Calculate relative y mouse event cursor position

src/input/windows.rs

@@ -26,7 +26,7 @@ use winapi::um::{
 
 use crossterm_winapi::{
     ButtonState, Console, ConsoleMode, EventFlags, Handle, InputEventType, KeyEventRecord,
-    MouseEvent,
+    MouseEvent, ScreenBuffer,
 };
 use lazy_static::lazy_static;
 
@@ -536,12 +536,21 @@ fn parse_mouse_event_record(event: &MouseEvent) -> Option<crate::MouseEvent> {
     // mimicks the behavior; additionally, in xterm, mouse move is only handled when a
     // mouse button is held down (ie. mouse drag)
 
+    let window_size = ScreenBuffer::current()
+        .unwrap()
+        .info()
+        .unwrap()
+        .terminal_window();
+
     // Windows returns (0, 0) for upper/left
     let xpos = event.mouse_position.x;
-    let ypos = event.mouse_position.y;
+    let mut ypos = event.mouse_position.y;
 
-    // TODO (@imdaveho): check if linux only provides coords for visible terminal window vs the total buffer
+    // The y position in with a mouse event is not relative to the window but absolute to screen buffer.
+    // This means that when the mouse cursor is at top left it will be x: 0, y: 2295 (e.g. y = number of cells counting from the absolute buffer height) instead of relative x: 0, y: 0 to the window.
+    ypos = ypos - window_size.top;
 
+    // TODO (@imdaveho): check if linux only provides coords for visible terminal window vs the total buffer
     match event.event_flags {
         EventFlags::PressOrRelease => {
             // Single click