class Prawn::Table::Cell

A Cell is a rectangular area of the page into which content is drawn. It has a framework for sizing itself and adding padding and simple styling. There are several standard Cell subclasses that handle things like text, Tables, and (in the future) stamps, images, and arbitrary content.

Cells are a basic building block for table support (see Prawn::Table).

Please subclass me if you want new content types! I'm designed to be very extensible. See the different standard Cell subclasses in lib/prawn/table/cell/*.rb for a template.

Constants

FPTolerance

A small amount added to the bounding box width to cover over floating- point errors when round-tripping from #content_width to width and back. This does not change cell positioning; it only slightly expands each cell's bounding box width so that rounding error does not prevent a cell from rendering.

Attributes

background_color[RW]

The background color, if any, for this cell. Specified in HTML RGB format, e.g., “ccffff”. The background is drawn under the whole cell, including any padding.

border_colors[R]

HTML RGB-format (“ccffff”) border colors: [top, right, bottom, left].

border_lines[R]

Line style

border_widths[R]

Width, in PDF points, of the cell's borders: [top, right, bottom, left].

borders[RW]

Specifies which borders to enable. Must be an array of zero or more of: [:left, :right, :top, :bottom].

colspan[R]

Number of columns this cell spans. Defaults to 1.

content[RW]

Specifies the content for the cell. Must be a “cellable” object. See the “Data” section of the Prawn::Table documentation for details on cellable objects.

height[W]

Manually specify the cell's height.

padding[R]

Amount of dead space (in PDF points) inside the borders but outside the content. Padding defaults to 5pt.

rowspan[R]

Number of rows this cell spans. Defaults to 1.

Public Class Methods

draw_cells(cells) click to toggle source

Given an array of pairs [cell, pt], draws each cell at its corresponding pt, making sure all backgrounds are behind all borders and content.

# File lib/prawn/table/cell.rb, line 406
def self.draw_cells(cells)
  cells.each do |cell, pt|
    cell.set_width_constraints
    cell.draw_background(pt)
  end

  cells.each do |cell, pt|
    cell.draw_borders(pt)
    cell.draw_bounded_content(pt)
  end
end
make(pdf, content, options={}) click to toggle source

Instantiates a Cell based on the given options. The particular class of cell returned depends on the :content argument. See the Prawn::Table documentation under “Data” for allowable content types.

# File lib/prawn/table/cell.rb, line 159
def self.make(pdf, content, options={})
  at = options.delete(:at) || [0, pdf.cursor]
  content = content.to_s if content.nil? || content.kind_of?(Numeric) ||
    content.kind_of?(Date)

  if content.is_a?(Hash)
    if img = content[:image]
      return Cell::Image.new(pdf, at, content)
    end
    options.update(content)
    content = options[:content]
  else
    options[:content] = content
  end

  options[:content] = content = "" if content.nil?

  case content
  when Prawn::Table::Cell
    content
  when String
    Cell::Text.new(pdf, at, options)
  when Prawn::Table
    Cell::Subtable.new(pdf, at, options)
  when Array
    subtable = Prawn::Table.new(options[:content], pdf, {})
    Cell::Subtable.new(pdf, at, options.merge(:content => subtable))
  else
    raise Errors::UnrecognizedTableContent
  end
end
new(pdf, point, options={}) click to toggle source

Sets up a cell on the document pdf, at the given x/y location point, with the given options. Cell, like Table, follows the “options set accessors” paradigm (see “Options” under the Table documentation), so any cell accessor cell.foo = :bar can be set by providing the option :foo => :bar here.

# File lib/prawn/table/cell.rb, line 205
def initialize(pdf, point, options={})
  @pdf   = pdf
  @point = point

  # Set defaults; these can be changed by options
  @padding       = [5, 5, 5, 5]
  @borders       = [:top, :bottom, :left, :right]
  @border_widths = [1] * 4
  @border_colors = ['000000'] * 4
  @border_lines  = [:solid] * 4
  @colspan = 1
  @rowspan = 1
  @dummy_cells = []

  options.each { |k, v| send("#{k}=", v) }

  @initializer_run = true
end

Public Instance Methods

avg_spanned_min_width() click to toggle source

Min-width of the span divided by the number of columns.

