Color::Gray is rendered as Color::White

[DarrenTsung]

Describe the bug When you style a Span with .fg(Color::Gray) or .bg(Color::Gray) it renders the Span as if Color::White was provided. It looks like the code just uses Color::White, which was unexpected to me: https://github.com/fdehau/tui-rs/blob/master/src/backend/termion.rs#L156, https://github.com/fdehau/tui-rs/blob/master/src/backend/termion.rs#L182.

To Reproduce Create a paragraph with a styled Span with Color::Gray, something like:

Spans::from(Span::styled(
    "hello world",
    Style::default().fg(Color::Gray),
)),

Expected behavior It renders something that is gray.

[fdehau]

You missed a section of the bug report template and it would be useful to understand the problem here. Could you report the following values: OS: [e.g. Linux,Windows] Terminal Emulator [e.g xterm, Konsole, Terminal, iTerm2, ConEmu] Font [e.g Inconsolata, Monospace] Crate version [e.g. 0.7] Backend [e.g termion, crossterm]

In addition, I just added a third tab to the demo that might help us debug your issue: #439. It would be nice if you can run on master:

cargo run --example termion_demo

navigate to the third tab and add a screenshot of what you are seeing. For example, here's mine:

[DarrenTsung]

Gotcha, I omitted it because I thought the bug was as simple as the code incorrectly using White instead of Gray (when rendering Gray), but I see now that it renders LightWhite when rendering White.

OS: MacOS Catalina 10.15.7 Terminal Emulator: iTerm2 (3.4.3) Font: Menlo Crate version: 0.10 (also on latest master) Backend: termion

Here's what I see on the third tab for the example (for me, gray looks the same as white):

I believe I'm using the iTerm2 snazzy color scheme: https://github.com/sindresorhus/iterm2-snazzy.