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

examples/epd1in54_no_graphics/src/main.rs

@@ -0,0 +1,105 @@
+#![deny(warnings)]
+
+use embedded_hal::prelude::*;
+use epd_waveshare::{epd1in54::EPD1in54, prelude::*};
+use linux_embedded_hal::{
+    spidev::{self, SpidevOptions},
+    sysfs_gpio::Direction,
+    Delay, Pin, Spidev,
+};
+
+// activate spi, gpio in raspi-config
+// needs to be run with sudo because of some sysfs_gpio permission problems and follow-up timing problems
+// see https://github.com/rust-embedded/rust-sysfs-gpio/issues/5 and follow-up issues
+
+fn main() {
+    if let Err(e) = run() {
+        eprintln!("Program exited early with error: {}", e);
+    }
+}
+
+fn run() -> Result<(), std::io::Error> {
+    // Configure SPI
+    // SPI settings are from eink-waveshare-rs documenation
+    let mut spi = Spidev::open("/dev/spidev0.0")?;
+    let options = SpidevOptions::new()
+        .bits_per_word(8)
+        .max_speed_hz(4_000_000)
+        .mode(spidev::SPI_MODE_0)
+        .build();
+    spi.configure(&options).expect("spi configuration");
+
+    // Configure Digital I/O Pin to be used as Chip Select for SPI
+    let cs_pin = Pin::new(26); //BCM7 CE0
+    cs_pin.export().expect("cs_pin export");
+    while !cs_pin.is_exported() {}
+    cs_pin
+        .set_direction(Direction::Out)
+        .expect("cs_pin Direction");
+    cs_pin.set_value(1).expect("cs_pin Value set to 1");
+
+    // Configure Busy Input Pin
+    let busy = Pin::new(5); //pin 29
+    busy.export().expect("busy export");
+    while !busy.is_exported() {}
+    busy.set_direction(Direction::In).expect("busy Direction");
+    //busy.set_value(1).expect("busy Value set to 1");
+
+    // Configure Data/Command OutputPin
+    let dc = Pin::new(6); //pin 31 //bcm6
+    dc.export().expect("dc export");
+    while !dc.is_exported() {}
+    dc.set_direction(Direction::Out).expect("dc Direction");
+    dc.set_value(1).expect("dc Value set to 1");
+
+    // Configure Reset OutputPin
+    let rst = Pin::new(16); //pin 36 //bcm16
+    rst.export().expect("rst export");
+    while !rst.is_exported() {}
+    rst.set_direction(Direction::Out).expect("rst Direction");
+    rst.set_value(1).expect("rst Value set to 1");
+
+    // Configure Delay
+    let mut delay = Delay {};
+
+    // Setup of the needed pins is finished here
+    // Now the "real" usage of the eink-waveshare-rs crate begins
+    let mut epd = EPD1in54::new(&mut spi, cs_pin, busy, dc, rst, &mut delay)?;
+
+    // Clear the full screen
+    epd.clear_frame(&mut spi)?;
+    epd.display_frame(&mut spi)?;
+
+    // Speeddemo
+    epd.set_lut(&mut spi, Some(RefreshLUT::QUICK))?;
+    let small_buffer = [Color::Black.get_byte_value(); 32]; //16x16
+    let number_of_runs = 1;
+    for i in 0..number_of_runs {
+        let offset = i * 8 % 150;
+        epd.update_partial_frame(&mut spi, &small_buffer, 25 + offset, 25 + offset, 16, 16)?;
+        epd.display_frame(&mut spi)?;
+    }
+
+    // Clear the full screen
+    epd.clear_frame(&mut spi)?;
+    epd.display_frame(&mut spi)?;
+
+    // Draw some squares
+    let small_buffer = [Color::Black.get_byte_value(); 3200]; //160x160
+    epd.update_partial_frame(&mut spi, &small_buffer, 20, 20, 160, 160)?;
+
+    let small_buffer = [Color::White.get_byte_value(); 800]; //80x80
+    epd.update_partial_frame(&mut spi, &small_buffer, 60, 60, 80, 80)?;
+
+    let small_buffer = [Color::Black.get_byte_value(); 8]; //8x8
+    epd.update_partial_frame(&mut spi, &small_buffer, 96, 96, 8, 8)?;
+
+    // Display updated frame
+    epd.display_frame(&mut spi)?;
+    delay.delay_ms(5000u16);
+
+    // Set the EPD to sleep
+    epd.sleep(&mut spi)?;
+
+    Ok(())
+}