Fix text position on Y-axis, we should take fontSize in mind to layou…

…t the Text/TSpan shapes, SVG coord tes case https://www.w3.org/TR/SVG/images/coords/OrigCoordSys.svg

lib/extract/extractText.js

@@ -80,7 +80,7 @@ function parseDelta(delta) {
     }
 }
 
-export default function(props, container) {
+export default function(props, container, ref) {
     const {
         x,
         y,
@@ -96,34 +96,45 @@ export default function(props, container) {
     let { children } = props;
     let content = null;
 
+    let fontProps = extractFont(props);
+    if (props.parentFontProps) {
+        fontProps = Object.assign({}, props.parentFontProps, fontProps);
+    }
 
     if (typeof children === 'string' || typeof children === 'number') {
         const childrenString = children.toString();
         if (container) {
-            children = <TSpan>{childrenString}</TSpan>;
+            children = <TSpan parentFontProps={fontProps}>{childrenString}</TSpan>;
         } else {
             content = childrenString;
             children = null;
         }
-    } else if (Children.count(children) > 1 || Array.isArray(children)) {
+    } else if (Children.count(children) >= 1 || Array.isArray(children)) {
         children = Children.map(children, child => {
             if (typeof child === 'string' || typeof child === 'number') {
-                return <TSpan>{child.toString()}</TSpan>;
+                return <TSpan parentFontProps={fontProps}>{child.toString()}</TSpan>;
             } else {
-                return child;
+                //return child;
+                return React.cloneElement(child, {
+                  parentFontProps: fontProps
+                });
             }
         });
     }
 
+    let posY = null;
+    if (!_.isNil(y) && fontProps.fontSize) {
+        posY = (parseFloat(y || 0) - parseFloat(fontProps.fontSize || 0)).toString();
+    }
     return {
         textAnchor: anchors[textAnchor] || 0,
-        font: extractFont(props),
+        font: fontProps,
         children,
         content,
         deltaX,
         deltaY,
         startOffset: (startOffset || 0).toString(),
         positionX: _.isNil(x) ? null : x.toString(),
-        positionY: _.isNil(y) ? null : y.toString()
+        positionY: posY
     };
 }