A macro script to convert polygonal drawings to walls

drawings-to-walls.js

let drawings = canvas.drawings.controlled;

drawings = drawings.map(drawing =>{
    switch (drawing.data.type) {
        case "f":
        case "p": {
            let { _id, points, rotation, x, y, width, height } = drawing.data;
            return { id: _id, valid: true, points, rotation, x, y, width, height };
        }
        case "r": {
            let { _id, rotation, x, y, width, height, strokeWidth } = drawing.data;
            const points = [
                [0 + (strokeWidth / 2), 0 + (strokeWidth / 2)],
                [width - (strokeWidth / 2), 0 + (strokeWidth / 2)],
                [width - (strokeWidth / 2), height - (strokeWidth / 2)],
                [0 + (strokeWidth / 2), height - (strokeWidth / 2)],
                [0 + (strokeWidth / 2), 0 + (strokeWidth / 2)]
            ];
            return { id: _id, valid: true, points, rotation, x, y, width, height };
        }
        default:
            return { id: drawing.data._id, valid: false };
    }
}).filter(drawing => {
    if (!drawing.valid) {
        ui.notifications.warn(`Drawing "${drawing.id}" is not a valid drawing type!`);
        return false;
    }
    return true;
});

if (drawings.length) {
    const newWalls = drawings.flatMap((drawing) => {
        const { x, y, width, height } = drawing;
        const xCenterOffset = width / 2;
        const yCenterOffset = height / 2;
        
        const θ = Math.toRadians(drawing.rotation);
        const cosθ = Math.cos(θ);
        const sinθ = Math.sin(θ);
        
        const points = drawing.points.map((point) => {
            const offsetX = point[0] - xCenterOffset;
            const offsetY = point[1] - yCenterOffset;
            const rotatedX = (offsetX * cosθ - offsetY * sinθ);
            const rotatedY = (offsetY * cosθ + offsetX * sinθ);
            return [rotatedX + x + xCenterOffset, rotatedY + y + yCenterOffset];
        });
        
        return points
            .slice(0, points.length - 1)
            .map((point, i) => ({ c: point.concat(points[i + 1]) }));
    });
    
    canvas.scene.createEmbeddedDocuments("Wall", newWalls);
    canvas.walls.activate();
} else {
    ui.notifications.error("No drawings selected!");
}

This macro no longer works on Foundry v10

@KageJittai Had the same problem. Reworked script a little bit:
https://gist.github.com/mrjackphil/49a435432458f7fcf7844a405dae0d59