Grass rendering/coloring doesn't seem to funtion correctly

[zndrmn]

None of these blocks render on the map at all, and sometimes it'll render with just a default dark green color. Minecraft 1.21.1 Pl3xMap-1.21.1-508

I know you don't do backports for updates but it would be very cool if you did for this small issue

Here's part of my config:

config.yml

world-settings:
  default:
    # Enables this world to be rendered on the map.
    enabled: true
    render:
      # Renderers to use. Each renderer will render a different
      # type of map. The built-in renderers include:
      # vintage_story, basic, biomes, flowermap, inhabited, night, nether_roof, and vanilla
      renderers:
        basic: overworld_basic
        biomes: overworld_biomes
        inhabited: inhabited
        nether_roof: nether_roof
      # World skylight value. This is used for the day/night cycle
      # map (not yet implemented) .Values are clamped to 0-15
      # with 0 being darkest and 15 being full bright.
      skylight: 15
      # Enables blending of biome grass/foliage/water colors similar to
      # the client's biome blending option.
      # Values are clamped to 0-7
      biome-blend: 3
      # Enable translucent fluids.
      # This will make the fluids look fancier and translucent,
      # so you can see the blocks below in shallow fluids.
      translucent-fluids: false
      # Enable translucent glass.
      # This will make the glass look fancier and translucent,
      # so you can see the blocks below.
      translucent-glass: true
      # Type of heightmap to render.
      # NONE has no heightmap drawn.
      # EVEN_ODD makes every other Y layer darker, like Dynmap.
      # HIGH_CONTRAST same as MODERN, but darker.
      # LOW_CONTRAST same as MODERN, but lighter.
      # MODERN is a clearer, more detailed view.
      # OLD_SCHOOL is the old type from v1.
      # VANILLA matches the in-game vanilla maps.
      # EVEN_ODD_HIGH_CONTRAST mix of EVEN_ODD and HIGH_CONTRAST.
      # EVEN_ODD_LOW_CONTRAST mix of EVEN_ODD and LOW_CONTRAST.
      # EVEN_ODD_MODERN mix of EVEN_ODD and MODERN.
      # EVEN_ODD_OLD_SCHOOL mix of EVEN_ODD and OLD_SCHOOL.
      # EVEN_ODD_VANILLA mix of EVEN_ODD and VANILLA.
      heightmap-type: VANILLA

colors.yml

  grass:
    - minecraft:fern
    - minecraft:grass
    - minecraft:short_grass
    - minecraft:grass_block
    - minecraft:large_fern
    - minecraft:potted_fern
    - minecraft:tall_grass

[granny]

You are looking at the wrong place. This is the comment above that grass section in the colors.yml file:

  # List of blocks that are considered grass when it comes
  # to coloring. Blocks listed here will use the biome's
  # grass color modifier when rendering.

What you want is to scroll up to the blocks.colors section of the config and set the colors for all of them to anything other than #000000 (Which they are by default). Keep in mind the colors.yml doesn't reload properly when running map reload. You'll have to restart your server for your changes to take affect.