Optimize memory footprint

@@ -12,6 +12,7 @@
 - Fix context painting empty Table
 - Fix Text decoration placements
 - Improve image buffer management
+- Optimize memory footprint
 
 ## 1.5.0
 

@@ -18,9 +18,9 @@
 
 part of pdf;
 
-class Ascii85Encoder extends Converter<List<int>, List<int>> {
+class Ascii85Encoder extends Converter<Uint8List, Uint8List> {
   @override
-  List<int> convert(List<int> input) {
+  Uint8List convert(Uint8List input) {
     final Uint8List output = Uint8List(_maxEncodedLen(input.length) + 2);
 
     int outputOffset = 0;

@@ -35,7 +35,7 @@ abstract class PdfDataType {
     return String.fromCharCodes(toStream().output());
   }
 
-  List<int> toList() {
+  Uint8List toList() {
     return toStream().output();
   }
 }
@@ -153,8 +153,8 @@ class PdfSecString extends PdfString {
       return super.output(s);
     }
 
-    final List<int> enc = object.pdfDocument.encryption.encrypt(value, object);
-    _output(s, Uint8List.fromList(enc));
+    final Uint8List enc = object.pdfDocument.encryption.encrypt(value, object);
+    _output(s, enc);
   }
 }
 

@@ -116,14 +116,14 @@ class PdfDocument {
   final Set<PdfFont> fonts = <PdfFont>{};
 
   /// Generates the document ID
-  List<int> _documentID;
-  List<int> get documentID {
+  Uint8List _documentID;
+  Uint8List get documentID {
     if (_documentID == null) {
       final math.Random rnd = math.Random();
-      _documentID = sha256
+      _documentID = Uint8List.fromList(sha256
           .convert(DateTime.now().toIso8601String().codeUnits +
               List<int>.generate(32, (_) => rnd.nextInt(256)))
-          .bytes;
+          .bytes);
     }
 
     return _documentID;
@@ -182,7 +182,7 @@ class PdfDocument {
     pos.close();
   }
 
-  List<int> save() {
+  Uint8List save() {
     final PdfStream os = PdfStream();
     _write(os);
     return os.output();

@@ -19,5 +19,5 @@ part of pdf;
 abstract class PdfEncryption extends PdfObject {
   PdfEncryption(PdfDocument pdfDocument) : super(pdfDocument, null);
 
-  List<int> encrypt(List<int> input, PdfObject object);
+  Uint8List encrypt(Uint8List input, PdfObject object);
 }

@@ -35,7 +35,7 @@ class PdfObjectStream extends PdfObject {
   /// defines if the stream needs to be converted to ascii85
   final bool isBinary;
 
-  List<int> _data;
+  Uint8List _data;
 
   @override
   void _prepare() {

@@ -20,30 +20,53 @@ part of pdf;
 
 class PdfStream {
   static const int precision = 5;
-  final List<int> _stream = <int>[];
+
+  static const int _grow = 65536;
+
+  Uint8List _stream = Uint8List(_grow);
+
+  int _offset = 0;
+
+  void _ensureCapacity(int size) {
+    if (_stream.length - _offset >= size) {
+      return;
+    }
+
+    final int newSize = math.max(_offset + size + _grow, _offset * 2);
+    final Uint8List newBuffer = Uint8List(newSize);
+    newBuffer.setAll(0, _stream);
+    _stream = newBuffer;
+  }
+
+  void putByte(int s) {
+    _ensureCapacity(1);
+    _stream[_offset++] = s;
+  }
+
+  void putBytes(List<int> s) {
+    _ensureCapacity(s.length);
+    _stream.setAll(_offset, s);
+    _offset += s.length;
+  }
 
   void putStream(PdfStream s) {
-    _stream.addAll(s._stream);
+    putBytes(s._stream);
   }
 
+  int get offset => _offset;
+
+  Uint8List output() => _stream.sublist(0, _offset);
+
   void putString(String s) {
     for (int codeUnit in s.codeUnits) {
       if (codeUnit <= 0x7f) {
-        _stream.add(codeUnit);
+        putByte(codeUnit);
       } else {
-        _stream.add(0x20);
+        putByte(0x20);
       }
     }
   }
 
