Opt-out from dart library

@@ -10,6 +10,7 @@
 - Fix PdfOutlineMode enum
 - Improve API documentation
 - Add support for Icon Fonts (MaterialIcons)
+- Opt-out from dart library
 
 ## 1.12.0
 

@@ -14,64 +14,27 @@
  * limitations under the License.
  */
 
-library pdf;
-
-import 'dart:collection';
-import 'dart:convert';
-import 'dart:math' as math;
-import 'dart:typed_data';
-
-import 'package:crypto/crypto.dart';
-import 'package:image/image.dart' as im;
-import 'package:meta/meta.dart';
-import 'package:path_parsing/path_parsing.dart';
-import 'package:utf/utf.dart';
-import 'package:vector_math/vector_math_64.dart';
-
-import 'io/interface.dart'
-    if (dart.library.io) 'io/vm.dart'
-    if (dart.library.js) 'io/js.dart';
-
-part 'src/annotation.dart';
-part 'src/arabic.dart';
-part 'src/array.dart';
-part 'src/ascii85.dart';
-part 'src/border.dart';
-part 'src/catalog.dart';
-part 'src/color.dart';
-part 'src/colors.dart';
-part 'src/data_types.dart';
-part 'src/document.dart';
-part 'src/encryption.dart';
-part 'src/exif.dart';
-part 'src/font.dart';
-part 'src/font_descriptor.dart';
-part 'src/font_metrics.dart';
-part 'src/formxobject.dart';
-part 'src/function.dart';
-part 'src/graphic_state.dart';
-part 'src/graphic_stream.dart';
-part 'src/graphics.dart';
-part 'src/image.dart';
-part 'src/info.dart';
-part 'src/names.dart';
-part 'src/object.dart';
-part 'src/object_stream.dart';
-part 'src/outline.dart';
-part 'src/output.dart';
-part 'src/page.dart';
-part 'src/page_format.dart';
-part 'src/page_list.dart';
-part 'src/point.dart';
-part 'src/rect.dart';
-part 'src/shading.dart';
-part 'src/signature.dart';
-part 'src/stream.dart';
-part 'src/ttf_parser.dart';
-part 'src/ttf_writer.dart';
-part 'src/ttffont.dart';
-part 'src/type1_font.dart';
-part 'src/type1_fonts.dart';
-part 'src/unicode_cmap.dart';
-part 'src/xobject.dart';
-part 'src/xref.dart';
+export 'src/annotation.dart';
+export 'src/arabic.dart';
+export 'src/border.dart';
+export 'src/color.dart';
+export 'src/colors.dart';
+export 'src/document.dart';
+export 'src/encryption.dart';
+export 'src/exif.dart';
+export 'src/font.dart';
+export 'src/font_metrics.dart';
+export 'src/function.dart';
+export 'src/graphic_state.dart';
+export 'src/graphics.dart';
+export 'src/image.dart';
+export 'src/info.dart';
+export 'src/outline.dart';
+export 'src/page.dart';
+export 'src/page_format.dart';
+export 'src/point.dart';
+export 'src/rect.dart';
+export 'src/shading.dart';
+export 'src/signature.dart';
+export 'src/ttf_parser.dart';
+export 'src/ttffont.dart';

@@ -14,7 +14,21 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'border.dart';
+import 'color.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'font.dart';
+import 'graphic_stream.dart';
+import 'graphics.dart';
+import 'object.dart';
+import 'page.dart';
+import 'point.dart';
+import 'rect.dart';
+import 'stream.dart';
 
 class PdfAnnot extends PdfObject {
   PdfAnnot(this.pdfPage, this.annot)
@@ -31,8 +45,8 @@ class PdfAnnot extends PdfObject {
 
   /// Output the annotation
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
     annot.build(pdfPage, this, params);
   }
 }

@@ -14,12 +14,6 @@
  * limitations under the License.
  */
 
-// https://github.com/agawish/Better-Arabic-Reshaper/tree/master/src/org/amr/arabic
-// http://mpcabd.xyz/python-arabic-text-reshaper/
-// https://github.com/Georeactor/alif-toolkit/tree/master/src
-
-part of pdf;
-
 /// Arabic shape substitutions functions
 class PdfArabic {
   /// Arabic shape substitutions: char code => (isolated, final, initial, medial).
@@ -224,7 +218,7 @@ class PdfArabic {
     return _arabicDiacritics.containsKey(letter);
   }
 
-  static bool _isArabicDiacriticValue(int letter) {
+  static bool isArabicDiacriticValue(int letter) {
     return _arabicDiacritics.containsValue(letter);
   }
 
@@ -240,7 +234,7 @@ class PdfArabic {
     final finalDiacritics = <int>[];
 
     for (var i = 0; i < letters.length; i++) {
-      if (_isArabicDiacriticValue(letters[i])) {
+      if (isArabicDiacriticValue(letters[i])) {
         effectedDiacritics.insert(0, letters[i]);
         if (tmpDiacritic.containsKey(letters[i])) {
           tmpDiacritic = tmpDiacritic[letters[i]];

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+import 'stream.dart';
 
 /// An array object
 class PdfArrayObject extends PdfObject {
@@ -29,8 +32,8 @@ class PdfArrayObject extends PdfObject {
   final PdfArray array;
 
   @override
-  void _writeContent(PdfStream os) {
-    super._writeContent(os);
+  void writeContent(PdfStream os) {
+    super.writeContent(os);
 
     array.output(os);
     os.putBytes(<int>[0x0a]);

@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:convert';
+import 'dart:typed_data';
 
 /// Ascii 85 encoder
 class Ascii85Encoder extends Converter<Uint8List, Uint8List> {

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'annotation.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
 
 /// Border style
 enum PdfBorderStyle {
@@ -58,8 +61,8 @@ class PdfBorder extends PdfObject {
   final List<double> dash;
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     params['/S'] =
         PdfName('/' + 'SDBIU'.substring(style.index, style.index + 1));

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'annotation.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'names.dart';
+import 'object.dart';
+import 'outline.dart';
+import 'page_list.dart';
 
