Display remaining time in slideshow

Author: mattfbacon

src/app/mod.rs

@@ -309,6 +309,12 @@ impl App {
 			ui.spinner().on_hover_text("Loading");
 		}
 
+		if let SlideshowState::Active { remaining } = self.slideshow {
+			ui.label(format!("\u{2398} {} s", remaining.ceil_secs()));
+			ui.ctx()
+				.request_repaint_after(std::time::Duration::from_secs(1));
+		}
+
 		if let Some(to_delete) = to_delete {
 			self.delete_file(ui, to_delete);
 		}

src/duration.rs

@@ -99,6 +99,14 @@ impl Duration {
 		az::cast::<_, f32>(self.micros) / SECS_MICROS_F
 	}
 
+	pub fn whole_secs(self) -> u32 {
+		self.micros / SECS_MICROS
+	}
+
+	pub fn ceil_secs(self) -> u32 {
+		self.micros.div_ceil(SECS_MICROS)
+	}
+
 	pub fn new_millis_f32(millis: f32) -> Result<Self, OutOfRange> {
 		az::checked_cast(millis * MILLIS_MICROS_F)
 			.ok_or(OutOfRange)