Re: TGraph: BuildLegend() and the Draw() default options

Hi Vassili,

There are 2 different views to this problem.   1-you consider TGraph in the same family that the vast majority of graphics primitives like TPolyLine, TLine, TBox, etc.

   These primitives can be drawn without any options, typically you draw many of them in the same pad and you do not expect

   a new canvas being created by each Draw, or the current pad being erased before drawing it.

  2-you consider TGraph in the family of high level primitives like TH1, TF1 where in this case the typical use is to draw

   one single object and you expect that the default is to erase the pad.

The current system allows you to draw TGraph in both modes.

Rene Brun

Maroussov wrote:
> Dear Oliver,
>
> what I meant: I expect very similar behavior of objects with Draw()
> method in ROOT. If I draw, for instance, TF1 I'll get some graphical
> output with default options and BuildLegend will use a proper
> background, but TGraph behaves somehow in a different way. Sure it is
> not a bug, but a feature, but I think with default options some output
> must always be produced... Shouldn't defaults be "AL"?
>
> Regards,
>
> Vassili
>
>
> On 06/24/2010 04:07 PM, Olivier Couet wrote:
>>
>>> For some reason it uses black background for the legend graphical
>>>
>> part, - please see the image attached. How to correct that?
>>
>> BuildLegend uses all the primitives attribute (see the help).
>> Very likely you did not set the Fill Area color and Fill area interior
>> style and the default values are used.
>>
>>
>
Received on Thu Jun 24 2010 - 17:25:04 CEST