New vendor option to disable gray mark fallback when no graphic or mark could be loaded

Description

Currently, when none of the external graphics or marks in a Graphic can be processed, a gray mark is used.
The specification is not super-clear on this part, it says that the fallback should be used when none is provided, but does not say what to do when they are provided, but the lookup fails.

To preserve backwards compatibility I'm adding a new boolean vendor option, "fallbackOnDefaultMark", defaulting to true, that can be used to disable the above behavior, and paint nothing instead.

Environment

None

Assignee

Andrea Aime

Reporter

Andrea Aime

Triage

None

Components

Fix versions

Priority

Medium
Configure