalidate();
}
public int getCurrentPaintColor() {
return paint.getColor();
}
class TheTask extends AsyncTask<Void, Integer, Void> {
Bitmap bmp;
Point pt;
int replacementColor, targetColor;
public TheTask(Bitmap bm, Point p, int sc, int tc) {
this.bmp = bm;
this.pt = p;
this.replacementColor = tc;
this.targetColor = sc;
pd.setMessage(getString(R.string.wait));
pd.show();
}
#Override
protected void onPreExecute() {
pd.show();
}
#Override
protected void onProgressUpdate(Integer... values) {
}
#Override
protected Void doInBackground(Void... params) {
FloodFill f = new FloodFill();
f.floodFill(bmp, pt, targetColor, replacementColor);
return null;
}
#Override
protected void onPostExecute(Void result) {
pd.dismiss();
invalidate();
}
}
}
public class FloodFill {
public void floodFill(Bitmap image, Point node, int targetColor,
int replacementColor) {
int width = image.getWidth();
int height = image.getHeight();
int target = targetColor;
int replacement = replacementColor;
if (target != replacement) {
Queue<Point> queue = new LinkedList<Point>();
do {
int x = node.x;
int y = node.y;
while (x > 0 && image.getPixel(x - 1, y) == target) {
x--;
}
boolean spanUp = false;
boolean spanDown = false;
while (x < width && image.getPixel(x, y) == target) {
image.setPixel(x, y, replacement);
if (!spanUp && y > 0
&& image.getPixel(x, y - 1) == target) {
queue.add(new Point(x, y - 1));
spanUp = true;
} else if (spanUp && y > 0
&& image.getPixel(x, y - 1) != target) {
spanUp = false;
}
if (!spanDown && y < height - 1
&& image.getPixel(x, y + 1) == target) {
queue.add(new Point(x, y + 1));
spanDown = true;
} else if (spanDown && y < height - 1
&& image.getPixel(x, y + 1) != target) {
spanDown = false;
}
x++;
}
} while ((node = queue.poll()) != null);
}
}
}
}

I guess you mean the undo method doesn't work. The possible reason is the previous drawing on the canvas is not removed. Try clearing the canvas before drawing in the onDraw() method.
#Override protected void onDraw(Canvas canvas) {
this.canvas = canvas;
canvas. drawColor(0,PorterDuff.Mode.CLEAR); //This clears the canvas.
paint.setColor(Color.GREEN);
//rest of the code
}

Seems it is impossible to return previous color it is required an array for each point to store the used color in every point.

