Reportlab - inverted image-CodePudding

I am trying to display some png pictures in my ReportLab canvas with the functions drawImage() but it is displaying the picture as inverted.

Original image :

Image in the report :

import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter, landscape, A4
from reportlab.lib.utils import ImageReader

fig = plt.figure()
#fig.patch.set_facecolor('#0c1c33')
#fig.patch.set_alpha(1)
data = [10,30,25,15,10]
plt.pie(data, labels = ['A', 'B', 'C', 'D', 'E'])
circle = plt.Circle( (0,0), 0.7, color='#0c1c33')
p = plt.gcf()
p.gca().add_artist(circle)
plt.savefig('test_donut.png')
plt.show()

my_canvas = canvas.Canvas("Test_Rapport.pdf",pagesize=(landscape(A4)),bottomup=0)
my_canvas.drawImage(ImageReader('test_donut.png'), 300, 150, width=200, height=150)
my_canvas.save()

Do you have an idea of how I could solve this problem ? Thanks in advance for your help and your time

CodePudding user response：

It is to do with the canvas coordinate system. Sometimes you would need to use bottomup=1 for drawImage() to work as desired, but if you already designed coordinates for the other elements on bottomup=0, then the text and everything else will not be where it should be if you change bottomup to be 1.

This is a fix you can try (scaling the canvas this way forces the image to flip back to how it should be, but the y-value then needs to be a negative value to make the image visible on the A4 page):

my_canvas = canvas.Canvas("Test_Rapport.pdf",pagesize=(landscape(A4)),bottomup=0)

my_canvas.saveState()
my_canvas.scale(1,-1)
x_val = 300
y_val = -150
my_canvas.drawImage(ImageReader('test_donut.png'), x_val, y_val, width=200, height=150)
my_canvas.restoreState()

my_canvas.save()