Implement ImageProvider

@@ -91,7 +91,7 @@ class Invoice {
 
   double get _grandTotal => _total * (1 + tax);
 
-  PdfImage _logo;
+  pw.MemoryImage _logo;
 
   Future<Uint8List> buildPdf(PdfPageFormat pageFormat) async {
     // Create a PDF document.
@@ -101,9 +101,8 @@ class Invoice {
     final font2 = await rootBundle.load('assets/roboto2.ttf');
     final font3 = await rootBundle.load('assets/roboto3.ttf');
 
-    _logo = PdfImage.file(
-      doc.document,
-      bytes: (await rootBundle.load('assets/logo.png')).buffer.asUint8List(),
+    _logo = pw.MemoryImage(
+      (await rootBundle.load('assets/logo.png')).buffer.asUint8List(),
     );
 
     // Add page to the PDF
@@ -191,7 +190,8 @@ class Invoice {
                     alignment: pw.Alignment.topRight,
                     padding: const pw.EdgeInsets.only(bottom: 8, left: 30),
                     height: 72,
-                    child: _logo != null ? pw.Image(_logo) : pw.PdfLogo(),
+                    child:
+                        _logo != null ? pw.Image.provider(_logo) : pw.PdfLogo(),
                   ),
                   // pw.Container(
                   //   color: baseColor,

@@ -29,9 +29,8 @@ const sep = 120.0;
 Future<Uint8List> generateResume(PdfPageFormat format) async {
   final doc = pw.Document(title: 'My Résumé', author: 'David PHAM-VAN');
 
-  final profileImage = PdfImage.file(
-    doc.document,
-    bytes: (await rootBundle.load('assets/profile.jpg')).buffer.asUint8List(),
+  final profileImage = pw.MemoryImage(
+    (await rootBundle.load('assets/profile.jpg')).buffer.asUint8List(),
   );
 
   final pageTheme = await _myPageTheme(format);
@@ -121,7 +120,7 @@ Future<Uint8List> generateResume(PdfPageFormat format) async {
                             width: 100,
                             height: 100,
                             color: lightGreen,
-                            child: pw.Image(profileImage),
+                            child: pw.Image.provider(profileImage),
                           ),
                         ),
                         pw.Column(children: <pw.Widget>[

@@ -79,6 +79,7 @@
 - Add Chart Widget [Marco Papula]
 - Add Divider and VerticalDivider Widget
 - Replace Theme with ThemeData
+- Implement ImageProvider
 
 ## 1.6.2
 

@@ -56,17 +56,15 @@ pdf.addPage(pw.Page(
 To load an image from a file:
 
 ```dart
-final image = PdfImage.file(
-  pdf.document,
-  bytes: File('test.webp').readAsBytesSync(),
+final image = pw.MemoryImage(
+  File('test.webp').readAsBytesSync(),
 );
 
-pdf.addPage(pw.Page(
-    build: (pw.Context context) {
-      return pw.Center(
-        child: pw.Image(image),
-      ); // Center
-    })); // Page
+pdf.addPage(pw.Page(build: (pw.Context context) {
+  return pw.Center(
+    child: pw.Image.provider(image),
+  ); // Center
+})); // Page
 ```
 
 To use a TrueType font:

@@ -50,6 +50,7 @@ part 'widgets/geometry.dart';
 part 'widgets/grid_view.dart';
 part 'widgets/icon.dart';
 part 'widgets/image.dart';
+part 'widgets/image_provider.dart';
 part 'widgets/multi_page.dart';
 part 'widgets/page.dart';
 part 'widgets/page_theme.dart';

@@ -144,20 +144,36 @@ class BoxBorder {
 
 @immutable
 class DecorationImage {
-  const DecorationImage(
-      {@required this.image,
-      this.fit = BoxFit.cover,
-      this.alignment = Alignment.center})
-      : assert(image != null),
+  @Deprecated('Use DecorationImage.provider()')
+  DecorationImage({
+    @required PdfImage image,
+    this.fit = BoxFit.cover,
+    this.alignment = Alignment.center,
+  })  : assert(image != null),
+        assert(fit != null),
+        assert(alignment != null),
+        image = ImageProxy(image),
+        dpi = null;
+
+  const DecorationImage.provider({
+    @required this.image,
+    this.fit = BoxFit.cover,
+    this.alignment = Alignment.center,
+    this.dpi,
+  })  : assert(image != null),
         assert(fit != null),
         assert(alignment != null);
 
