Class: Prawn::Table

Inherits:
Object
  • Object
show all
Defined in:
lib/prawn/table.rb,
lib/prawn/table/cell.rb,
lib/prawn/table/cells.rb,
lib/prawn/table/cell/text.rb,
lib/prawn/table/cell/image.rb,
lib/prawn/table/cell/in_table.rb,
lib/prawn/table/cell/subtable.rb,
lib/prawn/table/cell/span_dummy.rb

Overview

Next-generation table drawing for Prawn.

Data

Data, for a Prawn table, is a two-dimensional array of objects that can be converted to cells (“cellable” objects). Cellable objects can be:

String

Produces a text cell. This is the most common usage.

Prawn::Table::Cell

If you have already built a Cell or have a custom subclass of Cell you want to use in a table, you can pass through Cell objects.

Prawn::Table

Creates a subtable (a table within a cell). You can use Prawn::Document#make_table to create a table for use as a subtable without immediately drawing it. See examples/table/bill.rb for a somewhat complex use of subtables.

Array

Creates a simple subtable. Create a Table object using make_table (see above) if you need more control over the subtable’s styling.

Options

Prawn/Layout provides many options to control style and layout of your table. These options are implemented with a uniform interface: the :foo option always sets the foo= accessor. See the accessor and method documentation for full details on the options you can pass. Some highlights:

cell_style

A hash of style options to style all cells. See the documentation on Prawn::Table::Cell for all cell style options.

header

If set to true, the first row will be repeated on every page. The header must be included as the first row of your data. Row numbering (for styling and other row-specific options) always indexes based on your data array. Whether or not you have a header, row(n) always refers to the nth element (starting from 0) of the data array.

column_widths

Sets widths for individual columns. Manually setting widths can give better results than letting Prawn guess at them, as Prawn’s algorithm for defaulting widths is currently pretty boneheaded. If you experience problems like weird column widths or CannotFit errors, try manually setting widths on more columns.

position

Either :left (the default), :center, :right, or a number. Specifies the horizontal position of the table within its bounding box. If a number is provided, it specifies the distance in points from the left edge.

Initializer Block

If a block is passed to methods that initialize a table (Prawn::Table.new, Prawn::Document#table, Prawn::Document#make_table), it will be called after cell setup but before layout. This is a very flexible way to specify styling and layout constraints. This code sets up a table where the second through the fourth rows (1-3, indexed from 0) are each one inch (72 pt) wide:

pdf.table(data) do |table|
  table.rows(1..3).width = 72
end

As with Prawn::Document#initialize, if the block has no arguments, it will be evaluated in the context of the object itself. The above code could be rewritten as:

pdf.table(data) do
  rows(1..3).width = 72
end

Defined Under Namespace

Classes: Cell, Cells

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data, document, options = {}, &block) ⇒ Table

Set up a table on the given document. Arguments:

data

A two-dimensional array of cell-like objects. See the “Data” section above for the types of objects that can be put in a table.

document

The Prawn::Document instance on which to draw the table.

options

A hash of attributes and values for the table. See the “Options” block above for details on available options.



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# File 'lib/prawn/table.rb', line 126

def initialize(data, document, options={}, &block)
  @pdf = document
  @cells = make_cells(data)
  @header = false
  @epsilon = 1e-9
  options.each { |k, v| send("#{k}=", v) }

  if block
    block.arity < 1 ? instance_eval(&block) : block[self]
  end

  set_column_widths
  set_row_heights
  position_cells
end

Instance Attribute Details

#cells ⇒ Object (readonly)

Returns a Prawn::Table::Cells object representing all of the cells in this table.



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# File 'lib/prawn/table.rb', line 162

def cells
  @cells
end

#column_length ⇒ Object (readonly)

Number of columns in the table.



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# File 'lib/prawn/table.rb', line 148

def column_length
  @column_length
end

#header=(value) ⇒ Object (writeonly)

If true, designates the first row as a header row to be repeated on every page. Does not change row numbering – row numbers always index into the data array provided, with no modification.



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# File 'lib/prawn/table.rb', line 204

def header=(value)
  @header = value
end

#position=(value) ⇒ Object (writeonly)

Position (:left, :right, :center, or a number indicating distance in points from the left edge) of the table within its parent bounds.



