.. _quickstart:

Quickstart
==========

Getting started with |docx| is easy. Let's walk through the basics.


Opening a document
------------------

First thing you'll need is a document to work on. The easiest way is this::

    from docx import Document

    document = Document()

This opens up a blank document based on the default "template", pretty much
what you get when you start a new document in Word using the built-in
defaults. You can open and work on an existing Word document using |docx|,
but we'll keep things simple for the moment.


Adding a paragraph
------------------

Paragraphs are fundamental in Word. They're used for body text, but also for
headings and list items like bullets.

Here's the simplest way to add one::

    paragraph = document.add_paragraph('Lorem ipsum dolor sit amet.')

This method returns a reference to a paragraph, newly added paragraph at the
end of the document. The new paragraph reference is assigned to ``paragraph``
in this case, but I'll be leaving that out in the following examples unless
I have a need for it. In your code, often times you won't be doing anything
with the item after you've added it, so there's not a lot of sense in keep
a reference to it hanging around.

It's also possible to use one paragraph as a "cursor" and insert a new
paragraph directly above it::

    prior_paragraph = paragraph.insert_paragraph_before('Lorem ipsum')

This allows a paragraph to be inserted in the middle of a document, something
that's often important when modifying an existing document rather than
generating one from scratch.


Adding a heading
----------------

In anything but the shortest document, body text is divided into sections, each
of which starts with a heading. Here's how to add one::

    document.add_heading('The REAL meaning of the universe')

By default, this adds a top-level heading, what appears in Word as 'Heading 1'.
When you want a heading for a sub-section, just specify the level you want as
an integer between 1 and 9::

    document.add_heading('The role of dolphins', level=2)

If you specify a level of 0, a "Title" paragraph is added. This can be handy to
start a relatively short document that doesn't have a separate title page.


Adding a page break
-------------------

Every once in a while you want the text that comes next to go on a separate
page, even if the one you're on isn't full. A "hard" page break gets this
done::

    document.add_page_break()

If you find yourself using this very often, it's probably a sign you could
benefit by better understanding paragraph styles. One paragraph style property
you can set is to break a page immediately before each paragraph having that
style. So you might set your headings of a certain level to always start a new
page. More on styles later. They turn out to be critically important for really
getting the most out of Word.


Adding a table
--------------

One frequently encounters content that lends itself to tabular presentation,
lined up in neat rows and columns. Word does a pretty good job at this. Here's
how to add a table::

    table = document.add_table(rows=2, cols=2)

Tables have several properties and methods you'll need in order to populate
them. Accessing individual cells is probably a good place to start. As
a baseline, you can always access a cell by its row and column indicies::

    cell = table.cell(0, 1)

This gives you the right-hand cell in the top row of the table we just created.
Note that row and column indicies are zero-based, just like in list access.

Once you have a cell, you can put something in it::

    cell.text = 'parrot, possibly dead'

Frequently it's easier to access a row of cells at a time, for example when
populating a table of variable length from a data source. The ``.rows``
property of a table provides access to individual rows, each of which has a
``.cells`` property.  The ``.cells`` property on both ``Row`` and ``Column``
supports indexed access, like a list::

    row = table.rows[1]
    row.cells[0].text = 'Foo bar to you.'
    row.cells[1].text = 'And a hearty foo bar to you too sir!'

The ``.rows`` and ``.columns`` collections on a table are iterable, so you can
use them directly in a ``for`` loop. Same with the ``.cells`` sequences on
a row or column::

    for row in table.rows:
        for cell in row.cells:
            print(cell.text)

If you want a count of the rows or columns in the table, just use ``len()`` on
the sequence::

    row_count = len(table.rows)
    col_count = len(table.columns)

You can also add rows to a table incrementally like so::

    row = table.add_row()
    
This can be very handy for the variable length table scenario we mentioned
above::

    # get table data -------------
    items = get_things_from_database_or_something()

    # add table ------------------
    table = document.add_table(1, 3)

    # populate header row --------
    heading_cells = table.rows[0].cells
    heading_cells[0].text = 'Qty'
    heading_cells[1].text = 'SKU'
    heading_cells[2].text = 'Description'

    # add a data row for each item
    for item in items:
        cells = table.add_row().cells
        cells[0].text = str(item.qty)
        cells[1].text = item.sku
        cells[2].text = item.desc


The same works for columns, although I've yet to see a use case for it.

Word has a set of pre-formatted table styles you can pick from its table style
gallery. You can apply one of those to the table like this::

    table.style = 'LightShading-Accent1'

The style name is formed by removing all the spaces from the table style name.
You can find the table style name by hovering your mouse over its thumbnail in
Word's table style gallery.


Adding a picture
----------------

Word lets you place an image in a document using the ``Insert > Photo > Picture
from file...`` menu item. Here's how to do it in |docx|::

    document.add_picture('image-filename.png')

This example uses a path, which loads the image file from the local filesystem.
You can also use a *file-like object*, essentially any object that acts like an
open file. This might be handy if you're retrieving your image from a database
or over a network and don't want to get the filesystem involved.


