In the past, FTXUI switched from std::string to std::wstring to support
fullwidth characters. The reasons was that fullwidth characters can be
stored inside a single wchar_t.
Then FTXUI added support for combining characters. A single glygh
doesn't even fit a wchar_t. Instead, a glyph can be arbitrary large.
The usage of wstring doesn't really fit the new model and have several
drawbacks:
1. It doesn't simplify the implementation of FTXUI, because of combining
characters.
2. It reduces drawing performance by 2x.
3. It increase Screen's memory allocation by 2x.
This patch converts FTXUI to use std::string internally. It now exposes
std::string based API. The std::wstring API remains, but is now
deprecated.
Tests and examples haven't been update to show the breakage is limited.
They will be updated in a second set of patches.
Bug: https://github.com/ArthurSonzogni/FTXUI/issues/153
Co-authored-by: Tushar Maheshwari <tushar27192@gmail.com>
Allow Container::Vertical and Container::Horizontal to have an
external selector, similar to Container::Tab.
This is useful for implementing a menu of menu.
Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>
Modify the ftxui::Pixel. Instead of storing a wchar, store a
std::wstring. Now a single pixel can store multiple codepoints.
If a codepoint is of size <=0, it will be appended to the previous
pixel.
Only ftxui::text() is supported. ftxui::vtext support still needs to be
added.
This causes the following CPU and memory regression:
- Memory: Pixel size increases by 200% (16 byte => 48byte).
- CPU: Draw/Second decrease by 62.5% (16k draw/s => 6k draw/s on 80x80)
Both regressions are acceptable. There are still two orders of magnitude
(100x) before the levels where performance/memory concerns begins.
This fixes: https://github.com/ArthurSonzogni/FTXUI/issues/109
