pisa 3.0.33

XHTML/HTML/CSS to PDF converter

(C)opyright by Dirk Holtwick, Germany
dirk.holtwick@gmail.com
http://www.xhtml2pdf.com

# Table of Contents

# Introduction

pisa is a HTML/XHTML/CSS to PDF converter written in Python and based on Reportlab Toolkit, pyPDF, TechGame Networks CSS Library and HTML5lib. The primary focus is not on generating perfect printable webpages but to use HTML and CSS as commonly known tools to generate PDF files within Applications. For example generating documentations (like this one), generating invoices or other office documents etc.

# Installation

As pisa is a Python pakage an installed version of Python <http://www.python.org> is needed. For the moment Python 2.3 to 2.5 is supported. For Python 3000 a special version will be needed, because it is not compatible with the 2.x series. A proper version will be made available as soon as Python 3000 becomes stable.

The easiest way to install pisa is to use easy_install:

    $ easy_install pisa

But you may also download the source code of pisa, then enter the main directory and execute this command (on Linux and MacOS you may prepend a `sudo` command):

    $ python setup.py install

pisa needs also some additional Python packages to be installed to work. Please follow the setup instruction for each package:

- ReportlabToolkit 2.2+ (required)
  http://www.reportlab.org/downloads.html
  Provides the Python to PDF conversion functionality
- html5lib 0.11.1+ (required)
  http://code.google.com/p/html5lib/
  The parser for HTML and XHTML
- pyPdf 1.11+ (optional)
  http://pybrary.net/pyPdf/
  Will be used if you like to place another PDF as a watermark in the background of PDF pages
- PIL 1.1.6+ (optional)
  http://www.pythonware.com/products/pil/
  The Python Imaging Library (PIL) is requred by ReportLab for handling of different image formats like GIF and PNG.

## Windows precompiled version

For Windows a precompiled version exists that includes Python and all needed libraries. The package contains the file `xhtml2pdf.exe`. Please add the directory where `xhtml2pdf.exe` is placed to the Windows `PATH` variable.

The Windows version is distributed via the Website <http://www.xhtml2pdf.com> in the "Download" section.

# Command line

If you do not want to integrate pisa in your own application, you may use the command line tool that gives you a simple interface to the features of pisa. Just call `xhtml2pdf --help` to get the following help informations:

## Converting HTML data

To generate a PDF from an HTML file called `test.html` call:

    $ xhtml2pdf -s test.html

The resulting PDF will be called `test.pdf` (if this file is locked e.g. by the Adobe Reader it will be called `test-0.pdf` and so on). The `-s` option takes care that the PDF will be opened directly in the Operating Systems default viewer.

To convert more than one file you may use wildcard patterns like `*` and `?`:

    $ xhtml2pdf "test/test-*.html"

You may also directly access pages from the internet:

    $ xhtml2pdf -s http://www.xhtml2pdf.com/

## Using special properties

If the conversion doesn't work as expected some more informations may be usefull. You may turn on the output of warnings adding `-w` or even the debugging output by using `-d`.

Another reason could be, that the parsing failed. Consider trying the `-xhtml` and `-html` options. pisa uses the HTMLT5lib parser that offers two internal parsing modes: one for HTML and one for XHTML.

When generating the HTML output pisa uses an internal default CSS definition (otherwise all tags would appear with no diffences). To get an impression of how this one looks like start pisa like this:

    $ xhtml2pdf --css-dump > xhtml2pdf-default.css

The CSS will be dumped into the file `pisa-default.css`. You may modify this or even take a totaly self defined one and hand it in by using the `-css` option, e.g.:

    $ xhtml2pdf --css=xhtml2pdf-default.css test.html

# Python module

XXX TO BE COMPLETED

The integration into a Python program is quite easy. We will start with a simple "Hello World" example:

    import ho.pisa as pisa                        (1)

    def helloWorld():
      filename = __file__ + ".pdf"                (2)
      pdf = pisa.CreatePDF(                       (3)
        "Hello <strong>World</strong>",
        file(filename, "wb"))
      if not pdf.err:                             (4)
        pisa.startViewer(filename)                (5)

    if __name__=="__main__":
      pisa.showLogging()                          (6)
      helloWorld()