 /// Pdf Catalog object
 class PdfCatalog extends PdfObject {
@@ -41,9 +47,17 @@ class PdfCatalog extends PdfObject {
   /// The initial page mode
   final PdfNames names;
 
+  /// These map the page modes just defined to the pagemodes setting of Pdf.
+  static const List<String> _PdfPageModes = <String>[
+    '/UseNone',
+    '/UseOutlines',
+    '/UseThumbs',
+    '/FullScreen'
+  ];
+
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     /// the PDF specification version, overrides the header version starting from 1.4
     params['/Version'] = PdfName('/${pdfDocument.version}');
@@ -59,7 +73,7 @@ class PdfCatalog extends PdfObject {
     params['/Names'] = names.ref();
 
     // the /PageMode setting
-    params['/PageMode'] = PdfName(PdfDocument._PdfPageModes[pageMode.index]);
+    params['/PageMode'] = PdfName(_PdfPageModes[pageMode.index]);
 
     if (pdfDocument.sign != null) {
       params['/Perms'] = PdfDict(<String, PdfDataType>{

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:math' as math;
 
 /// Represents an RGB color
 class PdfColor {

@@ -14,9 +14,7 @@
  * limitations under the License.
  */
 
-// ignore_for_file: public_member_api_docs
-
-part of pdf;
+import 'color.dart';
 
 /// Material design colors
 class PdfColors {

@@ -14,9 +14,15 @@
  * limitations under the License.
  */
 
-// ignore_for_file: avoid_unused_constructor_parameters
+import 'dart:convert';
+import 'dart:typed_data';
 
-part of pdf;
+import 'package:meta/meta.dart';
+import 'package:utf/utf.dart';
+
+import 'color.dart';
+import 'object.dart';
+import 'stream.dart';
 
 abstract class PdfDataType {
   const PdfDataType();
@@ -97,7 +103,7 @@ class PdfString extends PdfDataType {
     return PdfString(_string(value), PdfStringFormat.litteral);
   }
 
-  factory PdfString.fromStream(PdfObject object, PdfStream value,
+  factory PdfString.fromStream(PdfStream value,
       [PdfStringFormat format = PdfStringFormat.litteral]) {
     return PdfString(value.output(), format);
   }

@@ -14,7 +14,27 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:math' as math;
+import 'dart:typed_data';
+
+import 'package:crypto/crypto.dart';
+
+import '../io/interface.dart'
+    if (dart.library.io) '../io/vm.dart'
+    if (dart.library.js) '../io/js.dart';
+import 'catalog.dart';
+import 'encryption.dart';
+import 'font.dart';
+import 'graphic_state.dart';
+import 'info.dart';
+import 'names.dart';
+import 'object.dart';
+import 'outline.dart';
+import 'output.dart';
+import 'page.dart';
+import 'page_list.dart';
+import 'signature.dart';
+import 'stream.dart';
 
 /// Display hint for the PDF viewer
 enum PdfPageMode {
@@ -102,14 +122,6 @@ class PdfDocument {
   /// The PDF specification version
   final String version = '1.7';
 
-  /// These map the page modes just defined to the pagemodes setting of Pdf.
-  static const List<String> _PdfPageModes = <String>[
-    '/UseNone',
-    '/UseOutlines',
-    '/UseThumbs',
-    '/FullScreen'
-  ];
-
   /// This holds the current fonts
   final Set<PdfFont> fonts = <PdfFont>{};
 
@@ -129,7 +141,7 @@ class PdfDocument {
   }
 
   /// Creates a new serial number
-  int _genSerial() => _objser++;
+  int genSerial() => _objser++;
 
   /// This returns a specific page. It's used mainly when using a
   /// Serialized template file.

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:typed_data';
+
+import 'document.dart';
+import 'object.dart';
 
 /// Encryption object
 abstract class PdfEncryption extends PdfObject {

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'image.dart';
 
 /// Jpeg metadata extraction
 class PdfJpegInfo {

@@ -14,13 +14,25 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:convert';
+
+import 'package:meta/meta.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'font_metrics.dart';
+import 'object.dart';
+import 'point.dart';
+import 'rect.dart';
+import 'stream.dart';
+import 'type1_font.dart';
+import 'type1_fonts.dart';
 
 /// Pdf font object
 abstract class PdfFont extends PdfObject {
   /// Constructs a [PdfFont]. This will attempt to map the font from a known
   /// font name to that in Pdf, defaulting to Helvetica if not possible.
-  PdfFont._create(PdfDocument pdfDocument, {@required this.subtype})
+  PdfFont.create(PdfDocument pdfDocument, {@required this.subtype})
       : assert(subtype != null),
         super(pdfDocument, '/Font') {
     pdfDocument.fonts.add(this);
@@ -28,87 +40,87 @@ abstract class PdfFont extends PdfObject {
 
   /// Monospaced slab serif typeface.
   factory PdfFont.courier(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
+    return PdfType1Font.create(
         pdfDocument, 'Courier', 0.910, -0.220, const <double>[]);
   }
 
   /// Bold monospaced slab serif typeface.
   factory PdfFont.courierBold(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
+    return PdfType1Font.create(
         pdfDocument, 'Courier-Bold', 0.910, -0.220, const <double>[]);
   }
 
   /// Bold and Italic monospaced slab serif typeface.
   factory PdfFont.courierBoldOblique(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
+    return PdfType1Font.create(
         pdfDocument, 'Courier-BoldOblique', 0.910, -0.220, const <double>[]);
   }
 
   /// Italic monospaced slab serif typeface.
   factory PdfFont.courierOblique(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
+    return PdfType1Font.create(
         pdfDocument, 'Courier-Oblique', 0.910, -0.220, const <double>[]);
   }
 
   /// Neo-grotesque design sans-serif typeface
   factory PdfFont.helvetica(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'Helvetica', 0.931, -0.225, _helveticaWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'Helvetica', 0.931, -0.225, helveticaWidths);
   }
 
   /// Bold Neo-grotesque design sans-serif typeface
   factory PdfFont.helveticaBold(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'Helvetica-Bold', 0.962, -0.228, _helveticaBoldWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'Helvetica-Bold', 0.962, -0.228, helveticaBoldWidths);
   }
 
