Setting the opacity of histogram line?

Newbie
1

Hi everyone,

I am trying to set the opacity of a TH1F histogramh_singles (red) line using

h_singles->SetLineColorAlpha(kRed, 0.164);

However, I am not seeing any visible changes in the canvas. Numerically I can see the opacity has been set but it doesn’t appear to be the case from visual inspection.

image
image869×538 32.6 KB

Can someone please suggest what is the right way of going about this?

Thanks a ton !

Edit 1: I think when I export to pdf (not png)it works.
image

2

As said here:

The transparency is available on all platforms when the flag OpenGL.CanvasPreferGL is set to 1 in $ROOTSYS/etc/system.rootrc , or on Mac with the Cocoa backend. On the file output it is visible with PDF, PNG, Gif, JPEG, SVG, TeX … but not PostScript.

1 Like
3

Thanks a lot for pointing the issue.