-  void putByte(int s) {
-    _stream.add(s);
-  }
-
-  void putBytes(List<int> s) {
-    _stream.addAll(s);
-  }
-
   void putNum(double d) {
     assert(d != double.infinity);
     putString(d.toStringAsFixed(precision));
@@ -62,44 +85,40 @@ class PdfStream {
     for (int c in s) {
       switch (c) {
         case 0x0a: // \n Line feed (LF)
-          _stream.add(0x5c);
-          _stream.add(0x6e);
+          putByte(0x5c);
+          putByte(0x6e);
           break;
         case 0x0d: // \r Carriage return (CR)
-          _stream.add(0x5c);
-          _stream.add(0x72);
+          putByte(0x5c);
+          putByte(0x72);
           break;
         case 0x09: // \t Horizontal tab (HT)
-          _stream.add(0x5c);
-          _stream.add(0x74);
+          putByte(0x5c);
+          putByte(0x74);
           break;
         case 0x08: // \b Backspace (BS)
-          _stream.add(0x5c);
-          _stream.add(0x62);
+          putByte(0x5c);
+          putByte(0x62);
           break;
         case 0x0c: // \f Form feed (FF)
-          _stream.add(0x5c);
-          _stream.add(0x66);
+          putByte(0x5c);
+          putByte(0x66);
           break;
         case 0x28: // \( Left parenthesis
-          _stream.add(0x5c);
-          _stream.add(0x28);
+          putByte(0x5c);
+          putByte(0x28);
           break;
         case 0x29: // \) Right parenthesis
-          _stream.add(0x5c);
-          _stream.add(0x29);
+          putByte(0x5c);
+          putByte(0x29);
           break;
         case 0x5c: // \\ Backslash
-          _stream.add(0x5c);
-          _stream.add(0x5c);
+          putByte(0x5c);
+          putByte(0x5c);
           break;
         default:
-          _stream.add(c);
+          putByte(c);
       }
     }
   }
-
-  int get offset => _stream.length;
-
-  List<int> output() => _stream;
 }

@@ -66,7 +66,7 @@ class Document {
     _pages.add(page);
   }
 
-  List<int> save() {
+  Uint8List save() {
     if (!_paint) {
       for (Page page in _pages) {
         page.postProcess(this);

@@ -61,7 +61,7 @@ void main() {
     final ReceivePort receivePort = ReceivePort();
 
     receivePort.listen((dynamic data) async {
-      if (data is List<int>) {
+      if (data is Uint8List) {
         print('Received a ${data.length} bytes PDF');
         final File file = File('isolate.pdf');
         await file.writeAsBytes(data);

@@ -9,6 +9,7 @@
 - Add Unit tests
 - Update example tab
 - Uniformize examples
+- Optimize memory footprint
 
 ## 3.1.0
 

@@ -15,9 +15,10 @@
  */
 
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:pdf/pdf.dart';
 
 /// Callback used to generate the Pdf document dynamically when the user
 /// changes the page settings: size and margins
-typedef LayoutCallback = FutureOr<List<int>> Function(PdfPageFormat format);
+typedef LayoutCallback = FutureOr<Uint8List> Function(PdfPageFormat format);

@@ -15,6 +15,7 @@
  */
 
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:flutter/rendering.dart' show Rect;
 import 'package:pdf/pdf.dart';
@@ -81,13 +82,13 @@ abstract class PrintingPlatform extends PlatformInterface {
 
   /// Displays a platform popup to share the Pdf document to another application
   Future<bool> sharePdf(
-    List<int> bytes,
+    Uint8List bytes,
     String filename,
     Rect bounds,
   );
 
   /// Convert an html document to a pdf data
-  Future<List<int>> convertHtml(
+  Future<Uint8List> convertHtml(
     String html,
     String baseUrl,
     PdfPageFormat format,
@@ -95,7 +96,7 @@ abstract class PrintingPlatform extends PlatformInterface {
 
   /// Convert a Pdf document to bitmap images
   Stream<PdfRaster> raster(
-    List<int> document,
+    Uint8List document,
     List<int> pages,
     double dpi,
   );

@@ -54,7 +54,7 @@ class MethodChannelPrinting extends PrintingPlatform {
             marginBottom: call.arguments['marginBottom'],
           );
 
-          final List<int> bytes = await job.onLayout(format);
+          final Uint8List bytes = await job.onLayout(format);
 
           if (bytes == null) {
             throw 'onLayout returned null';
@@ -186,7 +186,7 @@ class MethodChannelPrinting extends PrintingPlatform {
       onCompleted: Completer<bool>(),
     ));
 
-    final List<int> bytes = await onLayout(format);
+    final Uint8List bytes = await onLayout(format);
     if (bytes == null) {
       return false;
     }
@@ -205,7 +205,7 @@ class MethodChannelPrinting extends PrintingPlatform {
 
   @override
   Future<bool> sharePdf(
-    List<int> bytes,
+    Uint8List bytes,
     String filename,
     Rect bounds,
   ) async {
@@ -221,10 +221,10 @@ class MethodChannelPrinting extends PrintingPlatform {
   }
 
