Add support for multiline rendering

src/font.rs

@@ -2,9 +2,9 @@ use embedded_hal::delay::DelayNs;
 use esp_hal::DriverMode;
 use rusttype::{Font, Point, PositionedGlyph, Scale};
 
-use alloc::string::String;
 use alloc::vec;
 use alloc::vec::Vec;
+use alloc::{borrow::ToOwned, string::String};
 
 use crate::display::{self, Display, Position, Rgb565};
 
@@ -63,23 +63,30 @@ impl<'a> FontRenderer<'a> {
         h_align: HorizontalAlignment,
         v_align: VerticalAlignment,
     ) {
-        let data = self.prepare(text.into());
+        let text = text.into();
+        let rows = text.split("\n").collect::<Vec<&str>>();
 
-        let x = match h_align {
+        let start_y = match v_align {
-            HorizontalAlignment::RightToLeft => position.x - data.pixel_width as i16,
-            HorizontalAlignment::Center => position.x - (data.pixel_width as i16 / 2),
-            HorizontalAlignment::LeftToRight => position.x,
-        };
-        let y = match v_align {
-            VerticalAlignment::BottomToTop => position.y - self.height as i16,
-            VerticalAlignment::Center => position.y - (self.height as i16 / 2),
             VerticalAlignment::TopToBottom => position.y,
+            VerticalAlignment::Center => position.y - (self.height as i16 * rows.len() as i16) / 2,
+            VerticalAlignment::BottomToTop => position.y - (self.height as i16 * rows.len() as i16),
         };
 
-        self.raw_render(display, data, Position { x, y });
+        for (i, row) in rows.iter().enumerate() {
+            let data = self.prepare((*row).to_owned());
+
+            let x = match h_align {
+                HorizontalAlignment::RightToLeft => position.x - data.pixel_width as i16,
+                HorizontalAlignment::Center => position.x - (data.pixel_width as i16 / 2),
+                HorizontalAlignment::LeftToRight => position.x,
+            };
+            let y = start_y + (self.height * i as u32) as i16;
+
+            self.raw_render(display, data, Position { x, y });
+        }
     }
 
-    pub fn prepare(&self, text: String) -> RawRenderData<'a> {
+    fn prepare(&self, text: String) -> RawRenderData<'a> {
         let glyphs = self
             .font
             .layout(&text, self.scale, self.offset)
@@ -100,7 +107,7 @@ impl<'a> FontRenderer<'a> {
         }
     }
 
-    pub fn raw_render<'d, DM: DriverMode, Delay: DelayNs>(
+    fn raw_render<'d, DM: DriverMode, Delay: DelayNs>(
         &self,
         display: &mut Display<'d, DM, Delay>,
         data: RawRenderData<'a>,

src/main.rs

@@ -113,10 +113,10 @@ fn main() -> ! {
 
     font_renderer.render(
         &mut display,
-        "Hello World!",
+        "Hello\nWorld!",
-        Position::new(120, 120),
+        Position::new(0, 0),
-        HorizontalAlignment::Center,
+        HorizontalAlignment::LeftToRight,
-        VerticalAlignment::Center,
+        VerticalAlignment::TopToBottom,
     );
 
     let sim_rst = Output::new(peripherals.GPIO15, Level::High, OutputConfig::default());