-  final PdfImage image;
+  final ImageProvider image;
   final BoxFit fit;
   final Alignment alignment;
+  final double dpi;
 
   void paint(Context context, PdfRect box) {
-    final imageSize = PdfPoint(image.width.toDouble(), image.height.toDouble());
+    final _image = image.resolve(context, box.size, dpi: dpi);
+
+    final imageSize =
+        PdfPoint(_image.width.toDouble(), _image.height.toDouble());
     final sizes = applyBoxFit(fit, imageSize, box.size);
     final scaleX = sizes.destination.x / sizes.source.x;
     final scaleY = sizes.destination.y / sizes.source.y;
@@ -174,7 +190,7 @@ class DecorationImage {
       ..drawRect(box.x, box.y, box.width, box.height)
       ..clipPath()
       ..setTransform(mat)
-      ..drawImage(image, 0, 0, imageSize.x, imageSize.y)
+      ..drawImage(_image, 0, 0, imageSize.x, imageSize.y)
       ..restoreContext();
   }
 }

@@ -75,18 +75,27 @@ void _drawImageRect(PdfGraphics canvas, PdfImage image, PdfRect sourceRect,
 }
 
 class Image extends Widget {
+  @Deprecated('Use Image.provider instead')
   Image(
-    this.image, {
+    PdfImage image, {
     this.fit = BoxFit.contain,
     this.alignment = Alignment.center,
     this.width,
     this.height,
   })  : assert(image != null),
-        aspectRatio = image.height.toDouble() / image.width.toDouble();
+        image = ImageProxy(image),
+        dpi = null;
 
-  final PdfImage image;
+  Image.provider(
+    this.image, {
+    this.fit = BoxFit.contain,
+    this.alignment = Alignment.center,
+    this.width,
+    this.height,
+    this.dpi,
+  }) : assert(image != null);
 
-  final double aspectRatio;
+  final ImageProvider image;
 
   final BoxFit fit;
 
@@ -96,6 +105,8 @@ class Image extends Widget {
 
   final double height;
 
+  final double dpi;
+
   @override
   void layout(Context context, BoxConstraints constraints,
       {bool parentUsesSize = false}) {
@@ -119,9 +130,11 @@ class Image extends Widget {
   void paint(Context context) {
     super.paint(context);
 
+    final rect = context.localToGlobal(box);
+
     _paintImage(
       canvas: context.canvas,
-      image: image,
+      image: image.resolve(context, rect.size, dpi: dpi),
       rect: box,
       alignment: alignment,
       fit: fit,

+/*
+ * 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.
+ */
+
+part of widget;
+
+/// Identifies an image without committing to the precise final asset
+abstract class ImageProvider {
+  ImageProvider(
+    this._width,
+    this._height,
+    this.orientation,
+    this.dpi,
+  );
+
+  final double dpi;
+
+  final int _width;
+
+  /// Image width
+  int get width => orientation.index >= 4 ? _height : _width;
+
+  final int _height;
+
+  /// Image height
+  int get height => orientation.index < 4 ? _height : _width;
+
+  /// The internal orientation of the image
+  final PdfImageOrientation orientation;
+
+  final _cache = <int, PdfImage>{};
+
+  PdfImage buildImage(Context context, {int width, int height});
+
+  /// Resolves this image provider using the given context, returning a PdfImage
+  /// The image is automatically added to the document
+  PdfImage resolve(Context context, PdfPoint size, {double dpi}) {
+    assert(size != null);
+    final effectiveDpi = dpi ?? this.dpi;
+
+    if (effectiveDpi == null || _cache[0] != null) {
+      _cache[0] ??= buildImage(context);
+
+      assert(_cache[0].pdfDocument == context.document,
+          'Do not reuse an ImageProvider object across multiple documents');
+      return _cache[0];
+    }
+
+    final width = (size.x / PdfPageFormat.inch * effectiveDpi).toInt();
+    final height = (size.y / PdfPageFormat.inch * effectiveDpi).toInt();
+
+    if (!_cache.containsKey(width)) {
+      _cache[width] ??= buildImage(context, width: width, height: height);
+    }
+
+    assert(_cache[width].pdfDocument == context.document,
+        'Do not reuse an ImageProvider object across multiple documents');
+    return _cache[width];
+  }
+}
+
+class ImageProxy extends ImageProvider {
+  ImageProxy(
+    this._image, {
+    double dpi,
+  }) : super(_image.width, _image.height, _image.orientation, dpi);
+
+  /// The proxy image
+  final PdfImage _image;
+
+  @override
+  PdfImage buildImage(Context context, {int width, int height}) => _image;
+}
+
+class MemoryImage extends ImageProvider {
+  factory MemoryImage(
+    Uint8List bytes, {
+    PdfImageOrientation orientation,
+    double dpi,
+  }) {
+    final decoder = im.findDecoderForData(bytes);
+    if (decoder is im.JpegDecoder) {
+      final info = PdfJpegInfo(bytes);
+
+      return MemoryImage._(
+        bytes,
+        info.width,
+        info.height,
+        orientation ?? info.orientation,
+        dpi,
+      );
+    }
+
+    final info = decoder.startDecode(bytes);
+    return MemoryImage._(
+      bytes,
+      info.width,
+      info.height,
+      orientation ?? PdfImageOrientation.topLeft,
+      dpi,
+    );
+  }
+
+  MemoryImage._(
+    this.bytes,
+    int width,
+    int height,
+    PdfImageOrientation orientation,
+    double dpi,
+  ) : super(width, height, orientation, dpi);
+
+  /// The image data
+  final Uint8List bytes;
+
+  @override
+  PdfImage buildImage(Context context, {int width, int height}) {
+    if (width == null) {
+      return PdfImage.file(context.document, bytes: bytes);
+    }
+
+    final image = im.decodeImage(bytes);
+    print(width);
+    final resized = im.copyResize(image, width: width);
+    return PdfImage.fromImage(context.document, image: resized);
+  }
+}
+
+class ImageImage extends ImageProvider {
+  ImageImage(
+    this._image, {
+    double dpi,
+    PdfImageOrientation orientation,
+  }) : super(_image.width, _image.height,
+            orientation ?? PdfImageOrientation.topLeft, dpi);
+
+  /// The image data
+  final im.Image _image;
+
+  @override
+  PdfImage buildImage(Context context, {int width, int height}) {
+    if (width == null) {
+      return PdfImage.fromImage(context.document, image: _image);
+    }
+
+    final resized = im.copyResize(_image, width: width);
+    return PdfImage.fromImage(context.document, image: resized);
+  }
+}
+
+class RawImage extends ImageImage {
+  RawImage({
+    @required Uint8List bytes,
+    @required int width,
+    @required int height,
+    PdfImageOrientation orientation,
+    double dpi,
+  }) : super(im.Image.fromBytes(width, height, bytes),
+            orientation: orientation, dpi: dpi);
+}