   @override
-  Future<List<int>> convertHtml(
+  Future<Uint8List> convertHtml(
       String html, String baseUrl, PdfPageFormat format) async {
     final PrintJob job = _newPrintJob(PrintJob(
-      onHtmlRendered: Completer<List<int>>(),
+      onHtmlRendered: Completer<Uint8List>(),
     ));
 
     final Map<String, dynamic> params = <String, dynamic>{
@@ -240,14 +240,14 @@ class MethodChannelPrinting extends PrintingPlatform {
     };
 
     await _channel.invokeMethod<void>('convertHtml', params);
-    final List<int> result = await job.onHtmlRendered.future;
+    final Uint8List result = await job.onHtmlRendered.future;
     _printJobs.remove(job.index);
     return result;
   }
 
   @override
   Stream<PdfRaster> raster(
-    List<int> document,
+    Uint8List document,
     List<int> pages,
     double dpi,
   ) {

@@ -15,6 +15,7 @@
  */
 
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'callback.dart';
 import 'raster.dart';
@@ -28,7 +29,7 @@ class PrintJob {
   });
 
   final LayoutCallback onLayout;
-  final Completer<List<int>> onHtmlRendered;
+  final Completer<Uint8List> onHtmlRendered;
   final Completer<bool> onCompleted;
   final StreamController<PdfRaster> onPageRasterized;
 

@@ -15,6 +15,7 @@
  */
 
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:flutter/rendering.dart' show Rect, Offset;
 import 'package:meta/meta.dart';
@@ -83,7 +84,7 @@ mixin Printing {
   /// Displays a platform popup to share the Pdf document to another application
   static Future<bool> sharePdf({
     @Deprecated('use bytes with document.save()') PdfDocument document,
-    List<int> bytes,
+    Uint8List bytes,
     String filename = 'document.pdf',
     Rect bounds,
   }) {
@@ -105,7 +106,7 @@ mixin Printing {
   }
 
   /// Convert an html document to a pdf data
-  static Future<List<int>> convertHtml({
+  static Future<Uint8List> convertHtml({
     @required String html,
     String baseUrl,
     PdfPageFormat format = PdfPageFormat.standard,
@@ -134,7 +135,7 @@ mixin Printing {
   }
 
   static Stream<PdfRaster> raster(
-    List<int> document, {
+    Uint8List document, {
     List<int> pages,
     double dpi = PdfPageFormat.inch,
   }) {
@@ -150,7 +151,7 @@ mixin Printing {
   @Deprecated('use Printing.layoutPdf(onLayout: (_) => document.save());')
   static Future<void> printPdf({
     @Deprecated('use bytes with document.save()') PdfDocument document,
-    List<int> bytes,
+    Uint8List bytes,
   }) async {
     assert(document != null || bytes != null);
     assert(!(document == null && bytes == null));

@@ -56,7 +56,7 @@ class PrintingPlugin extends PrintingPlatform {
     String name,
     PdfPageFormat format,
   ) async {
-    final List<int> result = await onLayout(format);
+    final Uint8List result = await onLayout(format);
 
     if (result == null || result.isEmpty) {
       return false;
@@ -83,7 +83,7 @@ class PrintingPlugin extends PrintingPlatform {
     final String pdfUrl = html.Url.createObjectUrl(pdfFile);
     final html.HtmlDocument doc = js.context['document'];
 
-    final html.IFrameElement frame =
+    final html.Element frame =
         doc.getElementById(_frameId) ?? doc.createElement('iframe');
     frame.setAttribute(
       'style',
@@ -112,7 +112,7 @@ class PrintingPlugin extends PrintingPlatform {
 
   @override
   Future<bool> sharePdf(
-    List<int> bytes,
+    Uint8List bytes,
     String filename,
     Rect bounds,
   ) async {
@@ -130,7 +130,7 @@ class PrintingPlugin extends PrintingPlatform {
   }
 
   @override
-  Future<List<int>> convertHtml(
+  Future<Uint8List> convertHtml(
     String html,
     String baseUrl,
     PdfPageFormat format,
@@ -157,7 +157,7 @@ class PrintingPlugin extends PrintingPlatform {
 
   @override
   Stream<PdfRaster> raster(
-    List<int> document,
+    Uint8List document,
     List<int> pages,
     double dpi,
   ) {

@@ -15,7 +15,7 @@ dependencies:
     sdk: flutter
   flutter_web_plugins:
     sdk: flutter
-  pdf: ^1.3.15
+  pdf: ^1.6.0
   plugin_platform_interface: ^1.0.2
 
 dev_dependencies:

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+import 'dart:typed_data';
+
 import 'package:flutter_test/flutter_test.dart';
 import 'package:mockito/mockito.dart';
 import 'package:pdf/pdf.dart';
@@ -56,7 +58,7 @@ void main() {
 
     expect(
       await Printing.sharePdf(
-        bytes: <int>[],
+        bytes: Uint8List(0),
       ),
       null,
     );
@@ -106,7 +108,7 @@ void main() {
     );
 
     expect(
-      Printing.raster(<int>[]),
+      Printing.raster(Uint8List(0)),
       null,
     );
   });