endbasic-sdl 0.13.0

The EndBASIC programming language - SDL graphical console
Documentation 
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// EndBASIC
// Copyright 2021 Julio Merino
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

//! SDL2-based graphics terminal emulator.

use async_channel::Sender;
use endbasic_std::Signal;
use endbasic_std::console::{Console, ConsoleSpec, Resolution};
use std::cell::RefCell;
use std::fs::File;
use std::io::{self, Write};
use std::num::NonZeroU32;
use std::path::PathBuf;
use std::rc::Rc;
use tempfile::TempDir;

mod console;
mod font;
mod host;

/// Default resolution to use when none is provided.
const DEFAULT_RESOLUTION_PIXELS: (u32, u32) = (800, 600);

/// Default font to use when none is provided.
const DEFAULT_FONT_BYTES: &[u8] = include_bytes!("IBMPlexMono-Regular-6.0.0.ttf");

/// Default font size.
const DEFAULT_FONT_SIZE: u16 = 16;

/// Converts a flat string error message to an `io::Error`.
fn string_error_to_io_error(e: String) -> io::Error {
    io::Error::other(e)
}

/// Context to maintain a font on disk temporarily.
pub(crate) struct TempFont {
    dir: TempDir,
}

impl TempFont {
    /// Gets an instance of the default font.
    pub(crate) fn default_font() -> io::Result<Self> {
        let dir = tempfile::tempdir()?;
        let mut file = File::create(dir.path().join("font.ttf"))?;
        file.write_all(DEFAULT_FONT_BYTES)?;
        Ok(Self { dir })
    }

    /// Gets the path to the temporary font.
    pub(crate) fn path(&self) -> PathBuf {
        self.dir.path().join("font.ttf")
    }
}

/// Creates the graphical console based on the given `spec`.
pub fn setup(
    spec: &mut ConsoleSpec,
    signals_tx: Sender<Signal>,
) -> io::Result<Rc<RefCell<dyn Console>>> {
    let resolution: Resolution = spec.take_keyed_flag("resolution")?.unwrap_or_else(|| {
        let width = NonZeroU32::new(DEFAULT_RESOLUTION_PIXELS.0).unwrap();
        let height = NonZeroU32::new(DEFAULT_RESOLUTION_PIXELS.1).unwrap();
        Resolution::Windowed((width, height))
    });

    let default_fg_color = spec.take_keyed_flag::<u8>("fg_color")?;
    let default_bg_color = spec.take_keyed_flag::<u8>("bg_color")?;

    let font_path = spec.take_keyed_flag::<PathBuf>("font_path")?;

    let font_size = spec.take_keyed_flag("font_size")?.unwrap_or(DEFAULT_FONT_SIZE);

    let console = match font_path {
        None => {
            let default_font = TempFont::default_font()?;
            console::SdlConsole::new(
                resolution,
                default_fg_color,
                default_bg_color,
                default_font.path(),
                font_size,
                signals_tx,
            )?
            // The console has been created at this point, so it should be safe to drop
            // default_font and clean up the on-disk file backing it up.
        }
        Some(font_path) => console::SdlConsole::new(
            resolution,
            default_fg_color,
            default_bg_color,
            font_path.to_owned(),
            font_size,
            signals_tx,
        )?,
    };
    Ok(Rc::from(RefCell::from(console)))
}