Page Curl effect using harism page curl library, page background appears with black border in place of transparency.

Hi I am using Harism Library for page curl effect (https://github.com/harism/android_page_curl). The effect is working fine but my page background has some transparent part which appears black. I have tried the solution mentioned in github forum (https://github.com/harism/android_page_curl/issues/25), its works but after that curl is not working. You can check my query there as well. You can check the attached screen shot as well.

Thanks!

    Comments these lines in the activity
                   r.left += border;
                   r.right -= border;
                   r.top += border;
                   r.bottom -= border;

                    r.left += ((r.width() - imageWidth) / 2) - border;
                    r.right = r.left + imageWidth + border + border;
                    r.top += ((r.height() - imageHeight) / 2) - border;
                    r.bottom = r.top + imageHeight + border + border;
replace this function in the CurlView Activity

public void setMargins(float left, float top, float right, float bottom) {
        mRenderer.setMargins(left, top, right, bottom);
    }