Fpdf2

Added
- New `FPDF.pages_count` property, thanks to paulacampigotto
- Temporary changes to graphics state variables are now possible using `with FPDF.local_context():`, thanks to gmischler
- a mechanism to detect & downscale oversized images,
_cf._ [documentation](https://py-pdf.github.io/fpdf2/Images.html#oversized-images-detection-downscaling).
[Feedbacks](https://github.com/py-pdf/fpdf2/discussions) on this new feature are welcome!
- New `set_dash_pattern()`, which works with all lines and curves, thanks to gmischler.
- Templates now support drawing ellipses, thanks to gmischler
- New documentation on how to display equations, using Google Charts or `matplotlib`: [Maths](https://py-pdf.github.io/fpdf2/Maths.html)
- The whole documentation can now be downloaded as a PDF: [fpdf2-manual.pdf](https://py-pdf.github.io/fpdf2/fpdf2-manual.pdf)
- New sections have been added to [the tutorial](https://py-pdf.github.io/fpdf2/Tutorial.html), thanks to portfedh:

5. [Creating Tables](https://py-pdf.github.io/fpdf2/Tutorial.html#tuto-5-creating-tables)
6. [Creating links and mixing text styles](https://py-pdf.github.io/fpdf2/Tutorial.html#tuto-6-creating-links-and-mixing-text-styles)
- New translation of the tutorial in Hindi, thanks to Mridulbirla13: [हिंदी संस्करण](https://py-pdf.github.io/fpdf2/Tutorial-hi.html); [Deutsch](https://py-pdf.github.io/fpdf2/Tutorial-de.html), thanks to digidigital; and [Italian](https://py-pdf.github.io/fpdf2/Tutorial-it.html) thanks to xit4; [Русский](https://py-pdf.github.io/fpdf2/Tutorial-ru.html) thanks to AABur; and [português](https://py-pdf.github.io/fpdf2/Tutorial-pt.html) thanks to fuscati; [français](https://py-pdf.github.io/fpdf2/Tutorial-fr.html), thanks to Tititesouris
- While images transparency is still handled by default through the use of `SMask`,
this can be disabled by setting `pdf.allow_images_transparency = False`
in order to allow compliance with [PDF/A-1](https://en.wikipedia.org/wiki/PDF/A#Description)
- [`FPDF.arc`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.arc): new method added.
It enables to draw arcs in a PDF document.
- [`FPDF.solid_arc`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.solid_arc): new method added.
It enables to draw solid arcs in a PDF document. A solid arc combines an arc and a triangle to form a pie slice.
- [`FPDF.regular_polygon`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.regular_polygon): new method added, thanks to bettman-latin
Fixed
- All graphics state manipulations are now possible within a rotation context, thanks to gmischler
- The exception making the "x2" template field optional for barcode elements did not work correctly, fixed by gmischler
- It is now possible to get back to a previous page to add more content, _e.g._ with a 2-column layout, thanks to paulacampigotto
Changed
- All template elements now have a transparent default background instead of white, thanks to gmischler
- To reduce the size of generated PDFs, no `SMask` entry is inserted for images that are fully opaque
(= with an alpha channel containing only 0xff characters)
- The `rect`, `ellipse` & `circle` all have a `style` parameter in common.
They now all properly accept a value of `"D"` and raise a `ValueError` for invalid values.
Deprecated
- `dashed_line()` is now deprecated in favor of `set_dash_pattern()`

Fixed
- ensure support for old field names in `Template.code39` for backward compatibility

Added
- `Template()` has gained a more flexible cousin `FlexTemplate()`, _cf._ [documentation](https://py-pdf.github.io/fpdf2/Templates.html), thanks to gmischler
- markdown support in `multi_cell()`, thanks to Yeshi Namkhai
- base 64 images can now be provided to `FPDF.image`, thanks to MWhatsUp
- documentation on how to generate datamatrix barcodes using the `pystrich` lib: [documentation section](https://py-pdf.github.io/fpdf2/Barcodes.html#datamatrix),
thanks to MWhatsUp
- `write_html`: headings (`<h1>`, `<h2>`...) relative sizes can now be configured through an optional `heading_sizes` parameter
- a subclass of `HTML2FPDF` can now easily be used by setting `FPDF.HTML2FPDF_CLASS`,
_cf._ [documentation](https://py-pdf.github.io/fpdf2/DocumentOutlineAndTableOfContents.html#with-html)
Fixed
- `Template`: `split_multicell()` will not write spurious font data to the target document anymore, thanks to gmischler
- `Template`: rotation now should work correctly in all situations, thanks to gmischler
- `write_html`: headings (`<h1>`, `<h2>`...) can now contain non-ASCII characters without triggering a `UnicodeEncodeError`
- `Template`: CSV column types are now safely parsed, thanks to gmischler
- `cell(..., markdown=True)` "leaked" its final style (bold / italics / underline) onto the following cells
Changed
- `write_html`: the line height of headings (`<h1>`, `<h2>`...) is now properly scaled with its font size
- some `FPDF` methods should not be used inside a `rotation` context, or things can get broken.
This is now forbidden: an exception is now raised in those cases.
Deprecated
- `Template`: `code39` barcode input field names changed from `x/y/w/h` to `x1/y1/y2/size`

Added
- support for **emojis**! More precisely unicode characters above `0xFFFF` in general, thanks to moe-25
- `Template` can now insert justified text
- [`get_scale_factor`](https://py-pdf.github.io/fpdf2/fpdf/util.html#fpdf.util.get_scale_factor) utility function to obtain `FPDF.k` without having to create a document
- [`convert_unit`](https://py-pdf.github.io/fpdf2/fpdf/util.html#fpdf.util.convert_unit) utility function to convert a number, `x,y` point, or list of `x,y` points from one unit to another unit
Changed
- `fpdf.FPDF()` constructor now accepts ints or floats as a unit, and raises a `ValueError` if an invalid unit is provided.
Fixed
- `Template` `background` property is now properly supported - [203](https://github.com/py-pdf/fpdf2/pull/203)
⚠️ Beware that its default value changed from `0` to `0xffffff`, as a value of **zero would render the background as black**.
- `Template.parse_csv`: preserving numeric values when using CSV based templates - [205](https://github.com/py-pdf/fpdf2/pull/205)
- the code snippet to generate Code 39 barcodes in the documentation was missing the start & end `*` characters.
This has been fixed, and a warning is now triggered by the [`FPDF.code39`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.code39) method when those characters are missing.
Fixed
- Detect missing `uni=True` when loading cached fonts (page numbering was missing digits)

Added
- disable font caching when `fpdf.FPDF` constructor invoked with `font_cache_dir=None`, thanks to moe-25 !
- [`FPDF.circle`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.circle): new method added, thanks to viraj-shah18 !
- `write_html`: support setting HTML font colors by name and short hex codes
- [`FPDF.will_page_break`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.will_page_break)
utility method to let users know in advance when adding an elemnt will trigger a page break.
This can be useful to repeat table headers on each page for exemple,
_cf._ [documentation on Tables](https://py-pdf.github.io/fpdf2/Tables.html#repeat-table-header-on-each-page).
- [`FPDF.set_link`](https://py-pdf.github.io/fpdf2/fpdf/fpdf.html#fpdf.fpdf.FPDF.set_link) now support a new optional `x` parameter to set the horizontal position after following the link
Fixed
- fixed a bug when `fpdf.Template` was used to render QRCodes, due to a forced conversion to string (175)

Fixed
- erroneous page breaks occured for full-width / full-height images
- rendering issue of non-ASCII characaters with unicode fonts