Fontsize of Axis Labels in TMultiGraph


I’m facing an issue with TMultiGraph and SetLabelSize. When I set the size of the axis-labels via SetLabelSize to my desired value and then I do a UnZoom on the y-axis, the size of axis-labels on the y-axis and even on the x-axis gets reset to some kind of default value.

Please see the following example, which is basically a stripped-down version of the fifth example of the TMultiGraph class documentation.

TCanvas *c3 = new TCanvas(“c3”,“c3”,600, 400);

TMultiGraph * mg = new TMultiGraph(“mg”,“mg”);

const Int_t size = 10;

double x[size];
double y1[size];

for ( int i = 0; i < size ; ++i ) {
x[i] = i;
y1[i] = size - i;

TGraph * gr1 = new TGraph( size, x, y1 );

mg->Add( gr1 );



return c3;

After executing that, please go with the mouse on the y-axis and do “UnZoom”. You should see the fontsize of the x- and y-axis changing.

I’m using ROOT 5.34/07 (tags/v5-34-07@49362, Apr 26 2013, 13:01:34 on win32).

Thanks for discussion,

I see it when I unzoom the Y axis only. I’ll check.

I can confirm. It’s only when unzooming the y-axis, not when unzooming the x-axis.

Now fixed in the trunk an in 5.34.

Thank you so much!

Sorry to come back to this so late, but due to our IT company policy I’m not able to tell my IT department to install updates within a narrow time frame.

I now got the update to ROOT 5.34/13 (v5-34-13@v5-34-13, Dec 01 2013, 12:01:56 on win32) and tested the provided example again.

Please zoom to the y axis and after that do an unzoom. You will see the labels of x and y axis still resized.

for me it is fixed …
have you reinstalled the latest root ?
is it on windows only ?

I don’t know if it’s the “latest” ROOT. As mentioned in my previous post, after the recent update here it’s now version 5.34/13, which was the latest pro version as of last week. I guess, this should include your fix from a couple of months ago.

Also, I don’t have access to a non-windows version.

From what I remember about the issue back then, the behaviour has now slightly changed: Back then, you just had to click “unzoom” on the y axis.

Now, you have to actually first zoom into the y axis and after that do an unzoom. Then, you see the fontsize for the x and the y axis changing. I want to highlight, that this issue does not occur on zooming actions on the x axis.

ok … i see … will check…

In fact this fixed had very bad side effects and I was obliged to make some workaround which seems to
not be satisfactory… see
We must be careful there … the current state is “better” than the side effects it produced.