Python ReportLab set background colour

Question

I've had a quick look around the web and haven't been able to find a way to set the background colour of a PDF when generating one using ReportLab in Python. How does one set the background colour?

Answer 1

I figured out a makeshift way of doing it. Assuming you have an A4-sized page (which is the default), you can simply specify your own shape like so:

from reportlab.lib.colors import HexColor
from reportlab.pdfgen.canvas import Canvas
from reportlab.lib.units import cm
pdf = Canvas("bgColour.pdf")
pdf.setFillColor(HexColor("#99b0e7"))
path = pdf.beginPath()
path.moveTo(0*cm,0*cm)
path.lineTo(0*cm,30*cm)
path.lineTo(25*cm,30*cm)
path.lineTo(25*cm,0*cm)
#this creates a rectangle the size of the sheet
pdf.drawPath(path,True,True)
pdf.showPage()
pdf.save()

Of course, if you wanted a more robust method, you could substitute the exact measurements I have specified for variables which you can change dynamically e.g.:

x = 25
y = 30
path.moveTo(0*cm,0*cm)
path.lineTo(0*cm,y*cm)
path.lineTo(x*cm,y*cm)
path.lineTo(x*cm,0*cm)

Hopefully this helps anyone who finds themselves in a similar situation as I did!

Answer 2

Instead of using complex methods use this simple trick:

 import reportlab

from reportlab.pdfgen import canvas
from reportlab.lib.units import inch
from reportlab.lib.pagesizes import letter
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import inch
from reportlab.lib.units import cm

def background(c):
    c.setFillColorRGB(1,0,0)
    c.rect(5,5,652,792,fill=1)


c=canvas.Canvas("Background",pagesize=letter)
c.setTitle("Background")
background(c)
c.showPage()
c.save()

Just draw a rectangle with coordinates same as that of pdf page and fill with colour of choice.

Answer 3

The docs are unfortunately somewhat cryptic at times. But for anyone who stumbles across this and still uses report lab (like me)

This is an x-y grid. You need to think from lef to right and from bottom to top. Hopefully this helps to make sense of things.

For a top banner, about 10cm in height:

from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import cm

A4_height = A4[1]
A4_width = A4[0]
    
left_padding = 0
bottom_padding = A4_height - 10*cm
width = A4_width
height = A4_height - bottom_padding

canvas = Canvas()
canvas.setFillColorRGB(0,0,0)
canvas.rect(left_padding, bottom_padding, width, height, fill=1)

For a complete black page:

from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from reportlab.lib.units import cm

A4_height = A4[1]
A4_width = A4[0]
    
left_padding = 0
bottom_padding = 0
width = A4_width
height = A4_height

canvas = Canvas()
canvas.setFillColorRGB(0,0,0)
canvas.rect(left_padding, bottom_padding, width, height, fill=1)