fix: Enlarge and invert tool icon color for visibility

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

src/ViewportWidget.cpp

@@ -11,6 +11,8 @@
 #include <QWheelEvent>
 #include <QApplication>
 #include <QPainter>
+#include <QPixmap>
+#include <QImage>
 #include <QSvgRenderer>
 #include <QWheelEvent>
 #include <QApplication>
@@ -160,10 +162,20 @@ void ViewportWidget::paintGL()
     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(16, 16);
+            const QSize iconSize(32, 32);
             const QPoint iconPos = m_currentMousePos + QPoint(15, 15);
             const QRect iconRect(iconPos, iconSize);
-            renderer->render(&painter, iconRect);
+
+            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);
         }
     }