Fill area between curve and x-axes

ROOT
1

Dear All
I am trying to fill a range of the area under a graph using “F”, option.
I added to the data file two point with (xmin,0)&(xmax,0).
so the option F works perfectly for the full area.
if at the end I add the option
gr1->Draw(“APL”); it will draw curve with point and line. (1)
gr1->Draw(“APF”); it will draw a filled curved (2)
gr1->Draw(“APLF”); this option does not keep the line ?? (3)

How can I fill and Keep the line??
and is it possible to fill only a range from the curve, without adding an additional point (x_range,0)??

cheers
1.pdf (17.4 KB)
2.pdf (17.4 KB)
3.pdf (17.4 KB)

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2 
gr1->Draw("APF");
gr1->Draw("L");
gPad->RedrawAxis();
3

thank you it it works.
My second enquiry is I want to divide the graph into three parts and fill each part with different color.
such as
x=0 to x= 56 (gray)
x=56 to x= 82 (red)
x=82 to x=235 (…)
How can I fill it without adding additional points (56,0), (82,0) (235,0)??
is it possible with fill option, or I should follow some other method??

4

To do that you will need to make 3 different graphs.