Custom view being drawn sometimes

I have a custom view, that is sometimes being drawn and sometimes not .. this is reproduce-able across multiple phone.
Don't know why this is happening .. setDimensions() is being called during the onMeasure call of a GalleryGridElement (relative layout) which I use as gallery elements in my recyclerview.
One example would be .. going into the recycler view gallery activity, the circular progress view is there .. when you leave the activity and come back .. onResume creates a new adapter and gives it to the recycler view .. however the circular progress views don't show this time:
public class CircularProgressView extends View {
private Paint mIndicatorColour;
private RectF mIndicatorRect;
private Paint mBackCircleColour;
private static final float START_ANGLE = -90;
private volatile float mStopAngle = 0;
private float mOutterCircleStrokeWidth = 20;
private float mInnerCircleStrokeWidth = 16;
private float mViewWidth = 0, mViewHeight = 0;
private volatile int mCurrentProgress = 0;
private ExecutorService mExecutorService;
public CircularProgressView(Context context) {
super(context);
setUp();
}
public CircularProgressView(Context context, AttributeSet attrs) {
super(context, attrs);
setUp();
}
public CircularProgressView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
setUp();
}
private void setUp(){
mIndicatorRect = new RectF(0,0,300,300);
mIndicatorColour = new Paint();
mIndicatorColour.setColor(Color.parseColor("#D62F85"));
mIndicatorColour.setStyle(Paint.Style.STROKE);
mIndicatorColour.setStrokeWidth(mInnerCircleStrokeWidth);
mIndicatorColour.setAntiAlias(true);
mIndicatorColour.setDither(true);
mIndicatorColour.setStrokeJoin(Paint.Join.ROUND);
mIndicatorColour.setStrokeCap(Paint.Cap.ROUND);
mBackCircleColour = new Paint();
mBackCircleColour.setColor(Color.WHITE);
mBackCircleColour.setStyle(Paint.Style.STROKE);
mBackCircleColour.setStrokeWidth(mOutterCircleStrokeWidth);
mBackCircleColour.setAntiAlias(true);
mBackCircleColour.setDither(true);
mBackCircleColour.setStrokeJoin(Paint.Join.ROUND);
mBackCircleColour.setStrokeCap(Paint.Cap.ROUND);
mExecutorService = Executors.newSingleThreadExecutor();
}
public void setDimensions(float width, int scaleCircleThicknessValue){
mViewHeight = width;
mViewWidth = width;
mIndicatorRect.left = mIndicatorRect.top = mOutterCircleStrokeWidth;
mIndicatorRect.right = mIndicatorRect.bottom = width - mOutterCircleStrokeWidth;
mIndicatorColour.setStrokeWidth(mInnerCircleStrokeWidth);
mBackCircleColour.setStrokeWidth(mOutterCircleStrokeWidth);
mInnerCircleStrokeWidth = (0.1f * scaleCircleThicknessValue) * width;
mOutterCircleStrokeWidth = mInnerCircleStrokeWidth + 5;
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int desiredWidth = Math.round(mViewWidth);
int desiredHeight = Math.round(mViewHeight);
int width;
int height;
//Measure Width
if (widthMode == MeasureSpec.EXACTLY) {
//Must be this size
width = widthSize;
} else if (widthMode == MeasureSpec.AT_MOST) {
//Can't be bigger than...
width = Math.min(desiredWidth, widthSize);
} else {
//Be whatever you want
width = desiredWidth;
}
//Measure Height
if (heightMode == MeasureSpec.EXACTLY) {
//Must be this size
height = heightSize;
} else if (heightMode == MeasureSpec.AT_MOST) {
//Can't be bigger than...
height = Math.min(desiredHeight, heightSize);
} else {
//Be whatever you want
height = desiredHeight;
}
//Set values
setMeasuredDimension(width, height);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawArc(mIndicatorRect, 0, 360, false, mBackCircleColour);
canvas.drawArc(mIndicatorRect, START_ANGLE, mStopAngle, false, mIndicatorColour);
}
public synchronized void setProgress(final int progress) {
if ((mCurrentProgress != progress) && (progress > 0)) {
mCurrentProgress = progress;
mExecutorService.submit(new Runnable() {
#Override
public void run() {
final float currentAngle = mStopAngle;
float newAngle = (360f * ((float) progress / 100f));
float step = (Math.round(newAngle) - Math.round(currentAngle)) <= 1 ? 1 : (newAngle - currentAngle)/5f;
if (step < 0.01) {
newAngle = 359;
}
for (float i = currentAngle; i < newAngle; i += step) {
try {
mStopAngle = i;
postInvalidate();
Thread.sleep(1000 / 60);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
}
}
public float getProgress(){
return (360f-mStopAngle) < 1f ? 1 : mStopAngle / 360f;
}
}

Just following up on this incase someone runs into this issue:
Since I am using a custom view inside a custom view with the recycler view.
When I bind the view-holder to model, I make sure to completely re-render the view ... ie :
mCircularProgressView.setVisibility(VISIBLE);
mCircularProgressView.setDimensions(getWidth() * 0.82f, 1);
mCircularProgressView.requestLayout();
mCircularProgressView.postInvalidate();
This makes sure the view is drawn no matter what.

android - image alignment fault

My program is animating an imageView. This image should be in the very center of the screen. The problem is, that the image isn't in the center at all. I tried to do it with
if (x<0) {
x = this.getWidth()/2;
y = this.getHeight()/2;
}
but the program doesn't give the favored result. is it the wrong way to center it, or what's wrong?
public class AnimatedView extends ImageView{
private Context mContext;
int x = -1;
int y = -1;
private int xVelocity = 10;
private int yVelocity = 5;
private Handler h;
private final int FRAME_RATE = 30;
boolean continueAnimation = true;
private ImageView imageView;
private BitmapDrawable ball;
public AnimatedView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
h = new Handler();
imageView = (ImageView) findViewById(R.id.imageview1);
}
private Runnable r = new Runnable() {
#Override
public void run() {
if(continueAnimation) {
invalidate();
}
}
};
protected void onDraw(Canvas c) {
ball = (BitmapDrawable) mContext.getResources().getDrawable(R.drawable.ballrot);
if (x<0) {
x = this.getWidth()/2;
y = this.getHeight()/2;
}
else {
x += xVelocity;
if ((x > this.getWidth() - ball.getBitmap().getWidth()) || (x < 0)) {
boolean continueAnimation = false;
}
}
c.drawBitmap(ball.getBitmap(), x, y, null);
if(continueAnimation)
{
h.postDelayed(r, FRAME_RATE);
}
else {
x = this.getWidth()-ball.getBitmap().getWidth();
}
}
}