   /// Bold and Italic Neo-grotesque design sans-serif typeface
   factory PdfFont.helveticaBoldOblique(PdfDocument pdfDocument) {
-    return PdfType1Font._create(pdfDocument, 'Helvetica-BoldOblique', 0.962,
-        -0.228, _helveticaBoldObliqueWidths);
+    return PdfType1Font.create(pdfDocument, 'Helvetica-BoldOblique', 0.962,
+        -0.228, helveticaBoldObliqueWidths);
   }
 
   /// Italic Neo-grotesque design sans-serif typeface
   factory PdfFont.helveticaOblique(PdfDocument pdfDocument) {
-    return PdfType1Font._create(pdfDocument, 'Helvetica-Oblique', 0.931, -0.225,
-        _helveticaObliqueWidths);
+    return PdfType1Font.create(pdfDocument, 'Helvetica-Oblique', 0.931, -0.225,
+        helveticaObliqueWidths);
   }
 
   /// Serif typeface commissioned by the British newspaper The Times
   factory PdfFont.times(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'Times-Roman', 0.898, -0.218, _timesWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'Times-Roman', 0.898, -0.218, timesWidths);
   }
 
   /// Bold serif typeface commissioned by the British newspaper The Times
   factory PdfFont.timesBold(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'Times-Bold', 0.935, -0.218, _timesBoldWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'Times-Bold', 0.935, -0.218, timesBoldWidths);
   }
 
   /// Bold and Italic serif typeface commissioned by the British newspaper The Times
   factory PdfFont.timesBoldItalic(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'Times-BoldItalic', 0.921, -0.218, _timesBoldItalicWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'Times-BoldItalic', 0.921, -0.218, timesBoldItalicWidths);
   }
 
   /// Italic serif typeface commissioned by the British newspaper The Times
   factory PdfFont.timesItalic(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'Times-Italic', 0.883, -0.217, _timesItalicWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'Times-Italic', 0.883, -0.217, timesItalicWidths);
   }
 
   /// Complete unaccented serif Greek alphabet (upper and lower case) and a
   /// selection of commonly used mathematical symbols.
   factory PdfFont.symbol(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'Symbol', 1.010, -0.293, _symbolWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'Symbol', 1.010, -0.293, symbolWidths);
   }
 
   /// Hermann Zapf ornament glyphs or spacers, often employed to create box frames
   factory PdfFont.zapfDingbats(PdfDocument pdfDocument) {
-    return PdfType1Font._create(
-        pdfDocument, 'ZapfDingbats', 0.820, -0.143, _zapfDingbatsWidths);
+    return PdfType1Font.create(
+        pdfDocument, 'ZapfDingbats', 0.820, -0.143, zapfDingbatsWidths);
   }
 
   static const String _cannotDecodeMessage =
@@ -142,8 +154,8 @@ See https://github.com/DavBfr/dart_pdf/wiki/Fonts-Management
   int get unitsPerEm;
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     params['/Subtype'] = PdfName(subtype);
     params['/Name'] = PdfName(name);

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'object.dart';
+import 'object_stream.dart';
+import 'ttffont.dart';
 
 /// Font descriptor object
 class PdfFontDescriptor extends PdfObject {
@@ -33,8 +36,8 @@ class PdfFontDescriptor extends PdfObject {
   final PdfTtfFont ttfFont;
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     params['/FontName'] = PdfName('/' + ttfFont.fontName);
     params['/FontFile2'] = file.ref();

@@ -14,7 +14,11 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+
+import 'rect.dart';
 
 /// Describe dimensions for glyphs in a font
 @immutable

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:vector_math/vector_math_64.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'font.dart';
+import 'xobject.dart';
 
 /// Form XObject
 class PdfFormXObject extends PdfXObject {
@@ -38,8 +43,8 @@ class PdfFormXObject extends PdfXObject {
   }
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     // This holds any resources for this FormXObject
     final resources = PdfDict();

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
+
+import 'color.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+import 'object_stream.dart';
 
 abstract class PdfBaseFunction extends PdfObject {
   PdfBaseFunction(PdfDocument pdfDocument) : super(pdfDocument);
@@ -29,7 +35,7 @@ class PdfFunction extends PdfObjectStream implements PdfBaseFunction {
   final List<PdfColor> colors;
 
   @override
-  void _prepare() {
+  void prepare() {
     for (final color in colors) {
       buf.putBytes(<int>[
         (color.red * 255.0).round() & 0xff,
@@ -38,7 +44,7 @@ class PdfFunction extends PdfObjectStream implements PdfBaseFunction {
       ]);
     }
 
-    super._prepare();
+    super.prepare();
 
     params['/FunctionType'] = const PdfNum(0);
     params['/BitsPerSample'] = const PdfNum(8);
@@ -69,8 +75,8 @@ class PdfStitchingFunction extends PdfBaseFunction {
   final double domainEnd;
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     params['/FunctionType'] = const PdfNum(3);
     params['/Functions'] = PdfArray.fromObjects(functions);

@@ -16,7 +16,11 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
 
 /// Graphic state
 @immutable
@@ -71,8 +75,8 @@ class PdfGraphicStates extends PdfObject {
   }
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     for (var index = 0; index < _states.length; index++) {
       params['$_prefix$index'] = _states[index]._output();

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'document.dart';
+import 'font.dart';
+import 'graphic_state.dart';
+import 'object.dart';
+import 'shading.dart';
+import 'xobject.dart';
 
 /// Helper functions for graphic objects
 mixin PdfGraphicStream on PdfObject {
@@ -75,8 +81,8 @@ mixin PdfGraphicStream on PdfObject {
   }
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     // This holds any resources for this page
     final resources = PdfDict();

@@ -14,7 +14,22 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:collection';
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:path_parsing/path_parsing.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'color.dart';
+import 'data_types.dart';
+import 'font.dart';
+import 'graphic_state.dart';
+import 'graphic_stream.dart';
+import 'image.dart';
+import 'page.dart';
+import 'shading.dart';
+import 'stream.dart';
 
 /// Shape to be used at the corners of paths that are stroked
 enum PdfLineJoin {

