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androidbitmapregion

How to remove the drawing from a bitmap of a particular region in Android

I have a bitmap object.

I have a Region object that represents a small portion of the bitmap;

I want to remove drawing from the bitmap object of that particular region and make that portion transparent..

How to do it? any help....

I am using android api-level 8..

Solution

  • You can simply make a pixel transparent by using mBitmap.setPixel (100,100,Color.TRANSPARENT);, so basic idea is to iterate over all the pixel to make it transparent, but if you have to iterate over too many pixels, it might be slow.

    OR

    You can use PorterDuffXferMode to make a portion transparent,

    For an example create a paint object as mentioned below and pass it to the canvas:

    Paint mPaint = new Paint();
mPaint.setXferMode(new PorterDuffXferMode(PorterDuff.Mode.CLEAR));

    You can pass it to the canvas as described below:

     Canvas c = new Canvas(mBitmap);
 c.drawCircle(cx, cy, radius, paint);

    It is for the circle but hope you will get the hint to do it for the custom region as per your need.

    If still it is not working then you might have to disable Hardware Acceleration for that particular View. For more information, refer this Google DOC.

    Hope this will give you some hint.