@@ -19,7 +19,6 @@ import 'dart:io';
 import 'dart:isolate';
 import 'dart:typed_data';
 
-import 'package:pdf/pdf.dart';
 import 'package:pdf/widgets.dart';
 import 'package:test/test.dart';
 
@@ -35,12 +34,12 @@ class Message {
 void compute(Message message) {
   final pdf = Document();
 
-  final image = PdfImage.jpeg(
-    pdf.document,
-    image: message.image,
+  final image = MemoryImage(
+    message.image,
   );
 
-  pdf.addPage(Page(build: (Context context) => Center(child: Image(image))));
+  pdf.addPage(
+      Page(build: (Context context) => Center(child: Image.provider(image))));
 
   message.sendPort.send(pdf.save());
 }

@@ -17,29 +17,27 @@
 import 'dart:convert';
 import 'dart:io';
 
-import 'package:pdf/pdf.dart';
 import 'package:pdf/widgets.dart';
 import 'package:test/test.dart';
 
 import 'utils.dart';
 
 Document pdf;
-PdfImage image;
+MemoryImage image;
 
 void main() {
   setUpAll(() async {
     Document.debug = true;
     pdf = Document();
 
-    image = PdfImage.jpeg(
-      pdf.document,
-      image: await download('https://www.nfet.net/nfet.jpg'),
+    image = MemoryImage(
+      await download('https://www.nfet.net/nfet.jpg'),
     );
   });
 
   test('Pdf Jpeg Download', () async {
     pdf.addPage(Page(
-      build: (Context context) => Center(child: Image(image)),
+      build: (Context context) => Center(child: Image.provider(image)),
     ));
   });
 
@@ -51,10 +49,9 @@ void main() {
           crossAxisSpacing: 10,
           children: List<Widget>.generate(
             images.length,
-            (int index) => Image(
-              PdfImage.jpeg(
-                pdf.document,
-                image: base64.decode(images[index]),
+            (int index) => Image.provider(
+              MemoryImage(
+                base64.decode(images[index]),
               ),
             ),
           ),
@@ -72,7 +69,7 @@ void main() {
           return SizedBox(
             width: 200,
             height: 100,
-            child: Image(
+            child: Image.provider(
               image,
               fit: fit,
             ),
@@ -85,10 +82,9 @@ void main() {
   test('Pdf Image decode', () {
     final imageWidgets = imageFiles.map<Widget>(
       (String image) => SizedBox(
-        child: Image(
-          PdfImage.file(
-            pdf.document,
-            bytes: gzip.decode(base64.decode(image)),
+        child: Image.provider(
+          MemoryImage(
+            gzip.decode(base64.decode(image)),
           ),
         ),
         width: 200,

