st77916 0.1.0

A Rust driver for the ST77916 TFT-LCD display controller
Documentation 
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use crate::{
    Buffered, ControllerInterface, DoubleBuffered, DriverError, ResetInterface, St77916,
    St77916Color, Unbuffered,
};
use embedded_graphics_core::draw_target::DrawTarget;
use embedded_graphics_core::prelude::*;
use embedded_graphics_core::primitives::Rectangle;

// ===========================================================================
// Buffered DrawTarget — writes to framebuffer, flushed explicitly
// ===========================================================================

impl<IFACE, RST, COLOR> DrawTarget for St77916<IFACE, RST, Buffered<COLOR>>
where
    IFACE: ControllerInterface,
    RST: ResetInterface,
    COLOR: St77916Color,
{
    type Color = COLOR;
    type Error = core::convert::Infallible;

    fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
    where
        I: IntoIterator<Item = Pixel<Self::Color>>,
    {
        let w = self.config.width as i32;
        let h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;
        let stride = self.config.width as usize * bpp;

        let mut y_min: i32 = i32::MAX;
        let mut y_max: i32 = 0;

        for Pixel(coord, color) in pixels.into_iter() {
            if coord.x >= 0 && coord.x < w && coord.y >= 0 && coord.y < h {
                let offset = coord.y as usize * stride + coord.x as usize * bpp;
                color.encode(&mut self.buffer.data[offset..offset + bpp]);
                y_min = y_min.min(coord.y);
                y_max = y_max.max(coord.y);
            }
        }

        if y_min <= y_max {
            self.buffer.dirty.mark(y_min as u16, y_max as u16);
        }
        Ok(())
    }

    #[inline]
    fn fill_contiguous<I>(&mut self, area: &Rectangle, colors: I) -> Result<(), Self::Error>
    where
        I: IntoIterator<Item = Self::Color>,
    {
        let disp_w = self.config.width as i32;
        let disp_h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;
        let stride = self.config.width as usize * bpp;

        let x0 = area.top_left.x.max(0);
        let y0 = area.top_left.y.max(0);
        let x1 = (area.top_left.x + area.size.width as i32).min(disp_w);
        let y1 = (area.top_left.y + area.size.height as i32).min(disp_h);

        if x0 >= x1 || y0 >= y1 {
            return Ok(());
        }

        self.buffer.dirty.mark(y0 as u16, (y1 - 1) as u16);

        let area_w = area.size.width as usize;
        let clipped_w = (x1 - x0) as usize;
        let skip_left = (x0 - area.top_left.x) as usize;
        let skip_right = (area_w as i32 - (x1 - area.top_left.x)) as usize;
        let skip_top = ((y0 - area.top_left.y) as usize) * area_w;

        let fb = self.buffer.data.as_mut_slice();
        let mut iter = colors.into_iter();

        for _ in 0..skip_top {
            iter.next();
        }

        for y in y0..y1 {
            let row_start = y as usize * stride + x0 as usize * bpp;

            for _ in 0..skip_left {
                iter.next();
            }

            let row = &mut fb[row_start..row_start + clipped_w * bpp];
            for (chunk, color) in row.chunks_exact_mut(bpp).zip(&mut iter) {
                color.encode(chunk);
            }

            for _ in 0..skip_right {
                iter.next();
            }
        }

        Ok(())
    }

    fn fill_solid(&mut self, area: &Rectangle, color: Self::Color) -> Result<(), Self::Error> {
        let disp_w = self.config.width as i32;
        let disp_h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;
        let stride = self.config.width as usize * bpp;

        let x0 = area.top_left.x.max(0) as usize;
        let y0 = area.top_left.y.max(0) as usize;
        let x1 = (area.top_left.x + area.size.width as i32).min(disp_w) as usize;
        let y1 = (area.top_left.y + area.size.height as i32).min(disp_h) as usize;

        if x0 >= x1 || y0 >= y1 {
            return Ok(());
        }

        self.buffer.dirty.mark(y0 as u16, (y1 - 1) as u16);

        let row_bytes = (x1 - x0) * bpp;
        let fb = self.buffer.data.as_mut_slice();

        for y in y0..y1 {
            let start = y * stride + x0 * bpp;
            COLOR::fill_row(color, &mut fb[start..start + row_bytes]);
        }

