Watermarking with Prawn (using templates) - ruby

I need to be able to watermark a document that was created from a template. I have the following code right now:
# Note: the raw PDF text (body variable below) is sent from a remote server.
Prawn::Document.new(:template => StringIO.new(body), :page_size =>
'A4') do |document|
# ... including other pages and sections to the template here ...
# watermark
d.page_count.times do |i|
d.go_to_page i
d.stroke_line [d.bounds.left, d.bounds.bottom], [d.bounds.right, d.bounds.top]
d.draw_text "Watermark", :rotate => 45, :at => [100,100], :size => 100
end
end
This is ignoring the templated pages for some reason that I can't comprehend. Now here's where the plot thickens: if the server adds a watermark, then this code will work as expected (e.g. straight Ruby code = no overlaying text on the non-prawn-generated pages, yet watermarking works on a pre-watermarked template). My only guess is there is some way to create a z-index/layer that the server is doing but Prawn itself cannot.
Here is a portion of the code from the server that does the PDF
generation itself, this does the watermarking using iText:
PdfStamper stamper = new PdfStamper(...);
PdfContentByte over = stamper.GetOverContent(i + 1);
over.BeginText();
over.SetTextMatrix(20, 40);
over.SetFontAndSize(bf, 20);
over.SetColorFill(new Color(97, 150, 58));
over.ShowTextAligned(Element.ALIGN_CENTER,
watermarkText,
document.PageSize.Width / 2,
document.PageSize.Height / 2,
55);
over.EndText();
over.Stroke();
If that runs before I use the raw data in Prawn I can watermark, go
figure.
So my questions are:
Anyone know how I can achieve the same effect using prawn instead
of a hybrid? I'd rather handle the watermarking locally.
Is there a basic equivalent to GetOverContent() in Prawn?
Is there a better way to get a string of raw PDF data into Prawn
without using :template and StringIO? (I saw the #add_content method
but that didn't work)
TL;DR: I need to float text above the Prawn templated text a la
watermarking the document.
Any insight or paths I can research will be appreciated. If this
makes no sense I can clarify.

You could try stamping the document.
create_stamp("watermark") do
rotate(30, :origin => [-5, -5]) do
stroke_color "FF3333"
stroke_ellipse [0, 0], 29, 15
stroke_color "000000"
fill_color "993333"
font("Times-Roman") do
draw_text "Watermark", :at => [-23, -3]
end
fill_color "000000"
end
end
stamp_at "watermark", [210, 210]

create_stamp("stamp") do
fill_color "cc0000"
text_rendering_mode(:fill_stroke) do
transparent(0.5){
text_box "WATERMARK",
:size => 50,
:width => bounds.width,
:height => bounds.height,
:align => :center,
:valign => :center,
:at => [0, bounds.height],
:rotate => 45,
:rotate_around => :center
}
end
end
repeat (:all) do
stamp("stamp")
end

