CSI XTSMGRAPHICS Pi=2, Pa=1 should return dimensions that fit in text area

1 files changed, 66 insertions, 17 deletions

diff --git a/alacritty_terminal/src/term/mod.rs b/alacritty_terminal/src/term/mod.rs
index a35fade2..8461d256 100644
--- a/alacritty_terminal/src/term/mod.rs
+++ b/alacritty_terminal/src/term/mod.rs
@@ -1998,32 +1998,81 @@ impl<T: EventListener> Handler for Term<T> {
     fn graphics_attribute(&mut self, pi: u16, pa: u16) {
         // From Xterm documentation:
         //
+        //   CSI ? Pi ; Pa ; Pv S
+        //
         //   Pi = 1  -> item is number of color registers.
         //   Pi = 2  -> item is Sixel graphics geometry (in pixels).
+        //   Pi = 3  -> item is ReGIS graphics geometry (in pixels).
         //
         //   Pa = 1  -> read attribute.
+        //   Pa = 2  -> reset to default.
+        //   Pa = 3  -> set to value in Pv.
         //   Pa = 4  -> read the maximum allowed value.
         //
-        // Any other request reports an error.
+        //   Pv is ignored by xterm except when setting (Pa == 3).
+        //   Pv = n <- A single integer is used for color registers.
+        //   Pv = width ; height <- Two integers for graphics geometry.
+        //
+        //   xterm replies with a control sequence of the same form:
+        //
+        //   CSI ? Pi ; Ps ; Pv S
+        //
+        //   where Ps is the status:
+        //   Ps = 0  <- success.
+        //   Ps = 1  <- error in Pi.
+        //   Ps = 2  <- error in Pa.
+        //   Ps = 3  <- failure.
+        //
+        //   On success, Pv represents the value read or set.
 
-        let (ps, pv) = if pa == 1 || pa == 4 {
-            match pi {
-                1 => (0, &[sixel::MAX_COLOR_REGISTERS][..]),
-                2 => (0, &MAX_GRAPHIC_DIMENSIONS[..]),
-                _ => (1, &[][..]), // Report error in Pi
+        fn generate_response(pi: u16, ps: u16, pv: &[usize]) -> String {
+            let mut text = format!("\x1b[?{};{}", pi, ps);
+            for item in pv {
+                let _ = write!(&mut text, ";{}", item);
+            }
+            text.push('S');
+            text
+        }
+
+        let (ps, pv) = match pi {
+            1 => {
+                match pa {
+                    1 => (0, &[sixel::MAX_COLOR_REGISTERS][..]), // current value is always the maximum
+                    2 => (3, &[][..]), // Report unsupported
+                    3 => (3, &[][..]), // Report unsupported
+                    4 => (0, &[sixel::MAX_COLOR_REGISTERS][..]),
+                    _ => (2, &[][..]), // Report error in Pa
+                }
+            }
+            2 => {
+                match pa {
+                    1 => {
+                        self.event_proxy.send_event(Event::TextAreaSizeRequest(Arc::new(move |window_size| {
+                            let width = window_size.num_cols * window_size.cell_width;
+                            let height = window_size.num_lines * window_size.cell_height;
+                            let graphic_dimensions = [
+                                cmp::min(width as usize, MAX_GRAPHIC_DIMENSIONS[0]),
+                                cmp::min(height as usize, MAX_GRAPHIC_DIMENSIONS[1])];
+
+                            let (ps, pv) = (0, &graphic_dimensions[..]);
+                            generate_response(pi, ps, pv)
+                        })));
+                        return;
+                    }
+                    2 => (3, &[][..]), // Report unsupported
+                    3 => (3, &[][..]), // Report unsupported
+                    4 => (0, &MAX_GRAPHIC_DIMENSIONS[..]),
+                    _ => (2, &[][..]), // Report error in Pa
+                }
+            }
+            3 => {
+                (1, &[][..]) // Report error in Pi (ReGIS unknown)
+            }
+            _ => {
+                (1, &[][..]) // Report error in Pi
             }
-        } else {
-            (2, &[][..]) // Report error in Pa
         };
-
-        let mut text = format!("\x1b[?{};{}", pi, ps);
-
-        for item in pv {
-            let _ = write!(&mut text, ";{}", item);
-        }
-
-        text.push('S');
-        self.event_proxy.send_event(Event::PtyWrite(text));
+        self.event_proxy.send_event(Event::PtyWrite(generate_response(pi, ps, pv)));
     }
 
     fn start_sixel_graphic(&mut self, params: &Params) -> Option<Box<sixel::Parser>> {