@@ -14,7 +14,15 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:typed_data';
+
+import 'package:image/image.dart' as im;
+import 'package:meta/meta.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'exif.dart';
+import 'xobject.dart';
 
 /// Represents the position of the first pixel in the data stream
 /// This corresponds to the exif orientations

@@ -14,7 +14,9 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
 
 /// Information object
 class PdfInfo extends PdfObject {

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+import 'page.dart';
 
 /// Pdf Name object
 class PdfNames extends PdfObject {
@@ -46,8 +49,8 @@ class PdfNames extends PdfObject {
   }
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     final dests = PdfArray();
 

@@ -14,7 +14,11 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'stream.dart';
 
 /// Base Object used in the PDF file
 class PdfObject {
@@ -24,7 +28,7 @@ class PdfObject {
     this.pdfDocument, [
     String type,
   ])  : assert(pdfDocument != null),
-        objser = pdfDocument._genSerial() {
+        objser = pdfDocument.genSerial() {
     if (type != null) {
       params['/Type'] = PdfName(type);
     }
@@ -45,16 +49,16 @@ class PdfObject {
   final PdfDocument pdfDocument;
 
   /// Writes the object to the output stream.
-  void _write(PdfStream os) {
-    _prepare();
+  void write(PdfStream os) {
+    prepare();
     _writeStart(os);
-    _writeContent(os);
+    writeContent(os);
     _writeEnd(os);
   }
 
   /// Prepare the object to be written to the stream
   @mustCallSuper
-  void _prepare() {}
+  void prepare() {}
 
   /// The write method should call this before writing anything to the
   /// OutputStream. This will send the standard header for each object.
@@ -62,7 +66,7 @@ class PdfObject {
     os.putString('$objser $objgen obj\n');
   }
 
-  void _writeContent(PdfStream os) {
+  void writeContent(PdfStream os) {
     if (params.isNotEmpty) {
       params.output(os);
       os.putString('\n');

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:typed_data';
+
+import 'ascii85.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+import 'stream.dart';
 
 /// Stream Object
 class PdfObjectStream extends PdfObject {
@@ -34,8 +40,8 @@ class PdfObjectStream extends PdfObject {
   Uint8List _data;
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     if (params.containsKey('/Filter') && _data == null) {
       // The data is already in the right format
@@ -67,8 +73,8 @@ class PdfObjectStream extends PdfObject {
   }
 
   @override
-  void _writeContent(PdfStream os) {
-    super._writeContent(os);
+  void writeContent(PdfStream os) {
+    super.writeContent(os);
 
     os.putString('stream\n');
     os.putBytes(_data);

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'color.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+import 'page.dart';
+import 'rect.dart';
 
 /// Outline mode
 enum PdfOutlineMode {
@@ -96,8 +101,8 @@ class PdfOutline extends PdfObject {
   }
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     // These are for kids only
     if (parent != null) {

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'catalog.dart';
+import 'data_types.dart';
+import 'encryption.dart';
+import 'info.dart';
+import 'object.dart';
+import 'signature.dart';
+import 'stream.dart';
+import 'xref.dart';
 
 /// PDF document writer
 class PdfOutput {
@@ -61,7 +68,7 @@ class PdfOutput {
     }
 
     offsets.add(PdfXref(ob.objser, os.offset));
-    ob._write(os);
+    ob.write(os);
   }
 
   /// This closes the Stream, writing the xref table
@@ -138,7 +145,7 @@ class PdfOutput {
     os.putString('\nstartxref\n$xref\n%%EOF\n');
 
     if (signatureID != null) {
-      signatureID._writeSignature(os);
+      signatureID.writeSignature(os);
     }
   }
 

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'annotation.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'graphic_stream.dart';
+import 'graphics.dart';
+import 'object.dart';
+import 'object_stream.dart';
+import 'page_format.dart';
 
 /// Page object, which will hold any contents for this page.
 class PdfPage extends PdfObject with PdfGraphicStream {
@@ -55,8 +62,8 @@ class PdfPage extends PdfObject with PdfGraphicStream {
   }
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     // the /Parent pages object
     params['/Parent'] = pdfDocument.pdfPageList.ref();

@@ -14,7 +14,9 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:math' as math;
+
+import 'point.dart';
 
 class PdfPageFormat {
   const PdfPageFormat(this.width, this.height,

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+import 'page.dart';
 
 /// PdfPageList object
 class PdfPageList extends PdfObject {
@@ -28,8 +31,8 @@ class PdfPageList extends PdfObject {
   PdfPage getPage(int page) => pages[page];
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     params['/Kids'] = PdfArray.fromObjects(pages);
     params['/Count'] = PdfNum(pages.length);

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
 
 @immutable
 class PdfPoint {

@@ -14,7 +14,9 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
+
+import 'point.dart';
 
 @immutable
 class PdfRect {

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'function.dart';
+import 'object.dart';
+import 'point.dart';
+import 'rect.dart';
 
 enum PdfShadingType { axial, radial }
 
@@ -60,8 +67,8 @@ class PdfShading extends PdfObject {
   final double radius1;
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     params['/ShadingType'] = PdfNum(shadingType.index + 2);
     if (boundingBox != null) {

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'package:meta/meta.dart';
+
+import 'data_types.dart';
+import 'document.dart';
+import 'object.dart';
+import 'stream.dart';
 
 enum PdfSigFlags { signaturesExist, appendOnly }
 
@@ -39,15 +44,15 @@ class PdfSignature extends PdfObject {
   int _offsetEnd;
 
   @override
-  void _write(PdfStream os) {
+  void write(PdfStream os) {
     crypto.preSign(this, params);
 
     _offsetStart = os.offset + '$objser $objgen obj\n'.length;
-    super._write(os);
+    super.write(os);
     _offsetEnd = os.offset;
   }
 
-  void _writeSignature(PdfStream os) {
+  void writeSignature(PdfStream os) {
     assert(_offsetStart != null && _offsetEnd != null,
         'Must reserve the object space before signing the document');
 

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:typed_data';
 
 class PdfStream {
   static const int _grow = 65536;