        Ok(())
    }

    fn clear(&mut self, color: Self::Color) -> Result<(), Self::Error> {
        COLOR::fill_buf(color, &mut self.buffer.data);
        self.buffer.dirty.mark_all(self.config.height);
        Ok(())
    }
}

impl<IFACE, RST, COLOR> OriginDimensions for St77916<IFACE, RST, Buffered<COLOR>>
where
    IFACE: ControllerInterface,
    RST: ResetInterface,
    COLOR: St77916Color,
{
    fn size(&self) -> Size {
        Size::new(self.config.width as u32, self.config.height as u32)
    }
}

// ===========================================================================
// Unbuffered DrawTarget — sends pixels directly to the display, no buffer
// ===========================================================================

impl<IFACE, RST, COLOR> DrawTarget for St77916<IFACE, RST, Unbuffered<COLOR>>
where
    IFACE: ControllerInterface,
    RST: ResetInterface,
    COLOR: St77916Color,
{
    type Color = COLOR;
    type Error = DriverError<IFACE::Error, RST::Error>;

    fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
    where
        I: IntoIterator<Item = Pixel<Self::Color>>,
    {
        let w = self.config.width as i32;
        let h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;

        for Pixel(coord, color) in pixels.into_iter() {
            if coord.x >= 0 && coord.x < w && coord.y >= 0 && coord.y < h {
                let x = coord.x as u16;
                let y = coord.y as u16;
                self.set_window(x, y, x, y)?;
                let mut buf = [0u8; 4];
                color.encode(&mut buf[..bpp]);
                self.send_pixels(&buf[..bpp])?;
            }
        }
        Ok(())
    }

    fn fill_contiguous<I>(&mut self, area: &Rectangle, colors: I) -> Result<(), Self::Error>
    where
        I: IntoIterator<Item = Self::Color>,
    {
        let disp_w = self.config.width as i32;
        let disp_h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;

        let x0 = area.top_left.x.max(0);
        let y0 = area.top_left.y.max(0);
        let x1 = (area.top_left.x + area.size.width as i32).min(disp_w);
        let y1 = (area.top_left.y + area.size.height as i32).min(disp_h);

        if x0 >= x1 || y0 >= y1 {
            return Ok(());
        }

        let area_w = area.size.width as usize;
        let clipped_w = (x1 - x0) as usize;
        let skip_left = (x0 - area.top_left.x) as usize;
        let skip_right = (area_w as i32 - (x1 - area.top_left.x)) as usize;
        let skip_top = ((y0 - area.top_left.y) as usize) * area_w;

        // Set window for the entire clipped region, then stream row by row
        self.set_window(x0 as u16, y0 as u16, (x1 - 1) as u16, (y1 - 1) as u16)?;

        let mut iter = colors.into_iter();

        // Encode a row at a time into a stack/heap buffer and send it
        let row_bytes = clipped_w * bpp;
        let mut row_buf = alloc::vec![0u8; row_bytes];

        for _ in 0..skip_top {
            iter.next();
        }

        for _y in y0..y1 {
            for _ in 0..skip_left {
                iter.next();
            }

            for chunk in row_buf.chunks_exact_mut(bpp) {
                if let Some(color) = iter.next() {
                    color.encode(chunk);
                } else {
                    return Ok(());
                }
            }

            self.send_pixels(&row_buf)?;

            for _ in 0..skip_right {
                iter.next();
            }
        }

        Ok(())
    }

    fn fill_solid(&mut self, area: &Rectangle, color: Self::Color) -> Result<(), Self::Error> {
        let disp_w = self.config.width as i32;
        let disp_h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;

        let x0 = area.top_left.x.max(0) as u16;
        let y0 = area.top_left.y.max(0) as u16;
        let x1 = ((area.top_left.x + area.size.width as i32).min(disp_w) - 1) as u16;
        let y1 = ((area.top_left.y + area.size.height as i32).min(disp_h) - 1) as u16;

        if x0 > x1 || y0 > y1 {
            return Ok(());
        }

        self.set_window(x0, y0, x1, y1)?;

        let width = (x1 - x0 + 1) as usize;
        let height = (y1 - y0 + 1) as usize;
        let row_bytes = width * bpp;
        let mut row_buf = alloc::vec![0u8; row_bytes];
        COLOR::fill_row(color, &mut row_buf);

        for _ in 0..height {
            self.send_pixels(&row_buf)?;
        }

        Ok(())
    }

    fn clear(&mut self, color: Self::Color) -> Result<(), Self::Error> {
        let w = self.config.width;
        let h = self.config.height;
        let bpp = COLOR::BYTES_PER_PIXEL;

        self.set_window(0, 0, w - 1, h - 1)?;

        let row_bytes = w as usize * bpp;
        let mut row_buf = alloc::vec![0u8; row_bytes];
        COLOR::fill_row(color, &mut row_buf);

