added minimal ExtTable presentation

Author: mahrud

_includes/table.toric.html

@@ -2,6 +2,10 @@
 {% assign class     = include.class     | default: page.class %}
 {% assign dim       = class             | remove: 'fano-' | plus: 0 %}
 {% assign row_limit = include.row_limit | default: page.row_limit | default: 20 %}
+{% assign force_svg = include.force_svg | default: false %}
+{% if dim >= 4 %}
+{% assign force_svg = true %}
+{% endif %}
 
 <style>
 .pad3 {
@@ -33,6 +37,10 @@
 .row-toggle[aria-expanded="true"] {
   transform: rotate(90deg);
 }
+
+.minimal-matrix {
+  vertical-align: middle;
+}
 </style>
 
 <div class="table-wrap">
@@ -72,7 +80,7 @@
 	<span class="pad3">{{ X[1].rays[0] }}:</span>  ${{ X[1].degs     | latex_matrix: true }}$<br/>
 	<span class="pad3">{{ X[1].theta[0] }}:</span> ${{ X[1].theta[1] | latex_matrix: true }}$</td>
       <td class="align-middle ExtTable" data-sort="{{ X[1].Ext[1] }}">
-	${{ X[1].Ext[0] | latex_matrix: false }}$</td>
+	{{ X[1].Ext[0] | matrix_preview: false, force_svg }}</td>
     </tr>
     <tr id="details-{{ identifier }}" class="detail-row" style="display: none;">
       <td colspan="6">

_plugins/matrix.rb

@@ -1,24 +1,88 @@
 module MatrixFilters
+  CELL_SIZE = 7
+  T_COLORS = {
+    1 => '#c00',
+    2 => '#e66a00',
+    3 => '#c0a000',
+    4 => '#008800',
+    5 => '#0070c0',
+    6 => '#00c'
+  }.freeze
+
   def latex_matrix(input, transpose = false)
+    rows = matrix_rows(input, transpose)
+    return input if rows.empty?
+
+    latex_from_rows(rows)
+  end
+
+  def matrix_preview(input, transpose = false, force_svg = false, column_limit = 20)
+    rows = matrix_rows(input, transpose)
+    return input if rows.empty?
+
+    force_svg = force_svg || rows.first.length > column_limit.to_i
+    force_svg ? minimal_matrix_svg(rows) : "$#{latex_from_rows(rows)}$"
+  end
+
+  def strip_times(input)
+    input.gsub(/\*/, '')
+  end
+
+  def normalize_grouped_superscripts(input)
+    input.gsub(/\^\(([^()]*)\)/, '^{\1}')
+  end
+
+  def matrix_rows(input, transpose = false)
     columns = parse_brace_list(input.to_s.strip)
-    return input if columns.empty?
+    return [] if columns.empty?
 
     widths = columns.map(&:length).uniq
     raise ArgumentError, "matrix columns must all have the same length" unless widths.length == 1
 
-    rows = transpose ? columns.transpose : columns
+    transpose ? columns.transpose : columns
+  end
+
+  def latex_from_rows(rows)
     rows = rows.map do |row|
       row.map { |entry| normalize_grouped_superscripts(entry) }.join(' & ')
     end
     "\\begin{pmatrix}#{rows.join(' \\\\ ')}\\end{pmatrix}".gsub(/\*/, '')
   end
 
-  def strip_times(input)
-    input.gsub(/\*/, '')
+  def minimal_matrix_svg(rows)
+    width = rows.first.length * CELL_SIZE
+    height = rows.length * CELL_SIZE
+    black = +''
+    t_paths = Hash.new { |paths, exponent| paths[exponent] = +'' }
+
+    rows.each_with_index do |row, y_index|
+      row.each_with_index do |entry, x_index|
+        next if entry == '0'
+
+        x = x_index * CELL_SIZE
+        y = y_index * CELL_SIZE
+        path = "M#{x} #{y}h#{CELL_SIZE}v#{CELL_SIZE}h-#{CELL_SIZE}z"
+        exponent = t_exponent(entry)
+        exponent ? t_paths[exponent] << path : black << path
+      end
+    end
+
+    svg = %(<svg class="minimal-matrix" width="#{width}" height="#{height}" viewBox="0 0 #{width} #{height}" role="img" aria-label="#{rows.length} by #{rows.first.length} matrix preview" shape-rendering="crispEdges">)
+    svg << %(<path fill="#000" d="#{black}"/>) unless black.empty?
+    T_COLORS.each do |exponent, color|
+      path = t_paths[exponent]
+      svg << %(<path fill="#{color}" d="#{path}"/>) unless path.empty?
+    end
+    svg << %(</svg>)
   end
 
-  def normalize_grouped_superscripts(input)
-    input.gsub(/\^\(([^()]*)\)/, '^{\1}')
+  def t_exponent(entry)
+    exponents = entry.scan(/T(?:\^\(?(-?\d+)\)?)?/).map do |match|
+      match[0].nil? || match[0].empty? ? 1 : match[0].to_i
+    end
+    return nil if exponents.empty?
+
+    [[exponents.max, 1].max, 6].min
   end
 
   def parse_brace_list(source)