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:convert';
+import 'dart:math' as math;
+import 'dart:typed_data';
+
+import 'package:meta/meta.dart';
+import 'package:utf/utf.dart';
+
+import 'font_metrics.dart';
 
 @immutable
 class TtfGlyphInfo {

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:math' as math;
+import 'dart:typed_data';
+
+import 'ttf_parser.dart';
 
 /// Generate a TTF font copy with the minimal number of glyph to embedd
 /// into the PDF document

@@ -14,13 +14,27 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'arabic.dart';
+import 'array.dart';
+import 'data_types.dart';
+import 'document.dart';
+import 'font.dart';
+import 'font_descriptor.dart';
+import 'font_metrics.dart';
+import 'object_stream.dart';
+import 'stream.dart';
+import 'ttf_parser.dart';
+import 'ttf_writer.dart';
+import 'unicode_cmap.dart';
 
 class PdfTtfFont extends PdfFont {
   /// Constructs a [PdfTtfFont]
   PdfTtfFont(PdfDocument pdfDocument, ByteData bytes, {bool protect = false})
       : font = TtfParser(bytes),
-        super._create(pdfDocument, subtype: '/TrueType') {
+        super.create(pdfDocument, subtype: '/TrueType') {
     file = PdfObjectStream(pdfDocument, isBinary: true);
     unicodeCMap = PdfUnicodeCmap(pdfDocument, protect);
     descriptor = PdfFontDescriptor(this, file);
@@ -60,7 +74,7 @@ class PdfTtfFont extends PdfFont {
       return PdfFontMetrics.zero;
     }
 
-    if (PdfArabic._isArabicDiacriticValue(charCode)) {
+    if (PdfArabic.isArabicDiacriticValue(charCode)) {
       final metric = font.glyphInfoMap[g] ?? PdfFontMetrics.zero;
       return metric.copyWith(advanceWidth: 0);
     }
@@ -130,8 +144,8 @@ class PdfTtfFont extends PdfFont {
   }
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     if (font.unicode) {
       _buildType0(params);

@@ -14,7 +14,11 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'document.dart';
+import 'font.dart';
+import 'font_metrics.dart';
+import 'ttffont.dart';
 
 /// Type 1 font object.
 /// this font is a default PDF font available in all PDF readers,
@@ -26,14 +30,14 @@ part of pdf;
 /// see https://github.com/DavBfr/dart_pdf/wiki/Fonts-Management
 class PdfType1Font extends PdfFont {
   /// Constructs a [PdfTtfFont]
-  PdfType1Font._create(PdfDocument pdfDocument, this.fontName, this.ascent,
+  PdfType1Font.create(PdfDocument pdfDocument, this.fontName, this.ascent,
       this.descent, this.widths)
       : assert(() {
           print(
               '$fontName has no Unicode support see https://github.com/DavBfr/dart_pdf/wiki/Fonts-Management');
           return true;
         }()),
-        super._create(pdfDocument, subtype: '/Type1');
+        super.create(pdfDocument, subtype: '/Type1');
 
   @override
   final String fontName;
@@ -51,8 +55,8 @@ class PdfType1Font extends PdfFont {
   final List<double> widths;
 
   @override
-  void _prepare() {
-    super._prepare();
+  void prepare() {
+    super.prepare();
 
     params['/BaseFont'] = PdfName('/' + fontName);
   }

@@ -14,9 +14,7 @@
  * limitations under the License.
  */
 
-part of pdf;
-
-const List<double> _helveticaWidths = <double>[
+const List<double> helveticaWidths = <double>[
   0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, //
   0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, //
   0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, 0.500, //
@@ -45,7 +43,7 @@ const List<double> _helveticaWidths = <double>[
   0.500
 ];
 
-const List<double> _helveticaBoldWidths = <double>[
+const List<double> helveticaBoldWidths = <double>[
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
@@ -74,7 +72,7 @@ const List<double> _helveticaBoldWidths = <double>[
   0.556
 ];
 
-const List<double> _helveticaBoldObliqueWidths = <double>[
+const List<double> helveticaBoldObliqueWidths = <double>[
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
@@ -103,7 +101,7 @@ const List<double> _helveticaBoldObliqueWidths = <double>[
   0.556
 ];
 
-const List<double> _helveticaObliqueWidths = <double>[
+const List<double> helveticaObliqueWidths = <double>[
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
   0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, 0.278, //
@@ -132,7 +130,7 @@ const List<double> _helveticaObliqueWidths = <double>[
   0.500
 ];
 
-const List<double> _timesWidths = <double>[
+const List<double> timesWidths = <double>[
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
@@ -161,7 +159,7 @@ const List<double> _timesWidths = <double>[
   0.500, 0.500, 0.500, 0.500
 ];
 
-const List<double> _timesBoldWidths = <double>[
+const List<double> timesBoldWidths = <double>[
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
@@ -189,7 +187,7 @@ const List<double> _timesBoldWidths = <double>[
   0.500, 0.570, 0.500, 0.556, 0.556, 0.556, 0.556, 0.500, 0.556, 0.500
 ];
 
-const List<double> _timesBoldItalicWidths = <double>[
+const List<double> timesBoldItalicWidths = <double>[
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
@@ -218,7 +216,7 @@ const List<double> _timesBoldItalicWidths = <double>[
   0.556, 0.444, 0.500, 0.444
 ];
 
-const List<double> _timesItalicWidths = <double>[
+const List<double> timesItalicWidths = <double>[
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
   0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, 0.250, //
@@ -247,7 +245,7 @@ const List<double> _timesItalicWidths = <double>[
   0.500, 0.500, 0.444, 0.500, 0.444
 ];
 
-const List<double> _symbolWidths = <double>[
+const List<double> symbolWidths = <double>[
   0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, //
   0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, //
   0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, 0.587, //
@@ -276,7 +274,7 @@ const List<double> _symbolWidths = <double>[
   0.384, 0.494, 0.494, 0.494, 0.587
 ];
 
-const List<double> _zapfDingbatsWidths = <double>[
+const List<double> zapfDingbatsWidths = <double>[
   0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, //
   0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, //
   0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, 0.746, //

@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'document.dart';
+import 'object_stream.dart';
 
