Add support for Metadata XML

@@ -7,6 +7,7 @@
 - Improve GraphicState
 - Add SVG Color filter
 - Implement Compressed XREF
+- Add support for Metadata XML
 
 ## 3.1.0
 

@@ -30,6 +30,7 @@ export 'src/pdf/graphic_state.dart';
 export 'src/pdf/graphics.dart';
 export 'src/pdf/image.dart';
 export 'src/pdf/info.dart';
+export 'src/pdf/metadata.dart';
 export 'src/pdf/outline.dart';
 export 'src/pdf/page.dart';
 export 'src/pdf/page_format.dart';

@@ -17,6 +17,7 @@
 import 'annotation.dart';
 import 'data_types.dart';
 import 'document.dart';
+import 'metadata.dart';
 import 'names.dart';
 import 'object_dict.dart';
 import 'outline.dart';
@@ -38,6 +39,9 @@ class PdfCatalog extends PdfObjectDict {
   /// The outlines of the document
   PdfOutline? outlines;
 
+  /// The document metadata
+  PdfMetadata? metadata;
+
   /// The initial page mode
   final PdfPageMode pageMode;
 
@@ -66,6 +70,10 @@ class PdfCatalog extends PdfObjectDict {
       params['/Outlines'] = outlines!.ref();
     }
 
+    if (metadata != null) {
+      params['/Metadata'] = metadata!.ref();
+    }
+
     // the Names object
     params['/Names'] = names.ref();
 

@@ -595,15 +595,34 @@ class PdfDict<T extends PdfDataType> extends PdfDataType {
 }
 
 class PdfDictStream extends PdfDict<PdfDataType> {
-  const PdfDictStream({
+  factory PdfDictStream({
+    required PdfObject object,
+    Map<String, PdfDataType>? values,
+    Uint8List? data,
+    bool isBinary = false,
+    bool encrypt = true,
+    bool compress = true,
+  }) {
+    return PdfDictStream.values(
+      object: object,
+      values: values ?? {},
+      data: data ?? Uint8List(0),
+      encrypt: encrypt,
+      compress: compress,
+      isBinary: isBinary,
+    );
+  }
+
+  PdfDictStream.values({
     required this.object,
-    Map<String, PdfDataType> values = const <String, PdfDataType>{},
+    required Map<String, PdfDataType> values,
     required this.data,
     this.isBinary = false,
     this.encrypt = true,
+    this.compress = true,
   }) : super.values(values);
 
-  final Uint8List data;
+  Uint8List data;
 
   final PdfObject object;
 
@@ -611,6 +630,8 @@ class PdfDictStream extends PdfDict<PdfDataType> {
 
   final bool encrypt;
 
+  final bool compress;
+
   @override
   void output(PdfStream s) {
     final _values = PdfDict(values);
@@ -620,7 +641,7 @@ class PdfDictStream extends PdfDict<PdfDataType> {
     if (_values.containsKey('/Filter')) {
       // The data is already in the right format
       _data = data;
-    } else if (object.pdfDocument.deflate != null) {
+    } else if (compress && object.pdfDocument.deflate != null) {
       // Compress the data
       final newData = Uint8List.fromList(object.pdfDocument.deflate!(data));
       if (newData.lengthInBytes < data.lengthInBytes) {

@@ -123,6 +123,7 @@ class PdfDocument {
 
   /// This is the info object. Although this is an optional object, we
   /// include it.
+  @Deprecated('This can safely be removed.')
   PdfInfo? info;
 
   /// This is the Pages object, which is required by each Pdf Document

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:xml/xml.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+
+/// Pdf Metadata
+class PdfMetadata extends PdfObject<PdfDictStream> {
+  /// Store an Xml object
+  PdfMetadata(
+    PdfDocument pdfDocument,
+    this.metadata,
+  ) : super(
+          pdfDocument,
+          params: PdfDictStream(
+            object: pdfDocument.catalog,
+            compress: false,
+            encrypt: false,
+          ),
+        ) {
+    pdfDocument.catalog.metadata = this;
+  }
+
+  final XmlDocument metadata;
+
+  @override
+  void prepare() {
+    super.prepare();
+    params['/SubType'] = const PdfName('/XML');
+    params.data = Uint8List.fromList(utf8.encode(metadata.toString()));
+  }
+}

@@ -36,7 +36,7 @@ class PdfObjectStream extends PdfObjectDict {
 
   @override
   void writeContent(PdfStream os) {
-    PdfDictStream(
+    PdfDictStream.values(
       object: this,
       isBinary: isBinary,
       values: params.values,

@@ -52,10 +52,10 @@ class PdfOutput {
   final xref = PdfXrefTable();
 
   /// This is used to track the /Root object (catalog)
-  PdfObject? rootID;
+  PdfCatalog? rootID;
 
   /// This is used to track the /Info object (info)
-  PdfObject? infoID;
+  PdfInfo? infoID;
 
   /// This is used to track the /Encrypt object (encryption)
   PdfEncryption? encryptID;

@@ -17,6 +17,7 @@
 import 'dart:typed_data';
 
 import 'package:pdf/pdf.dart';
+import 'package:xml/xml.dart';
 
 import 'page.dart';
 import 'theme.dart';
@@ -34,6 +35,7 @@ class Document {
     String? subject,
     String? keywords,
     String? producer,
+    XmlDocument? metadata,
   }) : document = PdfDocument(
           pageMode: pageMode,
           deflate: deflate,
@@ -46,7 +48,7 @@ class Document {
         subject != null ||
         keywords != null ||
         producer != null) {
-      document.info = PdfInfo(
+      PdfInfo(
         document,
         title: title,
         author: author,
@@ -56,6 +58,9 @@ class Document {
         producer: producer,
       );
     }
+    if (metadata != null) {
+      PdfMetadata(document, metadata);
+    }
   }
 
   Document.load(
@@ -82,7 +87,7 @@ class Document {
         subject != null ||
         keywords != null ||
         producer != null) {
-      document.info = PdfInfo(
+      PdfInfo(
         document,
         title: title,
         author: author,

@@ -28,7 +28,7 @@ void main() {
     img.fillRange(0, img.length - 1, 0x12345678);
 
     final pdf = PdfDocument();
-    pdf.info = PdfInfo(pdf,
+    PdfInfo(pdf,
         author: 'David PHAM-VAN',
         creator: 'David PHAM-VAN',
         title: 'My Title',