Aseprite MCP Tools

Instructions

Implementation Reference

• aseprite_mcp/tools/palette.py:160-251 (handler)

  The handler function that extracts unique colors from an Aseprite image and creates a new palette.

  async def extract_palette_from_image(
      filename: str,
      max_colors: int = 16,
      output_filename: Optional[str] = None
  ) -> str:
      """Extract a color palette from an existing image.
  
      Args:
          filename: Name of the Aseprite file to extract palette from
          max_colors: Maximum number of colors to extract (default: 16)
          output_filename: Optional filename to save the palette
      """
      try:
          # Validate inputs
          file_path = validate_file_path(filename, must_exist=True)
          
          if max_colors < 1 or max_colors > 256:
              raise ValidationError("max_colors", max_colors, "Max colors must be between 1 and 256")
          
          # Build Lua script
          builder = LuaBuilder()
          builder.open_sprite(str(file_path))
          builder.add_line('local spr = app.activeSprite')
          builder.if_condition('not spr')
          builder.add_line('error("No active sprite")')
          builder.end_if()
          builder.add_line()
          
          # Extract unique colors
          builder.add_line('local colorSet = {}')
          builder.add_line('local colorList = {}')
          builder.add_line()
          
          # Iterate through all pixels in all cels
          builder.for_loop('_, cel', 'ipairs(spr.cels)')
          builder.add_line('local img = cel.image')
          builder.if_condition('img')
          builder.for_loop('y', 0, 'img.height - 1')
          builder.for_loop('x', 0, 'img.width - 1')
          builder.add_line('local pixel = img:getPixel(x, y)')
          builder.add_line('local color = spr.pixelColor.rgba(pixel)')
          builder.if_condition('color.a > 0')  # Skip transparent pixels
          builder.add_line('local key = string.format("%02X%02X%02X", color.r, color.g, color.b)')
          builder.if_condition('not colorSet[key]')
          builder.add_line('colorSet[key] = true')
          builder.add_line('table.insert(colorList, color)')
          builder.if_condition(f'#colorList >= {max_colors}')
          builder.add_line('break')
          builder.end_if()
          builder.end_if()
          builder.end_if()
          builder.end_loop()
          builder.if_condition(f'#colorList >= {max_colors}')
          builder.add_line('break')
          builder.end_if()
          builder.end_loop()
          builder.end_if()
          builder.if_condition(f'#colorList >= {max_colors}')
          builder.add_line('break')
          builder.end_if()
          builder.end_loop()
          builder.add_line()
          
          # Create palette from extracted colors
          builder.add_line('local palette = Palette(#colorList)')
          builder.for_loop('i, color', 'ipairs(colorList)')
          builder.add_line('palette:setColor(i - 1, color)')
          builder.end_loop()
          
          # Apply palette to sprite
          builder.add_line('spr:setPalette(palette)')
          
          # Save if output filename specified
          if output_filename:
              output_path = validate_file_path(output_filename, must_exist=False)
              builder.save_sprite(str(output_path))
          else:
              builder.save_sprite()
          
          builder.add_line('return #colorList')
          
          # Execute script
          cmd = get_command()
          success, output = cmd.execute_lua_script(builder.build())
          
          return f"Extracted palette with up to {max_colors} colors from {file_path}"
          
      except (ValidationError, AsepriteError) as e:
          return f"Failed to extract palette: {e}"
      except Exception as e:
          return f"Unexpected error: {e}"