Image size
~~~~~~~~~~

By default, the added image appears at *native* size. This is often bigger than
you want. Native size is calculated as ``pixels / dpi``. So a 300x300 pixel
image having 300 dpi resolution appears in a one inch square. The problem is
most images don't contain a dpi property and it defaults to 72 dpi. This would
make the same image appear 4.167 inches on a side, somewhere around half the
page.

To get the image the size you want, you can specify either its width or height
in convenient units, like inches or centimeters::

    from docx.shared import Inches

    document.add_picture('image-filename.png', width=Inches(1.0))

You're free to specify both width and height, but usually you wouldn't want to.
If you specify only one, |docx| uses it to calculate the properly scaled value
of the other. This way the *aspect ratio* is preserved and your picture doesn't
look stretched.

The ``Inches`` and ``Cm`` classes are provided to let you specify measurements
in handy units. Internally, |docx| uses English Metric Units, 914400 to the
inch. So if you forget and just put something like ``width=2`` you'll get an
extremely small image :). You'll need to import them from the ``docx.shared``
sub-package. You can use them in arithmetic just like they were an integer,
which in fact they are. So an expression like ``width = Inches(3)
/ thing_count`` works just fine.


Applying a paragraph style
--------------------------

If you don't know what a Word paragraph style is you should definitely check it
out. Basically it allows you to apply a whole set of formatting options to
a paragraph at once. It's a lot like CSS styles if you know what those are.

You can apply a paragraph style right when you create a paragraph::

    document.add_paragraph('Lorem ipsum dolor sit amet.', style='ListBullet')

This particular style causes the paragraph to appear as a bullet, a very handy
thing. You can also apply a style afterward. These two lines are equivalent to
the one above::

    paragraph = document.add_paragraph('Lorem ipsum dolor sit amet.')
    paragraph.style = 'ListBullet'

The style is specified using its style ID, 'ListBullet' in this example.
Generally, the style ID is formed by removing the spaces in the style name as
it appears in the Word user interface (UI). So the style 'List Number 3'
would be specified as ``'ListNumber3'``. However, note that if you are using
a localized version of Word, the style ID may be derived from the English
style name and may not correspond so neatly to its style name in the Word UI.


Applying bold and italic
------------------------

In order to understand how bold and italic work, you need to understand
a little about what goes on inside a paragraph. The short version is this:

#. A paragraph holds all the *block-level* formatting, like indentation, line
   height, tabs, and so forth.

#. Character-level formatting, such as bold and italic, are applied at the
   *run* level. All content within a paragraph must be within a run, but there
   can be more than one. So a paragraph with a bold word in the middle would
   need three runs, a normal one, a bold one containing the word, and another
   normal one for the text after.

When you add a paragraph by providing text to the ``.add_paragraph()`` method,
it gets put into a single run. You can add more using the ``.add_run()`` method
on the paragraph::

    paragraph = document.add_paragraph('Lorem ipsum ')
    paragraph.add_run('dolor sit amet.')

This produces a paragraph that looks just like one created from a single
string. It's not apparent where paragraph text is broken into runs unless you
look at the XML. Note the trailing space at the end of the first string. You
need to be explicit about where spaces appear at the beginning and end of
a run. They're not automatically inserted between runs. Expect to be caught by
that one a few times :).

|Run| objects have both a ``.bold`` and ``.italic`` property that allows you to
set their value for a run::

    paragraph = document.add_paragraph('Lorem ipsum ')
    run = paragraph.add_run('dolor')
    run.bold = True
    paragraph.add_run(' sit amet.')

which produces text that looks like this: 'Lorem ipsum **dolor** sit amet.'

Note that you can set bold or italic right on the result of ``.add_run()`` if
you don't need it for anything else::

    paragraph.add_run('dolor').bold = True
    
    # is equivalent to:

    run = paragraph.add_run('dolor')
    run.bold = True

    # except you don't have a reference to `run` afterward
    

It's not necessary to provide text to the ``.add_paragraph()`` method. This can
make your code simpler if you're building the paragraph up from runs anyway::

    paragraph = document.add_paragraph()
    paragraph.add_run('Lorem ipsum ')
    paragraph.add_run('dolor').bold = True
    paragraph.add_run(' sit amet.')
 

Applying a character style
--------------------------

In addition to paragraph styles, which specify a group of paragraph-level
settings, Word has *character styles* which specify a group of run-level
settings. In general you can think of a character style as specifying a font,
including its typeface, size, color, bold, italic, etc.

Like paragraph styles, a character style must already be defined in the
document you open with the ``Document()`` call (*see*
:ref:`understanding_styles`).

A character style can be specified when adding a new run::

    paragraph = document.add_paragraph('Normal text, ')
    paragraph.add_run('text with emphasis.', 'Emphasis')

You can also apply a style to a run after it is created. This code produces
the same result as the lines above::

    paragraph = document.add_paragraph('Normal text, ')
    run = paragraph.add_run('text with emphasis.')
    run.style = 'Emphasis'

As with a paragraph style, the style ID is formed by removing the spaces in
the name as it appears in the Word UI. So the style 'Subtle Emphasis' would
be specified as ``'SubtleEmphasis'``. Note that if you are using
a localized version of Word, the style ID may be derived from the English
style name and may not correspond to its style name in the Word UI.
