Bug getting transparent color

MichaelMott · September 2, 2022, 6:25am

ROOT Version: 6.24/06
Platform: Rocky Linux release 8.4
Compiler: gcc (GCC) 8.4.1

Hello together,

working with transparent colors I found an issue with the internal color array. Requesting multiple times the same non transparent color by rgb-float-values it results in the same color index. Doing this with a transparent color I always get a new color index. Please see example code:

#include <iostream>
#include "TColor.h"

int
main (int argc, char **argv)
{
  for (size_t i = 0; i < 10; ++i)
    {
      auto color = TColor::GetColor (0.0f, 0.0f, 0.0f);
      auto color_transparent = TColor::GetColorTransparent (color, 0.0f);
      auto free_color_idx = TColor::GetFreeColorIndex ();

      std::cout << "color=" << color << " color_transparent=" << color_transparent
                << " free_color_idx=" << free_color_idx << std::endl;
    }

  return 0;
}

I assume this behaviour results in use of == operator of the float-values in GetColorTransparent instead of a compare by a threshold (gColorThreshold).

Can you confirm this?

Bests,
Michael

couet · September 2, 2022, 6:41am

Welcome to the ROOT forum

Thanks for your report. I’ll check.

couet · September 2, 2022, 6:44am

It does not seem to behave as you said (with root master):

void mott()
{
  for (size_t i = 0; i < 10; ++i)
    {
      auto color = TColor::GetColor (0.0f, 0.0f, 0.0f);
      auto color_transparent = TColor::GetColorTransparent (color, 0.0f);
      auto free_color_idx    = TColor::GetFreeColorIndex ();

      std::cout << "color = " << color << " color_transparent = " << color_transparent
                << " free_color_idx = " << free_color_idx << std::endl;
    }
}

gives:

root [0] .x mott.C
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
root [1]

Your ROOT version is old. I remember having fixed something like that.

MichaelMott · September 2, 2022, 8:41am

Hi, thank you.

I will check it - sorry that I haven’t checked it against the master version.

Bests,
Michael

MichaelMott · September 2, 2022, 9:51am

Just downloaded current version of ROOT and done the test again. Sadly I got another result.

   ------------------------------------------------------------------
  | Welcome to ROOT 6.26/06                        https://root.cern |
  | (c) 1995-2021, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for linuxx8664gcc on Sep 02 2022, 09:27:00                 |
  | From tag , 28 July 2022                                          |
  | With c++ (GCC) 8.4.1 20200928 (Red Hat 8.4.1-1)                  |
  | Try '.help', '.demo', '.license', '.credits', '.quit'/'.q'       |
   ------------------------------------------------------------------

root [0] .x mott.C
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1180 free_color_idx = 1181
color = 1 color_transparent = 1181 free_color_idx = 1182
color = 1 color_transparent = 1182 free_color_idx = 1183
color = 1 color_transparent = 1183 free_color_idx = 1184
color = 1 color_transparent = 1184 free_color_idx = 1185
color = 1 color_transparent = 1185 free_color_idx = 1186
color = 1 color_transparent = 1186 free_color_idx = 1187
color = 1 color_transparent = 1187 free_color_idx = 1188
color = 1 color_transparent = 1188 free_color_idx = 1189

Do you have any idea?

Bests,
Michael

couet · September 2, 2022, 12:38pm

I am using master. Ie: 6.27/01

MichaelMott · September 5, 2022, 8:54am

I’ve tried it with the same version like you, but I still get a different output.

   ------------------------------------------------------------------
  | Welcome to ROOT 6.27/01                        https://root.cern |
  | (c) 1995-2021, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for linuxx8664gcc on Jan 07 2022, 07:52:00                 |
  | From remotes/origin/master@v6-25-02-9-g6cb82dd30e                |
  | With c++ (GCC) 8.4.1 20200928 (Red Hat 8.4.1-1)                  |
  | Try '.help', '.demo', '.license', '.credits', '.quit'/'.q'       |
   ------------------------------------------------------------------

root [0] .x mott.C
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1180 free_color_idx = 1181
color = 1 color_transparent = 1181 free_color_idx = 1182
color = 1 color_transparent = 1182 free_color_idx = 1183
color = 1 color_transparent = 1183 free_color_idx = 1184
color = 1 color_transparent = 1184 free_color_idx = 1185
color = 1 color_transparent = 1185 free_color_idx = 1186
color = 1 color_transparent = 1186 free_color_idx = 1187
color = 1 color_transparent = 1187 free_color_idx = 1188
color = 1 color_transparent = 1188 free_color_idx = 1189
root [1]

I don’t have a clue - do you have?

couet · September 5, 2022, 11:23am

That’s really weird. I tried again:

% root mott.C
   ------------------------------------------------------------------
  | Welcome to ROOT 6.27/01                        https://root.cern |
  | (c) 1995-2022, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for macosx64 on Sep 05 2022, 08:03:42                      |
  | From heads/master@v6-25-02-2126-g9b9027a245                      |
  | With Apple clang version 13.1.6 (clang-1316.0.21.2.5)            |
  | Try '.help'/'.?', '.demo', '.license', '.credits', '.quit'/'.q'  |
   ------------------------------------------------------------------

root [0] 
Processing mott.C...
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
root [1]

I am on Mac, bu that should not take any difference. That’s only array management. It should not be machine dependent. Do you have a rootlogon.C ? can you start root wit root -n ?

