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45 lines
1.9 KiB
Markdown
45 lines
1.9 KiB
Markdown
# Generate Sample PDFs With ReportLab
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The `reportlab` package has a `pdfgen` module that provides a `Canvas` API for
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programmatically constructing a PDF.
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I recently needed the most basic use of this to quickly construct a sample PDF
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that I could use as I experimented with [different `qpdf`
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commands](/workflow/remove-pages-from-a-pdf.md). I wanted to generate a 10-page
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PDF where each page included a large font number in the center. This way I could
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clearly see what was the first, second, third, and so on pages. Then I could
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quickly verify that the `qpdf` manipulations I was doing were working as
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expected.
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I was able to do this without any setup or install. Using a `uv` one-liner (does
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a 10-line heredoc count as a one-liner?), I generated a PDF with some basic
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canvas rendering on each page.
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```python
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❯ uv run --with reportlab python - <<'EOF'
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from reportlab.pdfgen import canvas
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N, W, H = 10, 612, 792
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c = canvas.Canvas("test.pdf", pagesize=(W, H))
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for i in range(1, N + 1):
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c.setFont("Helvetica-Bold", 220)
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c.drawCentredString(W / 2, H / 2 - 80, str(i))
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c.setFont("Helvetica", 28)
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c.drawCentredString(W / 2, 100, f"page {i} of {N}")
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c.showPage()
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c.save()
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EOF
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```
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The `--with` makes the `reportlab` package available to the command being run.
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The command being run is `python` which evaluates that block of heredoc text.
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Within the heredoc, I import `canvas` from the `reportlab` package that has been
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made available. I then create an in-memory PDF of a standard size. Then for-loop
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10 times to build each page of the PDF with a big number in the middle and a
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smaller `page x of N` lower down on the page. Finally, I save the PDF which
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writes it to the directory I executed this whole command from.
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I had Claude help with the `canvas` API, however there are some decent
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[`reportlab.pdfgen` docs
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here](https://docs.reportlab.com/reportlab/userguide/ch2_graphics/).
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