@@ -19,7 +19,6 @@ import 'dart:io';
 import 'dart:math' as math;
 import 'dart:typed_data';
 
-import 'package:pdf/pdf.dart';
 import 'package:pdf/widgets.dart';
 
 Future<Uint8List> download(
@@ -56,7 +55,7 @@ Future<Uint8List> download(
   return Uint8List.fromList(data);
 }
 
-PdfImage generateBitmap(PdfDocument pdf, int w, int h) {
+ImageProvider generateBitmap(int w, int h) {
   final bm = Uint32List(w * h);
   final dw = w.toDouble();
   final dh = h.toDouble();
@@ -69,9 +68,8 @@ PdfImage generateBitmap(PdfDocument pdf, int w, int h) {
     }
   }
 
-  return PdfImage(
-    pdf,
-    image: bm.buffer.asUint8List(),
+  return RawImage(
+    bytes: bm.buffer.asUint8List(),
     width: w,
     height: h,
   );

@@ -55,7 +55,7 @@ void main() {
   });
 
   test('Container Widgets Image', () {
-    final image = generateBitmap(pdf.document, 100, 200);
+    final image = generateBitmap(100, 200);
 
     final widgets = <Widget>[];
     for (var shape in BoxShape.values) {
@@ -66,7 +66,7 @@ void main() {
             decoration: BoxDecoration(
               shape: shape,
               borderRadiusEx: const BorderRadius.all(Radius.circular(10)),
-              image: DecorationImage(image: image, fit: fit),
+              image: DecorationImage.provider(image: image, fit: fit),
             ),
             width: 100,
             height: 100,

@@ -37,7 +37,7 @@ void main() {
       MultiPage(
         theme: ThemeData.withFont(icons: icons),
         build: (Context context) {
-          final iconList = List<IconData>();
+          final iconList = <IconData>[];
           final pdfFont = icons.getFont(context);
           if (pdfFont is PdfTtfFont) {
             iconList.addAll(

@@ -24,7 +24,7 @@ import 'package:test/test.dart';
 void main() {
   Document pdf;
   TextStyle symbol;
-  PdfImage im;
+  ImageProvider im;
 
   setUpAll(() {
     Document.debug = true;
@@ -43,7 +43,7 @@ void main() {
 
     final imData = zlib.decode(base64.decode(
         'eJz7//8/w388uOTCT6a4Ez96Q47++I+OI479mEVALyNU7z9seuNP/mAm196Ekz8YR+0dWHtBmJC9S+7/Zog89iMIKLYaHQPVJGLTD7MXpDfq+I9goNhPdPPDjv3YlnH6Jye6+2H21l/6yeB/4HsSDr1bQXrRwq8HqHcGyF6QXp9933N0tn/7Y7vn+/9gLPaih0PDlV9MIAzVm6ez7dsfzW3f/oMwzAx0e7FhoJutdbcj9MKw9frnL2J2POfBpxeEg478YLba/X0Wsl6lBXf+s0bP/s8ePXeWePJCvPEJNYMRZIYWSO/cq/9Z/Nv+M4bO+M8YDjFDJGkhzvSE7A6jRTdnsQR2wfXCMLHuMC5byyidvGgWE5JeZDOIcYdR+TpmkBno+mFmAAC+DGhl'));
-    im = PdfImage(pdf.document, image: imData, width: 16, height: 20);
+    im = RawImage(bytes: imData, width: 16, height: 20);
   });
 
   test('Pdf Widgets page 1', () {
@@ -85,7 +85,7 @@ void main() {
               Row(
                 mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                 children: <Widget>[
-                  Image(im),
+                  Image.provider(im),
                   PdfLogo(),
                   Column(
                     children: <Widget>[

@@ -55,12 +55,12 @@ To load an image from an ImageProvider:
 
 ```dart
 const imageProvider = const AssetImage('assets/image.png');
-final PdfImage image = await pdfImageFromImageProvider(pdf: doc.document, image: imageProvider);
+final image = await flutterImageProvider(imageProvider);
 
 doc.addPage(pw.Page(
     build: (pw.Context context) {
       return pw.Center(
-        child: pw.Image(image),
+        child: pw.Image.provider(image),
       ); // Center
     })); // Page
 ```

@@ -17,7 +17,7 @@
 import 'dart:async';
 import 'dart:ui' as ui;
 
