WIP FIXUP: Show DENMS for a minimum time

src/main.rs

@@ -585,6 +585,7 @@ async fn main(spawner: Spawner) -> ! {
                                         .update(screen::ScreenState::DenmWarning(cc))
                                         .inspect_err(log_screen_error);
                                 }
+                                // TODO: cancel screen, if None?
                                 _ => {}
                             }
 

src/screen.rs

@@ -7,6 +7,9 @@ use embedded_graphics::{geometry, mono_font, pixelcolor, primitives, text};
 
 use crate::applogic;
 
+#[cfg(feature = "denm")]
+const DENM_MIN_DISPLAY_TIME: esp_hal::time::Duration = esp_hal::time::Duration::from_secs(5);
+
 pub struct DisplaySize {
     width: u16,
     height: u16,
@@ -25,6 +28,8 @@ where
     prev_state: ScreenState,
     hb_state: bool,
     gnss_hb_state: bool,
+    #[cfg(feature = "denm")]
+    denm_display_start_time: esp_hal::time::Instant,
 
     // assets
     #[cfg(feature = "spat")]
@@ -135,6 +140,8 @@ where
             prev_state: ScreenState::Uninitialized,
             hb_state: false,
             gnss_hb_state: false,
+            #[cfg(feature = "denm")]
+            denm_display_start_time: esp_hal::time::Instant::EPOCH,
             #[cfg(feature = "spat")]
             bike_image,
             // #[cfg(feature = "denm")]
@@ -149,6 +156,27 @@ where
     }
 
     pub fn update(&mut self, state: ScreenState) -> Result<(), D::Error> {
+        #[cfg(feature = "denm")]
+        let now = esp_hal::time::Instant::now();
+
+        #[cfg(feature = "denm")]
+        // when a DENM was shown before, make sure it's shown for a minimum time
+        if let ScreenState::DenmWarning(_) = self.prev_state {
+            use core::ops::Sub;
+
+            // update DENM display, if there are updates
+            if self.prev_state != state
+                && let ScreenState::DenmWarning(cause_code_choice) = &state
+            {
+                return self.draw_denm_warning(cause_code_choice);
+            }
+
+            // otherwise early return when timer isn't expired yet
+            if now.sub(self.denm_display_start_time) < DENM_MIN_DISPLAY_TIME {
+                return Ok(());
+            }
+        }
+
         if self.prev_state != state {
             match &state {
                 ScreenState::Uninitialized | ScreenState::Initial => self.draw_slash_screen()?,
@@ -167,6 +195,7 @@ where
                 ScreenState::Error(msg) => self.draw_message(msg)?,
                 #[cfg(feature = "denm")]
                 ScreenState::DenmWarning(cause_code_choice) => {
+                    self.denm_display_start_time = now;
                     self.draw_denm_warning(cause_code_choice)?
                 }
             }