Related

Controlling content flow with Prawn

Let's say we want to display a title on the first page that takes up the top half of the page. The bottom half of the page should then fill up with our article text, and the text should continue to flow over into the subsequent pages until it runs out:
This is a pretty basic layout scenario but I don't understand how one would implement it in Prawn.
Here's some example code derived from their online documentation:
pdf = Prawn::Document.new do
text "The Prince", :align => :center, :size => 48
text "Niccolò Machiavelli", :align => :center, :size => 20
move_down 42
column_box([0, cursor], :columns => 3, :width => bounds.width) do
text((<<-END.gsub(/\s+/, ' ') + "\n\n") * 20)
All the States and Governments by which men are or ever have been ruled,
have been and are either Republics or Princedoms. Princedoms are either
hereditary, in which the bla bla bla bla .....
END
end
end.render
but that will just continue to show the title space for every page:
What's the right way to do this?
I have been fighting with this same problem. I ended up subclassing ColumnBox and adding a helper to invoke it like so:
module Prawn
class Document
def reflow_column_box(*args, &block)
init_column_box(block) do |parent_box|
map_to_absolute!(args[0])
#bounding_box = ReflowColumnBox.new(self, parent_box, *args)
end
end
private
class ReflowColumnBox < ColumnBox
def move_past_bottom
#current_column = (#current_column + 1) % #columns
#document.y = #y
if 0 == #current_column
#y = #parent.absolute_top
#document.start_new_page
end
end
end
end
end
Then it is invoked exactly like a normal column box, but on the next page break will reflow to the parents bounding box. Change your line:
column_box([0, cursor], :columns => 3, :width => bounds.width) do
to
reflow_column_box([0, cursor], :columns => 3, :width => bounds.width) do
Hope it helps you. Prawn is pretty low level, which is a two-edged sword, it sometimes fails to do what you need, but the tools are there to extend and build more complicated structures.
I know this is old, but I thought I'd share that a new option has been added to fix this in v0.14.0.
:reflow_margins is an option that sets column boxes to fill their parent boxes on new page creation.
column_box(reflow_margins: true, columns: 3)
So, the column_box method creates a bounding box. The documented behavior of the bounding box is that it starts at the same position as on the previous page if it changes to the next page. So the behavior you are seeing is basically correct, also not what you want. The suggested workaround I have found by googling is to use a span instead, because spans do not have this behavior.
The problem now is, how to build text columns with spans? They don't seem to support spans natively. I tried to build a small script that mimicks columns with spans. It creates one span for each column and aligns them accordingly. Then, the text is written with text_box, which has the overflow: :truncate option. This makes the method return the text that did not fit in the text box, so that this text can then be rendered in the next column. The code probably needs some tweaking, but it should be enough to demonstrate how to do this.
require 'prawn'
text_to_write = ((<<-END.gsub(/\s+/, ' ') + "\n\n") * 20)
All the States and Governments by which men are or ever have been ruled,
have been and are either Republics or Princedoms. Princedoms are either
hereditary, in which the bla bla bla bla .....
END
pdf = Prawn::Document.generate("test.pdf") do
text "The Prince", :align => :center, :size => 48
text "Niccolò Machiavelli", :align => :center, :size => 20
move_down 42
starting_y = cursor
starting_page = page_number
span(bounds.width / 3, position: :left) do
text_to_write = text_box text_to_write, at: [bounds.left, 0], overflow: :truncate
end
go_to_page(starting_page)
move_cursor_to(starting_y)
span(bounds.width / 3, position: :center) do
text_to_write = text_box text_to_write, at: [bounds.left, 0], overflow: :truncate
end
go_to_page(starting_page)
move_cursor_to(starting_y)
span(bounds.width / 3, position: :right) do
text_box text_to_write, at: [bounds.left, 0]
end
end
I know this is not an ideal solution. However, this was the best I could come up with.
Use floats.
float do
span((bounds.width / 3) - 20, :position => :left) do
# Row Table Code
end
end
float do
span((bounds.width / 3) - 20, :position => :center) do
# Row Table Code
end
end
float do
span((bounds.width / 3) - 20, :position => :right) do
# Row Table Code
end
end
Use Prawns grid layout instead. It is very well documented...and easier to control your layout.

Prawn doesn't seem to push layout down when using repeat(:all)

