Allow Annotations in TextSpan

 # 1.3.8
 * Add jpeg image loading function
 * Add Theme::copyFrom() method
+* Allow Annotations in TextSpan
 
 # 1.3.7
 * Add Pdf Creation date

@@ -42,69 +42,76 @@ class Anchor extends SingleChildWidget {
   }
 }
 
-class _Annotation extends SingleChildWidget {
-  _Annotation({Widget child}) : super(child: child);
-
-  @override
-  void debugPaint(Context context) {
-    context.canvas
-      ..setFillColor(PdfColors.pink)
-      ..drawRect(box.x, box.y, box.width, box.height)
-      ..fillPath();
+abstract class AnnotationBuilder {
+  PdfRect localToGlobal(Context context, PdfRect box) {
+    final Matrix4 mat = context.canvas.getTransform();
+    final Vector3 lt = mat.transform3(Vector3(box.left, box.bottom, 0));
+    final Vector3 rb = mat.transform3(Vector3(box.right, box.top, 0));
+    return PdfRect.fromLTRB(lt.x, lt.y, rb.x, rb.y);
   }
 
-  @override
-  void paint(Context context) {
-    super.paint(context);
-    paintChild(context);
-  }
+  void build(Context context, PdfRect box);
 }
 
-class Link extends _Annotation {
-  Link({@required Widget child, this.destination})
-      : assert(child != null),
-        super(child: child);
+class AnnotationLink extends AnnotationBuilder {
+  AnnotationLink(this.destination) : assert(destination != null);
 
   final String destination;
 
   @override
-  void paint(Context context) {
-    super.paint(context);
-
-    if (destination != null) {
-      final Matrix4 mat = context.canvas.getTransform();
-      final Vector3 lt = mat.transform3(Vector3(box.left, box.bottom, 0));
-      final Vector3 rb = mat.transform3(Vector3(box.right, box.top, 0));
-      final PdfRect ibox = PdfRect.fromLTRB(lt.x, lt.y, rb.x, rb.y);
+  void build(Context context, PdfRect box) {
     PdfAnnot.namedLink(
       context.page,
-        rect: ibox,
+      rect: localToGlobal(context, box),
       dest: destination,
     );
   }
-  }
 }
 
-class UrlLink extends _Annotation {
-  UrlLink({@required Widget child, @required this.destination})
-      : assert(child != null),
-        assert(destination != null),
-        super(child: child);
+class AnnotationUrl extends AnnotationBuilder {
+  AnnotationUrl(this.destination) : assert(destination != null);
 
   final String destination;
 
   @override
-  void paint(Context context) {
-    super.paint(context);
-
-    final Matrix4 mat = context.canvas.getTransform();
-    final Vector3 lt = mat.transform3(Vector3(box.left, box.bottom, 0));
-    final Vector3 rb = mat.transform3(Vector3(box.right, box.top, 0));
-    final PdfRect ibox = PdfRect.fromLTRB(lt.x, lt.y, rb.x, rb.y);
+  void build(Context context, PdfRect box) {
     PdfAnnot.urlLink(
       context.page,
-      rect: ibox,
+      rect: localToGlobal(context, box),
       dest: destination,
     );
   }
 }
+
+class Annotation extends SingleChildWidget {
+  Annotation({Widget child, this.builder}) : super(child: child);
+
+  final AnnotationBuilder builder;
+
+  @override
+  void debugPaint(Context context) {
+    context.canvas
+      ..setFillColor(PdfColors.pink)
+      ..drawRect(box.x, box.y, box.width, box.height)
+      ..fillPath();
+  }
+
+  @override
+  void paint(Context context) {
+    super.paint(context);
+    paintChild(context);
+    builder?.build(context, box);
+  }
+}
+
+class Link extends Annotation {
+  Link({@required Widget child, String destination})
+      : assert(child != null),
+        super(child: child, builder: AnnotationLink(destination));
+}
+
+class UrlLink extends Annotation {
+  UrlLink({@required Widget child, String destination})
+      : assert(child != null),
+        super(child: child, builder: AnnotationUrl(destination));
+}

@@ -19,7 +19,7 @@ part of widget;
 enum TextAlign { left, right, center, justify }
 
 class _Word {
-  _Word(this.text, this.style, this.metrics);
+  _Word(this.text, this.style, this.metrics, this.annotation);
 
   final String text;
 
@@ -29,6 +29,8 @@ class _Word {
 
   PdfPoint offset = PdfPoint.zero;
 
+  final AnnotationBuilder annotation;
+
   @override
   String toString() {
     return 'Word "$text" offset:$offset metrics:$metrics style:$style';
@@ -53,7 +55,7 @@ class _Word {
 }
 
 class TextSpan {
-  const TextSpan({this.style, this.text, this.children});
+  const TextSpan({this.style, this.text, this.children, this.annotation});
 
   final TextStyle style;
 
@@ -61,6 +63,8 @@ class TextSpan {
 
   final List<TextSpan> children;
 
+  final AnnotationBuilder annotation;
+
   String toPlainText() {
     final StringBuffer buffer = StringBuffer();
     visitTextSpan((TextSpan span) {
@@ -210,7 +214,7 @@ class RichText extends Widget {
         top = math.min(top ?? metrics.top, metrics.top);
         bottom = math.max(bottom ?? metrics.bottom, metrics.bottom);
 
-        final _Word wd = _Word(word, style, metrics);
+        final _Word wd = _Word(word, style, metrics, span.annotation);
         wd.offset = PdfPoint(offsetX, -offsetY);
 
         _words.add(wd);
@@ -264,6 +268,15 @@ class RichText extends Widget {
         }
       }
 
+      if (word.annotation != null) {
+        final PdfRect wordBox = PdfRect(
+            box.x + word.offset.x + word.metrics.left,
+            box.top + word.offset.y + word.metrics.top,
+            word.metrics.width,
+            word.metrics.height);
+        word.annotation.build(context, wordBox);
+      }
+
       context.canvas.drawString(
           currentStyle.font.getFont(context),
           currentStyle.fontSize * textScaleFactor,