Add bin and edit workflow

bin/gems/pdf-reader-2.14.1/lib/pdf/reader/page_layout.rb

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+# coding: utf-8
+# typed: strict
+# frozen_string_literal: true
+
+require 'pdf/reader/overlapping_runs_filter'
+require 'pdf/reader/zero_width_runs_filter'
+
+class PDF::Reader
+
+  # Takes a collection of TextRun objects and renders them into a single
+  # string that best approximates the way they'd appear on a render PDF page.
+  #
+  # media box should be a 4 number array that describes the dimensions of the
+  # page to be rendered as described by the page's MediaBox attribute
+  class PageLayout
+
+    DEFAULT_FONT_SIZE = 12
+
+    def initialize(runs, mediabox)
+      # mediabox is a 4-element array for now, but it'd be nice to switch to a
+      # PDF::Reader::Rectangle at some point
+      PDF::Reader::Error.validate_not_nil(mediabox, "mediabox")
+
+      @mediabox = process_mediabox(mediabox)
+      @runs = runs
+      @mean_font_size   = mean(@runs.map(&:font_size)) || DEFAULT_FONT_SIZE
+      @mean_font_size = DEFAULT_FONT_SIZE if @mean_font_size == 0
+      @median_glyph_width = median(@runs.map(&:mean_character_width)) || 0
+      @x_offset = @runs.map(&:x).sort.first || 0
+      lowest_y = @runs.map(&:y).sort.first || 0
+      @y_offset = lowest_y > 0 ? 0 : lowest_y
+    end
+
+    def to_s
+      return "" if @runs.empty?
+      return "" if row_count == 0
+
+      page = row_count.times.map { |i| " " * col_count }
+      @runs.each do |run|
+        x_pos = ((run.x - @x_offset) / col_multiplier).round
+        y_pos = row_count - ((run.y - @y_offset) / row_multiplier).round
+        if y_pos <= row_count && y_pos >= 0 && x_pos <= col_count && x_pos >= 0
+          local_string_insert(page[y_pos-1], run.text, x_pos)
+        end
+      end
+      interesting_rows(page).map(&:rstrip).join("\n")
+    end
+
+    private
+
+    def page_width
+      @mediabox.width
+    end
+
+    def page_height
+      @mediabox.height
+    end
+
+    # given an array of strings, return a new array with empty rows from the
+    # beginning and end removed.
+    #
+    #   interesting_rows([ "", "one", "two", "" ])
+    #   => [ "one", "two" ]
+    #
+    def interesting_rows(rows)
+      line_lengths = rows.map { |l| l.strip.length }
+
+      return [] if line_lengths.all?(&:zero?)
+
+      first_line_with_text = line_lengths.index { |l| l > 0 }
+      last_line_with_text  = line_lengths.size - line_lengths.reverse.index { |l| l > 0 }
+      interesting_line_count = last_line_with_text - first_line_with_text
+      rows[first_line_with_text, interesting_line_count].map
+    end
+
+    def row_count
+      @row_count ||= (page_height / @mean_font_size).floor
+    end
+
+    def col_count
+      @col_count ||= ((page_width  / @median_glyph_width) * 1.05).floor
+    end
+
+    def row_multiplier
+      @row_multiplier ||= page_height.to_f / row_count.to_f
+    end
+
+    def col_multiplier
+      @col_multiplier ||= page_width.to_f / col_count.to_f
+    end
+
+    def mean(collection)
+      if collection.size == 0
+        0
+      else
+        collection.inject(0) { |accum, v| accum + v} / collection.size.to_f
+      end
+    end
+
+    def median(collection)
+      if collection.size == 0
+        0
+      else
+        collection.sort[(collection.size * 0.5).floor]
+      end
+    end
+
+    def local_string_insert(haystack, needle, index)
+      haystack[Range.new(index, index + needle.length - 1)] = String.new(needle)
+    end
+
+    def process_mediabox(mediabox)
+      if mediabox.is_a?(Array)
+        msg = "Passing the mediabox to PageLayout as an Array is deprecated," +
+          " please use a Rectangle instead"
+        $stderr.puts msg
+        PDF::Reader::Rectangle.from_array(mediabox)
+      else
+        mediabox
+      end
+    end
+
+  end
+end