PDF MP operator

[PS-Interp]

I have a PDF job. The test case contains 12345 MP in its /Contents stream.

The PDF spec says that MP operator requires a name operand. But Adobe

printers and Acrobat seem to ignore the error. Does anybody know why?

[Test Screen Name]

Acrobat is not a validator. As an implementation, if there is no reason to use the result of an operator - which has no effect on display or printing - the operator is likely to be skipped. There is also no obligation to report an error even if one is detected.

Better forum for PDF language questions: PDF Language and Specifications

[PS-Interp]

Thanks so much for the response.Why you say that MP "has no effect on display or printing"? I could not reach the same conclusion from the spec.

[Test Screen Name]

Well, it doesn't affect the graphics state, and it doesn't mark the page, so I see that as "no effect". A renderer has to be aware of it enough to skip the operator and its operands, but this could be done without even being aware of the existence of the MP operator, since every operator leaves the stack clear.

[Test Screen Name]

What sort of effect are you thinking of?