 /// Unicode character map object
 class PdfUnicodeCmap extends PdfObjectStream {
@@ -28,7 +29,7 @@ class PdfUnicodeCmap extends PdfObjectStream {
   final bool protect;
 
   @override
-  void _prepare() {
+  void prepare() {
     if (protect) {
       cmap.fillRange(1, cmap.length, 0x20);
     }
@@ -62,6 +63,6 @@ class PdfUnicodeCmap extends PdfObjectStream {
         'CMapName currentdict /CMap defineresource pop\n'
         'end\n'
         'end');
-    super._prepare();
+    super.prepare();
   }
 }

@@ -14,7 +14,9 @@
  * limitations under the License.
  */
 
-part of pdf;
+import 'data_types.dart';
+import 'document.dart';
+import 'object_stream.dart';
 
 class PdfXObject extends PdfObjectStream {
   PdfXObject(PdfDocument pdfDocument, String subtype, {bool isBinary = false})

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-part of pdf;
-
 /// Cross-reference for a Pdf Object
 class PdfXref {
   /// Creates a cross-reference for a Pdf Object

@@ -14,54 +14,41 @@
  * limitations under the License.
  */
 
-library widget;
-
-import 'dart:collection';
-import 'dart:convert';
-import 'dart:math' as math;
-import 'dart:typed_data';
-
-import 'package:barcode/barcode.dart';
-import 'package:image/image.dart' as im;
-import 'package:meta/meta.dart';
-import 'package:pdf/pdf.dart';
-import 'package:vector_math/vector_math_64.dart';
-
 export 'package:barcode/barcode.dart';
 
-part 'widgets/annotations.dart';
-part 'widgets/barcode.dart';
-part 'widgets/basic.dart';
-part 'widgets/chart/bar_chart.dart';
-part 'widgets/chart/chart.dart';
-part 'widgets/chart/grid_axis.dart';
-part 'widgets/chart/grid_cartesian.dart';
-part 'widgets/chart/legend.dart';
-part 'widgets/chart/line_chart.dart';
-part 'widgets/clip.dart';
-part 'widgets/container.dart';
-part 'widgets/content.dart';
-part 'widgets/decoration.dart';
-part 'widgets/document.dart';
-part 'widgets/flex.dart';
-part 'widgets/font.dart';
-part 'widgets/forms.dart';
-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';
-part 'widgets/partitions.dart';
-part 'widgets/placeholders.dart';
-part 'widgets/progress.dart';
-part 'widgets/qrcode.dart';
-part 'widgets/stack.dart';
-part 'widgets/table.dart';
-part 'widgets/text.dart';
-part 'widgets/text_style.dart';
-part 'widgets/theme.dart';
-part 'widgets/widget.dart';
-part 'widgets/wrap.dart';
+export 'widgets/annotations.dart';
+export 'widgets/barcode.dart';
+export 'widgets/basic.dart';
+export 'widgets/chart/bar_chart.dart';
+export 'widgets/chart/chart.dart';
+export 'widgets/chart/grid_axis.dart';
+export 'widgets/chart/grid_cartesian.dart';
+export 'widgets/chart/legend.dart';
+export 'widgets/chart/line_chart.dart';
+export 'widgets/clip.dart';
+export 'widgets/container.dart';
+export 'widgets/content.dart';
+export 'widgets/decoration.dart';
+export 'widgets/document.dart';
+export 'widgets/flex.dart';
+export 'widgets/font.dart';
+export 'widgets/forms.dart';
+export 'widgets/geometry.dart';
+export 'widgets/grid_view.dart';
+export 'widgets/icon.dart';
+export 'widgets/image.dart';
+export 'widgets/image_provider.dart';
+export 'widgets/multi_page.dart';
+export 'widgets/page.dart';
+export 'widgets/page_theme.dart';
+export 'widgets/partitions.dart';
+export 'widgets/placeholders.dart';
+export 'widgets/progress.dart';
+export 'widgets/qrcode.dart';
+export 'widgets/stack.dart';
+export 'widgets/table.dart';
+export 'widgets/text.dart';
+export 'widgets/text_style.dart';
+export 'widgets/theme.dart';
+export 'widgets/widget.dart';
+export 'widgets/wrap.dart';

@@ -14,7 +14,15 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'basic.dart';
+import 'geometry.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 class Anchor extends SingleChildWidget {
   Anchor({

@@ -14,7 +14,21 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:barcode/barcode.dart';
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'basic.dart';
+import 'container.dart';
+import 'decoration.dart';
+import 'font.dart';
+import 'geometry.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 class _BarcodeWidget extends Widget {
   _BarcodeWidget({

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'container.dart';
+import 'decoration.dart';
+import 'geometry.dart';
+import 'widget.dart';
 
 enum BoxFit { fill, contain, cover, fitWidth, fitHeight, none, scaleDown }
 

@@ -14,7 +14,15 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import '../flex.dart';
+import '../geometry.dart';
+import '../widget.dart';
+import 'chart.dart';
+import 'grid_cartesian.dart';
+import 'line_chart.dart';
 
 class BarDataSet extends Dataset {
   BarDataSet({

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import '../container.dart';
+import '../decoration.dart';
+import '../flex.dart';
+import '../geometry.dart';
+import '../stack.dart';
+import '../widget.dart';
 
 /// This widget is in preview and the API is subject to change
 class Chart extends Widget implements Inherited {

@@ -14,7 +14,17 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:pdf/pdf.dart';
+
+import '../flex.dart';
+import '../geometry.dart';
+import '../text_style.dart';
+import '../theme.dart';
+import '../widget.dart';
+import 'chart.dart';
+import 'grid_cartesian.dart';
 
 typedef GridAxisFormat = String Function(num value);
 
@@ -53,7 +63,7 @@ abstract class GridAxis extends Widget {
 
   final double margin;
 
-  double _crossAxisPosition = 0;
+  double crossAxisPosition = 0;
 
   double _textMargin;
 
