Hello,
I need to get some clarifications about the pdf specification.
The specification says (in 11.6.6) that operator Do should perform the following actions when applied on a transparency group:
"Before execution of the transparency group XObject’s content stream, the current blend mode in the graphics state shall be initialized to
Normal, the current stroking and nonstroking alpha constants to 1.0, and the current soft mask to None."
Does this also apply when using a transparency group XObject as a soft mask? If not, should the newly produced soft mask really be affected by the previous soft mask and how?
Another thing that the Do operator is expected to do for form XObjects in general is to save the graphic state at the beginning of their stream and restore it at the end. How about that? It's not mentioned anywhere when talking about group XObjects used as soft masks but I assume it should be done for them as well.