image_mask_set(3)

🌸 NAME 🌸

okay so bestie, welcome to the image_mask_set(3) page — this is the Arcan Lua API, and we're about to make mask flags make sense. 💅

image_mask_set — Set a status flag on the specified object. periodt.

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✨ SYNOPSIS ✨

short and sweet, no cap:

nil
image_mask_set( vid, maskval )

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💅 DESCRIPTION 💅

okay so here's the vibe: images that are linked to each other via link_image get a number of their attributes redefined to be relative to the parent they're linked to. iconic, honestly. 🦋

but sometimes not all attributes are relevant to inherit, and those can be controlled through the image_mask_ set of functions. yep, that's the whole point.

the currently valid maskvals are:

• MASK_UNPICKABLE — if set, the image will be ignored for picking operations 🚫
• MASK_LIVING — (default) if set, the image will be deleted when the parent expires 💀
• MASK_POSITION — (default) image coordinate system origo 📍
• MASK_OPACITY — (default) image opacity 🫥
• MASK_ROTATION — (default) image rotation angle 🔄
• MASK_SCALE — (default) reserved, no-op 🎀
• MASK_MAPPING — if set, the image will use the texture coordinate set of its (non-world) parent 🗺️

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🎀 NOTES 🎀

1. heads up, bestie: an invalid maskval is considered a terminal state transition. so yeah, not a silly little experiment, fr fr. 💀

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🧚 EXAMPLE 🧚

here's the example, verbatim — no cap:

function image_mask_set0()
      a = fill_surface(32, 32, 255, 0, 0);
      b = instance_image(a);
      show_image({a, b});
      move_image(a, 32, 32);
      rotate_image(a, 120);
      image_mask_clearall(b);
      image_mask_set(b, MASK_ORIENTATION);
end

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💀 MISUSE 💀

and here's the MISUSE example, also verbatim — please don't:

function image_mask_set0()
      image_mask_set(WORLDID, math.random(1000));
end

yeah, this is literally listed under MISUSE. consider yourself warned, bestie. 🫶

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🔥 SEE ALSO 🔥

go give these pages some love too:

image_mask_toggle(3) image_mask_clear(3) image_mask_clearall(3)

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xoxo, the image manual · October 2026 · image_mask_set(3) 💖🫶✨