Terminal colors

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - Added windows support! (thank you to [@jarjk](https://github.com/jarjk) for helping out!)
 - Added keybindings (`0`/`$`) to scroll to left or right side of zoomed-in image ([#131](https://github.com/itsjunetime/tdf/pull/131), thank you [@IshDeshpa](https://github.com/IshDeshpa)!)
+- Added `-t` flag to use terminal foreground/background colors in pdf rendering ([#138](https://github.com/itsjunetime/tdf/pull/138), thank you [@unorsk](https://github.com/unorsk)!
 - Fixed issue with images clearing/flashing after displaying a certain number on kitty
 - (Internal) decreased runtime footprint of tokio runtime
 

src/main.rs

@@ -5,7 +5,7 @@ use core::{
 use std::{
 	borrow::Cow,
 	ffi::OsString,
-	io::{BufReader, Read as _, Stdout, Write as _, stdout},
+	io::{BufReader, IsTerminal as _, Read as _, Stdout, Write as _, stdout},
 	mem,
 	path::PathBuf,
 	sync::{Arc, Mutex},
@@ -116,6 +116,8 @@ async fn inner_main() -> Result<(), WrappedErr> {
 		optional -w,--white-color white: String
 		/// Custom black color, specified in css format (e.g "000000" or "rgb(0, 0, 0)")
 		optional -b,--black-color black: String
+		/// Use terminal foreground/background colors for the PDF
+		optional -t,--terminal-colors
 		/// Print the version and exit
 		optional --version
 		/// PDF file to read
@@ -137,37 +139,49 @@ async fn inner_main() -> Result<(), WrappedErr> {
 		.canonicalize()
 		.map_err(|e| WrappedErr(format!("Cannot canonicalize provided file: {e}").into()))?;
 
-	let black = flags
-		.black_color
-		.as_deref()
-		.map(|color| {
-			parse_color_to_i32(color).map_err(|e| {
-				WrappedErr(
-					format!(
-						"Couldn't parse black color {color:?}: {e} - is it formatted like a CSS color?"
+	if flags.terminal_colors && (flags.black_color.is_some() || flags.white_color.is_some()) {
+		return Err(WrappedErr(
+			"--terminal-colors cannot be combined with --black-color or --white-color".into()
+		));
+	}
+
+	let (black, white) = if flags.terminal_colors {
+		query_terminal_colors()
+	} else {
+		let black = flags
+			.black_color
+			.as_deref()
+			.map(|color| {
+				parse_color_to_i32(color).map_err(|e| {
+					WrappedErr(
+						format!(
+							"Couldn't parse black color {color:?}: {e} - is it formatted like a CSS color?"
+						)
+						.into()
 					)
-					.into()
-				)
+				})
 			})
-		})
-		.transpose()?
-		.unwrap_or(MUPDF_BLACK);
-
-	let white = flags
-		.white_color
-		.as_deref()
-		.map(|color| {
-			parse_color_to_i32(color).map_err(|e| {
-				WrappedErr(
-					format!(
-						"Couldn't parse white color {color:?}: {e} - is it formatted like a CSS color?"
+			.transpose()?
+			.unwrap_or(MUPDF_BLACK);
+
+		let white = flags
+			.white_color
+			.as_deref()
+			.map(|color| {
+				parse_color_to_i32(color).map_err(|e| {
+					WrappedErr(
+						format!(
+							"Couldn't parse white color {color:?}: {e} - is it formatted like a CSS color?"
+						)
+						.into()
 					)
-					.into()
-				)
+				})
 			})
-		})
-		.transpose()?
-		.unwrap_or(MUPDF_WHITE);
+			.transpose()?
+			.unwrap_or(MUPDF_WHITE);
+
+		(black, white)
+	};
 
 	// need to keep it around throughout the lifetime of the program, but don't rly need to use it.
 	// Just need to make sure it doesn't get dropped yet.
@@ -565,6 +579,89 @@ fn parse_color_to_i32(cs: &str) -> Result<i32, csscolorparser::ParseColorError>
 	Ok(i32::from_be_bytes([0, r, g, b]))
 }
 
