From 0250287ba0d3cdb1b288455728c3dd3940b3a16d Mon Sep 17 00:00:00 2001
From: Tanner Collin <git@tannercollin.com>
Date: Sat, 14 Feb 2026 21:19:08 -0700
Subject: [PATCH] fix: Eliminate tool icon lag with custom QCursor

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>
---
 src/ViewportWidget.cpp | 44 +++++++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/src/ViewportWidget.cpp b/src/ViewportWidget.cpp
index 1b7fd5d..2e8657c 100644
--- a/src/ViewportWidget.cpp
+++ b/src/ViewportWidget.cpp
@@ -159,26 +159,6 @@ void ViewportWidget::paintGL()
     }
     m_featureBrowser->paint(painter, width(), height());
 
-    if (m_currentPlane != SketchPlane::NONE && m_activeTool != static_cast<int>(ApplicationController::ToolType::None) && m_toolIcons.contains(m_activeTool)) {
-        QSvgRenderer* renderer = m_toolIcons.value(m_activeTool);
-        if (renderer && renderer->isValid()) {
-            const QSize iconSize(32, 32);
-            const QPoint iconPos = m_currentMousePos + QPoint(15, 15);
-            const QRect iconRect(iconPos, iconSize);
-
-            QPixmap pixmap(iconSize);
-            pixmap.fill(Qt::transparent);
-            QPainter pixmapPainter(&pixmap);
-            renderer->render(&pixmapPainter);
-            pixmapPainter.end();
-
-            QImage image = pixmap.toImage();
-            image.invertPixels(QImage::InvertRgb);
-
-            painter.drawImage(iconRect, image);
-        }
-    }
-
     painter.end();
 }
 
@@ -407,6 +387,30 @@ void ViewportWidget::onActiveToolChanged(int tool)
 {
     m_activeTool = tool;
     m_isDefiningLine = false;
+
+    if (tool == static_cast<int>(ApplicationController::ToolType::None)) {
+        unsetCursor();
+    } else {
+        if (m_toolIcons.contains(tool)) {
+            QSvgRenderer* renderer = m_toolIcons.value(tool);
+            if (renderer && renderer->isValid()) {
+                const QSize iconSize(32, 32);
+
+                QPixmap pixmap(iconSize);
+                pixmap.fill(Qt::transparent);
+                QPainter pixmapPainter(&pixmap);
+                renderer->render(&pixmapPainter);
+                pixmapPainter.end();
+
+                QImage image = pixmap.toImage();
+                image.invertPixels(QImage::InvertRgb);
+
+                setCursor(QCursor(QPixmap::fromImage(image), 16, 16));
+            }
+        } else {
+            unsetCursor();
+        }
+    }
 }
 
 QVector3D ViewportWidget::unproject(const QPoint& screenPos)