Comments:

(1) Import the pisa Python module
(2) Calculate a sample filename. If your demo is saved under `test.py` the filename will be `test.py.pdf`.
(3) The function `CreatePDF` is called with the source and the destination. In this case the source is a string and the destination is a fileobject. Other values will be discussed later (XXX to do!). An object will be returned as result and saved in `pdf`.
(4) The property `pdf.err` is checked to find out if errors occured
(5) If no errors occured a helper function will open a PDF Reader with the resulting file
(6) Errors and warnings are written as log entries by using the Python standard module `logging`. This helper enables printing warnings on the console.

## Create PDF

The main function of pisa is called CreatePDF(). It offers the following arguments in this order:

- src: The source to be parsed. This can be a file handle or a `String` - or even better - a `Unicode` object.
- dest: The destination for the resulting PDF. This has to be a file object wich will not be closed by `CreatePDF`. (XXX allow file name?)
- path: The original file path or URL. This is needed to calculate relative paths of images and style sheets. (XXX calculate automatically from src?)
- link_callback: Handler for special file paths (see below).
- debug: ** DEPRECATED **
- show_error_as_pdf: Boolean that indicates that the errors will be dumped into a PDF. This is usefull if that is the only way to show the errors like in simple web applications.
- default_css: Here you can pass a default CSS definition in as a `String`. If set to `None` the predefined CSS of pisa is used.
- xhtml: Boolean to force parsing the source as XHTML. By default the HTML5 parser tries to guess this.
- encoding: The encoding name of the source. By default this is guessed by the HTML5 parser. But HTML with no meta information this may not work an then this argument is helpfull.

## Link callback

Images, backgrounds and stylesheets are loaded form an HTML document. Normaly pisa expects these files to be found on the local drive. They may also be referenced relative to the original document. But the programmer might want to load form different kind of sources like the Internet via HTTP requests or from a database or anything else. Therefore you may define a `link_callback` that handles these reuests.

XXX

## Web applications

XXX

# Defaults

Some notes on some default values:

- Usually the position (0, 0) in PDF files is found in the lower left corner. For pisa it is the upper left corner like it is for HTML.
- The default page size is the German DIN A4 with portrait orientation.
- The name of the first layout template is `body`, but you better leave the name empty for defining the default template (XXX May be changed in the future!)

# Cascading Style Sheets

pisa supports a lot of Cascading Style Sheet (CSS). The following styles are supported:

    background-color
    border-bottom-color
    border-bottom-style
    border-bottom-width
    border-left-color
    border-left-style
    border-left-width
    border-right-color
    border-right-style
    border-right-width
    border-top-color
    border-top-style
    border-top-width
    color
    display
    font-family
    font-size
    font-style
    font-weight
    height
    line-height
    list-style-type
    margin-bottom
    margin-left
    margin-right
    margin-top
    padding-bottom
    padding-left
    padding-right
    padding-top
    page-break-after
    page-break-before
    size
    text-align
    text-decoration
    text-indent
    vertical-align
    white-space
    width
    zoom

And it adds some vendor specific styles:

    -pdf-frame-border
    -pdf-frame-break
    -pdf-frame-content
    -pdf-keep-with-next
    -pdf-next-page
    -pdf-outline
    -pdf-outline-level
    -pdf-outline-open
    -pdf-page-break

# Layout Definition

## Pages and Frames

Pages can be layouted by using some special CSS at-keywords and properties. All special properties start with `-pdf-` to mark them as vendor specific as defined by CSS 2.1. Layouts may be defined by page using the `@page` keyword. Then text flows in one or more frames which can be defined within the `@page` block by using `@frame`. Example:

    @page {
      @frame {
        margin: 1cm;
      }
    }

In the example we define an unnamed page template - though it will be used as the default template - having one frame with `1cm` margin to the page borders. The first frame of the page may also be defined within the `@page` block itself. See the equivalent example:

    @page {
      margin: 1cm;
    }

To define more frames just add some more `@frame` blocks. You may use the following properties to define the dimensions of the frame:

