matrix2tikz.m

function tikz = matrix2tikz( A, options )
%MATRIX2TIKZ converts a matrix into TikZ code.
% 
% Arguments:
% A is the matrix to be converted.
% 
% Optional arguments: 
% OPTIONS can be "hidegrid", "nogridlabels", "nocelllabels", "nozeros" or
%    combinations of those separated by spaces.
% 
% Copyright 2021, C. Minz. BSD 3-Clause License.
    
    % default options or input:
    showgrid = true;
    showgridlabels = true;
    showcelllabels = true;
    showzeros = true;
    if nargin > 1
        showgrid = ~contains( options, "hidegrid" );
        showgridlabels = ~contains( options, "nogridlabels" );
        showcelllabels = ~contains( options, "nocelllabels" );
        showzeros = ~contains( options, "nozeros" );
    end
    
    n = size( A );
    tab = char( 9 );
    % begin graphic
    tikz = "\begin{tikzpicture}" + newline; 
    tikz = tikz + tab + "% ### This matrix graphic is generated by matrix2tikz.m" + newline;
    tikz = tikz + tab + "% Parameters: " + newline;
    tikz = tikz + tab + "\def\gridL{0.35cm}" + newline;
    tikz = tikz + tab + "\colorlet{ScaleBot}{YorkBlue}" + newline;
    tikz = tikz + tab + "\colorlet{ScaleZer}{white}" + newline;
    tikz = tikz + tab + "\colorlet{ScaleTop}{YorkBlue}" + newline;
    tikz = tikz + tab + "\colorlet{negInfinity}{YorkGrey}" + newline;
    tikz = tikz + tab + "\colorlet{posInfinity}{YorkGrey}" + newline;
    tikz = tikz + tab + "\colorlet{ErrorColor}{YorkRed}" + newline;
    tikz = tikz + tab + "\colorlet{GridColor}{YorkLightGrey}" + newline;
    tikz = tikz + tab + "\colorlet{GridLabelColor}{YorkBlackTint}" + newline;
    tikz = tikz + tab + "\colorlet{CellLabelColor}{black}" + newline;
    tikz = tikz + tab + newline;
    % colour cells
    tikz = tikz + tab + "% Matrix cells: " + newline;
    Ascaled = A;
    Ascaled( A == Inf ) = NaN;
    Ascaled( A == -Inf ) = NaN;
    AscaledPos = Ascaled;
    AscaledNeg = -Ascaled;
    AscaledPos( A < 0 ) = 0;
    AscaledNeg( A >= 0 ) = 0;
    AscaledPos = 100 * AscaledPos ./ max( max( AscaledPos ) );
    AscaledNeg = 100 * AscaledNeg ./ max( max( AscaledNeg ) );
    Ascaled = AscaledPos + AscaledNeg;
    for i = 1 : n( 1 )
        for j = 1 : n( 2 )
            if isnan(A( i, j ))
                cellcolor = "ErrorColor";
                labeltext = "";
            elseif A( i, j ) == Inf
                cellcolor = "posInfinity";
                labeltext = "$\infty$";
            elseif A( i, j ) == -Inf 
                cellcolor = "negInfinity";
                labeltext = "$-\infty$";
            elseif A( i, j ) == 0
                cellcolor = "ScaleZer";
                if showzeros
                    labeltext = "$\cdot$";
                else
                    labeltext = "";
                end
            elseif A( i, j ) < 0
                cellcolor = sprintf( "ScaleBot!%0.3f!ScaleZer", Ascaled( i, j ) );
                labeltext = sprintf( "%0.1f", A( i, j ) );
            else
                cellcolor = sprintf( "ScaleTop!%0.3f!ScaleZer", Ascaled( i, j ) );
                labeltext = sprintf( "%0.1f", A( i, j ) );
            end
            tikz = tikz + tab + ...
                sprintf( "\\draw[%s, fill=%s] ", cellcolor, cellcolor ) + ...
                sprintf( "( %d*\\gridL, -%d*\\gridL ) ", j - 1, i - 1 ) + ...
                "rectangle " + ...
                sprintf( "( %d*\\gridL, -%d*\\gridL );", j, i ) + newline;
            if showcelllabels && labeltext ~= ""
                tikz = tikz + tab + "\draw[CellLabelColor] node at " + ...
                    sprintf( "( %d.5*\\gridL, -%d.5*\\gridL ) {\\tiny %s};", j - 1, i - 1, labeltext ) + ...
                    newline;
            end
        end
    end
    if showgrid
        tikz = tikz + tab + newline + tab + "% Grid: " + newline;
        % draw grid
        tikz = tikz + tab + "\draw[step = \gridL, GridColor] " + ...
            sprintf( "( 0, 0 ) grid ( %d*\\gridL, -%d*\\gridL );", n( 2 ), n( 1 ) ) + newline;
        tikz = tikz + tab + "\draw[GridColor] ( 0, 0 ) -- " + ...
            sprintf( "( %d*\\gridL, -%d*\\gridL );", n( 2 ), n( 1 ) ) + newline;
        if showgridlabels
            % draw row labels
            for i = 1 : n( 1 )
                tikz = tikz + tab + "\draw[GridLabelColor] node[left] at " + ...
                    sprintf( "( 0, -%d.5*\\gridL ) {\\tiny %d};", i - 1, i ) + newline;
            end
            % draw column labels
            for j = 1 : n( 2 )
                tikz = tikz + tab + "\draw[GridLabelColor] node[below left, rotate=45] at " + ...
                    sprintf( "( %d.5*\\gridL, -%d*\\gridL ) {\\tiny %d};", j - 1, n( 1 ), j ) + newline;
            end
        end
    end
    % end graphic
    tikz = tikz + "\end{tikzpicture}" + newline;
end