Module: Rpdfium::Table::Debugger

Defined in:
lib/rpdfium/table/debugger.rb

Overview

Generates a debug visualization: the page rendered to PNG with the detected edges and cell bboxes overlaid. Equivalent to pdfplumber.Page.to_image().debug_tablefinder().

Implemented in pure Ruby: rasterizes the page via render(), then draws over the bitmap by manipulating the RGBA bytes, and finally saves to PNG.

Constant Summary collapse

RED = 
[255, 0, 0, 200].freeze
GREEN = 
[0, 200, 0, 200].freeze
BLUE = 
[80, 80, 255, 120].freeze

Class Method Summary collapse

Class Method Details

.visualize(page, output_path, scale: 2.0, **table_opts) ⇒ Object 



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# File 'lib/rpdfium/table/debugger.rb', line 18

def visualize(page, output_path, scale: 2.0, **table_opts)
  extractor = Extractor.new(page, **table_opts)
  edges = extractor.edges
  intersections = extractor.intersections
  tables = extractor.tables

  w, h, bytes, _stride = page.render(scale: scale, output: :rgba)
  canvas = Canvas.new(w, h, bytes)

  # Draws edges. New format: each edge has orientation + x0/x1/top/bottom.
  # A horizontal edge has top == bottom; a vertical one has x0 == x1.
  edges.each do |e|
    canvas.line((e[:x0] * scale).to_i, (e[:top]    * scale).to_i,
                 (e[:x1] * scale).to_i, (e[:bottom] * scale).to_i, RED)
  end

  # Draws intersections (4px circles). They are Hashes keyed by [x, y].
  intersections.each_key do |(x, y)|
    canvas.dot((x * scale).to_i, (y * scale).to_i, GREEN, 4)
  end

  # Fills tables with transparent blue. Table#bbox is the tuple [x0, top, x1, bottom].
  tables.each do |t|
    x0, top, x1, bottom = t.bbox
    canvas.rect_fill((x0 * scale).to_i, (top    * scale).to_i,
                      (x1 * scale).to_i, (bottom * scale).to_i, BLUE)
  end

  Rpdfium::IO::PNG.write(output_path, w, h, canvas.bytes, stride: w * 4)
  output_path
end