Deprecating font caching mechanism + support for .pkl font files definitions (#347)

Author: Lucas-C

CHANGELOG.md

@@ -14,14 +14,26 @@ and [PEP 440](https://www.python.org/dev/peps/pep-0440/).
 - documentation on combining `borb` & `fpdf2`: [Creating a borb.pdf.document.Document from a FPDF instance](https://pyfpdf.github.io/fpdf2/ExistingPDFs.html)
 
 ### Changed
+- `fname` is now a required parameter for `FPDF.add_font()`
 - `image()` method now insert `.svg` images as PDF paths
+- the [defusedxml](https://pypi.org/project/defusedxml/) package was added as dependency in order to make SVG parsing safer
 - log level of `_substitute_page_number()` has been lowered from `INFO` to `DEBUG`
 
 ### Fixed
 - a bug in `get_string_width()` with unicode fonts and Markdown enabled,
   resulting in calls to `cell()` / `multi_cell()` with `align="R"` to display nothing - thanks @mcerveny for the fix!
 - a bug with incorrect width calculation of markdown text
 
+### Deprecated
+- the font caching mechanism, that used the `pickle` module, has been removed, for security reasons,
+  and because it provided little performance, and only for specific use cases - _cf._ [issue #345](https://github.com/PyFPDF/fpdf2/issues/345).
+  That means that the `font_cache_dir` optional parameter of `fpdf.FPDF` constructor
+  and the `uni` optional argument of `FPDF.add_font()` are deprecated.
+  The `fpdf.fpdf.load_cache` function has also been removed.
+
+To be extra clear: `uni=True` can now be removed from all calls to `FPDF.add_font()`.
+If the value of the `fname` argument passed to `add_font()` ends with `.ttf`, it is considered a TrueType font.
+
 ## [2.5.0] - 2022-01-22
 ### Added
 Thanks to @torque for contributing this massive new feature:

README.md

@@ -2,6 +2,7 @@
 [![Pypi latest version](https://img.shields.io/pypi/v/fpdf2.svg)](https://pypi.python.org/pypi/fpdf2)
 [![License: LGPL v3](https://img.shields.io/badge/License-LGPL%20v3-blue.svg)](https://www.gnu.org/licenses/lgpl-3.0)
 [![codecov](https://codecov.io/gh/PyFPDF/fpdf2/branch/master/graph/badge.svg)](https://codecov.io/gh/PyFPDF/fpdf2)
+[![security: bandit](https://img.shields.io/badge/security-bandit-yellow.svg)](https://github.com/PyCQA/bandit)
 [![Downloads per month](https://pepy.tech/badge/fpdf2/month)](https://pepy.tech/project/fpdf2)
 
 [![Discussions](https://img.shields.io/github/discussions/PyFPDF/fpdf2)](https://github.com/PyFPDF/fpdf2/discussions)

docs/EmojisSymbolsDingbats.md

@@ -11,7 +11,7 @@ Here is an example using the [DejaVu](https://dejavu-fonts.github.io) font:
 import fpdf
 
 pdf = fpdf.FPDF()
-pdf.add_font("DejaVuSans", fname="DejaVuSans.ttf", uni=True)
+pdf.add_font("DejaVuSans", fname="DejaVuSans.ttf")
 pdf.set_font("DejaVuSans", size=64)
 pdf.add_page()
 pdf.multi_cell(0, txt="".join([chr(0x1F600 + x) for x in range(68)]))

docs/Unicode.md

@@ -59,7 +59,7 @@ pdf.add_page()
 # Add a DejaVu Unicode font (uses UTF-8)
 # Supports more than 200 languages. For a coverage status see:
 # http://dejavu.svn.sourceforge.net/viewvc/dejavu/trunk/dejavu-fonts/langcover.txt
-pdf.add_font('DejaVu', fname='DejaVuSansCondensed.ttf', uni=True)
+pdf.add_font('DejaVu', fname='DejaVuSansCondensed.ttf')
 pdf.set_font('DejaVu', size=14)
 
 text = u"""
@@ -81,14 +81,14 @@ for txt in text.split('\n'):
 # Supports: Bengali, Devanagari, Gujarati, 
 #           Gurmukhi (including the variants for Punjabi) 
 #           Kannada, Malayalam, Oriya, Tamil, Telugu, Tibetan
-pdf.add_font('gargi', fname='gargi.ttf', uni=True) 
+pdf.add_font('gargi', fname='gargi.ttf')
 pdf.set_font('gargi', size=14)
 pdf.write(8, u'Hindi: नमस्ते दुनिया')
 pdf.ln(20)
 
 # Add a AR PL New Sung Unicode font (uses UTF-8)
 # The Open Source Chinese Font (also supports other east Asian languages)
-pdf.add_font('fireflysung', fname='fireflysung.ttf', uni=True)
+pdf.add_font('fireflysung', fname='fireflysung.ttf')
 pdf.set_font('fireflysung', size=14)
 pdf.write(8, u'Chinese: 你好世界\n')
 pdf.write(8, u'Japanese: こんにちは世界\n')
@@ -97,13 +97,13 @@ pdf.ln(10)
 # Add a Alee Unicode font (uses UTF-8)
 # General purpose Hangul truetype fonts that contain Korean syllable 
 # and Latin9 (iso8859-15) characters.
-pdf.add_font('eunjin', fname='Eunjin.ttf', uni=True)
+pdf.add_font('eunjin', fname='Eunjin.ttf')
 pdf.set_font('eunjin', size=14)
 pdf.write(8, u'Korean: 안녕하세요')
 pdf.ln(20)
 
 # Add a Fonts-TLWG (formerly ThaiFonts-Scalable) (uses UTF-8)
-pdf.add_font('waree', fname='Waree.ttf', uni=True)
+pdf.add_font('waree', fname='Waree.ttf')
 pdf.set_font('waree', size=14)
 pdf.write(8, u'Thai: สวัสดีชาวโลก')
 pdf.ln(20)