Move bounded drawing calculation from interfaces into the only call site (#113)

* Move bounded drawing calculation from interfaces into the only call site
* Add CHANGELOG.md entry for public interface change

Signed-off-by: Daniel Egger <[email protected]>

Author: therealprof

CHANGELOG.md

@@ -6,6 +6,10 @@
 
 ## [Unreleased] - ReleaseDate
 
+### Changed
+
+- **(breaking)** [#113](https://github.com/jamwaffles/ssd1306/pull/113) Removed public `send_bounded_data` from DisplayInterface and implementations
+
 ## [0.3.1] - 2020-03-21
 
 ### Fixed

src/interface/i2c.rs

@@ -61,52 +61,4 @@ where
                 .map_err(Error::Comm)
         })
     }
-
-    fn send_bounded_data(
-        &mut self,
-        buf: &[u8],
-        disp_width: usize,
-        upper_left: (u8, u8),
-        lower_right: (u8, u8),
-    ) -> Result<(), Self::Error> {
-        // Noop if the data buffer is empty
-        if buf.is_empty() {
-            return Ok(());
-        }
-
-        // Write buffer. Writes are sent in chunks of 16 bytes plus DC byte
-        let mut writebuf: [u8; 17] = [0x0; 17];
-
-        // Data mode
-        // 8.1.5.2 5) b) in the datasheet
-        writebuf[0] = 0x40;
-
-        // Divide by 8 since each row is actually 8 pixels tall
-        let num_pages = ((lower_right.1 - upper_left.1) / 8) as usize + 1;
-
-        // Each page is 8 bits tall, so calculate which page number to start at (rounded down) from
-        // the top of the display
-        let starting_page = (upper_left.1 / 8) as usize;
-
-        // Calculate start and end X coordinates for each page
-        let page_lower = upper_left.0 as usize;
-        let page_upper = lower_right.0 as usize;
-
-        buf.chunks(disp_width)
-            .skip(starting_page)
-            .take(num_pages)
-            .map(|s| &s[page_lower..page_upper])
-            .try_for_each(|c| {
-                c.chunks(16).try_for_each(|c| {
-                    let chunk_len = c.len();
-
-                    // Copy over all data from buffer, leaving the data command byte intact
-                    writebuf[1..=chunk_len].copy_from_slice(c);
-
-                    self.i2c
-                        .write(self.addr, &writebuf[0..=chunk_len])
-                        .map_err(Error::Comm)
-                })
-            })
-    }
 }

src/interface/mod.rs

@@ -61,17 +61,6 @@ pub trait DisplayInterface {
     fn send_commands(&mut self, cmd: &[u8]) -> Result<(), Self::Error>;
     /// Send data to display.
     fn send_data(&mut self, buf: &[u8]) -> Result<(), Self::Error>;
-    /// Send data to display, taking advantage of bounded data.
-    ///
-    /// upper_left and lower_right should contain the x and y coordinates of the
-    /// minimum bounding rectangle of the modified pixels.
-    fn send_bounded_data(
-        &mut self,
-        buf: &[u8],
-        disp_width: usize,
-        upper_left: (u8, u8),
-        lower_right: (u8, u8),
-    ) -> Result<(), Self::Error>;
 }
 
 pub use self::{i2c::I2cInterface, spi::SpiInterface};

src/interface/spi.rs

@@ -46,31 +46,4 @@ where
 
         self.spi.write(&buf).map_err(Error::Comm)
     }
-
-    fn send_bounded_data(
-        &mut self,
-        buf: &[u8],
-        disp_width: usize,
-        upper_left: (u8, u8),
-        lower_right: (u8, u8),
-    ) -> Result<(), Self::Error> {
-        self.dc.set_high().map_err(Error::Pin)?;
-
-        // Divide by 8 since each row is actually 8 pixels tall
-        let num_pages = ((lower_right.1 - upper_left.1) / 8) as usize + 1;
-
-        // Each page is 8 bits tall, so calculate which page number to start at (rounded down) from
-        // the top of the display
-        let starting_page = (upper_left.1 / 8) as usize;
-
-        // Calculate start and end X coordinates for each page
-        let page_lower = upper_left.0 as usize;
-        let page_upper = lower_right.0 as usize;
-
-        buf.chunks(disp_width)
-            .skip(starting_page)
-            .take(num_pages)
-            .map(|s| &s[page_lower..page_upper])
-            .try_for_each(|c| self.spi.write(&c).map_err(Error::Comm))
-    }
 }

src/properties.rs

@@ -151,8 +151,23 @@ where
         upper_left: (u8, u8),
         lower_right: (u8, u8),
     ) -> Result<(), DI::Error> {
-        self.iface
-            .send_bounded_data(&buffer, disp_width, upper_left, lower_right)
+        // Divide by 8 since each row is actually 8 pixels tall
+        let num_pages = ((lower_right.1 - upper_left.1) / 8) as usize + 1;
+
+        // Each page is 8 bits tall, so calculate which page number to start at (rounded down) from
+        // the top of the display
+        let starting_page = (upper_left.1 / 8) as usize;
+
+        // Calculate start and end X coordinates for each page
+        let page_lower = upper_left.0 as usize;
+        let page_upper = lower_right.0 as usize;
+
+        buffer
+            .chunks(disp_width)
+            .skip(starting_page)
+            .take(num_pages)
+            .map(|s| &s[page_lower..page_upper])
+            .try_for_each(|c| self.iface.send_data(&c))
     }
 
     /// Get the configured display size

src/test_helpers.rs

@@ -70,13 +70,4 @@ impl DisplayInterface for StubInterface {
     fn send_data(&mut self, _buf: &[u8]) -> Result<(), ()> {
         Ok(())
     }
-    fn send_bounded_data(
-        &mut self,
-        _buf: &[u8],
-        _disp_width: usize,
-        _upper_left: (u8, u8),
-        _lower_right: (u8, u8),
-    ) -> Result<(), ()> {
-        Ok(())
-    }
 }