# File lib/prawn/table/cell.rb, line 80
def avg_spanned_min_width
  min_width.to_f / colspan
end
border_bottom_color() click to toggle source
# File lib/prawn/table/cell.rb, line 561
def border_bottom_color
  @border_colors[2]
end
border_bottom_color=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 565
def border_bottom_color=(val)
  @border_colors[2] = val
end
border_bottom_line() click to toggle source
# File lib/prawn/table/cell.rb, line 687
def border_bottom_line
  @borders.include?(:bottom) ? @border_lines[2] : 0
end
border_bottom_line=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 691
def border_bottom_line=(val)
  @border_lines[2] = val
end
border_bottom_width() click to toggle source
# File lib/prawn/table/cell.rb, line 619
def border_bottom_width
  @borders.include?(:bottom) ? @border_widths[2] : 0
end
border_bottom_width=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 623
def border_bottom_width=(val)
  @border_widths[2] = val
end
border_color=(color) click to toggle source

Sets border colors on this cell. The argument can be one of:

  • an integer (sets all colors)

  • a two-element array [vertical, horizontal]

  • a three-element array [top, horizontal, bottom]

  • a four-element array [top, right, bottom, left]

# File lib/prawn/table/cell.rb, line 518
def border_color=(color)
  @border_colors = case
  when color.nil?
    ["000000"] * 4
  when String === color # all colors
    [color, color, color, color]
  when color.length == 2 # vert, horiz
    [color[0], color[1], color[0], color[1]]
  when color.length == 3 # top, horiz, bottom
    [color[0], color[1], color[2], color[1]]
  when color.length == 4 # top, right, bottom, left
    [color[0], color[1], color[2], color[3]]
  else
    raise ArgumentError, ":border_color must be a string " +
      "or an array [v,h] or [t,r,b,l]"
  end
end
Also aliased as: border_colors=
border_colors=(color)
Alias for: border_color=
border_left_color() click to toggle source
# File lib/prawn/table/cell.rb, line 569
def border_left_color
  @border_colors[3]
end
border_left_color=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 573
def border_left_color=(val)
  @border_colors[3] = val
end
border_left_line() click to toggle source
# File lib/prawn/table/cell.rb, line 695
def border_left_line
  @borders.include?(:left) ? @border_lines[3] : 0
end
border_left_line=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 699
def border_left_line=(val)
  @border_lines[3] = val
end
border_left_width() click to toggle source
# File lib/prawn/table/cell.rb, line 627
def border_left_width
  @borders.include?(:left) ? @border_widths[3] : 0
end
border_left_width=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 631
def border_left_width=(val)
  @border_widths[3] = val
end
border_line=(line) click to toggle source

Sets border line style on this cell. The argument can be one of:

Possible values are: :solid, :dashed, :dotted

  • one value (sets all lines)

  • a two-element array [vertical, horizontal]

  • a three-element array [top, horizontal, bottom]

  • a four-element array [top, right, bottom, left]

# File lib/prawn/table/cell.rb, line 652
def border_line=(line)
  @border_lines = case
  when line.nil?
    [:solid] * 4
  when line.length == 1 # all lines
    [line[0]] * 4
  when line.length == 2
    [line[0], line[1], line[0], line[1]]
  when line.length == 3
    [line[0], line[1], line[2], line[1]]
  when line.length == 4
    [line[0], line[1], line[2], line[3]]
  else
    raise ArgumentError, "border_line must be one of :solid, :dashed, "
      ":dotted or an array [v,h] or [t,r,b,l]"
  end
end
Also aliased as: border_lines=
border_lines=(line)
Alias for: border_line=
border_right_color() click to toggle source
# File lib/prawn/table/cell.rb, line 553
def border_right_color
  @border_colors[1]
end
border_right_color=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 557
def border_right_color=(val)
  @border_colors[1] = val
end
border_right_line() click to toggle source
# File lib/prawn/table/cell.rb, line 679
def border_right_line
  @borders.include?(:right) ? @border_lines[1] : 0
end
border_right_line=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 683
def border_right_line=(val)
  @border_lines[1] = val
end
border_right_width() click to toggle source
# File lib/prawn/table/cell.rb, line 611
def border_right_width
  @borders.include?(:right) ? @border_widths[1] : 0
end
border_right_width=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 615
def border_right_width=(val)
  @border_widths[1] = val
end
border_top_color() click to toggle source
# File lib/prawn/table/cell.rb, line 537
def border_top_color
  @border_colors[0]
end
border_top_color=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 541
def border_top_color=(val)
  @border_colors[0] = val
end
border_top_line() click to toggle source
# File lib/prawn/table/cell.rb, line 671
def border_top_line
  @borders.include?(:top) ? @border_lines[0] : 0
end
border_top_line=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 675
def border_top_line=(val)
  @border_lines[0] = val
end
border_top_width() click to toggle source
# File lib/prawn/table/cell.rb, line 603
def border_top_width
  @borders.include?(:top) ? @border_widths[0] : 0
end
border_top_width=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 607
def border_top_width=(val)
  @border_widths[0] = val
end
border_width=(width) click to toggle source

