Reportlab Canvas Image Not Showing

问题

Background

I am writing some code to set up a shared document "template" [ common header and footer ] in ReportLab using a SimpleDocTemplate ( reportlab.platypus.SimpleDocTemplate ). The code snippet below is a function that is to be passed into the SimpleDocTemplate build(...) method as the value of either the onFirstPage or onLaterPages parameter.

def setup_header_and_footer(canvas, doc):
    """
    ...edited out...
    """
    canvas.line(0 * mm, 174 * mm, 297 * mm, 174 * mm)
    logo_filename = settings.STATIC_ROOT + os.sep + "images/huqas_logo.jpg"
    canvas.drawImage(logo_filename, 20 * mm, 45 * mm)

    canvas.drawRightString(287 * mm, 200 * mm, "<edited out>")
    canvas.drawString(20 * mm, 15 * mm, "Generated on %s" % datetime.now().strftime("%A %d %B %Y %I:%M:%S %p"))
    canvas.line(0 * mm, 20 * mm, 297 * mm, 20 * mm)

Further Information

The page / canvas has been set up with A4 landscape dimensions
I have confirmed that logo_filename is a valid path, and that the image exists at that location in the filesystem
Reportlab does not raise any exception

The Problem

My lines and strings render OK, but the image is not visible in the resulting PDFs

I have looked at this question but I still do not understand why the canvas would "behave" when calling eg canvas.line(0 * mm, 174 * mm, 297 * mm, 174 * mm) but fail when calling canvas.drawImage("file name", 20 * mm, 45 * mm). I have also scoured the documentation to no avail. What am I missing?

Update

Changing from canvas.drawImage(logo_filename, 20 * mm, 45 * mm) to canvas.drawInlineImage(logo_filename, 20 * mm, 45 * mm) appears to "fix" the issue [ without changing any other line of code ]. I am still puzzled as to why drawImage did not work.

来源：https://stackoverflow.com/questions/13010930/reportlab-canvas-image-not-showing

标签

python

reportlab