keys.zig

const ROWS: u8 = 4;
const COLS: u8 = 15;
const KEYS = ROWS * COLS;

pub const Key = struct {
    label: [:0]const u8,
    width: u8,

    col: u8 = 0,
    row: u8 = 0,
};

pub const keys = calc_key_positions(.{
    Key{ .label = "a", .width = 1 },
    Key{ .label = "a", .width = 3 },
    Key{ .label = "a", .width = 1 },
    Key{ .label = "a", .width = 2 },
    Key{ .label = "a", .width = 1 },
    Key{ .label = "a", .width = 4 },
    Key{ .label = "a", .width = 1 },
});

// Take a list of keys, determine column/row for each key based on width of preceding keys.
pub fn calc_key_positions(...) []Key {
    var col: u8 = 0;
    var row: u8 = 0;
    
    for (...) |*key| {
        key.*.col = col;
        key.*.row = row;

        col += key.*.width;

        if(col >= COLS) {
            col = 0;
            row += 1;
        }
    }

    return ...;
}