        for _ in 0..h {
            self.send_pixels(&row_buf)?;
        }

        Ok(())
    }
}

// ===========================================================================
// DoubleBuffered DrawTarget — writes to back buffer, flushed explicitly
// ===========================================================================

impl<IFACE, RST, COLOR> DrawTarget for St77916<IFACE, RST, DoubleBuffered<COLOR>>
where
    IFACE: ControllerInterface,
    RST: ResetInterface,
    COLOR: St77916Color,
{
    type Color = COLOR;
    type Error = core::convert::Infallible;

    fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
    where
        I: IntoIterator<Item = Pixel<Self::Color>>,
    {
        let w = self.config.width as i32;
        let h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;
        let stride = self.config.width as usize * bpp;
        let fb = self.buffer.back_mut().as_mut_slice();

        for Pixel(coord, color) in pixels.into_iter() {
            if coord.x >= 0 && coord.x < w && coord.y >= 0 && coord.y < h {
                let offset = coord.y as usize * stride + coord.x as usize * bpp;
                color.encode(&mut fb[offset..offset + bpp]);
            }
        }
        Ok(())
    }

    fn fill_contiguous<I>(&mut self, area: &Rectangle, colors: I) -> Result<(), Self::Error>
    where
        I: IntoIterator<Item = Self::Color>,
    {
        let disp_w = self.config.width as i32;
        let disp_h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;
        let stride = self.config.width as usize * bpp;
        let fb = self.buffer.back_mut().as_mut_slice();

        let x0 = area.top_left.x.max(0) as usize;
        let y0 = area.top_left.y.max(0) as usize;
        let x1 = (area.top_left.x + area.size.width as i32).min(disp_w) as usize;
        let y1 = (area.top_left.y + area.size.height as i32).min(disp_h) as usize;

        if x0 >= x1 || y0 >= y1 {
            for _ in colors {}
            return Ok(());
        }

        let src_w = area.size.width as usize;
        let mut iter = colors.into_iter();

        for src_row in 0..area.size.height as usize {
            let dst_row = area.top_left.y as usize + src_row;
            if dst_row < y0 || dst_row >= y1 {
                for _ in 0..src_w {
                    iter.next();
                }
                continue;
            }
            for src_col in 0..src_w {
                if let Some(c) = iter.next() {
                    let dst_col = area.top_left.x as usize + src_col;
                    if dst_col >= x0 && dst_col < x1 {
                        let offset = dst_row * stride + dst_col * bpp;
                        c.encode(&mut fb[offset..offset + bpp]);
                    }
                }
            }
        }
        Ok(())
    }

    fn fill_solid(&mut self, area: &Rectangle, color: Self::Color) -> Result<(), Self::Error> {
        let disp_w = self.config.width as i32;
        let disp_h = self.config.height as i32;
        let bpp = COLOR::BYTES_PER_PIXEL;
        let stride = self.config.width as usize * bpp;

        let x0 = area.top_left.x.max(0) as usize;
        let y0 = area.top_left.y.max(0) as usize;
        let x1 = (area.top_left.x + area.size.width as i32).min(disp_w) as usize;
        let y1 = (area.top_left.y + area.size.height as i32).min(disp_h) as usize;

        if x0 >= x1 || y0 >= y1 {
            return Ok(());
        }

        let row_bytes = (x1 - x0) * bpp;
        let fb = self.buffer.back_mut().as_mut_slice();

        for y in y0..y1 {
            let start = y * stride + x0 * bpp;
            COLOR::fill_row(color, &mut fb[start..start + row_bytes]);
        }
        Ok(())
    }

    fn clear(&mut self, color: Self::Color) -> Result<(), Self::Error> {
        COLOR::fill_buf(color, self.buffer.back_mut().as_mut_slice());
        Ok(())
    }
}

impl<IFACE, RST, COLOR> OriginDimensions for St77916<IFACE, RST, DoubleBuffered<COLOR>>
where
    IFACE: ControllerInterface,
    RST: ResetInterface,
    COLOR: St77916Color,
{
    fn size(&self) -> Size {
        Size::new(self.config.width as u32, self.config.height as u32)
    }
}

impl<IFACE, RST, COLOR> OriginDimensions for St77916<IFACE, RST, Unbuffered<COLOR>>
where
    IFACE: ControllerInterface,
    RST: ResetInterface,
    COLOR: St77916Color,
{
    fn size(&self) -> Size {
        Size::new(self.config.width as u32, self.config.height as u32)
    }
}