@@ -173,7 +183,7 @@ class FixedAxis<T extends num> extends GridAxis {
   double toChart(num input) {
     final offset = transfer(values.first);
     final total = transfer(values.last) - offset;
-    final start = _crossAxisPosition + _marginStart;
+    final start = crossAxisPosition + _marginStart;
     switch (direction) {
       case Axis.horizontal:
         return box.left +
@@ -219,7 +229,7 @@ class FixedAxis<T extends num> extends GridAxis {
         _axisTick ??= false;
         final minStart = metricsFirst.maxWidth / 2;
         _marginEnd = math.max(_marginEnd, metrics.maxWidth / 2);
-        _crossAxisPosition = math.max(_crossAxisPosition, minStart);
+        crossAxisPosition = math.max(crossAxisPosition, minStart);
         axisPosition = math.max(axisPosition, maxHeight + _textMargin);
         box = PdfRect(0, 0, size.x, axisPosition);
         break;
@@ -229,7 +239,7 @@ class FixedAxis<T extends num> extends GridAxis {
         _marginEnd = math.max(_marginEnd, metrics.maxHeight / 2);
         final minStart = metricsFirst.maxHeight / 2;
         _marginEnd = math.max(_marginEnd, metrics.maxWidth / 2);
-        _crossAxisPosition = math.max(_crossAxisPosition, minStart);
+        crossAxisPosition = math.max(crossAxisPosition, minStart);
         axisPosition = math.max(axisPosition, maxWidth + _textMargin);
         box = PdfRect(0, 0, axisPosition, size.y);
         break;
@@ -239,13 +249,13 @@ class FixedAxis<T extends num> extends GridAxis {
   void _drawYValues(Context context) {
     context.canvas
       ..moveTo(axisPosition, box.top)
-      ..lineTo(axisPosition, box.bottom + _crossAxisPosition);
+      ..lineTo(axisPosition, box.bottom + crossAxisPosition);
 
     if (_axisTick && _textMargin > 0) {
       context.canvas
-        ..moveTo(axisPosition, box.bottom + _crossAxisPosition)
+        ..moveTo(axisPosition, box.bottom + crossAxisPosition)
         ..lineTo(
-            axisPosition - _textMargin / 2, box.bottom + _crossAxisPosition);
+            axisPosition - _textMargin / 2, box.bottom + crossAxisPosition);
     }
 
     if (ticks && _textMargin > 0) {
@@ -284,13 +294,13 @@ class FixedAxis<T extends num> extends GridAxis {
 
   void _drawXValues(Context context) {
     context.canvas
-      ..moveTo(box.left + _crossAxisPosition, axisPosition)
+      ..moveTo(box.left + crossAxisPosition, axisPosition)
       ..lineTo(box.right, axisPosition);
 
     if (_axisTick && _textMargin > 0) {
       context.canvas
-        ..moveTo(box.left + _crossAxisPosition, axisPosition)
-        ..lineTo(box.left + _crossAxisPosition, axisPosition - _textMargin);
+        ..moveTo(box.left + crossAxisPosition, axisPosition)
+        ..lineTo(box.left + crossAxisPosition, axisPosition - _textMargin);
     }
 
     if (ticks && _textMargin > 0) {
@@ -379,8 +389,8 @@ class FixedAxis<T extends num> extends GridAxis {
       case Axis.vertical:
         context.canvas
           ..setFillColor(PdfColors.grey300)
-          ..drawRect(box.x, box.y + _crossAxisPosition, box.width,
-              box.height - _crossAxisPosition)
+          ..drawRect(box.x, box.y + crossAxisPosition, box.width,
+              box.height - crossAxisPosition)
           ..fillPath();
         break;
     }

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import '../flex.dart';
+import '../geometry.dart';
+import '../widget.dart';
+import 'chart.dart';
+import 'grid_axis.dart';
 
 class CartesianGrid extends ChartGrid {
   CartesianGrid({
@@ -41,18 +50,18 @@ class CartesianGrid extends ChartGrid {
     // In simple conditions, this loop will run only 2 times.
     var count = 5;
     while (count-- > 0) {
-      _xAxis._crossAxisPosition = _yAxis.axisPosition;
+      _xAxis.crossAxisPosition = _yAxis.axisPosition;
       _xAxis.axisPosition =
-          math.max(_xAxis.axisPosition, _yAxis._crossAxisPosition);
+          math.max(_xAxis.axisPosition, _yAxis.crossAxisPosition);
       _xAxis.layout(context, constraints);
       assert(_xAxis.box != null);
-      _yAxis._crossAxisPosition = _xAxis.axisPosition;
+      _yAxis.crossAxisPosition = _xAxis.axisPosition;
       _yAxis.axisPosition =
-          math.max(_yAxis.axisPosition, _xAxis._crossAxisPosition);
+          math.max(_yAxis.axisPosition, _xAxis.crossAxisPosition);
       _yAxis.layout(context, constraints);
       assert(_yAxis.box != null);
-      if (_yAxis._crossAxisPosition == _xAxis.axisPosition &&
-          _xAxis._crossAxisPosition == _yAxis.axisPosition) {
+      if (_yAxis.crossAxisPosition == _xAxis.axisPosition &&
+          _xAxis.crossAxisPosition == _yAxis.axisPosition) {
         break;
       }
     }

@@ -14,7 +14,19 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:pdf/pdf.dart';
+
+import '../basic.dart';
+import '../container.dart';
+import '../decoration.dart';
+import '../flex.dart';
+import '../geometry.dart';
+import '../text.dart';
+import '../text_style.dart';
+import '../theme.dart';
+import '../widget.dart';
+import '../wrap.dart';
+import 'chart.dart';
 
 class ChartLegend extends StatelessWidget {
   ChartLegend({

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import '../geometry.dart';
+import '../widget.dart';
+import 'chart.dart';
+import 'grid_cartesian.dart';
 
 class LineChartValue extends ChartValue {
   const LineChartValue(this.x, this.y);

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'widget.dart';
 
 class ClipRect extends SingleChildWidget {
   ClipRect({Widget child}) : super(child: child);

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'basic.dart';
+import 'decoration.dart';
+import 'geometry.dart';
+import 'widget.dart';
 
 class DecoratedBox extends SingleChildWidget {
   DecoratedBox(

@@ -14,7 +14,21 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'annotations.dart';
+import 'basic.dart';
+import 'container.dart';
+import 'decoration.dart';
+import 'flex.dart';
+import 'geometry.dart';
+import 'text.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 class Header extends StatelessWidget {
   Header({

