mod codes; pub mod custom_char; mod of_node; pub mod special_char; use std::fs::{File, OpenOptions}; use std::path::Path; use std::io::BufWriter; use std::io::Result; use std::io::Write; use codes::SpecialCode; use codes::WriteInto; // Increment this number when appropriate: // // NUMBER_OF_LCD_SCREENS_DESTROYED_DURING_TESTING: 1 /// A screen that allows you to send commands to a charlcd driver (or whatever /// that implements the [`Write`] trait). /// /// # Simple example /// /// ```no_run /// extern crate charlcd; /// /// use charlcd::Screen; /// use std::io::Write; /// /// fn main() -> std::io::Result<()> { /// let mut screen = Screen::default()?; // will use "/dev/lcd" charlcd driver /// /// screen.clear()?; /// screen.write(b"hello, world!")?; /// screen.flash_backlight()?; /// screen.flush()?; // send all the previous commands to the driver at once /// /// Ok(()) /// } /// ``` pub struct Screen { writer: T, } macro_rules! write_simple_code { ($self:expr, $code:expr) => {{ $code.write_into(&mut $self.writer)?; Ok(()) }}; } impl Screen where T: Write, { /// Create a new [`Screen`] instance that will use the provided [`Write`] /// under the hood to send commands. pub fn new(writer: T) -> Screen { Screen { writer } } /// Clean the rest of the current line, from current cursor position. /// /// # Live footage (before and after) /// ![kill_eol_before](https://crates.microjoe.org/charlcd/media/docs/kill_eol_before.jpg) /// ![kill_eol](https://crates.microjoe.org/charlcd/media/docs/kill_eol.jpg) /// pub fn kill_eol(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::KillEndOfLine) } /// Reinitialize the display to its default hardware values. /// /// # Live footage (before and after) /// ![full](https://crates.microjoe.org/charlcd/media/docs/full.jpg) /// ![clear](https://crates.microjoe.org/charlcd/media/docs/clear.jpg) /// /// Note: we observe that the cursor *and* blink are activated after a call /// to [`Screen::reinit()`], although the [`Screen::blink_on()`] and /// [`Screen::cursor_on()`] methods are *not* called in this function. We /// can deduce it is a hardware default to put back the blink and cursor on /// at initialization. /// /// You may want to disable them after a call to this function by using the /// [`Screen::blink_off()`] and [`Screen::cursor_off()`] functions. pub fn reinit(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::ReinitializeDisplay) } /// Disable the display. /// /// The displayed content is not lost and kept into the screen buffer. Call /// [`Screen::display_on()`] to display back what was printed to the screen. /// /// # Live footage (before and after) /// ![full](https://crates.microjoe.org/charlcd/media/docs/full.jpg) /// ![display_off](https://crates.microjoe.org/charlcd/media/docs/display_off.jpg) /// pub fn display_off(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::DisplayOff) } /// Enable the display. /// /// The content of the screen buffer will be displayed back with no change. /// /// # Live footage (before and after) /// ![display_off](https://crates.microjoe.org/charlcd/media/docs/display_off.jpg) /// ![full](https://crates.microjoe.org/charlcd/media/docs/full.jpg) /// pub fn display_on(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::DisplayOn) } /// Enable the underscore cursor (independent of blinking cursor). /// /// # Live footage (before and after) /// ![test_clear](https://crates.microjoe.org/charlcd/media/docs/test_clear.jpg) /// ![cursor_on](https://crates.microjoe.org/charlcd/media/docs/cursor_on.jpg) /// pub fn cursor_on(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::CursorOn) } /// Disable the underscore cursor (independent of blinking cursor). /// /// # Live footage (before and after) /// ![test](https://crates.microjoe.org/charlcd/media/docs/test.jpg) /// ![cursor_off](https://crates.microjoe.org/charlcd/media/docs/blink_on.jpg) /// pub fn cursor_off(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::CursorOff) } /// Enable the blinking cursor (independent of underscore cursor). /// /// # Live footage (before and after) /// ![test_clear](https://crates.microjoe.org/charlcd/media/docs/test_clear.jpg) /// ![blink_on](https://crates.microjoe.org/charlcd/media/docs/blink_on.jpg) /// /// Note: due to long exposure duration of the camera (1 second), the /// blinking cursor appears dim in the footage. /// pub fn blink_on(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::BlinkOn) } /// Disable