Translation from arc-seconds ROI to percentage ROI used in Kakadu fails for some requests

[Keith Hughitt]

Example:

http://www.helioviewer.org/api/index.php?action=getTile&uri=%2FAIA%2F193%2F2010%2F12%2F19%2F2010_12_19__04_03_43_84__SDO_AIA_AIA_193.jp2&x1=-0.3&x2=1228.5&y1=-2457.2999999999997&y2=-1228.5&format=jpg&imageScale=2.4&jp2Width=4096&jp2Height=4096&jp2Scale=0.6&instrument=AIA&detector=AIA&measurement=193&offsetX=0.5&offsetY=-0.5

Even though the height is non-zero, the kakadu region that is generated for the request is:

  -region \{0,0.5\},\{0,0.5\}

which has a zero height (format for input is {<top>,<left>},{<height>,<width>}).

Occurs very infrequently so marking as low priority for now.