# Gimp.Image.prototype.convert_indexed

    function convert_indexed(dither_type: Gimp.ConvertDitherType, palette_type: Gimp.ConvertPaletteType, num_cols: Number(gint), alpha_dither: Boolean, remove_unused: Boolean, palette: String): Boolean {
        // Gjs wrapper for gimp_image_convert_indexed()
    }

Convert specified image to and Indexed image

This procedure converts the specified image to 'indexed' color. This process requires an image in RGB or Grayscale mode. The 'palette_type' specifies what kind of palette to use, A type of '0' means to use an optimal palette of 'num_cols' generated from the colors in the image. A type of '1' means to re-use the previous palette (not currently implemented). A type of '2' means to use the so-called WWW-optimized palette. Type '3' means to use only black and white colors. A type of '4' means to use a palette from the gimp palettes directories. The 'dither type' specifies what kind of dithering to use. '0' means no dithering, '1' means standard Floyd-Steinberg error diffusion, '2' means Floyd-Steinberg error diffusion with reduced bleeding, '3' means dithering based on pixel location ('Fixed' dithering).

dither_type

  The dither type to use.

palette_type

  The type of palette to use.

num_cols

  The number of colors to quantize to, ignored unless (palette_type == GIMP_CONVERT_PALETTE_GENERATE).

alpha_dither

  Dither transparency to fake partial opacity.

remove_unused

  Remove unused or duplicate color entries from final palette, ignored if (palette_type == GIMP_CONVERT_PALETTE_GENERATE).

palette

  The name of the custom palette to use, ignored unless (palette_type == GIMP_CONVERT_PALETTE_CUSTOM).

Returns

  TRUE on success.