add flex node & demo

doric-Qt/example/doric/shader/DoricFlexNode.h

@@ -0,0 +1,28 @@
+#ifndef DORICFLEXNODE_H
+#define DORICFLEXNODE_H
+
+#include "DoricExport.h"
+
+#include "shader/DoricStackNode.h"
+
+#include "yoga/YGLayout.h"
+
+class DORIC_EXPORT DoricFlexNode : public DoricGroupNode {
+
+public:
+  using DoricGroupNode::DoricGroupNode;
+
+  QQuickItem *build() override;
+
+  virtual void blend(QQuickItem *view, QString name, QJsonValue prop) override;
+
+  virtual void blendSubNode(DoricViewNode *subNode,
+                            QJsonValue flexConfig) override;
+
+private:
+  void blendYoga(YGLayout *yoga, QJsonValue flexConfig);
+
+  void blendYoga(YGLayout *yoga, QString name, QJsonValue prop);
+};
+
+#endif // DORICFLEXNODE_H