+fn query_terminal_colors() -> (i32, i32) {
+	if !std::io::stdin().is_terminal() || !std::io::stdout().is_terminal() {
+		return (MUPDF_BLACK, MUPDF_WHITE);
+	}
+
+	let Ok(()) = enable_raw_mode() else {
+		return (MUPDF_BLACK, MUPDF_WHITE);
+	};
+
+	struct RawModeGuard;
+	impl Drop for RawModeGuard {
+		fn drop(&mut self) {
+			let _ = disable_raw_mode();
+		}
+	}
+	let _guard = RawModeGuard;
+
+	let stdin = std::io::stdin();
+	let mut handle = stdin.lock();
+
+	let fg = query_osc_color(10, &mut handle);
+	let bg = query_osc_color(11, &mut handle);
+	drop(handle);
+
+	(fg.unwrap_or(MUPDF_BLACK), bg.unwrap_or(MUPDF_WHITE))
+}
+
+fn query_osc_color(osc: u8, handle: &mut std::io::StdinLock<'_>) -> Option<i32> {
+	print!("\x1b]{osc};?\x1b\\");
+	std::io::stdout().flush().ok()?;
+
+	// response looks like "\u{1b}]10;rgb:rrrr/bbbb/gggg\u{1b}\\" or "\u{1b}]10;rgb:rr/bb/gg\u{1b}\\"
+	// or if osc is 11, "\u{1b}]11;rgb:rrrr/bbbb/gggg\u{1b}\\" or "\u{1b}]11;rgb:rr/bb/gg\u{1b}\\"
+
+	// We expect the response to be either 19 or 25 bytes.
+	let mut response_buf = [0u8; 25];
+
+	handle.read_exact(&mut response_buf[..19])
+		.inspect_err(|e| eprintln!("Couldn't get a response from your terminal for querying OSC {osc}; please file a bug with tdf with your terminal emulator (underlying err: {e})"))
+		.ok()?;
+
+	let two_digit_colors = response_buf[11] == b'/';
+
+	if !two_digit_colors {
+		handle.read_exact(&mut response_buf[19..])
+			.inspect_err(|e| eprintln!("Couldn't get a response from your terminal for querying OSC {osc}; please file a bug with tdf with your terminal emulator (underlying err: {e})"))
+			.ok()?;
+	}
+
+	osc_response_buf_to_color(response_buf)
+}
+
+fn osc_response_buf_to_color(response_buf: [u8; 25]) -> Option<i32> {
+	fn parse(ascii_hex_bytes: &[u8]) -> Option<u8> {
+		let mut color = 0;
+
+		for byte in ascii_hex_bytes {
+			color = (color << 4)
+				+ (match byte {
+					b'0'..=b'9' => byte - b'0',
+					b'A'..=b'F' => byte - (b'A' - 10),
+					b'a'..=b'f' => byte - (b'a' - 10),
+					_ => return None
+				});
+		}
+
+		Some(color)
+	}
+
+	let two_digit_colors = response_buf[11] == b'/';
+
+	// this is minimimal validation.
+	// the response either has `rrrr/gggg/bbbb` or `rr/gg/bb` starting at byte 9.
+	// So we grab the first two digits out of the r, g, and b sections (since we can only support
+	// 8-bit colors with mupdf; we can't do the 16-bits that the terminal might respond with), we
+	// parse them, and we return it as an i32.
+	let r = parse(&response_buf[9..11])?;
+	let g = parse(&response_buf[if two_digit_colors { 12..14 } else { 14..16 }])?;
+	let b = parse(&response_buf[if two_digit_colors { 15..17 } else { 19..21 }])?;
+
+	Some(i32::from_be_bytes([0, r, g, b]))
+}
+
 fn get_font_size_through_stdio() -> Result<(u16, u16), WrappedErr> {
 	// send the command code to get the terminal window size
 	print!("\x1b[14t");
@@ -631,3 +728,19 @@ fn get_font_size_through_stdio() -> Result<(u16, u16), WrappedErr> {
 
 	Ok((w, h))
 }
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn osc_response_parsing() {
+		fn eq(bytes: [u8; 25], r: u8, g: u8, b: u8) {
+			let resp = osc_response_buf_to_color(bytes);
+			assert_eq!(resp, Some(i32::from_be_bytes([0, r, g, b])));
+		}
+
+		eq(*b"\x1b]10;rgb:11/22/33\x1b\\000000", 0x11, 0x22, 0x33);
+		eq(*b"\x1b]11;rgb:aa11/23bf/fff0\x1b1", 0xaa, 0x23, 0xff);
+	}
+}