Reportlab : How to switch between portrait and landscape?

Question

I am using reportlab to generate a pdf report automatically from dynamic data. As the content sometimes is too large to be displayed in portrait, I am trying to switch to landscape for large content.

Here is how my report generation works :

Main function :

doc = DocTemplate(...)           //Doctemplate is a customed BaseDocTemplate class
array = []
some_data= "Here is some data displayed in portrait" 

array.append(Paragraph(some_data))

large_data = "this data is too large to be displayed in portrait"
array.append(Paragraph(large_data))

... // Some more data is added after this

doc.build(array, canvasmaker=NumberedCanvas)

What I am looking for is a way to be able to switch from portrait to landscape at each step, as I don't know the number of pages that will be needed to display it. I am still new to reportlab and even a bit with python, so I do not see how I can use the solutions provided by reportlab (PageTemplates, flowables) properly as I am building the whole document at the end.

Here are my other useful classes for this case :

class DocTemplate(BaseDocTemplate, ):
def __init__(self, filename, **kw):
    apply(BaseDocTemplate.__init__, (self, filename), kw)
    f = Frame(2.6*cm, 2.8*cm, 16*cm, 22.7*cm, id='f')
    pt = PageTemplate('RectPage', [f], onPage=beforeDrawPage, onPageEnd=afterDrawPage)
    //beforeDrawPage and afterDrawPage fill the headers of the page (that also need to be in landscape)
    self.addPageTemplates(pt)

I think I shall add another page template or frame, but I don't see how i can switch from one to the other during the data appending phase.

class NumberedCanvas(canvas.Canvas):
def __init__(self, *args, **kwargs):
    canvas.Canvas.__init__(self, *args, **kwargs)

    self._saved_page_states = []

def showPage(self):
    self._saved_page_states.append(dict(self.__dict__))
    self._startPage()

def save(self):
    """add page info to each page (page x of y)"""
    num_pages = len(self._saved_page_states)
    for state in self._saved_page_states:
        self.__dict__.update(state)
        self.draw_page_number(num_pages)
        canvas.Canvas.showPage(self)
    self.setTitle("Title")
    canvas.Canvas.save(self)
    self._doc.SaveToFile(self._filename, self)

def draw_page_number(self, page_count):
    self.setFont("Helvetica", 11)
    self.drawRightString(18.5*cm, 26.8*cm,
        "PAGE %d / %d" % (self._pageNumber, page_count))

I hope I did'nt forgot anything to be clear.

Many thanks in advance.

score 47 · Answer 1 · answered Jun 06 '12 at 05:09

47

Use the landscape and portrait functions that are already in the pagesizes module.

from reportlab.lib.pagesizes import letter, landscape
c = canvas.Canvas(file, pagesize=landscape(letter))

answered Jun 06 '12 at 05:09

Alex

2,350
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score 20 · Accepted Answer · answered May 09 '11 at 12:30

20

I finally figured out the best way to do it by myself :

I added a new PageTemplate in my DocTemplate with landscape settings, and then simply used NextPageTemplate from the reportlab.platypus package :

array.append(NextPageTemplate('landscape'))

To get back in portrait, i use :

array.append(NextPageTemplate('portrait'))

This allows a pretty nice flexibility.

answered May 09 '11 at 12:30

Mathieu C.

453
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1

`array` is the `story` – TNT Aug 29 '14 at 15:55
1

I got `ValueError: can't find template('landscape') handle_nextPageTemplate args=('landscape',)` – rajagopalx Jun 02 '18 at 19:16
1

I figured out. https://stackoverflow.com/questions/50660395/reportlab-how-to-change-page-orientation/50660701 – rajagopalx Jun 02 '18 at 20:05

score 7 · Answer 3 · answered May 06 '11 at 15:57

This is how I switch between portrait and landscape modes, but I determine which orientation beforehand:

from reportlab.lib.pagesizes import letter, A4

lWidth, lHeight = letter

if orientation == 'landscape':
    canvas.setPageSize((lHeight, lWidth))
else:
    canvas.setPageSize((lWidth, lHeight))

user12082570 · Answer 4 · 2019-09-18T02:54:40.253

6

doc=SimpleDocTemplate(..., pagesize=(A4[1],A4[0]))

edited Sep 18 '19 at 02:54

answered Sep 18 '19 at 02:45

user12082570

61
1
2

This is an 8 year old question, with an accepted answer and the provided answer was flagged for review as a Low Quality Post. Here are some guidelines for [How do I write a good answer?](https://stackoverflow.com/help/how-to-answer). This provided answer may be correct, but it could benefit from an explanation. Code only answers are not considered "good" answers. From [review](https://stackoverflow.com/review/low-quality-posts/24077487). – Trenton McKinney Sep 18 '19 at 04:38
This seems like an interesting alternative solution, so it's worth adding a short paragraph explaining it, so that it doesn't get deleted. – joanis Sep 18 '19 at 12:11
I'm going to guess that the explanation is that A4 is a tuple with x and y. Then just flipping x and y is the same as rotating the page. – Carl Kroeger Ihl Dec 06 '19 at 17:44
Knowing that `A4` can be imported as following `from reportlab.lib.pagesizes import A4`. `A4` determining the size of the page as `(width, height)`, so by doing as the suggested answer we are switching the `width` and `height` of the new created template page which means eventually `landscape` page size. – Mu Sa Apr 28 '22 at 17:05

score 0 · Answer 5 · answered Jan 11 '19 at 15:56

Also if anyone was looking for another way to change between landscape and portrait, you can also pass in the rotation as a keyword argument to BaseDocTemplate.

self._document = BaseDocTemplate(self._filename,
                                 pageSize=self._page_size,
                                 topMargin=1.5*cm,
                                 bottomMargin=1.5*cm,
                                 leftMargin=1*cm,
                                 rightMargin=1*cm,
                                 rotation=90,
                                 showBoundary=False
                                 )

Reportlab : How to switch between portrait and landscape?

5 Answers5

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