Sets border widths on this cell. The argument can be one of:

  • an integer (sets all widths)

  • a two-element array [vertical, horizontal]

  • a three-element array [top, horizontal, bottom]

  • a four-element array [top, right, bottom, left]

# File lib/prawn/table/cell.rb, line 584
def border_width=(width)
  @border_widths = case
  when width.nil?
    ["000000"] * 4
  when Numeric === width # all widths
    [width, width, width, width]
  when width.length == 2 # vert, horiz
    [width[0], width[1], width[0], width[1]]
  when width.length == 3 # top, horiz, bottom
    [width[0], width[1], width[2], width[1]]
  when width.length == 4 # top, right, bottom, left
    [width[0], width[1], width[2], width[3]]
  else
    raise ArgumentError, ":border_width must be a string " +
      "or an array [v,h] or [t,r,b,l]"
  end
end
Also aliased as: border_widths=
border_widths=(width)
Alias for: border_width=
colspan=(span) click to toggle source

Indicates the number of columns that this cell is to span. Defaults to 1.

This must be provided as part of the table data, like so:

pdf.table([["foo", {:content => "bar", :colspan => 2}]])

Setting colspan from the initializer block is invalid because layout has already run. For example, this will NOT work:

pdf.table([["foo", "bar"]]) { cells[0, 1].colspan = 2 }
# File lib/prawn/table/cell.rb, line 360
def colspan=(span)
  if @initializer_run
    raise Prawn::Errors::InvalidTableSpan,
      "colspan must be provided in the table's structure, never in the " +
      "initialization block. See Prawn's documentation for details."
  end

  @colspan = span
end
content_height() click to toggle source

Returns the height of the bare content in the cell, excluding padding.

# File lib/prawn/table/cell.rb, line 326
def content_height
  if @height # manually set
    return @height - padding_top - padding_bottom
  end

  natural_content_height
end
content_width() click to toggle source

Returns the width of the bare content in the cell, excluding padding.

# File lib/prawn/table/cell.rb, line 276
def content_width
  if @width # manually set
    return @width - padding_left - padding_right
  end

  natural_content_width
end
draw(pt=[x, y]) click to toggle source

Draws the cell onto the document. Pass in a point [x,y] to override the location at which the cell is drawn.

If drawing a group of cells at known positions, look into ::draw_cells, which ensures that the backgrounds, borders, and content are all drawn in correct order so as not to overlap.

# File lib/prawn/table/cell.rb, line 398
def draw(pt=[x, y])
  Prawn::Table::Cell.draw_cells([[self, pt]])
end
draw_background(pt) click to toggle source

Draws the cell's background color.

# File lib/prawn/table/cell.rb, line 705
def draw_background(pt)
  if @background_color
    @pdf.mask(:fill_color) do
      @pdf.fill_color @background_color
      @pdf.fill_rectangle pt, width, height
    end
  end
end
draw_borders(pt) click to toggle source

Draws borders around the cell. Borders are centered on the bounds of the cell outside of any padding, so the caller is responsible for setting appropriate padding to ensure the border does not overlap with cell content.

# File lib/prawn/table/cell.rb, line 719
def draw_borders(pt)
  x, y = pt

  @pdf.mask(:line_width, :stroke_color) do
    @borders.each do |border|
      idx = {:top => 0, :right => 1, :bottom => 2, :left => 3}[border]
      border_color = @border_colors[idx]
      border_width = @border_widths[idx]
      border_line  = @border_lines[idx]

      next if border_width <= 0

      # Left and right borders are drawn one-half border beyond the center
      # of the corner, so that the corners end up square.
      from, to = case border
                 when :top
                   [[x, y], [x+width, y]]
                 when :bottom
                   [[x, y-height], [x+width, y-height]]
                 when :left
                   [[x, y + (border_top_width / 2.0)],
                    [x, y - height - (border_bottom_width / 2.0)]]
                 when :right
                   [[x+width, y + (border_top_width / 2.0)],
                    [x+width, y - height - (border_bottom_width / 2.0)]]
                 end

      case border_line
      when :dashed
        @pdf.dash border_width * 4
      when :dotted
        @pdf.dash border_width, :space => border_width * 2
      when :solid
        # normal line style
      else
        raise ArgumentError, "border_line must be :solid, :dotted or" +
          " :dashed"
      end
      
      @pdf.line_width   = border_width
      @pdf.stroke_color = border_color
      @pdf.stroke_line(from, to)
      @pdf.undash
    end
  end
end
draw_bounded_content(pt) click to toggle source

Draws the cell's content at the point provided.