the blinking cursor (independent of underscore cursor). /// /// # Live footage (before and after) /// ![test](https://crates.microjoe.org/charlcd/media/docs/test.jpg) /// ![blink_off](https://crates.microjoe.org/charlcd/media/docs/cursor_on.jpg) /// pub fn blink_off(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::BlinkOff) } /// Enable the backlight. pub fn backlight_on(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::BacklightOn) } /// Disable the backlight. pub fn backlight_off(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::BacklightOff) } /// Flash the backlight during a small duration. /// /// The exact duration is specified in the driver. As of today, the default /// value is set to 4 seconds (see the `LCD_BL_TEMPO_PERIOD` define of /// the `charlcd.c` driver in your Linux tree). pub fn flash_backlight(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::FlashBacklight) } /// Clear the screen and return the cursor at original (0, 0) XY position. /// /// # Live footage (before and after) /// ![test](https://crates.microjoe.org/charlcd/media/docs/test.jpg) /// ![clear](https://crates.microjoe.org/charlcd/media/docs/clear.jpg) /// pub fn clear(&mut self) -> std::io::Result<()> { self.write(&[0x0c])?; // '\f' escape not defined in Rust Ok(()) } /// Move the cursor back one character, and delete the character at this /// position. /// /// This is an utility function that will send the raw byte value for the /// `'\b'` escape sequence. This sequence is valid in C, but is not /// available in Rust. /// /// # Live footage (before and after) /// ![test](https://crates.microjoe.org/charlcd/media/docs/test.jpg) /// ![back](https://crates.microjoe.org/charlcd/media/docs/back.jpg) /// pub fn back(&mut self) -> std::io::Result<()> { self.write(&[0x08])?; // '\b' escape not defined in Rust Ok(()) } // Less-used (and some non-working?) methods below /// Shift cursor left. /// /// # Live footage (before and after) /// ![test](https://crates.microjoe.org/charlcd/media/docs/test.jpg) /// ![shift_cursor_left](https://crates.microjoe.org/charlcd/media/docs/shift_cursor_left.jpg) /// pub fn shift_cursor_left(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::ShiftCursorLeft) } /// Shift cursor right. /// /// # Live footage (before and after) /// ![test](https://crates.microjoe.org/charlcd/media/docs/test.jpg) /// ![shift_cursor_right](https://crates.microjoe.org/charlcd/media/docs/shift_cursor_right.jpg) /// pub fn shift_cursor_right(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::ShiftCursorRight) } /// Shift display left. /// /// # Live footage (before and after) /// ![shift](https://crates.microjoe.org/charlcd/media/docs/shift.jpg) /// ![shift_display_left](https://crates.microjoe.org/charlcd/media/docs/shift_display_left.jpg) /// /// Note: we can observe that the shift will create an artefact on the n+2 /// line, as the extra characters will be shifted there. pub fn shift_display_left(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::ShiftDisplayLeft) } /// Shift display right. /// /// # Live footage (before and after) /// ![shift](https://crates.microjoe.org/charlcd/media/docs/shift.jpg) /// ![shift_display_right](https://crates.microjoe.org/charlcd/media/docs/shift_display_right.jpg) /// /// Note: we can observe that the shift will create an artefact on the n+2 /// line, as the extra characters will be shifted there. pub fn shift_display_right(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::ShiftDisplayRight) } /// Enable one line mode. /// /// # Live footage (before and after) /// ![full](https://crates.microjoe.org/charlcd/media/docs/full.jpg) /// ![one_line](https://crates.microjoe.org/charlcd/media/docs/one_line.jpg) /// /// We can see that the screen seems to disable power for the second and /// fourth line of the display (in case of a 4 lines one). Cutting the /// power for half the screen means that the contrast adjustment will not /// be correct anymore, as the screen uses less power by managing only half /// of the characters. /// /// A manual recalibration of the contrast will be necessary if you change /// between [`Screen::one_line()`] and [`Screen::two_lines()`] modes. pub fn one_line(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::OneLine) } /// Enable two lines mode. /// /// # Live footage (before and