To calculate center position programmatically you need to know the size of the object to be centered and container where the object reside.
centerx = container.getWidth()/2 - obj.getWidth()/2;
centery = container.getHeight()/2 - obj.getHeight()/2;
With assumption that you use top left position of object

Changing path size without changing previous paths

I have an app for erasing the background, And I used a seekbar for changing the size of Eraser. but when I change the progress of SeekBar, the previous path change.
I want to change the path size without changing the previous paths
Main Activity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.image_overlay_bitmap);
scratchView = (WScratchView) findViewById(R.id.scratch_view);
global = ((Global) getApplicationContext());
scratchView.setRevealSize(1);
SeekBar seekbar = (SeekBar) findViewById(R.id.myseek);
seekbar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
#Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
scratchView.setRevealSize(progress);
}
});
if (getIntent().getExtras().getBoolean("isFromCrop")) {
Log.i("width", "" + global.getBitmap().getWidth());
Log.i("height", "" + global.getBitmap().getHeight());
// set bitmap to scratchview
// Bitmap bitmap =
// BitmapFactory.decodeResource(getResources(),R.drawable.test);
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
/*
* int height = displaymetrics.heightPixels; int width =
* displaymetrics.widthPixels;
*/
int height = global.getBitmap().getHeight();
int width = global.getBitmap().getWidth();
Bitmap scaledBitmap = Bitmap.createBitmap(width, height,
Config.ARGB_8888);
float ratioX = width / (float) global.getBitmap().getWidth();
float ratioY = height / (float) global.getBitmap().getHeight();
float middleX = width / 2.0f;
float middleY = height / 2.0f;
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(ratioX, ratioY, middleX, middleY);
Canvas canvas = new Canvas(scaledBitmap);
canvas.setMatrix(scaleMatrix);
canvas.drawBitmap(global.getBitmap(), middleX
- global.getBitmap().getWidth() / 2, middleY
- global.getBitmap().getHeight() / 2, new Paint(
Paint.FILTER_BITMAP_FLAG));
i = seekbar.getProgress();
scratchView.setRevealSize(i);
} else {
SharedPreferences settings = getApplicationContext()
.getSharedPreferences("pref", 0);
settings = getApplicationContext().getSharedPreferences("pref", 0);
String picture = settings.getString("file_path", "");
Bitmap mbitmap = BitmapFactory.decodeFile(picture);
scratchView.setScratchBitmap(mbitmap);
}
/*
* scratchView.setScratchBitmap(getResizedBitmap(global.getBitmap(),
* width, height));
*/
// scratchView.setOverlayColor(1);
//i = seekbar.getProgress();
// seekbar.setMax(100);
}
public Bitmap getResizedBitmap(Bitmap bm, int newHeight, int newWidth) {
int width = bm.getWidth();
int height = bm.getHeight();
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
Log.i("scalewidth", "" + scaleWidth);
Log.i("scaleheight", "" + scaleHeight);
// CREATE A MATRIX FOR THE MANIPULATION
Matrix matrix = new Matrix();
// RESIZE THE BIT MAP
matrix.postScale(scaleWidth, scaleHeight);
// RECREATE THE NEW BITMAP
Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height,
matrix, false);
return resizedBitmap;
}
private File captureImage() {
// TODO Auto-generated method stub
OutputStream output;
Calendar cal = Calendar.getInstance();
Bitmap bitmap = Bitmap.createBitmap(scratchView.getWidth(),
scratchView.getHeight(), Config.ARGB_8888);
bitmap = ThumbnailUtils.extractThumbnail(bitmap,
scratchView.getWidth(), scratchView.getHeight());
Canvas b = new Canvas(bitmap);
scratchView.draw(b);
// Find the SD Card path
File filepath = Environment.getExternalStorageDirectory();
// Create a new folder in SD Card
File dir = new File(filepath.getAbsolutePath() + "/demotemp/");
dir.mkdirs();
mImagename = "imageTemp" + ".png";
// Create a name for the saved image
file = new File(dir, mImagename);
