Painting positioning

[mesoscopic]

I've written a modified AnvilLoader that loads certain entities from the Anvil format, like display entities and armor stands.
However, I've been stuck on paintings for a while - the position stored in NBT data seems to be different from Minestom's entity position. Despite numerous attempts to shift their position based on dimensions, they either seem to do nothing or move somewhere entirely unexpected. I'm sure there's a simple solution, but I wasn't able to find any documentation about paintings.

// ...

public class Entities {
    public static void handle(NBTCompound data, Instance world){
        switch (data.getString("id")) {
            // ...
            case "minecraft:painting":
                initPainting(data, world);
                break;
            default:
                break;
        }
    }
    // ...
    private static Vec vecFromList(NBTList<NBTDouble> list){
        return new Vec(list.get(0).getValue(),list.get(1).getValue(),list.get(2).getValue());
    }
    private static net.minestom.server.entity.metadata.other.PaintingMeta.Orientation paintingOrientation(NBTCompound data){
        int num = data.getByte("facing");
        net.minestom.server.entity.metadata.other.PaintingMeta.Orientation[] list = {net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.SOUTH, net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.WEST, net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.NORTH, net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.EAST};
        return list[num];
    }
    private static Variant paintingVariant(NBTCompound data){
        String name = data.getString("variant");
        return Variant.fromNamespaceId(name);
    }
    private static void initPainting(NBTCompound data, Instance world){
        NBTList<NBTFloat> rot = data.getList("Rotation");
        Pos pos;
        Entity painting = new Entity(EntityType.PAINTING);
        PaintingMeta pmeta = (PaintingMeta) painting.getEntityMeta();
        var orientation = paintingOrientation(data);
        pmeta.setOrientation(orientation);
        var variant = paintingVariant(data);

        pos = new Pos(vecFromList(data.getList("Pos")), rot.get(0).getValue(), rot.get(1).getValue());
        pmeta.setVariant(variant);
        painting.setInstance(world, pos);
    }
    // ...
}

[mesoscopic]

After scouring GitHub (turns out almost nobody uses paintings) I found the answer - it did turn out to be quite simple

private static void initPainting(NBTCompound data, Instance world){
    Entity painting = new Entity(EntityType.PAINTING);
    NBTList<NBTDouble> pos = data.getList("Pos");
    PaintingMeta pmeta = (PaintingMeta) painting.getEntityMeta();
    net.minestom.server.entity.metadata.other.PaintingMeta.Orientation o = paintingOrientation(data);
    pmeta.setOrientation(o);
    pmeta.setVariant(paintingVariant(data));
    boolean ceilZ = false;
    if(o == net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.WEST || o == net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.EAST) ceilZ = true;
    painting.setInstance(world, new Pos(pos.get(0).getValue(), Math.ceil(pos.get(1).getValue()) - 1, ceilZ?(Math.ceil(pos.get(2).getValue()) + 1):(pos.get(2).getValue())));
}

[mesoscopic]

It turns out, my previous answer was entirely wrong (I only tested thoroughly with paintings facing a certain direction). It's as simple as this: in Minestom a painting's position is stored as the bottom left corner, and in Minecraft it is stored as the center. So, this is what worked for me (also updated to 1.20.6):

private static void initPainting(CompoundBinaryTag data, Instance world){
    Entity painting = new Entity(EntityType.PAINTING);
    Vec pos = vecFromDoubles(data.getList("Pos"));
    ListBinaryTag rot = data.getList("Rotation");
    PaintingMeta meta = (PaintingMeta) painting.getEntityMeta();
    net.minestom.server.entity.metadata.other.PaintingMeta.Orientation orientation = paintingOrientation(data);
    meta.setOrientation(orientation);
    Variant variant = Variant.fromNamespaceId(data.getString("variant"));
    meta.setVariant(variant);
    if(orientation == net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.WEST || orientation == net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.EAST){
        pos = pos.withZ(pos.z() + (variant.width()/32)*(orientation == net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.WEST ? -1 : 0));
    } else {
        pos = pos.withX(pos.x() + (variant.width()/32)*(orientation == net.minestom.server.entity.metadata.other.PaintingMeta.Orientation.SOUTH ? -1 : 0));
    }
    pos = pos.withY(pos.y() - variant.height()/32);
    painting.setInstance(world, new Pos(pos, rot.getFloat(0), rot.getFloat(1)));
}