square to deg v2

% This function takes in a square positon on the chess board,
% e.g. 'A2' or 'h8'
% Returns motor angles based off calibration values

% +------------------------+
% |a8                    h8|
% |                        |
% |                        |
% |                        |
% |                        |
% |a1                   h1 |
% +------------------------+

% TODO:
% If X,Y motor axes not perpendicular and parallel to
% respective sides of chess board, need to calculate
% based off the board being diagonal
function [bigDC, smallDC] = squareToDegrees(spot)
[ndata, text, alldata] = xlsread('locations.xlsx');
    % Make sure spot is 2 chars long
    if length(spot) ~= 2
       fprintf("Error: square spot not 2 chars.\n");
       return;
    end
    if length(alldata) <= 4
        fprintf("Error reading excel file"\n);
        return;
    end

    % Get ascii values for spot
    ascii = double(spot);

    %% Get shit from excel
    % ascii(2) = 49 for '1', 56 for '8' (-48 gives 1through8)
    row = (((ascii(2) - 48)));

    % ascii(1) = 97 for a, 104 for h (-96 gives 1through8)
    col = (ascii(1) - 96);

    %fprintf("row %d, col %d\n", row, col);
    coord = alldata{row, col};
    %fprintf("%s\n", coord);

    if length(coord) < 4
       % ESTIMATE
       [bigDC, smallDC] = estimateHorizontally(spot);
       %[bigDC, smallDC] = estimateVertically(spot);

    else
        [bigDC, smallDC] = coordToValues(coord);
    end

    %% Change string coordinate to xy vals
    function [x, y] = coordToValues(coord)
        coord = strrep(coord, '(', '');
        coord = strrep(coord, ')', '');

        coord = strrep(coord, ' ', '');
        split = strsplit(coord, ',');
        x = str2double(split{1});
        y = str2double(split{2});
    end
    function [x, y] = estimateHorizontally(spot)
        x = 0; y = 0;
        % get left coord
        lSpot = spot;
        coord = nan;
        while isnan(coord)
            lSpot = strcat(char(lSpot(1) - 1), lSpot(2));
            coord = alldata{lSpot(2) - 48, lSpot(1) - 96};
        end
        [leftX, leftY] = coordToValues(coord);

        % get right coord
        rSpot = spot;
        coord = nan;
        while isnan(coord)
            rSpot = strcat(char(rSpot(1) + 1), rSpot(2));
            coord = alldata{rSpot(2) - 48, rSpot(1) - 96};
        end
        [rightX, rightY] = coordToValues(coord);

        % Line b/t 2
        deltaX = rightX - leftX;
        slopeX = deltaX / (rSpot(1) - lSpot(1));
        x = leftX + slopeX * (spot(1) - lSpot(1));

        deltaY = rightY - leftY;
        slopeY = deltaY / (rSpot(1) - lSpot(1));
        y = leftY + slopeY * (spot(1) - lSpot(1));
    end
end