// Show a toast message on successful save
Toast.makeText(ImageOverlayBitmap.this, "Image Saved to SD Card",
Toast.LENGTH_SHORT).show();
try {
output = new FileOutputStream(file);
// Compress into png format image from 0% - 100%
bitmap.compress(Bitmap.CompressFormat.PNG, 100, output);
output.flush();
output.close();
}
catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return file;
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void onClickHandler(View view) {
switch (view.getId()) {
case R.id.reset_button:
captureImage();
SharedPreferences settings = getApplicationContext()
.getSharedPreferences("pref", 0);
settings = getApplicationContext().getSharedPreferences("pref", 0);
SharedPreferences.Editor editor = settings.edit();
editor.putString("file_path", file.getPath());
editor.commit();
Intent i = new Intent(ImageOverlayBitmap.this,
SelectedImgActivity.class);
global.setfile_path(file.getPath());
i.putExtra("isBackgroundSet", false);
startActivity(i);
finish();
// scratchView.resetView();
break;
}
} }
Draw Activity
public WScratchView(Context ctx, AttributeSet attrs) {
super(ctx, attrs);
init(ctx, attrs);
}
public WScratchView(Context context) {
super(context);
init(context, null);
}
private void init(Context context, AttributeSet attrs) {
mContext = context;
// default value
mOverlayColor = DEFAULT_COLOR;
mRevealSize = DEFAULT_REVEAL_SIZE;
setZOrderOnTop(true);
SurfaceHolder holder = getHolder();
holder.addCallback(this);
holder.setFormat(PixelFormat.TRANSPARENT);
mOverlayPaint = new Paint();
mOverlayPaint.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
mOverlayPaint.setStyle(Paint.Style.STROKE);
mOverlayPaint.setStrokeCap(Paint.Cap.ROUND);
mOverlayPaint.setStrokeJoin(Paint.Join.ROUND);
// convert drawable to bitmap if drawable already set in xml
if (mScratchDrawable != null) {
mScratchBitmap = ((BitmapDrawable) mScratchDrawable).getBitmap();
}
mBitmapPaint = new Paint();
mBitmapPaint.setAntiAlias(true);
mBitmapPaint.setFilterBitmap(true);
mBitmapPaint.setDither(true);
}
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mScratchBitmap != null) {
if (mMatrix == null) {
float scaleWidth = (float) canvas.getWidth() / mScratchBitmap.getWidth();
float scaleHeight = (float) canvas.getHeight() / mScratchBitmap.getHeight();
mMatrix = new Matrix();
mMatrix.postScale(scaleWidth, scaleHeight);
}
canvas.drawBitmap(mScratchBitmap, mMatrix, mBitmapPaint);
} else {
canvas.drawColor(mOverlayColor);
}
for (Path path : mPathList) {
mOverlayPaint.setAntiAlias(mIsAntiAlias);
mOverlayPaint.setStrokeWidth(mRevealSize);
canvas.drawPath(path, mOverlayPaint);
}
}
private void updateScratchedPercentage() {
if(mOnScratchCallback == null) return;
mOnScratchCallback.onScratch(getScratchedRatio());
}
#Override
public boolean onTouchEvent(MotionEvent me) {
synchronized (mThread.getSurfaceHolder()) {
if (!mIsScratchable) {
return true;
}
switch (me.getAction()) {
case MotionEvent.ACTION_DOWN:
path = new Path();
path.moveTo(me.getX(), me.getY());
startX = me.getX();
startY = me.getY();
mPathList.add(path);
break;
case MotionEvent.ACTION_MOVE:
//if (mScratchStart) {
if (path.isEmpty()) {
path.lineTo(me.getX(), me.getY());
} else {
if (isScratch(startX, me.getX(), startY, me.getY())) {
mScratchStart = true;
}
updateScratchedPercentage();
break;
case MotionEvent.ACTION_UP:
mPathList.add(path);
// mScratchStart = false;
break;
}
return true;
}
}
private boolean isScratch(float oldX, float x, float oldY, float y) {
float distance = (float) Math.sqrt(Math.pow(oldX - x, 2) + Math.pow(oldY - y, 2));
if (distance > mRevealSize * 2) {
return true;
} else {
return false;
}
}
#Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
// do nothing
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mScratchedTestBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
mScratchedTestCanvas = new Canvas(mScratchedTestBitmap);