after) /// ![one_line](https://crates.microjoe.org/charlcd/media/docs/one_line.jpg) /// ![two_lines](https://crates.microjoe.org/charlcd/media/docs/two_lines.jpg) /// /// This will mess up the screen if coming from [`Screen::one_line()`] mode. /// /// A manual recalibration of the contrast will be necessary if you change /// between [`Screen::one_line()`] and [`Screen::two_lines()`] modes. pub fn two_lines(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::TwoLines) } /// Enable small font mode. /// /// Note: this function seems to have no effect on the screen after tests /// with multiple screen variants. No relevant footage available. pub fn small_font(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::SmallFont) } /// Enable big font mode. /// /// Note: this function seems to have no effect on the screen after tests /// with multiple screen variants. No relevant footage available. pub fn large_font(&mut self) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::LargeFont) } /// Custom character create pub fn custom_char(&mut self, code: u8, value: [u8; 8]) -> std::io::Result<()> { let mut res = 0u64; let mut i = 0; for b in value.iter().rev() { res |= (*b as u64) << i; i += 8; } write_simple_code!(self, SpecialCode::Generator(code, res)) } pub fn gotoxy(&mut self, x: u32, y: u32) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::GotoXY(Some(x), Some(y))) } pub fn gotox(&mut self, x: u32) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::GotoXY(Some(x), None)) } pub fn gotoy(&mut self, y: u32) -> std::io::Result<()> { write_simple_code!(self, SpecialCode::GotoXY(None, Some(y))) } } // Reimplement Write trait for Screen, so that user can call the write and // flush methods of the inner writer. impl Write for Screen where T: Write, { fn write(&mut self, buf: &[u8]) -> Result { self.writer.write(buf) } fn flush(&mut self) -> Result<()> { self.writer.flush() } } // Concrete screen based on a File, to write to the real charlcd driver (or to // another file). pub type FileScreen = Screen>; const DEFAULT_SCREEN_DEV_PATH: &str = "/dev/lcd"; impl FileScreen { /// Create a Screen instance based on the passed path to the device. pub fn from_dev_path(path: &Path) -> std::io::Result { let file = OpenOptions::new().write(true).open(path)?; let buf = BufWriter::new(file); Ok(Screen::new(buf)) } /// Create a default Screen instance based on `/dev/lcd` device driver /// path. pub fn default() -> std::io::Result { Screen::from_dev_path(&Path::new(DEFAULT_SCREEN_DEV_PATH)) } /// Get the width of the screen, in number of characters it can display. /// /// # Example /// /// ```no_run /// extern crate charlcd; /// /// use charlcd::FileScreen; /// /// fn main() -> std::io::Result<()> { /// let screen = FileScreen::default()?; // the screen is 20x4 in this test /// /// let width = screen.width()?; /// assert_eq!(width, 20); /// /// Ok(()) /// } /// ``` /// /// # Important note /// /// The implementation behind this function is currently a hack that will /// go find the value in the `auxdisplay` platform device tree node in /// `/sys/devices/platform/auxdisplay/of_node/*`. This is because the /// `charlcd` driver does not export the `width` nor `height` fields to /// userspace. /// /// In the future, this function may be able to read the value directly /// from the `/dev/lcd` device if a proper `ioctl` or `read` call is /// implemented for this purpose. /// pub fn width(&self) -> std::io::Result { of_node::display_width_chars() } /// Get the height of the screen, in number of characters it can display. /// /// # Example /// /// ```no_run /// extern crate charlcd; /// /// use charlcd::FileScreen; /// /// fn main() -> std::io::Result<()> { /// let screen = FileScreen::default()?; // the screen is 20x4 in this test /// /// let height = screen.height()?; /// assert_eq!(height, 4); /// /// Ok(()) /// } /// ``` /// /// # Important note /// /// The implementation behind this function is currently a hack that will /// go find the value in the `auxdisplay` platform device tree node in /// `/sys/devices/platform/auxdisplay/of_node/*`. This is because the /// `charlcd` driver does not export the `width` nor `height` fields to /// userspace. /// /// In the future, this function may be able to read the value directly /// from the `/dev/lcd` device if a proper `ioctl` or `read` call is /// implemented for this purpose. /// pub fn height(&self) -> std::io::Result { of_node::display_height_chars() } }