Wile_E_Coyote · September 5, 2022, 11:32am

@couet I tried your “mott” on several Linux / x86_64 (gcc 11.2.0, 7.5.0, 4.8.5) systems with ROOT 6.26/06, 6.24/06, 6.22/08, 6.20/08, and 6.18/04, and I also always got different “free_color_idx” (I have no “rootlogon.C”).

MichaelMott · September 5, 2022, 11:48am

@couet I found a rootlogon.C in tutorials directory.

If I start mott.C with root -n there is no difference. I got a new free_color_idx every color request.

couet · September 5, 2022, 11:54am

Ok, i will need to investigate on a Linux machine. Thanks for your feedback.

couet · September 5, 2022, 2:00pm

well…

$ uname -a
Linux root-ubuntu-2004-1 5.4.0-73-generic #82-Ubuntu SMP Wed Apr 14 17:39:42 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
sftnight@root-ubuntu-2004-1:~/couet/build$ root mott.C
   ------------------------------------------------------------------
  | Welcome to ROOT 6.27/01                        https://root.cern |
  | (c) 1995-2022, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for linuxx8664gcc on Sep 05 2022, 12:32:28                 |
  | From heads/master@v6-25-02-2128-gb0aea2e155                      |
  | With c++ (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0                   |
  | Try '.help'/'.?', '.demo', '.license', '.credits', '.quit'/'.q'  |
   ------------------------------------------------------------------

root [0] 
Processing mott.C...
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
root [1]

Wile_E_Coyote · September 5, 2022, 2:37pm

Try ROOT 6.26/06 and 6.24/06 so that we have a comparison.

MichaelMott · September 6, 2022, 7:52am

Was this a true machine or a virtualized. May it depens on that?

Even on another server I got the same (counting color index) result.

couet · September 7, 2022, 6:50am

Ok I see the following on my IMac:

6.27/01 :

% root mott.C
   ------------------------------------------------------------------
  | Welcome to ROOT 6.27/01                        https://root.cern |
  | (c) 1995-2022, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for macosx64 on Sep 07 2022, 06:31:43                      |
  | From heads/master@v6-25-02-2141-g5c9164ec54                      |
  | With Apple clang version 13.1.6 (clang-1316.0.21.2.5)            |
  | Try '.help'/'.?', '.demo', '.license', '.credits', '.quit'/'.q'  |
   ------------------------------------------------------------------

root [0] 
Processing mott.C...
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
root [1]

6.26/07:

% root mott.C
   ------------------------------------------------------------------
  | Welcome to ROOT 6.26/07                        https://root.cern |
  | (c) 1995-2021, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for macosx64 on Sep 06 2022, 14:21:10                      |
  | From heads/v6-26-00-patches@v6-26-06-33-g2cef31413d              |
  | With Apple clang version 13.1.6 (clang-1316.0.21.2.5)            |
  | Try '.help', '.demo', '.license', '.credits', '.quit'/'.q'       |
   ------------------------------------------------------------------

root [0] 
Processing mott.C...
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1180 free_color_idx = 1181
color = 1 color_transparent = 1181 free_color_idx = 1182
color = 1 color_transparent = 1182 free_color_idx = 1183
color = 1 color_transparent = 1183 free_color_idx = 1184
color = 1 color_transparent = 1184 free_color_idx = 1185
color = 1 color_transparent = 1185 free_color_idx = 1186
color = 1 color_transparent = 1186 free_color_idx = 1187
color = 1 color_transparent = 1187 free_color_idx = 1188
color = 1 color_transparent = 1188 free_color_idx = 1189
root [1]

So seems to have been fixed between these two versions.

MichaelMott · September 7, 2022, 7:12am

Is it possible to get the 6.27/01 as source code?
Than I can compile it here to check if it’s a problem with the pre-build CentOs package since I’m running Rocky Linux.

Wile_E_Coyote · September 7, 2022, 7:23am

For today, “6.27/01” is just the head of the “master” branch (and “6.26/07” is the head of the “v6-26-00-patches” branch).

couet · September 7, 2022, 7:27am

git clone https://github.com/root-project/root.git root
mkdir build
cd build
cmake ../root
make -j8
source bin/thisroot.sh
root --version

MichaelMott · September 7, 2022, 8:59am

Wham - after compiling 6.27/01 by my own it works. I don’t know why it not worked with the precompiled version.

   ------------------------------------------------------------------
  | Welcome to ROOT 6.27/01                        https://root.cern |
  | (c) 1995-2022, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for linuxx8664gcc on Sep 07 2022, 07:41:45                 |
  | From heads/master@v6-25-02-2141-g5c9164ec54                      |
  | With c++ (GCC) 8.4.1 20200928 (Red Hat 8.4.1-1)                  |
  | Try '.help'/'.?', '.demo', '.license', '.credits', '.quit'/'.q'  |
   ------------------------------------------------------------------

root [0] .x mott.C
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
color = 1 color_transparent = 1179 free_color_idx = 1180
root [1]

couet · September 7, 2022, 9:39am

As @Wile_E_Coyote said the master head might is a bt ahead even if the version number is the same.