class TGaxis: public TLine, public TAttText

 TGaxis default constructor.

 TGaxis normal constructor.
 See explanation of parameters in PaintAxis.

 TGaxis constructor with a TF1 to map axis values.

  See explanation of parameters in PaintAxis
  Instead of the wmin,wmax arguments of the normal constructor, the
  name of a TF1 function can be specified. This function will be used
  by TGaxis::PaintAxis to map the user coordinates to the axis values
  and ticks.
  Examples:
void gaxis3a()
{
   gStyle->SetOptStat(0);

   TH2F *h2 = new TH2F("h","Axes",100,0,10,100,-2,2);
   h2->Draw();

   TF1 *f1=new TF1("f1","-x",-10,10);
   TGaxis *A1 = new TGaxis(0,2,10,2,"f1",510,"-");
   A1->SetTitle("axis with decreasing values");
   A1->Draw();

   TF1 *f2=new TF1("f2","exp(x)",0,2);
   TGaxis *A2 = new TGaxis(1,1,9,1,"f2");
   A2->SetTitle("exponential axis");
   A2->SetLabelSize(0.03);
   A2->SetTitleSize(0.03);
   A2->SetTitleOffset(1.2);
   A2->Draw();

   TF1 *f3=new TF1("f3","log10(x)",1,1000);
   TGaxis *A3 = new TGaxis(2,-2,2,0,"f3",505,"G");
   A3->SetTitle("logarithmic axis");
   A3->SetLabelSize(0.03);
   A3->SetTitleSize(0.03);
   A3->SetTitleOffset(1.2);
   A3->Draw();
}

 Copy constructor.

 Assignement operator.

 TGaxis default destructor.

 If center = kTRUE axis labels are centered in the center of the bin.
 The default is to center on the primary tick marks.
 This option does not make sense if there are more bins than tick marks.

 If center = kTRUE axis title will be centered.
 The default is right adjusted.

 Draw this axis with new attributes.

 Static function returning fgMaxDigits (See SetMaxDigits).

 Copy TAxis attributes to this TGaxis.

 Draw this axis with its current attributes.

 Control function to draw an axis.

 Original authors: O.Couet C.E.Vandoni N.Cremel-Somon.
 Modified and converted to C++ class by Rene Brun.

 _Input parameters:

  xmin      : X origin coordinate in WC space.
  xmax      : X end axis coordinate in WC space.
  ymin      : Y origin coordinate in WC space.
  ymax      : Y end axis coordinate in WC space.
  wmin      : Lowest value for the tick mark
              labels written on the axis.
  wmax      : Highest value for the tick mark labels
              written on the axis.
  ndiv      : Number of divisions.

       ndiv=N1 + 100*N2 + 10000*N3
       N1=number of 1st divisions.
       N2=number of 2nd divisions.
       N3=number of 3rd divisions.
           e.g.:
           nndi=0 --> no tick marks.
           nndi=2 --> 2 divisions, one tick mark in the middle
                      of the axis.

  chopt :  options (see below).

       chopt='G': loGarithmic scale, default is linear.
       chopt='B': Blank axis. Useful to superpose axis.

 Orientation of tick marks on axis.


   Tick marks are normally drawn on the positive side of the axis,
   however, if x0=x1, then negative.

       chopt='+': tick marks are drawn on Positive side. (default)
       chopt='-': tick mark are drawn on the negative side.
       i.e: '+-' --> tick marks are drawn on both sides of the axis.
       chopt='U': Unlabeled axis, default is labeled.

 Size of tick marks

 By default, tick marks have a length equal to 3 per cent of the
 axis length.
 When the option "S" is specified, the length of the tick marks
 is equal to fTickSize*axis_length, where fTickSize may be set
 via TGaxis::SetTickSize.

 Position of labels on axis.


   Labels are normally drawn on side opposite to tick marks.
   However:

       chopt='=': on Equal side

 Orientation of labels on axis.


   Labels are normally drawn parallel to the axis.
   However if x0=x1, then Orthogonal
           if y0=Y1, then Parallel

 Position of labels on tick marks.


