Any presentation element, such as a shape filled transparency gradient, that is not otherwise supported by the PDF export should be rasterized appropriately and substituted for the original when exporting to PDF.

Rasterization parameters could be added as options to the PDF export dialog (e.g., setting the dpi), or if the interface were extended further even allow per-object control over this.

Currently users must rasterize non-conformant objects by exporting to a suitable format, importing and replacing the original object with the rasterized object. This is sub-optimal in that:

1. it requires the user notice or previously be aware of each case that causes an issue
2. it requires the user to go through multiple steps for each object
3. it requires making changes to the document

Although this is listed as a PDF export enhancement request it equally applies to postscript printing for the same reasons.

I like this option too for an upcoming PGS.