(Draft) Add Type 3 Fonts Functionality and Support for Color Fonts 🎨

[andersonhc]

Initial Draft: Type 3 Fonts and Color Fonts Support

Fixes #224

This PR introduces the initial implementation for Type 3 fonts and Color Fonts in PDFs. 🚀

Features:

• Type 3 Fonts:
  • Type 3 fonts can now be added to a PDF, enabling custom, embedded font glyphs.
• Raster-Based Color Fonts:
  • Basic functionality for raster formats (CBDT+CBLC, SBIX) is working.
• SVG-Based Color Fonts:
  • Work in progress for SVG formats (SVG, COLRv0, COLRv1).
  • The next step is to refactor fpdf.draw_path() to produce the desired output without writing directly to the buffer.

Next Steps:

• Add support for SVG color fonts.
• Perform cleanup and optimization for better performance and maintainability.

Checklist:

• A unit test is covering the code added / modified by this PR

• This PR is ready to be merged

• In case of a new feature, docstrings have been added, with also some documentation in the docs/ folder

• A mention of the change is present in CHANGELOG.md

By submitting this pull request, I confirm that my contribution is made under the terms of the GNU LGPL 3.0 license.

[Lucas-C]

I'm no expert on fonts, but feel free to ping me if you want a review on this PR at some point 🙂

And thank you for working on this feature! 👍

[andersonhc]

I'm no expert on fonts, but feel free to ping me if you want a review on this PR at some point 🙂

And thank you for working on this feature! 👍

Only missing COLRv1 support and some housekeeping... we should have a reviewable version soon.

[Oripy]

I don't know if this is the right place to report this, but I found a regression in the font_color branch linked to offset_rendering():

The following code fails with an AttributeError: 'FPDF' object has no attribute '_current_draw_context'

import fpdf

pdf = fpdf.FPDF()
pdf.add_page()

pdf.add_font(fname='DejaVuSans.ttf')
pdf.add_font(fname='NotoColorEmoji.ttf')

pdf.set_font('DejaVuSans', size=14)
pdf.set_fallback_fonts(['NotoColorEmoji'])

pdf.multi_cell(text='abcdefghijklmnoqrtuvwxyz é 0123456789 🔴🟢🔵💀☠️', w=0)

with pdf.offset_rendering() as dummy:
    dummy.multi_cell(100, None, "test")

pdf.output('issue_1446.pdf')