From ecdb57585d5a7d300bc13d455e7a528e4b627437 Mon Sep 17 00:00:00 2001
From: Uladzislau Trybukhouski <uladzislau.trybukhouski@jetbrains.com>
Date: Thu, 2 Jul 2026 18:00:32 +0200
Subject: [PATCH] [terminal] IJPL-245227 Fix miscalculating cursor position on
 mouse click when prompt contains wide characters

(cherry picked from commit ea2eb6143170bd1a8b87a4b3ef50cbabae72ae3e)

IJ-CR-212254

GitOrigin-RevId: c99add843506d9576c8f4cc5ef1d5c69320437fd
---
 .../view/impl/TerminalEventDispatcher.kt      | 35 +++++++++++++------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/plugins/terminal/frontend/src/com/intellij/terminal/frontend/view/impl/TerminalEventDispatcher.kt b/plugins/terminal/frontend/src/com/intellij/terminal/frontend/view/impl/TerminalEventDispatcher.kt
index 67e63a5becb1..074929799464 100644
--- a/plugins/terminal/frontend/src/com/intellij/terminal/frontend/view/impl/TerminalEventDispatcher.kt
+++ b/plugins/terminal/frontend/src/com/intellij/terminal/frontend/view/impl/TerminalEventDispatcher.kt
@@ -11,11 +11,13 @@ import com.intellij.openapi.application.WriteIntentReadAction
 import com.intellij.openapi.diagnostic.logger
 import com.intellij.openapi.diagnostic.trace
 import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.editor.VisualPosition
 import com.intellij.openapi.editor.event.EditorMouseEvent
 import com.intellij.openapi.editor.event.EditorMouseListener
 import com.intellij.openapi.editor.event.EditorMouseMotionListener
 import com.intellij.openapi.editor.ex.EditorEx
 import com.intellij.openapi.editor.ex.FocusChangeListener
+import com.intellij.openapi.editor.impl.EditorImpl
 import com.intellij.openapi.util.Disposer
 import com.intellij.openapi.util.registry.Registry
 import com.intellij.terminal.JBTerminalSystemSettingsProviderBase
@@ -28,6 +30,7 @@ import org.jetbrains.annotations.NonNls
 import org.jetbrains.plugins.terminal.TerminalEscapeBehaviorChangeNotification
 import org.jetbrains.plugins.terminal.block.reworked.TerminalSessionModel
 import java.awt.AWTEvent
+import java.awt.Point
 import java.awt.event.InputEvent
 import java.awt.event.KeyAdapter
 import java.awt.event.KeyEvent
@@ -325,15 +328,15 @@ internal fun setupMouseEventsHandling(
   editor.addEditorMouseListener(object : EditorMouseListener {
     override fun mousePressed(event: EditorMouseEvent) {
       if (settings.enableMouseReporting() && isRemoteMouseAction(event.mouseEvent)) {
-        val p = event.visualPosition
-        eventsHandler.mousePressed(p.column, p.line, event.mouseEvent)
+        val cell = editor.mousePointToGridCell(event.mouseEvent.point, event.visualPosition.line)
+        eventsHandler.mousePressed(cell.column, cell.line, event.mouseEvent)
       }
     }
 
     override fun mouseReleased(event: EditorMouseEvent) {
       if (settings.enableMouseReporting() && isRemoteMouseAction(event.mouseEvent)) {
-        val p = event.visualPosition
-        eventsHandler.mouseReleased(p.column, p.line, event.mouseEvent)
+        val cell = editor.mousePointToGridCell(event.mouseEvent.point, event.visualPosition.line)
+        eventsHandler.mouseReleased(cell.column, cell.line, event.mouseEvent)
       }
     }
   }, disposable)
@@ -341,25 +344,37 @@ internal fun setupMouseEventsHandling(
   editor.addEditorMouseMotionListener(object : EditorMouseMotionListener {
     override fun mouseMoved(event: EditorMouseEvent) {
       if (settings.enableMouseReporting() && isRemoteMouseAction(event.mouseEvent)) {
-        val p = event.visualPosition
-        eventsHandler.mouseMoved(p.column, p.line, event.mouseEvent)
+        val cell = editor.mousePointToGridCell(event.mouseEvent.point, event.visualPosition.line)
+        eventsHandler.mouseMoved(cell.column, cell.line, event.mouseEvent)
       }
     }
 
     override fun mouseDragged(event: EditorMouseEvent) {
       if (settings.enableMouseReporting() && isRemoteMouseAction(event.mouseEvent)) {
-        val p = event.visualPosition
-        eventsHandler.mouseDragged(p.column, p.line, event.mouseEvent)
+        val cell = editor.mousePointToGridCell(event.mouseEvent.point, event.visualPosition.line)
+        eventsHandler.mouseDragged(cell.column, cell.line, event.mouseEvent)
       }
     }
   }, disposable)
 
   val mouseWheelListener = MouseWheelListener { event ->
-    val p = editor.xyToVisualPosition(event.point)
-    eventsHandler.mouseWheelMoved(p.column, p.line, event)
+    val cell = editor.mousePointToGridCell(event.point, editor.xyToVisualPosition(event.point).line)
+    eventsHandler.mouseWheelMoved(cell.column, cell.line, event)
   }
   editor.scrollPane.addMouseWheelListener(mouseWheelListener)
   Disposer.register(disposable, Disposable {
     editor.scrollPane.removeMouseWheelListener(mouseWheelListener)
   })
+}
+
+/**
+ * Maps a mouse point to the terminal grid cell physically under the pointer (floor by the fixed cell width),
+ * so a double-width (CJK) character correctly spans two cells. Unlike [Editor.xyToVisualPosition], which rounds
+ * to the nearest character boundary and counts such a character as a single column.
+ */
+private fun EditorEx.mousePointToGridCell(point: Point, line: Int): VisualPosition {
+  val grid = checkNotNull((this as? EditorImpl)?.characterGrid) { "The editor is not in the character grid mode" }
+  val lineStartX = visualPositionToXY(VisualPosition(line, 0)).x
+  val column = ((point.x - lineStartX) / grid.charWidth).toInt().coerceIn(0, (grid.columns - 1).coerceAtLeast(0))
+  return VisualPosition(line, column)
 }
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