[ROOT] Strange Tree draw behavior

From: Luca Grandi (luca.grandi@pv.infn.it)
Date: Thu Dec 16 2004 - 14:06:02 MET

Dear all,

I found a strange behavior using tree Draw on a specific frame.

When i plot a tree without a predefined frame and i change the Y axis scale
from linear to log the range is fixed by root and several points of the plot
are excluded. For this reason I have followed a suggestion to create a
predefined frame to fix the logarithmic range for the Y axis.
I am using the following example

TCanvas *c7 = new TCanvas("c7","Lifetime",+0,+0,900,680);
TH2F frame7("frame","Lifetime", 1, 0, 60, 1000, 1, 1000);

Now with the treeviewer I plot on the frame a first plot with

tv_tree->Draw("br.var1:br.var2","several cuts","same");

At this point everything is OK.

When I want to add another plot (with a similar command) on the same frame
but with different cuts it creates a strange plot where the points are
placed in a way different from what they look like when I plot them
singularly. In other words the points are placed in a strange way and
filling some region of the plot that are wrong (I know this since when I
plot the second plot as first I found a regular behavior).



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