Android: Bitmap: How to save a canvas with a green background in Android?

Question

I use Bitmap to create an Image digital signature. When saving the signature on the device, only the signature was saved with a black background. I want a green background with a signature.

Here it is my raster code

// Bitmap View public class MyView extends View implements OnClickListener { public int height; public int width; private Bitmap mBitmap; private Path mPath; private Paint mBitmapPaint; public MyView(Context c) { super(c); mPath = new Path(); mBitmapPaint = new Paint(Paint.DITHER_FLAG); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); Wid = w; Ht = h; mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); mCanvas = new Canvas(mBitmap); } @Override protected void onDraw(final Canvas canvas) { canvas.drawColor(0xFFFFFFFF); canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint); canvas.drawPath(mPath, mPaint); // onclick listner for SAVE button saveButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { //capture the image try { saveAsJpg(mBitmap); startActivity(new Intent(Paint.this, SignatureActivity.class)); finish(); } catch (IOException e) { e.printStackTrace(); } } }); } private float mX, mY; private static final float TOUCH_TOLERANCE = 4; private void touch_start(float x, float y) { mPath.reset(); mPath.moveTo(x, y); mX = x; mY = y; System.out.println("---- " +mX); } 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); // commit the path to our offscreen mCanvas.drawPath(mPath, mPaint); // kill this so we don't double draw mPath.reset(); } @Override public boolean onTouchEvent(MotionEvent event) { float x = event.getX(); float y = event.getY(); 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; } 

I can see a green background when creating a signature, but it remains on a black black background. please help me, thanks in advance

Answer 1

@rahul You can also use this in onDraw

  canvas.drawColor(Color.GREEN); 

Please check my code update

 @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); mCanvas = new Canvas(mBitmap); mCanvas.drawColor(Color.GREEN); super.onSizeChanged(w, h, oldw, oldh); } 

Answer 2

Try changing this in onDraw

  canvas.drawColor(0xFFFF0000); 

Answer 3

canvas.drawColor changes the canvas but not the bitmap, you can fill the bitmap

 bitmap.eraseColor(color); 

Answer 4

Try this code to save the file.

 FileOutputStream fos = new FileOutputStream(Yourpath); bitmap.compress(CompressFormat.JPEG, 80, fos); 

As you have posted what you want to keep, this will work.