How set matrix in PDFRenderer to get bitmap without cropmark (mediabox,cropbox)

I try to re-render bitmap from pdf with scale and translation, and all is good but when i zoom in pdf page is re-render with cropmark.

I use PDFRender control, this is my code

Matrix nM = new Matrix();

RectF r1 = new RectF(0,0,viewWidth/2,viewHeight);

RectF src = new RectF(0,0,mCurrentPage.getWidth(),mCurrentPage.getHeight());

nM.postScale(scaleX, scaleY);

nM.postTranslate(transX, transY);

nM.mapRect(r1);

nM.setRectToRect(src,r1, Matrix.ScaleToFit.FILL);

mCurrentPage.render(bitmap,null, nM,PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);

When I not set change matrix(nM) to null is render without cropmark but is render all page not zoom in.