You have to set a ColorFilter
for you Paint
(I applied GREEN for better visualization):
BitmapShader shader = new BitmapShader(squaredBitmap, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP);
paint.setShader(shader);
paint.setAntiAlias(true);
PorterDuff.Mode mMode = PorterDuff.Mode.OVERLAY;
paint.setColorFilter(new PorterDuffColorFilter(Color.GREEN, mMode));