Replace history graph colors in lovelace

chart-colors.js

// Add this to your lovelace resources as
// url: /local/chart-colors.js
// type: module

customElements.whenDefined('ha-chart-base').then(() => {

  // Find the HaChartBase class
  const HaChartBase = customElements.get('ha-chart-base');

  // Write a new color list generator
  function getColorList(cnt) {
    let retval = [];
    // This one just makes a list of all magenta
    while(cnt--)
      retval.push(Color().rgb(255,0,255));
    return retval;
  }

  // Replace the color list generator in the base class
  HaChartBase.getColorList = getColorList;

  // Force lovelace to redraw everything
  const  ev = new Event("ll-rebuild", {
      bubbles: true,
      cancelable: false,
      composed: true,
  });
  var root = document.querySelector("home-assistant");
  root = root && root.shadowRoot;
  root = root && root.querySelector("home-assistant-main");
  root = root && root.shadowRoot;
  root = root && root.querySelector("app-drawer-layout partial-panel-resolver");
  root = root && root.shadowRoot || root;
  root = root && root.querySelector("ha-panel-lovelace");
  root = root && root.shadowRoot;
  root = root && root.querySelector("hui-root");
  root = root && root.shadowRoot;
  root = root && root.querySelector("ha-app-layout #view");
  root = root && root.firstElementChild;
  if (root) root.dispatchEvent(ev);
});

Took a look at it.
Replacing getColorByIndex is not going to happen.
You can replace _generateData of state-history-chart-line with one that first runs the original, and then goes through this._chartData and replaces the colors one by one, though.

So, I'm not a programmer and I don't know how to compile .ts to make a .js that replaces _generateData.
Not really the place for this but:
Assuming I can figure out how to compile a card from source, would it make sense to just fork the charts from the HA frontend source, modify the 'colors.ts' file, and compile custom cards that I use instead of the stock chart cards? Is that a possible thing?

Hi Thomas!
I have added the file chart-colors.js in my HA resources: /local/chart-colors.js
I have created the file chart-colors.js and put it inside "/config/www/"where HA gets the files in "local".
I have restarted HA but I still don't see the colour of these charts changing

Is there any way to be able to change that graph line to another colour?

Thank you very much for your help!

As noted above, this doesn't work since 2021.7.0

Thank you Thomas for your quick reply.
Would you happen to know how to change the colour of that graph line directly by entering a string in the HA theme?
Thanks again for your help!

Hallo, is this issue solved/closed somehow? Did someone find any clue?
Still need to find some way to custiomize horizontal history bar graph colors.
Thank you.
W.

Yes! Posting for all the lost souls that see this in the future:

You just have to make or add to a theme. Make a theme.yaml file and use graph-color-1:, graph-color-2:, etc., to change the colors of the line graphs.
Like this:

#
My Theme:
  graph-color-1: "#c6dbef"
  graph-color-2: "#9ecae1"
  graph-color-3: "#6baed6"
  graph-color-4: "#4292c6"
  graph-color-5: "#2171b5"
  graph-color-6: "#08519c"
  graph-color-7: "#08306b"

For the horizontal history graphs you can use a theme to change:

state-on-color:
state-off-color:
state-home-color:
state-not_home-color:
state-unavailable-color:
state-unknown-color:
state-idle-color:

It's great!

....
For the horizontal history graphs you can use a theme to change:

hi, thanks for a pretty fast answer, and thank you for this partial work-arround - I will definitely implement this...
is there plz also a way to make custom colors for other states than just for basic ones in the horizontal history graph?

(e.g.: instead of the state "off" there is also "offline", "down", "closed" etc., for some entities...)
I can't imagine mapping all those entities to some virtual helpers with "off" state, since there are hundreds oh these... the best would be imho, if there is just some user predefined 'color-states-array' used in the Theme.yaml in the same way as you wrote.
thx.

@backcountrymountains - I found this additional documentation: https://www.home-assistant.io/integrations/frontend/#state-color It looks like those options are just for "binary" sensors, have you come across a way to set the color for other states (like those for a sensor, where there might be 3 or more states)?