}
#Override
public void surfaceCreated(SurfaceHolder arg0) {
mThread = new WScratchViewThread(getHolder(), this);
mThread.setRunning(true);
mThread.start();
mScratchedTestBitmap = Bitmap.createBitmap(arg0.getSurfaceFrame().width(), arg0.getSurfaceFrame().height(), Bitmap.Config.ARGB_8888);
mScratchedTestCanvas = new Canvas(mScratchedTestBitmap);
}
#Override
public void surfaceDestroyed(SurfaceHolder arg0) {
boolean retry = true;
mThread.setRunning(false);
while (retry) {
try {
mThread.join();
retry = false;
} catch (InterruptedException e) {
// do nothing but keep retry
}
}
}
class WScratchViewThread extends Thread {
private SurfaceHolder mSurfaceHolder;
private WScratchView mView;
private boolean mRun = false;
public WScratchViewThread(SurfaceHolder surfaceHolder, WScratchView view) {
mSurfaceHolder = surfaceHolder;
mView = view;
}
public void setRunning(boolean run) {
mRun = run;
}
public SurfaceHolder getSurfaceHolder() {
return mSurfaceHolder;
}
#Override
public void run() {
Canvas c;
while (mRun) {
c = null;
try {
c = mSurfaceHolder.lockCanvas(null);
synchronized (mSurfaceHolder) {
if (c != null) {
mView.draw(c);
}
}
} finally {
if (c != null) {
mSurfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
#Override
public void resetView() {
synchronized (mThread.getSurfaceHolder()) {
mPathList.clear();
}
}
#Override
public boolean isScratchable() {
return mIsScratchable;
}
#Override
public void setScratchable(boolean flag) {
mIsScratchable = flag;
}
#Override
public void setOverlayColor(int ResId) {
mOverlayColor = ResId;
}
#Override
public void setRevealSize(int size) {
Canvas canvas = new Canvas();
//mScratchedTestBitmap = Bitmap.createBitmap(mScratchedTestBitmap.getWidth(), mScratchedTestBitmap.getWidth(), Bitmap.Config.ARGB_8888);
//mScratchedTestCanvas = new Canvas(mScratchedTestBitmap);
canvas.drawBitmap(mScratchBitmap,mMatrix, mBitmapPaint);
mRevealSize = size;
}
#Override
public void setAntiAlias(boolean flag) {
mIsAntiAlias = flag;
}
#Override
public void setScratchDrawable(Drawable d) {
mScratchDrawable = d;
if (mScratchDrawable != null) {
mScratchBitmap = ((BitmapDrawable) mScratchDrawable).getBitmap();
}
}
#Override
public void setScratchBitmap(Bitmap b) {
mScratchBitmap = b;
}
#Override
public float getScratchedRatio() {
return getScratchedRatio(DEFAULT_SCRATCH_TEST_SPEED);
}
/**
* thanks to https://github.com/daveyfong for providing this method
*/
#Override
public float getScratchedRatio(int speed) {
if (null == mScratchedTestBitmap) {
return 0;
}
draw(mScratchedTestCanvas);
final int width = mScratchedTestBitmap.getWidth();
final int height = mScratchedTestBitmap.getHeight();
int count = 0;
for (int i = 0; i < width; i += speed) {
for (int j = 0; j < height; j += speed) {
if (0 == Color.alpha(mScratchedTestBitmap.getPixel(i, j))) {
count++;
}
}
}
float completed = (float) count / ((width / speed) * (height / speed)) * 100;
return completed;
}
public void setOnScratchCallback(OnScratchCallback callback) {
mOnScratchCallback = callback;
}
public static abstract class OnScratchCallback{
public abstract void onScratch(float percentage);
}
#Override
public void setScratchAll(boolean scratchAll) {
// TODO Auto-generated method stub
}
#Override
public void setBackgroundClickable(boolean clickable) {
// TODO Auto-generated method stub
} }

I noticed that in your onDraw() routine, you are setting the stroke width of every path to mRevealSize. Also, this mRevealSize is what is changed by the SeekBar.
I think what you need to do is capture the stroke width mRevealSize every time an erase path is made by the user, and store that stroke width in a list that complements mPathList. Then your onDraw() would have:
for (int i = 0; i < mPathList.size(); i++) {
mOverlayPaint.setAntiAlias(mIsAntiAlias);
mOverlayPaint.setStrokeWidth(mStrokeList.get(i));
canvas.drawPath(mPathList.get(i), mOverlayPaint);
}