resolves #6 add support for AsciiDoc table cells (including nested ta…

…bles) (PR #707)

- use custom Cell implementation to support AsciiDoc table cells
- supports colspan, rowspan and vertical alignment
- works best if column is assigned an explicit (relative) width
- does not permit content that exceeds the height of one page
- extra padding from last block is added to bottom of cell
- does not (yet) inherit font properties from table cell

Also resolves duplicates #315, #445 and #358.

lib/asciidoctor-pdf/converter.rb

@@ -1460,16 +1460,14 @@ def convert_table node
           cell_data[:content] = preserve_indentation cell.text, (node.document.attr 'tabsize')
           cell_data[:inline_format] = true
         when :asciidoc
-          unless defined? @asciidoc_cell_warning
-            @asciidoc_cell_warning = true
-            warn 'asciidoctor: WARNING: The \'a\' (AsciiDoc) table cell style is not supported by this converter. The source of these cells will be treated as paragraph content.'
-          end
-          # TODO finish me
+          asciidoc_cell = ::Prawn::Table::Cell::AsciiDoc.new self,
+              (cell_data.merge content: cell.inner_document, font_style: (val = theme.table_font_style) ? val.to_sym : nil)
+          cell_data = { content: asciidoc_cell }
         else
           cell_data[:font_style] = (val = theme.table_font_style) ? val.to_sym : nil
         end
         unless cell_data.key? :content
-          # NOTE effectively the same as calling cell.content
+          # NOTE effectively the same as calling cell.content (should we use that instead?)
           # TODO hard breaks not quite the same result as separate paragraphs; need custom cell impl
           if (cell_text = cell.text).include? LF
             cell_data[:content] = cell_text.split(BlankLineRx).map {|l| l.tr_s(WhitespaceChars, ' ') }.join(DoubleLF)
@@ -1561,7 +1559,7 @@ def convert_table node
     theme_margin :block, :top
 
     table table_data, table_settings do
-      # NOTE capture resolved table width
+      # NOTE call width to capture resolved table width
       table_width = width
       @pdf.layout_table_caption node, table_width, alignment if node.title? && caption_side == :top
       if grid == 'none' && frame == 'none'

lib/asciidoctor-pdf/prawn-table_ext.rb

@@ -1,2 +1,3 @@
 require 'prawn/table' unless defined? Prawn::Table::VERSION
+require_relative 'prawn-table_ext/cell/asciidoc'
 require_relative 'prawn-table_ext/cell/text'

lib/asciidoctor-pdf/prawn-table_ext/cell/asciidoc.rb

@@ -0,0 +1,69 @@
+module Prawn; class Table; class Cell
+  class AsciiDoc < Cell
+    attr_accessor :align
+    attr_accessor :valign
+
+    def initialize pdf, opts = {}
+      @font_options = {}
+      super pdf, [], opts
+    end
+
+    def font_style= val
+      @font_options[:style] = val
+    end
+
+    def text_color= val
+      @font_options[:color] = val
+    end
+
+    def size= val
+      @font_options[:size] = val
+    end
+
+    def font= val
+      @font_options[:family] = val
+    end
+
+    # NOTE automatic image sizing only works if cell has fixed width
+    def dry_run
+      cell = self
+      max_height = nil
+      height, _, _ = @pdf.dry_run do
+        max_height = bounds.height
+        # NOTE we should be able to use cell.max_width, but returns 0 in some conditions (like when colspan > 1)
+        indent cell.padding_left, bounds.width - cell.width + cell.padding_right do
+          # HACK force margin_top to be applied
+          move_down 0.0001
+          # TODO truncate margin bottom of last block
+          convert_content_for_block cell.content
+        end
+      end
+      # FIXME prawn-table doesn't support cell taller than a single page
+      [max_height, height].min
+    end
+
+    def natural_content_width
+      # QUESTION can we get a better estimate of the natural width?
+      @natural_width ||= (@pdf.bounds.width - padding_left - padding_right)
+    end
+
+    def natural_content_height
+      # NOTE when natural_content_height is called, we already know max width
+      @natural_height ||= dry_run
+    end
+
+    def draw_content
+      pdf = @pdf
+      # NOTE draw_bounded_content adds FPTolerance to width and height, which causes content to overflow
+      pdf.bounds.instance_variable_set :@width, spanned_content_width
+      pdf.bounds.instance_variable_set :@height, spanned_content_height
+      if @valign != :top && (excess_y = spanned_content_height - natural_content_height) > 0
+        pdf.move_down(@valign == :center ? (excess_y.fdiv 2) : excess_y)
+      end
+      # TODO apply horizontal alignment (right now must use alignment on content block)
+      # QUESTION inherit table cell font properties?
+      pdf.convert_content_for_block content
+      nil
+    end
+  end
+end; end; end