-import 'package:flutter/rendering.dart';
+import 'package:flutter/rendering.dart' as rdr;
 import 'package:flutter/services.dart';
 import 'package:meta/meta.dart';
 import 'package:pdf/pdf.dart';
@@ -25,6 +25,7 @@ import 'package:pdf/widgets.dart';
 
 /// Loads an image from a Flutter [ui.Image]
 /// into a [PdfImage] instance
+@Deprecated('Use flutterImageProvider')
 Future<PdfImage> pdfImageFromImage(
     {@required PdfDocument pdf, @required ui.Image image}) async {
   final bytes = await image.toByteData(format: ui.ImageByteFormat.rawRgba);
@@ -37,16 +38,17 @@ Future<PdfImage> pdfImageFromImage(
 
 /// Loads an image from a Flutter [ImageProvider]
 /// into a [PdfImage] instance
+@Deprecated('Use flutterImageProvider')
 Future<PdfImage> pdfImageFromImageProvider(
     {@required PdfDocument pdf,
-    @required ImageProvider image,
-    ImageConfiguration configuration,
-    ImageErrorListener onError}) async {
+    @required rdr.ImageProvider image,
+    rdr.ImageConfiguration configuration,
+    rdr.ImageErrorListener onError}) async {
   final completer = Completer<PdfImage>();
-  final stream = image.resolve(configuration ?? ImageConfiguration.empty);
+  final stream = image.resolve(configuration ?? rdr.ImageConfiguration.empty);
 
-  ImageStreamListener listener;
-  listener = ImageStreamListener((ImageInfo image, bool sync) async {
+  rdr.ImageStreamListener listener;
+  listener = rdr.ImageStreamListener((rdr.ImageInfo image, bool sync) async {
     final result = await pdfImageFromImage(pdf: pdf, image: image.image);
     if (!completer.isCompleted) {
       completer.complete(result);
@@ -68,6 +70,46 @@ Future<PdfImage> pdfImageFromImageProvider(
   return completer.future;
 }
 
+/// Loads an image from a Flutter [ImageProvider]
+/// into an [ImageProvider] instance
+Future<ImageProvider> flutterImageProvider(
+  rdr.ImageProvider image, {
+  rdr.ImageConfiguration configuration,
+  rdr.ImageErrorListener onError,
+}) async {
+  final completer = Completer<ImageProvider>();
+  final stream = image.resolve(configuration ?? rdr.ImageConfiguration.empty);
+
+  rdr.ImageStreamListener listener;
+  listener = rdr.ImageStreamListener((rdr.ImageInfo image, bool sync) async {
+    final bytes =
+        await image.image.toByteData(format: ui.ImageByteFormat.rawRgba);
+
+    final result = RawImage(
+        bytes: bytes.buffer.asUint8List(),
+        width: image.image.width,
+        height: image.image.height);
+
+    if (!completer.isCompleted) {
+      completer.complete(result);
+    }
+    stream.removeListener(listener);
+  }, onError: (dynamic exception, StackTrace stackTrace) {
+    if (!completer.isCompleted) {
+      completer.complete(null);
+    }
+    if (onError != null) {
+      onError(exception, stackTrace);
+    } else {
+      // https://groups.google.com/forum/#!topic/flutter-announce/hp1RNIgej38
+      assert(false, 'image failed to load');
+    }
+  });
+
+  stream.addListener(listener);
+  return completer.future;
+}
+
 /// Loads a font from an asset bundle key. If used multiple times with the same font name,
 /// it will be included multiple times in the pdf file
 Future<TtfFont> fontFromAssetBundle(String key, AssetBundle bundle) async {

@@ -18,7 +18,7 @@ dependencies:
   image: ^2.1.4
   js: ^0.6.1
   meta: ^1.1.5
-  pdf: ^1.11.1
+  pdf: ^1.13.0
   plugin_platform_interface: ^1.0.2
 
 dev_dependencies:

@@ -45,15 +45,15 @@ void main() {
     // expect(await Printing.platformVersion, '42');
   });
 
-  test('pdfImageFromImageProvider(FileImage)', () async {
-    final image = await pdfImageFromImageProvider(
-        pdf: doc.document, image: FileImage(File('$path/example.png')));
+  test('flutterImageProvider(FileImage)', () async {
+    final image =
+        await flutterImageProvider(FileImage(File('$path/example.png')));
 
     doc.addPage(
       pw.Page(
         build: (pw.Context context) => pw.Center(
           child: pw.Container(
-            child: pw.Image(image),
+            child: pw.Image.provider(image),
           ),
         ),
       ),