Various improvements (#25)

- Added is_busy to Waveshare_Interface
- Added IS_BUSY_LOW const for all supported epds
- Added is_busy to DisplayInterface
- moved width, height and default_background_color directly to epd4in2 module
- Added VarDisplay (a variable buffersize display/graphic driver)
- Removed all Buffers (Buffer1in54,...) and instead made specialised Displays (Display1in54,...) with included Buffers
- Updated and added more examples
- Cargo fmt/clippy
- Improved Docs/Readmes

src/epd2in9/graphics.rs

@@ -1,40 +1,69 @@
 use crate::epd2in9::{DEFAULT_BACKGROUND_COLOR, HEIGHT, WIDTH};
+use crate::graphics::{Display, DisplayRotation};
+use crate::prelude::*;
+use embedded_graphics::prelude::*;
 
-/// Full size buffer for use with the 2in9 EPD
+/// Display with Fullsize buffer for use with the 2in9 EPD
 ///
 /// Can also be manuall constructed:
 /// `buffer: [DEFAULT_BACKGROUND_COLOR.get_byte_value(); WIDTH / 8 * HEIGHT]`
-pub struct Buffer2in9 {
-    pub buffer: [u8; WIDTH as usize * HEIGHT as usize / 8],
+pub struct Display2in9 {
+    buffer: [u8; WIDTH as usize * HEIGHT as usize / 8],
+    rotation: DisplayRotation,
 }
 
-impl Default for Buffer2in9 {
+impl Default for Display2in9 {
     fn default() -> Self {
-        Buffer2in9 {
+        Display2in9 {
             buffer: [DEFAULT_BACKGROUND_COLOR.get_byte_value();
                 WIDTH as usize * HEIGHT as usize / 8],
+            rotation: DisplayRotation::default(),
         }
     }
 }
 
+impl Drawing<Color> for Display2in9 {
+    fn draw<T>(&mut self, item_pixels: T)
+    where
+        T: Iterator<Item = Pixel<Color>>,
+    {
+        self.draw_helper(WIDTH, HEIGHT, item_pixels);
+    }
+}
+
+impl Display for Display2in9 {
+    fn buffer(&self) -> &[u8] {
+        &self.buffer
+    }
+
+    fn get_mut_buffer(&mut self) -> &mut [u8] {
+        &mut self.buffer
+    }
+
+    fn set_rotation(&mut self, rotation: DisplayRotation) {
+        self.rotation = rotation;
+    }
+
+    fn rotation(&self) -> DisplayRotation {
+        self.rotation
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::graphics::Display;
 
     // test buffer length
     #[test]
     fn graphics_size() {
-        let mut buffer = Buffer2in9::default();
-        let display = Display::new(WIDTH, HEIGHT, &mut buffer.buffer);
+        let display = Display2in9::default();
         assert_eq!(display.buffer().len(), 4736);
     }
 
     // test default background color on all bytes
     #[test]
     fn graphics_default() {
-        let mut buffer = Buffer2in9::default();
-        let display = Display::new(WIDTH, HEIGHT, &mut buffer.buffer);
+        let display = Display2in9::default();
         for &byte in display.buffer() {
             assert_eq!(byte, DEFAULT_BACKGROUND_COLOR.get_byte_value());
         }

src/epd2in9/mod.rs

@@ -4,19 +4,19 @@
 //!
 //! # Example for the 2.9 in E-Ink Display
 //!
-//! ```ignore
+//! ```rust,ignore
 //! use epd_waveshare::{
-//!     epd2in9::{EPD2in9, Buffer2in9},
+//!     epd2in9::{EPD2in9, Display2in9},
 //!     graphics::{Display, DisplayRotation},
 //!     prelude::*,
 //! };
+//! use embedded_graphics::Drawing;
 //!
 //! // Setup EPD
-//! let mut epd = EPD2in9::new(&mut spi, cs_pin, busy_in, dc, rst, &mut delay)?;
+//! let mut epd = EPD2in9::new(&mut spi, cs_pin, busy_in, dc, rst, &mut delay).unwrap();
 //!
 //! // Use display graphics
-//! let mut buffer = Buffer2in9::default();
-//! let mut display = Display::new(epd.width(), epd.height(), &mut buffer.buffer);
+//! let mut display = Display2in9::default();
 //!
 //! // Write some hello world in the screenbuffer
 //! display.draw(
@@ -38,6 +38,7 @@
 pub const WIDTH: u32 = 128;
 pub const HEIGHT: u32 = 296;
 pub const DEFAULT_BACKGROUND_COLOR: Color = Color::White;
+const IS_BUSY_LOW: bool = false;
 
 use embedded_hal::{
     blocking::{delay::*, spi::Write},
@@ -55,8 +56,10 @@ use crate::traits::*;
 
 use crate::interface::DisplayInterface;
 
+#[cfg(feature = "graphics")]
 mod graphics;
-pub use crate::epd2in9::graphics::Buffer2in9;
+#[cfg(feature = "graphics")]
+pub use crate::epd2in9::graphics::Display2in9;
 
 /// EPD2in9 driver
 ///
@@ -247,6 +250,10 @@ where
             RefreshLUT::QUICK => self.set_lut_helper(spi, &LUT_PARTIAL_UPDATE),
         }
     }
+
+    fn is_busy(&self) -> bool {
+        self.interface.is_busy(IS_BUSY_LOW)
+    }
 }
 
 impl<SPI, CS, BUSY, DC, RST> EPD2in9<SPI, CS, BUSY, DC, RST>
@@ -258,7 +265,7 @@ where
     RST: OutputPin,
 {
     fn wait_until_idle(&mut self) {
-        self.interface.wait_until_idle(false);
+        self.interface.wait_until_idle(IS_BUSY_LOW);
     }
 
     fn use_full_frame(&mut self, spi: &mut SPI) -> Result<(), SPI::Error> {