Graphical click

hii to all root user…

i want to put marker on histogram or any kind of graphs by just mouse clicking on canvas how can i do that…

You can add one or more marker on top of any picture by using the graphics editor.
If you have a canvas:
-go to the canvas menu bar and ijn “View” select “View Editor”
-in the editor in “View” select “ToolBar”
-in the tool bar select the primitive Marker

For more info about the graphics editor see Help button in canvas