From 598b7efa74504efa42cf197b0875397f451bb9b6 Mon Sep 17 00:00:00 2001
From: Ottatop <ottatop1227@gmail.com>
Date: Wed, 3 Jul 2024 17:55:44 -0500
Subject: [PATCH] Invalidate snapshots when swapping windows

Hack to make the snapshot location correct
---
 src/grab/move_grab.rs       |  8 ++++++++
 src/layout.rs               |  1 -
 src/render/util/snapshot.rs | 15 ++++++---------
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/grab/move_grab.rs b/src/grab/move_grab.rs
index b21bece..57e65b5 100644
--- a/src/grab/move_grab.rs
+++ b/src/grab/move_grab.rs
@@ -165,6 +165,14 @@ impl PointerGrab<State> for MoveSurfaceGrab {
 
                 let output = self.window.output(&state.pinnacle);
 
+                // HACK: Snapshots may not be cleared and updated when swapping two windows of the same size;
+                // this causes new snapshots attempts to fizzle and the currently stored snapshot
+                // will have the wrong location. We're just gonna invalidate all window snapshots here
+                // because I'm too lazy to rearchitect stuff to make it more sensible.
+                for window in state.pinnacle.windows.iter() {
+                    window.with_state_mut(|state| state.snapshot.take());
+                }
+
                 if let Some(output) = output.as_ref() {
                     state.capture_snapshots_on_output(output, [self.window.clone()]);
                 }
diff --git a/src/layout.rs b/src/layout.rs
index 4a1f311..ac882fc 100644
--- a/src/layout.rs
+++ b/src/layout.rs
@@ -128,7 +128,6 @@ impl Pinnacle {
         pending_wins
     }
 
-    /// Swaps two windows in the main window vec and updates all windows.
     pub fn swap_window_positions(&mut self, win1: &WindowElement, win2: &WindowElement) {
         let win1_index = self.windows.iter().position(|win| win == win1);
         let win2_index = self.windows.iter().position(|win| win == win2);
diff --git a/src/render/util/snapshot.rs b/src/render/util/snapshot.rs
index fa10995..a019e54 100644
--- a/src/render/util/snapshot.rs
+++ b/src/render/util/snapshot.rs
@@ -132,19 +132,16 @@ impl WindowElement {
         location: Point<i32, Logical>,
         scale: Scale<f64>,
         alpha: f32,
-    ) -> LayoutSnapshot {
+    ) -> Option<LayoutSnapshot> {
         self.with_state_mut(|state| {
             if state.snapshot.is_none() || self.is_x11() {
                 let elements = self.texture_render_elements(renderer, location, scale, alpha);
-
-                state.snapshot = Some(RenderSnapshot::new(elements, scale));
+                if !elements.is_empty() {
+                    state.snapshot = Some(RenderSnapshot::new(elements, scale));
+                }
             }
 
-            let Some(ret) = state.snapshot.clone() else {
-                unreachable!()
-            };
-
-            ret
+            state.snapshot.clone()
         })
     }
 }
@@ -212,7 +209,7 @@ pub fn capture_snapshots_on_output(
                 1.0,
             );
 
-            Some(SnapshotTarget::Snapshot(snapshot))
+            snapshot.map(SnapshotTarget::Snapshot)
         } else {
             Some(SnapshotTarget::Window(win))
         }