From 427379a2eb30408db93090b5bbd6433a73a0a487 Mon Sep 17 00:00:00 2001
From: Craig Watson <craig@watsons.ch>
Date: Sun, 8 Jan 2017 14:11:57 -0500
Subject: [PATCH] Set minimum size for protractor

---
 src/tools/UBGraphicsProtractor.cpp | 13 ++++++++-----
 src/tools/UBGraphicsProtractor.h   |  1 +
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/tools/UBGraphicsProtractor.cpp b/src/tools/UBGraphicsProtractor.cpp
index 85ef4b93..39f28d48 100644
--- a/src/tools/UBGraphicsProtractor.cpp
+++ b/src/tools/UBGraphicsProtractor.cpp
@@ -41,6 +41,7 @@
 
 
 const QRectF UBGraphicsProtractor::sDefaultRect = QRectF(-250, -250, 500, 500);
+const qreal UBGraphicsProtractor::minRadius = 70;
 
 UBGraphicsProtractor::UBGraphicsProtractor()
         : QGraphicsEllipseItem(sDefaultRect)
@@ -213,11 +214,13 @@ void UBGraphicsProtractor::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
 
 
     case Resize :
-        prepareGeometryChange();
-        setTransform(QTransform::fromTranslate(rect().center().x(), rect().center().y()), true);
-        setTransform(QTransform::fromScale(scaleFactor, scaleFactor), true);
-        setTransform(QTransform::fromTranslate(-rect().center().x(), -rect().center().y()), true);
-        mScaleFactor *= scaleFactor;
+        if (radius() * mScaleFactor * scaleFactor > minRadius) {
+            prepareGeometryChange();
+            setTransform(QTransform::fromTranslate(rect().center().x(), rect().center().y()), true);
+            setTransform(QTransform::fromScale(scaleFactor, scaleFactor), true);
+            setTransform(QTransform::fromTranslate(-rect().center().x(), -rect().center().y()), true);
+            mScaleFactor *= scaleFactor;
+        }
         break;
 
     case MoveMarker :
diff --git a/src/tools/UBGraphicsProtractor.h b/src/tools/UBGraphicsProtractor.h
index 74f68155..42dd591f 100644
--- a/src/tools/UBGraphicsProtractor.h
+++ b/src/tools/UBGraphicsProtractor.h
@@ -119,6 +119,7 @@ class UBGraphicsProtractor : public UBAbstractDrawRuler, public QGraphicsEllipse
         QGraphicsSvgItem* mRotateSvgItem;
 
         static const QRectF sDefaultRect;
+        static const qreal minRadius;
 
         virtual void rotateAroundCenter(qreal angle);
         virtual QPointF    rotationCenter() const;