resize the bitmap canvas

Question

I am trying to draw rectangle on top of image and I am having trouble placing the art on the image. Only part of Rectangle shows up somewhere in bottom of screen. Here is what I am doing:

sinewave is the image from res>drawable folder

public void onDraw(Canvas canvas) 
{
     Bitmap myBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.sinewave);
     canvas.drawBitmap(myBitmap, 0, 0, null);

     Paint myPaint = new Paint();
     myPaint.setColor(Color.GREEN);
     myPaint.setStyle(Paint.Style.STROKE);
     myPaint.setStrokeWidth(3);
     canvas.drawRect(0, 35 ,80 , 20, myPaint);
}

I am not able to go beyond 35, I want to place the rectangle right in the middle of sinewave's image. Can some one help me with their ideas.

Answer 1

I'm not sure if this would work, but there is a getScaledHeight and width method on the bitmap you could try. If this gets the right bounds this would draw a rectangle on the outer border, but you could adjust to get it where you need.

int height = bm.getScaledHeight(canvas);
int width = bm.getScaledWidth(canvas);
Rect r = new Rect(0, 0, width, height);
canvas.drawRect(r, paint);