use-palette

name	use-palette
description	Set up and change colors with BLIT386's palette-first system of numbered color slots. Use whenever the user sets up colors, mentions colors, themes, or palettes, or wants to recolor things at runtime by changing a slot.

Use the palette (colors)

BLIT386 is palette-first: fill numbered color slots once, then draw with the slot numbers. Change a slot and everything drawn with it changes.

When to use

Use whenever you set up colors, the user mentions colors or themes, or you need to recolor things at runtime.

Make a palette in init()

async init() {
    this.palette = BT.paletteCreate(16); // room for 16 colors; slot 0 is transparent

    this.palette.set(1, new Color32(230, 80, 60)); // each channel 0..255
    this.palette.set(2, new Color32(20, 24, 40)); // background
    this.palette.set(3, Color32.white); // named presets are getters (no parentheses)

    BT.paletteSet(this.palette); // from now on, draw with slot numbers
    return true;
}

Change a color later (the palette is live)

update() {
    if (this.hurt) {
        this.palette.set(1, new Color32(255, 255, 255)); // everything in slot 1 flashes white next frame
    }
}

Key calls

• BT.paletteCreate(size?) (method) – new palette (default 256 slots).
• palette.set(index, color) / palette.get(index) (methods) – write / read a slot.
• BT.paletteSet(palette) (method) – make a palette active.
• palette.applyHUD(startSlot?) (method) – fill six ready-made HUD colors (white, background, label, header, dim, code) in one call.
• Built-in retro palettes: Palette.vga(), Palette.cga(), Palette.c64(), Palette.nes(), Palette.gameboy(), Palette.pico8().
• Color32 presets are getters (no parentheses): Color32.white, Color32.black, Color32.red, Color32.green, Color32.blue, Color32.yellow, Color32.cyan, Color32.magenta. Also Color32.fromHex('#ff8800') and named colors via Color32.resolveNamedColor('cornflowerblue').

Notes

• Slot 0 is always transparent – start visible colors at slot 1.
• new Color32(r, g, b) or new Color32(r, g, b, a) (alpha 0..255).
• Recoloring by changing slots is cheaper than redrawing. For animated color motion see the animate-the-palette skill.

See docs/palette.md.