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# File 'lib/prawn/table.rb', line 157

def position=(value)
  @position = value
end

#row_colors=(value) ⇒ Object (writeonly)

Accepts an Array of alternating row colors to stripe the table.



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# File 'lib/prawn/table.rb', line 208

def row_colors=(value)
  @row_colors = value
end

#row_length ⇒ Object (readonly)

Number of rows in the table.



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# File 'lib/prawn/table.rb', line 144

def row_length
  @row_length
end

#width ⇒ Object

Returns the width of the table in PDF points.



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# File 'lib/prawn/table.rb', line 166

def width
  @width ||= [natural_width, @pdf.bounds.width].min
end

Instance Method Details

#cell_style=(style_hash) ⇒ Object

Sets styles for all cells.

pdf.table(data, :cell_style => { :borders => [:left, :right] })



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# File 'lib/prawn/table.rb', line 214

def cell_style=(style_hash)
  cells.style(style_hash)
end

#column_widths ⇒ Object

Calculate and return the constrained column widths, taking into account each cell’s min_width, max_width, and any user-specified constraints on the table or column size.

Because the natural widths can be silly, this does not always work so well at guessing a good size for columns that have vastly different content. If you see weird problems like CannotFit errors or shockingly bad column sizes, you should specify more column widths manually.



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# File 'lib/prawn/table.rb', line 335

def column_widths
  @column_widths ||= begin
    if width - cells.min_width < -epsilon
      raise Errors::CannotFit,
        "Table's width was set too small to contain its contents " +
        "(min width #{cells.min_width}, requested #{width})"
    end

    if width - cells.max_width > epsilon
      raise Errors::CannotFit,
        "Table's width was set larger than its contents' maximum width " +
        "(max width #{cells.max_width}, requested #{width})"
    end

    if width - natural_width < -epsilon
      # Shrink the table to fit the requested width.
      f = (width - cells.min_width).to_f / (natural_width - cells.min_width)

      (0...column_length).map do |c|
        min, nat = column(c).min_width, natural_column_widths[c]
        (f * (nat - min)) + min
      end
    elsif width - natural_width > epsilon
      # Expand the table to fit the requested width.
      f = (width - cells.width).to_f / (cells.max_width - cells.width)

      (0...column_length).map do |c|
        nat, max = natural_column_widths[c], column(c).max_width
        (f * (max - nat)) + nat
      end
    else
      natural_column_widths
    end
  end
end

#column_widths=(widths) ⇒ Object

Sets column widths for the table. The argument can be one of the following types:

Array

[w0, w1, w2, ...] (specify a width for each column)

Hash

{0 => w0, 1 => w1, ...} (keys are column names, values are widths)

Numeric

72 (sets width for all columns)



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# File 'lib/prawn/table.rb', line 181

def column_widths=(widths)
  case widths
  when Array
    widths.each_with_index { |w, i| column(i).width = w }
  when Hash
    widths.each { |i, w| column(i).width = w }
  when Numeric
    cells.width = widths
  else
    raise ArgumentError, "cannot interpret column widths"
  end
end

#columns(col_spec) ⇒ Object Also known as: column

Selects the given columns (0-based) for styling. Returns a Cells object – see the documentation on Cells for things you can do with cells.



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# File 'lib/prawn/table/cells.rb', line 23

def columns(col_spec)
  cells.columns(col_spec)
end

#draw ⇒ Object

Draws the table onto the document at the document’s current y-position.



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# File 'lib/prawn/table.rb', line 239

def draw
  with_position do
    # The cell y-positions are based on an infinitely long canvas. The offset
    # keeps track of how much we have to add to the original, theoretical
    # y-position to get to the actual position on the current page.
    offset = @pdf.y