# File lib/prawn/table/cell.rb, line 420
def draw_bounded_content(pt)
  @pdf.float do
    @pdf.bounding_box([pt[0] + padding_left, pt[1] - padding_top],
                      :width  => spanned_content_width + FPTolerance,
                      :height => spanned_content_height + FPTolerance) do
      draw_content
    end
  end
end
draw_content() click to toggle source

Draws cell content within the cell's bounding box. Must be implemented in subclasses.

# File lib/prawn/table/cell.rb, line 769
def draw_content
  raise NotImplementedError, "subclasses must implement draw_content"
end
height() click to toggle source

Returns the cell's height in points, inclusive of padding. If the cell is the master cell of a rowspan, returns the width of the entire span group.

# File lib/prawn/table/cell.rb, line 311
def height
  return height_ignoring_span if @colspan == 1 && @rowspan == 1

  # We're in a span group; get the maximum height per row (including the
  # master cell) and sum each row.
  row_heights = Hash.new(0)
  dummy_cells.each do |cell|
    row_heights[cell.row] = [row_heights[cell.row], cell.height].max
  end
  row_heights[row] = [row_heights[row], height_ignoring_span].max
  row_heights.values.inject(0, &:+)
end
height_ignoring_span() click to toggle source

Returns the cell's height in points, inclusive of padding, in its first row only.

# File lib/prawn/table/cell.rb, line 301
def height_ignoring_span
  # We can't ||= here because the FP error accumulates on the round-trip
  # from #content_height.
  @height || (content_height + padding_top + padding_bottom)
end
max_width() click to toggle source

Maximum width of the entire span group this cell controls.

# File lib/prawn/table/cell.rb, line 94
def max_width
  return max_width_ignoring_span if @colspan == 1

  # Sum the smallest max-width from each column in the group, including
  # myself.
  max_widths = Hash.new(0)
  dummy_cells.each do |cell|
    max_widths[cell.column] =
      [max_widths[cell.column], cell.max_width].min
  end
  max_widths[column] = [max_widths[column], max_width_ignoring_span].min
  max_widths.values.inject(0, &:+)
end
max_width_ignoring_span() click to toggle source

If provided, the maximum width that this cell can be drawn in, within its column.

# File lib/prawn/table/cell.rb, line 87
def max_width_ignoring_span
  set_width_constraints
  @max_width
end
min_width() click to toggle source

Minimum width of the entire span group this cell controls.

# File lib/prawn/table/cell.rb, line 65
def min_width
  return min_width_ignoring_span if @colspan == 1

  # Sum up the largest min-width from each column, including myself.
  min_widths = Hash.new(0)
  dummy_cells.each do |cell|
    min_widths[cell.column] =
      [min_widths[cell.column], cell.min_width].max
  end
  min_widths[column] = [min_widths[column], min_width_ignoring_span].max
  min_widths.values.inject(0, &:+)
end
min_width_ignoring_span() click to toggle source

If provided, the minimum width that this cell in its column will permit.

# File lib/prawn/table/cell.rb, line 58
def min_width_ignoring_span
  set_width_constraints
  @min_width
end
natural_content_height() click to toggle source

Returns the height this cell would naturally take on, absent constraints. Must be implemented in subclasses.

# File lib/prawn/table/cell.rb, line 343
def natural_content_height
  raise NotImplementedError,
    "subclasses must implement natural_content_height"
end
natural_content_width() click to toggle source

Returns the width this cell would naturally take on, absent other constraints. Must be implemented in subclasses.

# File lib/prawn/table/cell.rb, line 293
def natural_content_width
  raise NotImplementedError,
    "subclasses must implement natural_content_width"
end
padding=(pad) click to toggle source

Sets padding on this cell. The argument can be one of:

  • an integer (sets all padding)

  • a two-element array [vertical, horizontal]

  • a three-element array [top, horizontal, bottom]

  • a four-element array [top, right, bottom, left]

