Python reportLab platypus: bottom image

Question

I'm working with the reportlab library and I have doubts about adding an image using a SimpleDocTemplate.

I have dynamic content and I don't know how much space it occupies. What happens is that I want to add a logo at the bottom of the page (always in the same place). The way I'm doing it is to add things to a list: eg [text, spacer, table, spacer, logo] and then build it. The place of the logo depends on other variables.

Could you help me to accomplish this behavior?

I know that this can be done using absolute positioning (eg using drawImage in a canvas class) but I don't know how to combine the way I'm doing it with this.

Thanks in advance

Answer 1

I got a heading for the reports that I generate that I produce like this code (where the PageTemplate generates the heading for each paper.

from reportlab.platypus import Table, TableStyle, Paragraph
from reportlab.platypus.frames import Frame
from reportlab.platypus.doctemplate import PageTemplate, BaseDocTemplate

class MyDocTemplate(BaseDocTemplate):
    def __init__(self, filename, tr, param1, param2, plugin_dir, **kw):
        self.allowSplitting = 0
        BaseDocTemplate.__init__(self, filename, **kw)
        self.tr = tr
        self.plugin_dir = plugin_dir
        frame = Frame(self.leftMargin, self.bottomMargin, self.width, self.height - 2 * cm, id='normal')
        template = PageTemplate(id='test', frames=frame, onPage=partial(self.header, param1=param1, param2=param2))
        self.addPageTemplates(template)

    def header(self, canvas, doc, param1, param2):
        canvas.saveState()
        canvas.drawString(30, 750, self.tr('Simple report from GeoDataFarm'))
        canvas.drawString(30, 733, self.tr('For the growing season of ') + str(param1))
        canvas.drawImage(self.plugin_dir + '\\img\\icon.png', 500, 765, width=50, height=50)
        canvas.drawString(500, 750, 'Generated:')
        canvas.drawString(500, 733, param2)
        canvas.line(30, 723, 580, 723)
        #w, h = content.wrap(doc.width, doc.topMargin)
        #content.drawOn(canvas, doc.leftMargin, doc.height + doc.topMargin - h)
        canvas.restoreState()

doc = MyDocTemplate(report_name, self.tr, self.plugin_dir, '2018', '2018-09-21')
story = []
data_tbl = [['col1', 'col2'],[1, 2],[3, 4]]
table = Table(data_tbl, repeatRows=1, hAlign='LEFT', colWidths=[380/l_heading] * l_heading)
table.setStyle(TableStyle([('FONTSIZE', (0, 0), (l_heading, 0), 16)]))
story.append(table)
doc.build(story)

Answer 2

The chances are you want to put the image in a footer (closer to axel_ande's answer). That way the image will go in the same place on every page, but only be defined once.

If you want to put an image at the bottom of a page but not in the footer, you could try the TopPadder wrapper object:

from reportlab.platypus.doctemplate import SimpleDocTemplate
from reportlab.platypus.flowables import TopPadder
from reportlab.platypus import Table, Paragraph

from reportlab.lib.styles import getSampleStyleSheet
from reportlab.lib import colors

import numpy as np


document = SimpleDocTemplate('padding_test.pdf')

table = Table(np.random.rand(2,2).tolist(),
              style=[('GRID', (0, 0), (-1, -1), 0.5, colors.black)])
styles = getSampleStyleSheet()
paragraph = Paragraph('Some paragraphs', style=styles['Normal'])

document.build([
    paragraph,
    TopPadder(table),
])

# This should generate a single pdf page with text at the top and a table at the bottom.

I stumbled across this when looking through the code , the only documentation I could find on it was in the release notes . In my example I wrap a table simply so the example code is stand-alone.

Hope this helps!