Object
Next-generation table drawing for Prawn.
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. |
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. | |
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. |
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. |
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
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. |
# File lib/prawn/table.rb, line 119 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
Sets styles for all cells.
pdf.table(data, :cell_style => { :borders => [:left, :right] })
# File lib/prawn/table.rb, line 197 def cell_style=(style_hash) cells.style(style_hash) end
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.
# File lib/prawn/table.rb, line 314 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, column(c).width (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 = column(c).width, column(c).max_width (f * (max - nat)) + nat end else natural_column_widths end end end
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) |
# File lib/prawn/table.rb, line 164 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
Selects the given columns (0-based) for styling. Returns a Cells object – see the documentation on Cells for things you can do with cells.
# File lib/prawn/table/cells.rb, line 29 def columns(col_spec) cells.columns(col_spec) end
Draws the table onto the document at the document’s current y-position.
# File lib/prawn/table.rb, line 222 def draw # 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) index = @header ? (cell.row - 1) : cell.row 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
Returns the height of the table in PDF points.
# File lib/prawn/table.rb, line 179 def height cells.height end
Returns an array with the height of each row.
# File lib/prawn/table.rb, line 352 def row_heights @natural_row_heights ||= (0...row_length).map{ |r| row(r).height } end
Selects the given rows (0-based) for styling. Returns a Cells object – see the documentation on Cells for things you can do with cells.
# File lib/prawn/table/cells.rb, line 21 def rows(row_spec) cells.rows(row_spec) end
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
# File lib/prawn/table.rb, line 216 def style(stylable, style_hash={}, &block) stylable.style(style_hash, &block) end
Raises an error if the data provided cannot be converted into a valid table.
# File lib/prawn/table.rb, line 385 def assert_proper_table_data(data) if data.nil? || data.empty? raise Prawn::Errors::EmptyTable, "data must be a non-empty, non-nil, two dimensional array " + "of cell-convertible objects" end unless data.all? { |e| Array === e } raise Prawn::Errors::InvalidTableData, "data must be a two dimensional array of cellable objects" end end
If the table has a header, draw it at the current position.
# File lib/prawn/table.rb, line 400 def draw_header if @header y = @pdf.cursor row(0).each do |cell| cell.y = y cell.draw end @pdf.move_cursor_to(y - row(0).height) end end
Converts the array of cellable objects given into instances of Prawn::Table::Cell, and sets up their in-table properties so that they know their own position in the table.
# File lib/prawn/table.rb, line 362 def make_cells(data) assert_proper_table_data(data) cells = [] @row_length = data.length @column_length = data.map{ |r| r.length }.max data.each_with_index do |row_cells, row_number| row_cells.each_with_index do |cell_data, column_number| cell = Cell.make(@pdf, cell_data) cell.extend(Cell::InTable) cell.row = row_number cell.column = column_number cells << cell end end cells end
Returns an array of each column’s natural (unconstrained) width.
# File lib/prawn/table.rb, line 413 def natural_column_widths @natural_column_widths ||= (0...column_length).map { |c| column(c).width } end
Returns the “natural” (unconstrained) width of the table. This may be extremely silly; for example, the unconstrained width of a paragraph of text is the width it would assume if it were not wrapped at all. Could be a mile long.
# File lib/prawn/table.rb, line 422 def natural_width @natural_width ||= natural_column_widths.inject(0) { |sum, w| sum + w } end
Set each cell’s position based on the widths and heights of cells preceding it.
# File lib/prawn/table.rb, line 447 def position_cells # Calculate x- and y-positions as running sums of widths / heights. x_positions = column_widths.inject([0]) { |ary, x| ary << (ary.last + x); ary }[0..-2] x_positions.each_with_index { |x, i| column(i).x = x } # y-positions assume an infinitely long canvas starting at zero -- this # is corrected for in Table#draw, and page breaks are properly inserted. y_positions = row_heights.inject([0]) { |ary, y| ary << (ary.last - y); ary}[0..-2] y_positions.each_with_index { |y, i| row(i).y = y } end
Assigns the calculated column widths to each cell. This ensures that each cell in a column is the same width. After this method is called, subsequent calls to column_widths and width should return the finalized values that will be used to ink the table.
# File lib/prawn/table.rb, line 431 def set_column_widths column_widths.each_with_index do |w, col_num| column(col_num).width = w end end
Generated with the Darkfish Rdoc Generator 2.