Feat: support themes

[DivadNojnarg]

Currently a parameter but not correctly implemented. See https://g6.antv.antgroup.com/manual/theme/overview.

[DivadNojnarg]

This is partly supported here:

themes <- list(
  "light" = list(
    theme = 'light',
    node = list(
      style = list(
        size = 4
      ),
      palette = list(
        type = 'group',
        field = 'cluster'
      )
    ),
    plugins = list(
      list(
        type = 'background',
        background = '#fff'
      )
    )
  ),
  "dark" = list(
    theme = 'dark',
    node = list(
      style = list(
        size = 4
      ),
      palette = list(
        type = 'group',
        field = 'cluster'
      )
    ),
    plugins = list(
      list(
        type = 'background',
        background = '#000'
      )
    )
  ),
  "blue" = list(
    theme = 'light',
    node = list(
      style = list(
        size = 4
      ),
      palette = list(
        type = 'group',
        field = 'cluster',
        color = "blues",
        invert = TRUE
      )
    ),
    plugins = list(
      list(
        type = 'background',
        background = '#f3faff'
      )
    )
  ),
  "yellow" = list(
    theme = 'light',
    node = list(
      style = list(
        size = 4
      ),
      palette = list(
        type = 'group',
        field = 'cluster',
        color = c(
          '#ffe7ba',
          '#ffd591',
          '#ffc069',
          '#ffa940',
          '#fa8c16',
          '#d46b08',
          '#ad4e00',
          '#873800',
          '#612500'
        )
      )
    ),
    plugins = list(
      list(
        type = 'background',
        background = '#fcf9f1'
      )
    )
  )
)

and then calling:

g6_proxy("graph") |>
      g6_set_theme(themes[[input$theme]])

I think we can do much better to help people create themes...