Whiptail change background color dynamically from magenta?

Question

How would one change the background color on the fly for Whiptail. For example red, green, or yellow, Blue seams to be a lack of color. I checked How to get rid of purple background color in newt apps? which really breaks the system. If you want permanent blue it is OK.

I know that it can be done as when you install Ubuntu they change the background color when you don't get matching passwords for example. Non of the manuals for Whiptail discuss how.

I do know that it deal with newt as this is its base, but even there they don't tell you how.

Solution

Internal colour palette of whiptail may be overwritten at compilation by providing a path to a file containing color definitions.

In ubuntu sudo update-alternatives --config newt-palette provides a way of selecting between ubuntu palette and original palette.

The location of this file can be overriden by setting the NEWT_COLORS_FILE to point to an alternative file.

Furthermore both previous overrides can be overriden by setting the NEWT_COLORS environment variable.

The structure of the definitions is:

name=[fg],[bg][;|:|\n|\r|\t]name2=[fg],[bg]]...

name can be:

root                  root fg, bg
border                border fg, bg
window                window fg, bg
shadow                shadow fg, bg
title                 title fg, bg
button                button fg, bg
actbutton             active button fg, bg
checkbox              checkbox fg, bg
actcheckbox           active checkbox fg, bg
entry                 entry box fg, bg
label                 label fg, bg
listbox               listbox fg, bg
actlistbox            active listbox fg, bg
textbox               textbox fg, bg
acttextbox            active textbox fg, bg
helpline              help line
roottext              root text
emptyscale            scale full
fullscale             scale empty
disentry              disabled entry fg, bg
compactbutton         compact button fg, bg
actsellistbox         active & sel listbox
sellistbox            selected listbox

bg and fg can be:

color0  or black
color1  or red
color2  or green
color3  or brown
color4  or blue
color5  or magenta
color6  or cyan
color7  or lightgray
color8  or gray
color9  or brightred
color10 or brightgreen
color11 or yellow
color12 or brightblue
color13 or brightmagenta
color14 or brightcyan
color15 or white

Example displaying a message box with red window background:

#!/bin/sh

NEWT_COLORS='
  window=,red
  border=white,red
  textbox=white,red
  button=black,white
' \
whiptail --msgbox "passwords don't match" 0 0

Appending to ubuntu colors:

#!/bin/bash

readarray -t newtcols < /etc/newt/palette

newtcols_error=(
   window=,red
   border=white,red
   textbox=white,red
   button=black,white
)

NEWT_COLORS="${newtcols[@]} ${newtcols_error[@]}" \
whiptail --msgbox "passwords don't match" 0 0

Comments

[Eric]

Yes works except for one thing the root background goes to blue, I tried to add root to NEWT_COLORS but the root background goes to black. What is the variable to get the root background to magenta like Ubuntu uses?

[Admin]

root=,magenta. Please note that there is only 1 override that takes place. If you set NEWT_COLORS none of the overrides takes place.

[Eric]

I did exactly that and it makes the background black. I also found out that if you don't do NEWT_COLORS on all whiptail windows they are black background. Which means that it affects all whiptails.

[Admin]

@Eric, if you set an invalid color to an elements it makes it black. i.e. root=,mageta would make root window black.

[Eric]

There must be a problem with Ubuntu 14.04 as I get the black background for root. When I do it in Ubuntu 16.04 it works perfectly (magenta root background). Would you know if there is a difference between the two?

[Admin]

@Eric, try sudo apt-get install --reinstall libnewt0.52. This will probably fix your problem.

[Eric]

@Anonis, no go but will be replacing shortly. Question, how would you make an array for "Appending to ubuntu colors:" above so that you can change colors on fly. I have function that I call from for loop things happen so fast that most people would not see that things have changed that is why I would like to change that colors.

[Admin]

@Eric, You'll can dynamically change color of each dialog, but you can't after it's displayed. You can create a sequence of dialogs to show progress, or use a gauge. If this does not serve your needs, imho, whiptail is not the tool for the job.