Add closestAngle function to Qt object to help with rotation animations.

Includes test and doc.

2 files changed, 21 insertions, 0 deletions

diff --git a/src/declarative/qml/qmlengine.cpp b/src/declarative/qml/qmlengine.cpp
index c562e02..2926791 100644
--- a/src/declarative/qml/qmlengine.cpp
+++ b/src/declarative/qml/qmlengine.cpp
@@ -147,6 +147,7 @@ QmlEnginePrivate::QmlEnginePrivate(QmlEngine *e)
     qtObject.setProperty(QLatin1String("tint"), scriptEngine.newFunction(QmlEnginePrivate::tint, 2));
 
     //misc methods
+    qtObject.setProperty(QLatin1String("closestAngle"), scriptEngine.newFunction(QmlEnginePrivate::closestAngle, 2));
     qtObject.setProperty(QLatin1String("playSound"), scriptEngine.newFunction(QmlEnginePrivate::playSound, 1));
     qtObject.setProperty(QLatin1String("openUrlExternally"),scriptEngine.newFunction(desktopOpenUrl, 1));
 
@@ -810,6 +811,25 @@ QScriptValue QmlEnginePrivate::desktopOpenUrl(QScriptContext *ctxt, QScriptEngin
     return e->newVariant(QVariant(ret));
 }
 
+QScriptValue QmlEnginePrivate::closestAngle(QScriptContext *ctxt, QScriptEngine *e)
+{
+    if(ctxt->argumentCount() < 2)
+        return e->newVariant(QVariant(0.0));
+    qreal a = ctxt->argument(0).toNumber();
+    qreal b = ctxt->argument(1).toNumber();
+    qreal ret = b;
+    qreal diff = b-a;
+    while(diff > 180.0){
+        ret -= 360.0;
+        diff -= 360.0;
+    }
+    while(diff < -180.0){
+        ret += 360.0;
+        diff += 360.0;
+    }
+    return e->newVariant(QVariant(ret));
+}
+
 QScriptValue QmlEnginePrivate::tint(QScriptContext *ctxt, QScriptEngine *engine)
 {
     if(ctxt->argumentCount() != 2)
diff --git a/src/declarative/qml/qmlengine_p.h b/src/declarative/qml/qmlengine_p.h
index b050ef6..3c60b5c 100644
--- a/src/declarative/qml/qmlengine_p.h
+++ b/src/declarative/qml/qmlengine_p.h
@@ -269,6 +269,7 @@ public:
     static QScriptValue darker(QScriptContext*, QScriptEngine*);
     static QScriptValue tint(QScriptContext*, QScriptEngine*);
 
+    static QScriptValue closestAngle(QScriptContext*, QScriptEngine*);
     static QScriptValue playSound(QScriptContext*, QScriptEngine*);
     static QScriptValue desktopOpenUrl(QScriptContext*, QScriptEngine*);