Specifies the trim box defining the intended dimensions of the finished page after trimming.
To include the production-related content (e.g., printing instructions, cut marks or color bars), the trim box may be smaller than the PdfPageTreeObject.MediaBox setting.
The default setting is the page’s PdfPageTreeObject.CropBox value.
The PDF page unit of measurement is points, which measures 1/72 of an inch (0.3528 mm). You can convert this unit of measurement, e.g., to pixels using the Units.PointsToPixelsF method.