Re: Text over a few pads

From: Rene Brun (Rene.Brun@cern.ch)
Date: Wed Dec 08 1999 - 18:21:07 MET


Hi Damir,
Yes, this is possible, using the Root transparent pads feature.
We announced this new feature in version 2.20, but this is not yet
well documented. In the release notes, you can find:
- TPad: implemented transparent pads. A pad is made transparent by
  setting its fill style (using SetFillStyle()) in the range 4000-4100.
  Where 4000 is fully transparent and 4100 fully opaque. All magic
  is done in the method PaintBox() using the new (private) methods
  CopyBackgroundPixmaps() and CopyBackgroundPixmap(). Transparent pads
  need to always be updated if anything in the canvas is changed
  or moved. This is handled in PaintModified().

- TAttFill: new method IsTransparent(). Returns true is fill style is
  in the range 4000-4100.

So, suppose you have an existing canvas with several pads.
You create a new pad (transparent) covering for example the entire
canvas.
Then you draw you primitives in this pad.
The same can be achieved with the graphics editor.

example:
root [0] .x tutorials/h1draw.C
root [1] TPad *newpad=new TPad("newpad","a transparent pad",0,0,1,1);
root [2] newpad.SetFillStyle(4000);
root [3] newpad.Draw();
root [4] newpad.cd();
root [5] // create some primitives, etc

Rene Brun


Damir Buskulic wrote:
> 
> Hi,
> 
> I would like to draw a label or text going on top of a few pads, like
> "preliminary" or some such.
> How do I do this ?
> If I draw the text on a pad, it is clipped at the pad border. If I plot
> it on the underlying canvas, it is hidden by the pads...
> 
> Any (simple ?) solution
> 
> Damir
> --
> =====================================================================
> | Damir Buskulic                  | Universite de Savoie/LAPP       |
> |                                 | Chemin de Bellevue, B.P. 110    |
> | Tel : +33 (0)450091600          | F-74941 Annecy-le-Vieux Cedex   |
> | e-mail: buskulic@lapp.in2p3.fr  | FRANCE                          |
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