Deal with negative coordinate data

[martinleopold]

...
{"type":"stroke","node":{"y":38.88999938964844,"x":44.060001373291016,"pressure":0.1568627506494522,"timeDiff":9}},
{"type":"stroke","node":{"y":-1,"x":-1,"pressure":0.1568627506494522,"timeDiff":8}},
{"status":"up","type":"updown","time":1512055509053,"color":0}]

[martinleopold]

Seems to be introduced by the PenTest client side web app.

PenTest Server Log (Xcode):

HANDLE process stroke: {"type":"stroke","node":{"y":50.659999847412109,"x":19.979999542236328,"pressure":0.15686275064945221,"timeDiff":8}}
HANDLE process stroke: {"type":"stroke","node":{"y":50.590000152587891,"x":19.690000534057617,"pressure":0.15686275064945221,"timeDiff":9}}
HANDLE process stroke: {"status":"up","type":"updown","time":1512058299311,"color":0}

-> correct

PenTest WebSocket Client Log:

RESPONSE: {"type":"stroke","node":{"y":50.659999847412109,"x":19.979999542236328,"pressure":0.15686275064945221,"timeDiff":8}}
RESPONSE: {"type":"stroke","node":{"y":50.590000152587891,"x":19.690000534057617,"pressure":0.15686275064945221,"timeDiff":9}}
RESPONSE: {"status":"up","type":"updown","time":1512058299311,"color":0}

-> correct

Saved JSON:

{"type":"stroke","node":{"y":50.65999984741211,"x":19.979999542236328,"pressure":0.1568627506494522,"timeDiff":8}},
{"type":"stroke","node":{"y":-1,"x":-1,"pressure":0.1568627506494522,"timeDiff":9}},
{"status":"up","type":"updown","time":1512058299311,"color":0}]

-> introduced error in last stroke event