- `marign`
- `margin-top`
- `margin-left`
- `margin-right`
- `margin-bottom`
- `top`
- `left`
- `right`
- `bottom`
- `width`
- `height`

Here is a more complex example:

    @page lastPage {
      top: 1cm;
      left: 2cm;
      right: 2cm;
      height: 2cm;
      @frame middle {
        margin: 3cm;
      }
      @frame footer {
        bottom: 2cm;
        margin-left: 1cm;
        margin-right: 1cm;
        height: 1cm;
      }
    }

Layout scheme:

                     top
         +--------------------------+   ---
         |        margin-top        |   /|\
         |    +---------------+     |    |
         |    |               |     |
         |    |               |     |  height
         |    |               |     |

By default the Frame uses the whole page and is defined to begin in the upper left corner and end in the lower right corner. Now you can add the position of the frame using `top`, `left`, `bottom` and `right`. If you now add `height` and you have a value other than zero in `top` the `bottom` will be modified. (XXX If you had not defined `top` but `bottom` the `height` will be ...)

## Page size and orientation

A page layout may also define the page size and the orientation of the paper using the `size` property as defined in CSS 3. Here is an example defining page size "DIN A5" with "landscape" orientation (default orientation is "portrait"):

    @page {
      size: a5 landscape;
      margin: 1cm;
    }

Here is the complete list of valid page size identifiers:

- `a0` ... `a6`
- `b0` ... `b6`
- `letter`
- `legal`
- `elevenseventeen`

## PDF watermark/ background

For the use of PDF backgrounds specify the source file in the `background-image` property, like this:

    @page {
      background-image: url(bg.pdf);
    }

## Static frames

Some frames should be static like headers and footers that means they are on every page but do not change content. The only information that may change is the page number. Here is a simple example that show how to make an element named by ID the content of a static frame. In this case it is the ID `footer`.

    <html>
    <style>
    @page {
      margin: 1cm;
      margin-bottom: 2.5cm;
      @frame footer {
        -pdf-frame-content: footerContent;
        bottom: 2cm;
        margin-left: 1cm;
        margin-right: 1cm;
        height: 1cm;
      }
    }
    </style>
    <body>
      Some text
      <div id="footerContent">
        This is a footer on page #<pdf:pagenumber>
      </div>
    </body>
    </html>

For better debugging you may want to add this property for each frame definition: `-pdf-frame-border: 1`. It will paint a border around the frame.

# Fonts

By default there is just a certain set of fonts available for PDF. Here is the complete list - and their repective alias names - pisa knows by default (the names are not case sensitive):

- Times-Roman: Times New Roman, Times, Georgia, serif
- Helvetica: Arial, Verdana, Geneva, sansserif, sans
- Courier: Courier New, monospace, monospaced, mono
- ZapfDingbats
- Symbol

But you may also embed new font faces by using the `@font-face` keyword in CSS like this:

    @font-face {
      font-family: Example, "Example Font";
      src: url(example.ttf);
    }

The `font-family` property defines the names under which the embedded font will be known. `src` defines the place of the fonts source file. This can be a TrueType font or a Postscript font. The file name of the first has to end with `.ttf` the latter with one of `.pfb` or `.afm`. For Postscript font pass just one filename like `<name>``.afm` or `<name>``.pfb`, the missing one will be calculated automatically.

To define other shapes you may do like this:

    /* Normal */
    @font-face {
       font-family: DejaMono;
       src: url(font/DejaVuSansMono.ttf);
    }

    /* Bold */
    @font-face {
       font-family: DejaMono;
       src: url(font/DejaVuSansMono-Bold.ttf);
       font-weight: bold;
    }

    /* Italic */
    @font-face {
       font-family: DejaMono;
       src: url(font/DejaVuSansMono-Oblique.ttf);
       font-style: italic;
    }

    /* Bold and italic */
    @font-face {
       font-family: DejaMono;
       src: url(font/DejaVuSansMono-BoldOblique.ttf);
       font-weight: bold;
       font-style: italic;
    }