# File lib/prawn/table/cell.rb, line 461
def padding=(pad)
  @padding = case
  when pad.nil?
    [0, 0, 0, 0]
  when Numeric === pad # all padding
    [pad, pad, pad, pad]
  when pad.length == 2 # vert, horiz
    [pad[0], pad[1], pad[0], pad[1]]
  when pad.length == 3 # top, horiz, bottom
    [pad[0], pad[1], pad[2], pad[1]]
  when pad.length == 4 # top, right, bottom, left
    [pad[0], pad[1], pad[2], pad[3]]
  else
    raise ArgumentError, ":padding must be a number or an array [v,h] " +
      "or [t,r,b,l]"
  end
end
padding_bottom() click to toggle source
# File lib/prawn/table/cell.rb, line 495
def padding_bottom
  @padding[2]
end
padding_bottom=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 499
def padding_bottom=(val)
  @padding[2] = val
end
padding_left() click to toggle source
# File lib/prawn/table/cell.rb, line 503
def padding_left
  @padding[3]
end
padding_left=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 507
def padding_left=(val)
  @padding[3] = val
end
padding_right() click to toggle source
# File lib/prawn/table/cell.rb, line 487
def padding_right
  @padding[1]
end
padding_right=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 491
def padding_right=(val)
  @padding[1] = val
end
padding_top() click to toggle source
# File lib/prawn/table/cell.rb, line 479
def padding_top
  @padding[0]
end
padding_top=(val) click to toggle source
# File lib/prawn/table/cell.rb, line 483
def padding_top=(val)
  @padding[0] = val
end
rowspan=(span) click to toggle source

Indicates the number of rows that this cell is to span. Defaults to 1.

This must be provided as part of the table data, like so:

pdf.table([["foo", {:content => "bar", :rowspan => 2}], ["baz"]])

Setting rowspan from the initializer block is invalid because layout has already run. For example, this will NOT work:

pdf.table([["foo", "bar"], ["baz"]]) { cells[0, 1].rowspan = 2 }
# File lib/prawn/table/cell.rb, line 381
def rowspan=(span)
  if @initializer_run
    raise Prawn::Errors::InvalidTableSpan,
      "rowspan must be provided in the table's structure, never in the " +
      "initialization block. See Prawn's documentation for details."
  end

  @rowspan = span
end
set_width_constraints() click to toggle source

Sets the cell's minimum and maximum width. Deferred until requested because padding and size can change.

# File lib/prawn/table/cell.rb, line 638
def set_width_constraints
  @min_width ||= padding_left + padding_right
  @max_width ||= @pdf.bounds.width
end
spanned_content_height() click to toggle source

Height of the entire span group.

# File lib/prawn/table/cell.rb, line 336
def spanned_content_height
  height - padding_top - padding_bottom
end
spanned_content_width() click to toggle source

Width of the entire span group.

# File lib/prawn/table/cell.rb, line 286
def spanned_content_width
  width - padding_left - padding_right
end
style(options={}, &block) click to toggle source

Supports setting multiple properties at once.

cell.style(:padding => 0, :border_width => 2)

is the same as:

cell.padding = 0
cell.border_width = 2
# File lib/prawn/table/cell.rb, line 233
def style(options={}, &block)
  options.each { |k, v| send("#{k}=", v) }

  # The block form supports running a single block for multiple cells, as
  # in Cells#style.
  block.call(self) if block
end
width() click to toggle source

Returns the cell's width in points, inclusive of padding. If the cell is the master cell of a colspan, returns the width of the entire span group.

# File lib/prawn/table/cell.rb, line 254
def width
  return width_ignoring_span if @colspan == 1 && @rowspan == 1

  # We're in a span group; get the maximum width per column (including
  # the master cell) and sum each column.
  column_widths = Hash.new(0)
  dummy_cells.each do |cell|
    column_widths[cell.column] =
      [column_widths[cell.column], cell.width].max
  end
  column_widths[column] = [column_widths[column], width_ignoring_span].max
  column_widths.values.inject(0, &:+)
end
width=(w) click to toggle source

Manually sets the cell's width, inclusive of padding.

# File lib/prawn/table/cell.rb, line 270
def width=(w)
  @width = @min_width = @max_width = w
end
width_ignoring_span() click to toggle source

Returns the width of the cell in its first column alone, ignoring any colspans.

# File lib/prawn/table/cell.rb, line 244
def width_ignoring_span
  # We can't ||= here because the FP error accumulates on the round-trip
  # from #content_width.
  @width || (content_width + padding_left + padding_right)
end
x() click to toggle source

x-position of the cell within the parent bounds.

# File lib/prawn/table/cell.rb, line 432
def x
  @point[0]
end
x=(val) click to toggle source

Set the x-position of the cell within the parent bounds.

# File lib/prawn/table/cell.rb, line 438
def x=(val)
  @point[0] = val
end
y() click to toggle source

y-position of the cell within the parent bounds.

# File lib/prawn/table/cell.rb, line 444
def y
  @point[1]
end
y=(val) click to toggle source

Set the y-position of the cell within the parent bounds.

# File lib/prawn/table/cell.rb, line 450
def y=(val)
  @point[1] = val
end