lottie/vector: added reset() api to VRle class.

Change-Id: Iace73912f6ab4510c0adb15387029e2038ad15be

src/vector/vrle.cpp

@@ -291,6 +291,7 @@ public:
     void           translate(const VPoint &pt);
     void           opAdd(const VRleImpl &other, VRleImpl &res);
     VRect          bbox();
+    void           reset();
 
 public:
     VRect                   m_bbox;
@@ -327,6 +328,14 @@ VRect VRleImpl::bbox()
     return m_bbox;
 }
 
+void VRleImpl::reset()
+{
+    m_spans.clear();
+    m_bbox = VRect();
+    mOffset = VPoint();
+    mBboxDirty = false;
+}
+
 void VRleImpl::translate(const VPoint &pt)
 {
     // take care of last offset if applied
@@ -759,6 +768,12 @@ const VRle::Span *VRle::data() const
     return d->impl.m_spans.data();
 }
 
+void VRle::reset()
+{
+    detach();
+    d->impl.reset();
+}
+
 VRle VRle::toRle(const VRect &rect)
 {
     if (rect.isEmpty()) return VRle();

src/vector/vrle.h

@@ -35,6 +35,7 @@ public:
     VRle &intersect(const VRect &r);
     int   size() const;
     const VRle::Span * data() const;
+    void               reset();
     VRle               operator~() const;
     VRle               operator+(const VRle &o) const;
     VRle               operator-(const VRle &o) const;