Don't crash if terminal window size can't be found

src/builder.rs

@@ -101,11 +101,7 @@ impl<'a> PresentationBuilder<'a> {
         }
         self.needs_enter_column = false;
         let last_valid = matches!(last, RenderOperation::EnterColumn { .. } | RenderOperation::ExitLayout);
-        if last_valid {
-            Ok(())
-        } else {
-            Err(BuildError::NotInsideColumn)
-        }
+        if last_valid { Ok(()) } else { Err(BuildError::NotInsideColumn) }
     }
 
     fn push_slide_prelude(&mut self) {

src/lib.rs

@@ -10,6 +10,6 @@ pub mod presentation;
 pub mod presenter;
 pub mod render;
 pub mod resource;
+pub mod splash;
 pub mod style;
 pub mod theme;
-pub mod splash;

src/render/layout.rs

@@ -58,7 +58,11 @@ impl Layout {
     }
 
     fn fit_to_columns(dimensions: &WindowSize, required_fit: u16, actual_fit: u16) -> u16 {
-        if required_fit > dimensions.columns { 0 } else { actual_fit }
+        if required_fit > dimensions.columns {
+            0
+        } else {
+            actual_fit
+        }
     }
 }
 
@@ -161,7 +165,7 @@ mod test {
         Positioning{ max_line_length: 60, start_column: 20 }
     )]
     fn layout(#[case] alignment: Alignment, #[case] length: u16, #[case] expected: Positioning) {
-        let dimensions = WindowSize { rows: 0, columns: 100, width: 0, height: 0 };
+        let dimensions = WindowSize { rows: 0, columns: 100, width: 0, height: 0, has_pixels: true };
         let positioning = Layout::new(alignment).compute(&dimensions, length);
         assert_eq!(positioning, expected);
     }

src/render/media.rs

@@ -44,6 +44,9 @@ impl MediaRender {
         position: CursorPosition,
         dimensions: &WindowSize,
     ) -> Result<(), RenderImageError> {
+        if !dimensions.has_pixels {
+            return Err(RenderImageError::NoWindowSize);
+        }
         let image = &image.0;
 
         // Compute the image's width in columns by translating pixels -> columns.
@@ -97,4 +100,7 @@ pub enum RenderImageError {
 
     #[error("invalid image: {0}")]
     InvalidImage(#[from] InvalidImage),
+
+    #[error("no window size support in terminal")]
+    NoWindowSize,
 }

src/render/properties.rs

@@ -1,5 +1,5 @@
-use crossterm::{cursor::position, terminal::window_size};
-use std::io;
+use crossterm::{cursor::position, terminal};
+use std::io::{self, ErrorKind};
 
 /// The size of the terminal window.
 ///
@@ -11,13 +11,21 @@ pub struct WindowSize {
     pub columns: u16,
     pub height: u16,
     pub width: u16,
+    pub has_pixels: bool,
 }
 
 impl WindowSize {
     /// Get the current window size.
     pub fn current() -> io::Result<Self> {
-        let size = window_size()?;
-        Ok(size.into())
+        match terminal::window_size() {
+            Ok(size) => Ok(size.into()),
+            Err(e) if e.kind() == ErrorKind::Unsupported => {
+                // Fall back to a `WindowSize` that doesn't have pixel support.
+                let size = terminal::size()?;
+                Ok(size.into())
+            }
+            Err(e) => Err(e),
+        }
     }
 
     /// Shrink a window by the given number of rows.
@@ -31,6 +39,7 @@ impl WindowSize {
             columns: self.columns,
             height: self.height.saturating_sub(height_to_shrink),
             width: self.width,
+            has_pixels: self.has_pixels,
         }
     }
 
@@ -45,6 +54,7 @@ impl WindowSize {
             columns: self.columns.saturating_sub(amount),
             height: self.height,
             width: self.width.saturating_sub(width_to_shrink),
+            has_pixels: self.has_pixels,
         }
     }
 
@@ -61,7 +71,13 @@ impl WindowSize {
 
 impl From<crossterm::terminal::WindowSize> for WindowSize {
     fn from(size: crossterm::terminal::WindowSize) -> Self {
-        Self { rows: size.rows, columns: size.columns, width: size.width, height: size.height }
+        Self { rows: size.rows, columns: size.columns, width: size.width, height: size.height, has_pixels: true }
+    }
+}
+
+impl From<(u16, u16)> for WindowSize {
+    fn from((columns, rows): (u16, u16)) -> Self {
+        Self { columns, rows, width: 0, height: 0, has_pixels: false }
     }
 }
 
@@ -86,7 +102,7 @@ mod test {
 
     #[test]
     fn shrink() {
-        let dimensions = WindowSize { rows: 10, columns: 10, width: 200, height: 100 };
+        let dimensions = WindowSize { rows: 10, columns: 10, width: 200, height: 100, has_pixels: true };
         assert_eq!(dimensions.pixels_per_column(), 20.0);
         assert_eq!(dimensions.pixels_per_row(), 10.0);
 
@@ -97,5 +113,7 @@ mod test {
         let new_dimensions = new_dimensions.shrink_columns(3);
         assert_eq!(new_dimensions.columns, 7);
         assert_eq!(new_dimensions.width, 140);
+
+        assert!(new_dimensions.has_pixels);
     }
 }

src/render/terminal.rs

@@ -94,6 +94,7 @@ where
     fn drop(&mut self) {
         let _ = self.writer.queue(terminal::LeaveAlternateScreen);
         let _ = self.writer.queue(cursor::Show);
+        let _ = self.writer.flush();
         let _ = terminal::disable_raw_mode();
     }
 }