@@ -14,7 +14,17 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:image/image.dart' as im;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'basic.dart';
+import 'geometry.dart';
+import 'image_provider.dart';
+import 'widget.dart';
 
 enum DecorationPosition { background, foreground }
 

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:typed_data';
+
+import 'package:pdf/pdf.dart';
+
+import 'page.dart';
+import 'theme.dart';
 
 class Document {
   Document(

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'basic.dart';
+import 'geometry.dart';
+import 'multi_page.dart';
+import 'widget.dart';
 
 enum FlexFit {
   tight,

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:typed_data';
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'widget.dart';
 
 enum Type1Fonts {
   courier,

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'container.dart';
+import 'decoration.dart';
+import 'geometry.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 class Checkbox extends SingleChildWidget {
   Checkbox({

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'basic.dart';
 
 @immutable
 class BoxConstraints {

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'flex.dart';
+import 'geometry.dart';
+import 'multi_page.dart';
+import 'widget.dart';
 
 class _GridViewContext extends WidgetContext {
   int firstChild = 0;

@@ -14,7 +14,17 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'basic.dart';
+import 'font.dart';
+import 'geometry.dart';
+import 'text.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 /// A description of an icon fulfilled by a font glyph.
 @immutable

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'basic.dart';
+import 'geometry.dart';
+import 'image_provider.dart';
+import 'widget.dart';
 
 void _paintImage({
   @required PdfGraphics canvas,

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:typed_data';
+
+import 'package:image/image.dart' as im;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'widget.dart';
 
 /// Identifies an image without committing to the precise final asset
 abstract class ImageProvider {

@@ -14,7 +14,21 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'document.dart';
+import 'flex.dart';
+import 'geometry.dart';
+import 'page.dart';
+import 'page_theme.dart';
+import 'text.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 abstract class WidgetContext {
   WidgetContext clone();

@@ -14,7 +14,19 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'document.dart';
+import 'geometry.dart';
+import 'page_theme.dart';
+import 'text.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 typedef BuildCallback = Widget Function(Context context);
 typedef BuildListCallback = List<Widget> Function(Context context);
@@ -84,12 +96,10 @@ class Page {
       ..fillPath();
   }
 
-  @protected
   void generate(Document document) {
     _pdfPage = PdfPage(document.document, pageFormat: pageFormat);
   }
 
-  @protected
   void postProcess(Document document) {
     final canvas = _pdfPage.getGraphics();
     final _margin = margin;

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'geometry.dart';
+import 'page.dart';
+import 'text.dart';
+import 'theme.dart';
 
 @immutable
 class PageTheme {

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'flex.dart';
+import 'geometry.dart';
+import 'multi_page.dart';
+import 'widget.dart';
 
 class Partition implements SpanningWidget {
   Partition({

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:pdf/pdf.dart';
+
+import 'basic.dart';
+import 'geometry.dart';
+import 'image.dart';
+import 'text.dart';
+import 'text_style.dart';
+import 'widget.dart';
 
 class Placeholder extends Widget {
   Placeholder(

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'geometry.dart';
+import 'widget.dart';
 
 class CircularProgressIndicator extends Widget {
   CircularProgressIndicator(

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:barcode/barcode.dart';
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'barcode.dart';
+import 'decoration.dart';
+import 'geometry.dart';
+import 'widget.dart';
 
 typedef QrError = void Function(dynamic error);
 

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'geometry.dart';
+import 'widget.dart';
 
 /// How to size the non-positioned children of a [Stack].
 enum StackFit { loose, expand, passthrough }

@@ -14,7 +14,21 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'container.dart';
+import 'decoration.dart';
+import 'flex.dart';
+import 'geometry.dart';
+import 'multi_page.dart';
+import 'text.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 /// A horizontal group of cells in a [Table].
 @immutable

@@ -14,7 +14,17 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'annotations.dart';
+import 'document.dart';
+import 'geometry.dart';
+import 'text_style.dart';
+import 'theme.dart';
+import 'widget.dart';
 
 enum TextAlign { left, right, center, justify }
 

@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+
+import 'decoration.dart';
+import 'font.dart';
+import 'text.dart';
+import 'widget.dart';
 
 enum FontWeight { normal, bold }
 

@@ -14,7 +14,14 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'package:meta/meta.dart';
+
+import 'basic.dart';
+import 'font.dart';
+import 'icon.dart';
+import 'text.dart';
+import 'text_style.dart';
+import 'widget.dart';
 
 @immutable
 class ThemeData extends Inherited {

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:collection';
+import 'dart:math' as math;
+
+import 'package:meta/meta.dart';
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'document.dart';
+import 'geometry.dart';
+import 'page.dart';
 
 @immutable
 class Context {
@@ -106,13 +115,11 @@ abstract class Widget {
 
   /// First widget pass to calculate the children layout and
   /// bounding [box]
-  @protected
   void layout(Context context, BoxConstraints constraints,
       {bool parentUsesSize = false});
 
   /// Draw itself and its children, according to the calculated
   /// [box.offset]
-  @protected
   @mustCallSuper
   void paint(Context context) {
     assert(() {

@@ -14,7 +14,15 @@
  * limitations under the License.
  */
 
-part of widget;
+import 'dart:math' as math;
+
+import 'package:pdf/pdf.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+import 'flex.dart';
+import 'geometry.dart';
+import 'multi_page.dart';
+import 'widget.dart';
 
 /// How [Wrap] should align objects.
 enum WrapAlignment {

@@ -16,7 +16,7 @@
 
 import 'dart:typed_data';
 
-import 'package:pdf/pdf.dart';
+import 'package:pdf/src/data_types.dart';
 import 'package:test/test.dart';
 
 void main() {

@@ -17,6 +17,7 @@
 import 'dart:io';
 
 import 'package:pdf/pdf.dart';
+import 'package:pdf/src/ttf_writer.dart';
 import 'package:test/test.dart';
 
 void printText(