set default value of colorTheme and iconTheme preference

[tom-shan]

vscode python plugin will read workbench.colorTheme,
if not find it will use the default value of Default Light+
(https://github.com/microsoft/vscode-python/blob/2008c14f4ca7305ad6aaee436174fe24a5a6c283/src/client/datascience/webViewHost.ts#L175)
which will cause the mismatch of jupyter notebook and current theia theme colors.

BTW set the default value of workbench.iconTheme

Signed-off-by: tom-shan swt0008411@163.com

What it does

How to test

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[akosyakov]

It does not work for end products, since they can change default values dynamically and values cannot be hard coded. The real default values can be retrieved from ThemeService.defaultTheme and IconThemeService.default. I'm not sure how properly fix it right now. Probably the default preference provider should listen to this service and react to changes of default values.

cc @spoenemann @jbicker How do you change the default theme for Arduino Pro IDE?

[jbicker]

@akosyakov
We set it in package.json in the app folder:

...
"theia": {
    "frontend": {
      "config": {
        "applicationName": "Your app name",
        "defaultTheme": "your-theme-id",
        "preferences": {
          "editor.autoSave": "on"
        }
      }
    },
...

[akosyakov]

ok, then we have to:

• introduce defaultIconTheme as well which can be configured in package.json
• make sure that extensions cannot change default themes programmatically only via package.json
• use default color and icon themes from FrontendApplicationConfigProvider.get() for preferences and corresponding services

@tom-shan Let me know if you need more hints.

[akosyakov]

It does not work, I've tried to change to in package.json and rebuild:

"defaultTheme": "light",
        "defaultIconTheme": "vs-minimal",

but on the start icon theme was none, and color theme was dark :(

[tom-shan]

Sorry, got the reason, theme colors and icon colors provided by plugins have not been registered when reading https://github.com/eclipse-theia/theia/blob/master/packages/core/src/browser/theming.ts#L42 and https://github.com/eclipse-theia/theia/blob/master/packages/core/src/browser/icon-theme-service.ts#L80.

[akosyakov]

@tom-shan it would explain icon theme, but color theme is not registered by plugins. I'm worrying that delaying reading from preferences will lead to flickering. Need to think how to test different cases.

[tom-shan]

it would explain icon theme, but color theme is not registered by plugin

I tested again with the previous version (without delaying reading from preferences) and can not repoduce the color theme problem now.

[tom-shan]

I'm worrying that delaying reading from preferences will lead to flickering. Need to think how to test different cases.

the flicker really exists, have tested two cases:
1 default color theme: light
"workbench.colorTheme" in settings.json: Monokai
1.1 pre-cleaning chrome site data
dark -> light -> Monokai
1.2 no pre-cleaning chrome site data
Monokai

2 default color theme: Monokai
"workbench.colorTheme" in settings.json: light
1.1 pre-cleaning chrome site data
dark -> Monokai -> light
1.2 no pre-cleaning chrome site data
light

[akosyakov]

@tom-shan ok, could you revert it to previous version, I will try to test it more. I don't think current version is good it delays theming load too much, especially for restored themes from browser caches it should happen even before preload screen.

[tom-shan]

@akosyakov please try again

[akosyakov]

I've tried it but it's still blinking between dark and default theme on refresh, i.e. try to change to red and then refresh. I will have a look tomorrow what can be done.

[akosyakov]

Closed in favor of #8381 @tom-shan it is based on your PR and you are added as a co-author in the commit