function arrangePhotos() {
    /* Layout of photos:
     * +---------------+
     * |   6 5 4 3 2   |
     * | 7           1 |
     * |   dashboard   |
     * +---------------+
     */

    var photoWidth = 175;
    var roomAreaPadding = 10;
    var verticalPadding = Math.max(10, roomArea.width * 0.01);
    var horizontalSpacing = Math.max(30, roomArea.height * 0.1);
    var verticalSpacing = (roomArea.width - photoWidth * 7 - verticalPadding * 2) / 6;

    // Position 1-7
    var regions = [
        { x: verticalPadding + (photoWidth + verticalSpacing) * 6, y: roomAreaPadding + horizontalSpacing * 2 },
        { x: verticalPadding + (photoWidth + verticalSpacing) * 5, y: roomAreaPadding + horizontalSpacing },
        { x: verticalPadding + (photoWidth + verticalSpacing) * 4, y: roomAreaPadding },
        { x: verticalPadding + (photoWidth + verticalSpacing) * 3, y: roomAreaPadding },
        { x: verticalPadding + (photoWidth + verticalSpacing) * 2, y: roomAreaPadding },
        { x: verticalPadding + photoWidth + verticalSpacing, y: roomAreaPadding + horizontalSpacing },
        { x: verticalPadding, y: roomAreaPadding + horizontalSpacing * 2 },
    ];

    var regularSeatIndex = [
        [4],
        [3, 5],
        [1, 4, 7],
        [1, 3, 5, 7],
        [1, 3, 4, 5, 7],
        [1, 2, 3, 5, 6, 7],
        [1, 2, 3, 4, 5, 6, 7],
    ];
    var seatIndex = regularSeatIndex[playerNum - 2];

    var item, region, i;

    for (i = 0; i < playerNum - 1; i++) {
        item = photos.itemAt(i);
        if (!item)
            continue;

        region = regions[seatIndex[i] - 1];
        item.x = region.x;
        item.y = region.y;
    }
}

callbacks["AddPlayer"] = function(jsonData) {
    // jsonData: string screenName, string avatar
    for (let i = 0; i < photoModel.length; i++) {
        if (photoModel[i].screenName === "") {
            let data = JSON.parse(jsonData);
            let name = data[0];
            let avatar = data[1];
            photoModel[i] = {
                general: avatar,
                screenName: name,
                role: "unknown",
                kingdom: "qun",
                netstate: "online",
                maxHp: 0,
                hp: 0,
                seatNumber: i + 1,
                isDead: false,
                dying: false,
                faceturned: false,
                chained: false,
                drank: false,
                isOwner: false
            };
            photoModel = photoModel;
            arrangePhotos();
            return;
        }
    }
}

callbacks["RemovePlayer"] = function(jsonData) {
    // jsonData: string screenName
    let name = JSON.parse(jsonData)[0];
    for (let i = 0; i < photoModel.length; i++) {
        if (photoModel[i].screenName === name) {
            photoModel[i] = {
                general: "",
                screenName: "",
                role: "unknown",
                kingdom: "qun",
                netstate: "online",
                maxHp: 0,
                hp: 0,
                seatNumber: i + 1,
                isDead: false,
                dying: false,
                faceturned: false,
                chained: false,
                drank: false,
                isOwner: false
            };
            photoModel = photoModel;
            arrangePhotos();
            return;
        }
    }
}

/*
callbacks["RoomOwner"] = function(jsonData) {
    // jsonData: int uid of the owner
    toast.show(J)
}
*/