   Labels are centered on tick marks.
   However , if x0=x1, then they are right adjusted.

       chopt='R': labels are Right adjusted on tick mark.
                    (default is centered)
       chopt='L': labels are Left adjusted on tick mark.
       chopt='C': labels are Centered on tick mark.
       chopt='M': In the Middle of the divisions.

 Format of labels.


   Blank characters are stripped, and then the
   label is correctly aligned. the dot, if last
   character of the string, is also stripped,
   unless the option "." (a dot, or period) is specified.
   if SetDecimals(kTRUE) has been called (bit TAxis::kDecimals set).
   all labels have the same number of decimals after the "."
   The same is true if gStyle->SetStripDecimals(kFALSE) has been called.

   In the following, we have some parameters, like
   tick marks length and characters height (in percentage
   of the length of the axis (WC))
   The default values are as follows:

   Primary tick marks: 3.0 %
   Secondary tick marks: 1.5 %
   Third order tick marks: .75 %
   Characters height for labels: 4%

   Labels offset: 1.0 %

 optional grid.


       chopt='W': cross-Wire
   In case of a log axis, the grid is only drawn for the primary tick marks
   if the number of secondary and tertiary divisions is 0.

 Axis bining optimization.


   By default the axis bining is optimized .

       chopt='N': No bining optimization
       chopt='I': Integer labelling

 Maximum Number of Digits for the axis labels

 See the static function TGaxis::SetMaxDigits

 Time representation.


   Axis labels may be considered as times, plotted in a defined time format.
   The format is set with SetTimeFormat().
   wmin and wmax are considered as two time values in seconds.
   The time axis will be spread around the time offset value (set with
   SetTimeOffset() ). Actually it will go from TimeOffset+wmin to
   TimeOffset+wmax.
   see examples in tutorials timeonaxis.C and timeonaxis2.C

       chopt='t': Plot times with a defined format instead of values

 Axis labels optimisation.

   This method adjusts the bining of the axis
   in order to have integer values for the labels.

 Input parameters:

  A1,A2    : Old WMIN,WMAX .
  binLow,binHigh : New WMIN,WMAX .
  nold     : Old NDIV (primary divisions)
  nbins    : New NDIV .

 Find first and last character of a label.

 Rotate axis coordinates.

 Save primitive as a C++ statement(s) on output stream out

 Set the Decimals flag
 By default, blank characters are stripped, and then the
 label is correctly aligned. The dot, if last character of the string,
 is also stripped, unless this option is specified.
 One can disable the option by calling axis.SetDecimals(kTRUE).
 Note the bit is set in fBits (as opposed to fBits2 in TAxis!)

 Specify a function to map the axis values.

 Static function to set fgMaxDigits for axis with the bin content
 (y axis for 1-d histogram, z axis for 2-d histogram)
 fgMaxDigits is the maximum number of digits permitted for the axis
 labels above which the notation with 10^N is used.
 For example, to accept 6 digits number like 900000 on an axis
 call TGaxis::SetMaxDigits(6). The default value is 5.
 fgMaxDigits must be greater than 0.

 Change the name of the axis.

 Set the kMoreLogLabels bit flag.
 When this option is selected more labels are drawn when in log scale
 and there is a small number of decades  (<3).
 Note that this option is automatically inherited from TAxis

 Set the NoExponent flag.
 By default, an exponent of the form 10^N is used when the label values
 are either all very small or very large.
 One can disable the exponent by calling axis.SetNoExponent(kTRUE).

 To set axis options.

 Change the title of the axis.

 Change the format used for time plotting.
 The format string for date and time use the same options as the one used
 in the standard strftime C function, i.e. :
   for date :
     %a abbreviated weekday name
     %b abbreviated month name
     %d day of the month (01-31)
     %m month (01-12)
     %y year without century

   for time :
     %H hour (24-hour clock)
     %I hour (12-hour clock)
     %p local equivalent of AM or PM
     %M minute (00-59)
     %S seconds (00-61)
     %% %

 Change the time offset.
 If option = "gmt" the time offset is treated as a GMT time.

 Stream an object of class TGaxis.