I am generating a document with data that flows onto each subsequent page, each page has a standard header. However, when I use repeat(:all) to put the header on each page, I find that on every page but the first page, the next content is not being moved down by the size of the header banner I have put on the page.
My code for generating the banner:
class SmartsoftPdf < Prawn::Document
BOX_MARGIN = 30
RHYTHM = 10
INNER_MARGIN = 30
# Colors
#
BLACK = "000000"
LIGHT_GRAY = "F2F2F2"
GRAY = "DDDDDD"
DARK_GRAY = "333333"
BROWN = "A4441C"
ORANGE = "F28157"
LIGHT_GOLD = "FBFBBE"
DARK_GOLD = "EBE389"
BLUE = "08C"
GREEN = "00ff00"
RED = "ff0000"
def show_header(text,date)
header_box do
image "#{Rails.root}/app/assets/images/smart_records_logo_h60.png", :height => 40
draw_text text,
:at => [80,25], :size => 12, :style => :bold, :color => BLUE
draw_text "Date: #{ausDate(date)}",
:at => [bounds.right - 100,bounds.top - 15], :size => 10 if date
end
end
def header_box(&block)
bounding_box([-bounds.absolute_left, cursor + BOX_MARGIN + 8],
:width => bounds.absolute_left + bounds.absolute_right,
:height => BOX_MARGIN*2) do
fill_color LIGHT_GRAY
fill_rectangle([bounds.left, bounds.top],
bounds.right,
bounds.top - bounds.bottom)
fill_color BLACK
move_down(RHYTHM)
indent(BOX_MARGIN, &block)
end
stroke_color GRAY
stroke_horizontal_line(-BOX_MARGIN, bounds.width + BOX_MARGIN, :at => cursor)
stroke_color BLACK
move_down(RHYTHM*4)
end
end
Then within the pdf generation itself I do:
repeat(:all) do
show_header("Custom Report",DateTime.now())
end
However, when I start putting content onto the pages, I expect when the content overflows onto the next page that the content will show up after the header. I'm finding that the header overlaps the content instead.
Here is an image which illustrates the problem: http://i.imgur.com/mSy2but.png
Am I building the header box incorrectly? Do I need to do something additional to make it so that the content which spills into the next page gets pushed down the appropriate amount?
Okay. I have solved this myself. Most recent version of Prawn has a better way to handle this case. When you use repeat(:all) the page is reopened AFTER document creation and your content creation items are then added. This doesn't push the page down. The correct way to add this header to every page is to use the "canvas" method which allows you to operate out of the bounds of the page margin. Use canvas to draw a box at the top of the page, and set the top_margin of the page to push all content below the banner.
canvas do
bounding_box([bounds.left,bounds.top],
:width => bounds.absolute_left + bounds.absolute_right,
:height => BOX_MARGIN*2) do
fill_color LIGHT_GRAY
fill_rectangle([bounds.left, bounds.top],
bounds.right,
bounds.top - bounds.bottom)
fill_color BLACK
move_down(RHYTHM)
indent(BOX_MARGIN, &block)
end
stroke_color GRAY
stroke_horizontal_line(-BOX_MARGIN, bounds.width + BOX_MARGIN, :at => cursor)
stroke_color BLACK
end
at document creation...
def initialize(options = {})
super(:page_layout => :landscape,:top_margin => HEIGHT_OF_BANNER)
end

Understanding Tk Listbox in ruby

I'm trying to make a small program to mung some data into usable form. One thing I'd like it to do is to be able to select some files and perform actions on them, so I thought i'd use the listbox object in Tk to do that. I want to be able to open a file and see its filename displayed in the listbox. As far as I've read this is precisely what using listvariable in the listbox is for. Yet when I run my code the listbox is never updated (although items already in the listvariable variable are displayed fine).
So here's a close to MWE for this. What am I doing wrong, and what fundamental idea have I misunderstood?
require 'tk'
require 'tkextlib/tile'
$path_list = []
$populate_list = TkVariable.new( $path_list )
def get_file
file = Tk.getOpenFile
file = open(file) unless file.empty?
path = File.basename(file, ".out")
if $path_list.include?(path)
Tk.messageBox(
'type' => "ok",
'icon' => "warning",
'title' => " - Minimum Working Example - ",
'message' => "This file has already been added! Nothing was added to the list"
)
else
$path_list.push(path)
end
end
root = TkRoot.new {title "- Minimum Working Example -"}
frame = Tk::Tile::Frame.new(root) {padding "3 3 12 12"}.grid( :sticky => 'nsew') # 'north south east west'
TkGrid.columnconfigure root, 0, :weight => 1; TkGrid.rowconfigure root, 0, :weight => 1
$file_listbox = Tk::Listbox.new(frame) {
listvariable $populate_list}.grid( :column => 1, :row => 0, :rowspan => 6)
Tk::Tile::Button.new(frame) {
width 15; text 'Open file...'; command {get_file}}.grid( :column => 0, :row => 1)
Tk.mainloop
Do I maybe have to write it in some other order?
Just add one line of code:
$populate_list.value = $path_list
under this one:
$path_list.push(path)
It works for me, although looks weird.
TkVariable create a proxy for you ruby variable, thus bridge your ruby var references with Tk widgets. But i don't know why changes in proxy var don't affect the var it points to. I'm not sure whether it should do that automatically.

