Bridging would be relatively easy: figure out what the moz-cairo context is actually drawing to; construct a system-cairo context to draw to the same target; set its state to match the state of the moz-cairo context.
Bridging would be relatively easy: figure out what the moz-cairo context is actually drawing to; construct a system-cairo context to draw to the same target; set its state to match the state of the moz-cairo context.