umils
Number of millimetres which equal one current paper unit
Description
When a device is nominated, the default unit of measure is a millimetre. A call to gDefinePictureUnits() will set the current units so that one new unit of measure is equal to umils millimetres, e.g. a call to gDefinePictureUnits(25.4) sets the current paper units to inches. gDefinePictureUnits() must be called before the start of any graphical output. If umils is less than or equal to zero, an error message is output and the current units are not changed.
Users may, at any time, set up a viewport to map user coordinates of any range onto the current device or paper limits using the routine gSetViewport2D().