Create 3 color conditional formatting with axlsx

With axlsx, the following
color_scale = Axlsx::ColorScale.new do |c_s|
c_s.colors[1].rgb = "FFFFFF00"
end
color_scale.add :type => :percentile, :val => 50, :color => "FF00FF00"
worksheet.add_conditional_formatting("B3:B100", { :type => :colorScale, :operator => :greaterThan, :formula => "100000", :priority => 1, :color_scale => color_scale })
creates a basic 3 color conditional formatting, but the colors are pretty garish, making it hard to distinguish between slightly smaller and slightly larger values.
Is it necessary to reverse-engineer the colors Excel uses in order to create something that looks like the default 3 color conditional formatting that Excel provides?
For color scales, Excel will by default prefer Themes, while Axlsx is currently expecting you to specify exactly what you want. This is partly for interoperability but mostly because I have not ran into a use case that requires similarity to Excel's defaults.
That said, Axlsx should do what it can to give you some sensible defaults and I am sure you can understand how your request is an excellent opportunity to improve this area.
Would you be so kind as to send me a sample xlsx of what you are trying to achieve?
I am sure that I can add a bit of sugar in to make you a bit happier with the results you are seeing now and hopefully benefit the other users of the gem.
UPDATE 2012.11.16
Axlsx has been updated to version 1.3.4 to provide two class methods on ColorScale to create new ColorScale objects with sensible defaults for two-tone and three-tone color scaling.
Examples:
# to make a three tone color scale
color_scale = Axlsx::ColorScale.three_tone
# to make a two tone color scale
color_scale = Axlsx::ColorScale.two_tone
# To make a customized color scale you, pass hashes consisting of
# type, val and color key-value pairs as arguments to the initializer.
# This example that creates the same three tone color scale as
# Axlsx::ColorScale.three_tone
color_scale = Axlsx::ColorScale.new({:type => :min, :val => 0, :color => 'FFF8696B'},
{:type => :percent, :val => '50', :color => 'FFFFEB84'},
{:type => :max, :val => 0, :color => 'FF63BE7B'})

Prawn PDF: create a template without the default page

I want to create a document with prawn one or more pages long that uses a different template for each page.
Prawn::Document.generate("test.pdf") do
doc.faces.each do |face|
start_new_page(:template => face.background_path)
end
end
This works and creates a document, however the first page is a blank letter sized page and then my pages added with start_new_page show up. Is there a way to have prawn not generate that first page?
thanks!
pdf = Prawn::Document.new(:skip_page_creation => true)
doc.faces.each do |face|
pdf.start_new_page(:template => face.background_path)
< your page building code here >
end
should work if I'm reading the docs correctly.
My controller code looks like:
def pdf
#person = Person.find(params[:id])
send_data #person.as_pdf, :filename => "#{#person.pdfName}.pdf", :type => "application/pdf"
end
and the as_pdf method in person.rb looks like
def as_pdf(type = 'short')
pdf = Prawn::Document.new(:margin => [36, 36, 36, 36] )
driver = self.pdf_layout_info
driver.each do |element|
< lots of ugly layout logic >
end
pdf.render
end

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