# Outlines/ Bookmarks

PDF supports outlines (Adobe calls them "bookmarks"). By default pisa defines the `<h1>` to `<h6>` tags to be shown in the outline. But you can specify exactly for every tag which outline behaviour it should have. Therefore you may want to use the following vendor specific styles:

- `-pdf-outline`
  set it to "true" if the block element should appear in the outline
- `-pdf-outline-level`
  set the value starting with "0" for the level on which the outline should appear. Missing predecessors are inserted automatically with the same name as the current outline
- `-pdf-outline-open`
  set to "true" if the outline should be shown uncollapsed

Example:

    h1 {
      -pdf-outline: true;
      -pdf-level: 0;
      -pdf-open: false;
    }

# Table of Contents

It is possible to automatically generate a Table of Contents (TOC) with pisa. By default all headings from `<h1>` to `<h6>` will be inserted into that TOC. But you may change that behaviour by setting the CSS property `-pdf-outline` to `true` or `false`. To generate the TOC simply insert `<pdf:toc />` into your document. You then may modify the look of it by defining styles for the `pdf:toc` tag and the classes `pdftoc.pdftoclevel0` to `pdftoc.pdftoclevel5`. Here is a simple example for a nice looking CSS:

    pdftoc {
        color: #666;
    }
    pdftoc.pdftoclevel0 {
        font-weight: bold;
        margin-top: 0.5em;
    }
    pdftoc.pdftoclevel1 {
        margin-left: 1em;
    }
    pdftoc.pdftoclevel2 {
        margin-left: 2em;
        font-style: italic;
    }

# Tables

Tables are supported but may behave a little different to the way you might expect them to do. These restriction are due to the underlying table mechanism of ReportLab.

- The main restriction is that table cells that are longer than one page lead to an error
- Tables can not float left or right and can not be inlined

## Long cells

Pisa is not able to split table cells that are larger than the available space. To work around it you may define what should happen in this case. The `-pdf-keep-in-frame-mode` can be one of: "error", "overflow", "shrink", "truncate", where "shrink" is the default value.

    table {
        -pdf-keep-in-frame-mode: shrink;
    }

## Cell widths

The table renderer is not able to adjust the width of the table automatically. Therefore you should explicitly set the width of the table and to the table rows or cells.

## Headers

It is possible to repeat table rows if a page break occurs within a table. The number of repeated rows is passed in the attribute `repeat`. Example:

    <table repeat="1">
      <tr><th>Column 1</th><th>...</th></tr>
      ...
    </table>

## Borders

Borders are supported. Use corresponding CSS styles.

# Images

## Size

By default JPG images are supported. If the Python Imaging Library (PIL) is installed the file types supported by it are available too. As mapping pixels to points is not trivial the images may appear bigger in the PDF as in the browser. To adjust this you may want to use the `zoom` style. Here is a small example:

    img { zoom: 80%; }

## Position/ floating

Since Reportlab Toolkit does not yet support the use of images within paragraphs, images are always rendered in a seperate paragraph. Therefore floating is not available yet.

# Barcodes

XXX TO BE WRITTEN

<pdf:barcode>

# Custom Tags

pisa provides some custom tags. They are all prefixed by the namespace identifier `pdf:`. As the HTML5 parser used by pisa does not know about these specific tags it may be confused if they are without a block. To avoid problems you may condsider sourrounding them by `<div>` tags, like this:

    <div>
       <pdf:toc />
    </div>

## Tag-Definitions

### pdf:barcode

Creates a barcode.

### pdf:pagenumber

Prints current page number. The argument "example" defines the space the page number will require e.g. "00".

### pdf:nexttemplate

Defines the template to be used on the next page.

### pdf:nextpage

Create a new page after this position.

### pdf:nextframe

Jump to next unused frame on the same page or to the first on a new page. You may not jump to a named frame.

### pdf:spacer

Creates an object of a specific size.

### pdf:toc

Creates a Table of Contents.

# License

pisa is copyrighted by Dirk Holtwick, Germany.
pisa is distributed by Dirk Holtwick, Schreiberstra�e 2, 47058 Duisburg, Germany.
pisa is licensed under the GNU Gerneral Public License version 2.

For commercial usage of pisa a developer license can be purchased!