From 36c9d607b226a4aa5c1fb9ee2536522a4daca96e Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Sun, 17 Sep 2023 11:49:25 -0700
Subject: [PATCH] core: do not send repeat mouse events if cell didn't change

---
 src/Surface.zig        | 10 ++++++++--
 src/terminal/point.zig |  4 ++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/Surface.zig b/src/Surface.zig
index 97890b828..e3d84acd1 100644
--- a/src/Surface.zig
+++ b/src/Surface.zig
@@ -117,7 +117,7 @@ const Mouse = struct {
     left_click_time: std.time.Instant = undefined,
 
     /// The last x/y sent for mouse reports.
-    event_point: terminal.point.Viewport = .{},
+    event_point: ?terminal.point.Viewport = null,
 
     /// Pending scroll amounts for high-precision scrolls
     pending_scroll_x: f64 = 0,
@@ -1329,7 +1329,13 @@ fn mouseReport(
     // This format reports X/Y
     const viewport_point = self.posToViewport(pos.x, pos.y);
 
-    // Record our new point
+    // Record our new point. We only want to send a mouse event if the
+    // cell changed, unless we're tracking raw pixels.
+    if (self.io.terminal.flags.mouse_format != .sgr_pixels) {
+        if (self.mouse.event_point) |last_point| {
+            if (last_point.eql(viewport_point)) return;
+        }
+    }
     self.mouse.event_point = viewport_point;
 
     // Get the code we'll actually write
diff --git a/src/terminal/point.zig b/src/terminal/point.zig
index df35f2cd0..b0f851acd 100644
--- a/src/terminal/point.zig
+++ b/src/terminal/point.zig
@@ -20,6 +20,10 @@ pub const Viewport = struct {
         };
     }
 
+    pub fn eql(self: Viewport, other: Viewport) bool {
+        return self.x == other.x and self.y == other.y;
+    }
+
     test "toScreen with no scrollback" {
         const testing = std.testing;
         const alloc = testing.allocator;