class TFileDrawMap: public TNamed

TFileDrawMap

 This class is automatically called by TFile::DrawMap
 It draws a canvas showing the internal structure of a ROOT file.
 Each key or basket in a file is shown with a fill area drawn
 at the byte position of the key/basket in the file.
 The Y axis of the canvas shows the number of Kbytes/Mbytes.
 The X axis shows the bytes between y(i) and y(i+1).
 A color corresponding to the class in the key/basket is automatically
 selected using the class unique identifier.

 When moving the mouse in the canvas, the "Event Status" panels
 shows the object corresponding to the mouse position.
 if the object is a key, it shows the class and object name as well as
    the file directory name if the file has sub-directories.
 if the object is a basket, it shows:
   -the name of the Tree
   -the name of the branch
   -the basket number
   -the entry number in the basket

 Special keys like the StreamerInfo record, the Keys List Record
 and the Free Blocks Record are also shown.

 When clicking the right mouse button, a pop-up menu is shown
 with its title identifying the picked object and with the items:
   -DrawObject: in case of a key, the Draw function of the object is called
                in case of a basket, the branch is drawn for all entries
   -DumpObject: in case of a key, the Dump function of the object is called
                in case of a basket, tree->Show(entry) is called
   -InspectObject: the Inspect function is called for the object.

 The normal axis zoom functionality can be used to zoom or unzoom
 One can also use the TCanvas context menu SetCanvasSize to make
 a larger canvas and use the canvas scroll bars.

 When the class is built, it is possible to identify a subset of the
 objects to be shown. For example, to view only the keys with
 names starting with "abc", set the argument keys to "abc*".
 The default is to view all the objects.
 The argument options can also be used (only one option currently)
 When the option "same" is given, the new picture is suprimposed.
 The option "same" is useful, eg:
  to draw all keys with names = "abc" in a first pass
 then all keys with names = "uv*" in a second pass, etc.