    # Reference bounds are the non-stretchy bounds used to decide when to
    # flow to a new column / page.
    ref_bounds = @pdf.reference_bounds

    last_y = @pdf.y

    # Determine whether we're at the top of the current bounds (margin box or
    # bounding box). If we're at the top, we couldn't gain any more room by
    # breaking to the next page -- this means, in particular, that if the
    # first row is taller than the margin box, we will only move to the next
    # page if we're below the top. Some floating-point tolerance is added to
    # the calculation.
    #
    # Note that we use the actual bounds, not the reference bounds. This is
    # because even if we are in a stretchy bounding box, flowing to the next
    # page will not buy us any space if we are at the top.
    if @pdf.y > @pdf.bounds.height + @pdf.bounds.absolute_bottom - 0.001
      # we're at the top of our bounds
      started_new_page_at_row = 0
    else
      started_new_page_at_row = -1

      # If there isn't enough room left on the page to fit the first data row
      # (excluding the header), start the table on the next page.
      needed_height = row(0).height
      needed_height += row(1).height if @header
      if needed_height > @pdf.y - ref_bounds.absolute_bottom
        @pdf.bounds.move_past_bottom
        offset = @pdf.y
        started_new_page_at_row = 0
      end
    end

    # Track cells to be drawn on this page. They will all be drawn when this
    # page is finished.
    cells_this_page = []

    @cells.each do |cell|
      if cell.height > (cell.y + offset) - ref_bounds.absolute_bottom &&
         cell.row > started_new_page_at_row
        # Ink all cells on the current page
        Cell.draw_cells(cells_this_page)
        cells_this_page = []

        # start a new page or column
        @pdf.bounds.move_past_bottom
        draw_header unless cell.row == 0
        offset = @pdf.y - cell.y
        started_new_page_at_row = cell.row
      end
   
      # Don't modify cell.x / cell.y here, as we want to reuse the original
      # values when re-inking the table. #draw should be able to be called
      # multiple times.
      x, y = cell.x, cell.y
      y += offset 

      # Translate coordinates to the bounds we are in, since drawing is 
      # relative to the cursor, not ref_bounds.
      x += @pdf.bounds.left_side - @pdf.bounds.absolute_left
      y -= @pdf.bounds.absolute_bottom

      # Set background color, if any.
      if @row_colors && (!@header || cell.row > 0)
        # Ensure coloring restarts on every page (to make sure the header
        # and first row of a page are not colored the same way).
        index = cell.row - [started_new_page_at_row, @header ? 1 : 0].max
        cell.background_color ||= @row_colors[index % @row_colors.length]
      end

      cells_this_page << [cell, [x, y]]
      last_y = y
    end
    # Draw the last page of cells
    Cell.draw_cells(cells_this_page)

    @pdf.move_cursor_to(last_y - @cells.last.height)
  end
end

#height ⇒ Object

Returns the height of the table in PDF points.



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# File 'lib/prawn/table.rb', line 196

def height
  cells.height
end

#row_heights ⇒ Object

Returns an array with the height of each row.



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# File 'lib/prawn/table.rb', line 373

def row_heights
  @natural_row_heights ||=
    begin
      heights_by_row = Hash.new(0)
      cells.each do |cell|
        next if cell.is_a?(Cell::SpanDummy)

        # Split the height of row-spanned cells evenly by rows
        height_per_row = cell.height.to_f / cell.rowspan
        cell.rowspan.times do |i|
          heights_by_row[cell.row + i] =
            [heights_by_row[cell.row + i], height_per_row].max
        end
      end
      heights_by_row.sort_by { |row, _| row }.map { |_, h| h }
    end
end

#rows(row_spec) ⇒ Object Also known as: row

Selects the given rows (0-based) for styling. Returns a Cells object – see the documentation on Cells for things you can do with cells.



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# File 'lib/prawn/table/cells.rb', line 15

def rows(row_spec)
  cells.rows(row_spec)
end

#style(stylable, style_hash = {}, &block) ⇒ Object

Allows generic stylable content. This is an alternate syntax that some prefer to the attribute-based syntax. This code using style:

pdf.table(data) do
  style(row(0), :background_color => 'ff00ff')
  style(column(0)) { |c| c.border_width += 1 }
end

is equivalent to:

pdf.table(data) do
  row(0).style :background_color => 'ff00ff'
  column(0).style { |c| c.border_width += 1 }
end



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# File 'lib/prawn/table.rb', line 233

def style(stylable, style_hash={}, &block)
  stylable.style(style_hash, &block)
end