Move TextStyle class to its own file

@@ -43,6 +43,7 @@ part 'widgets/progress.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';

+/*
+ * 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;
+
+enum FontWeight { normal, bold }
+
+enum FontStyle { normal, italic }
+
+@immutable
+class TextStyle {
+  const TextStyle({
+    this.inherit = true,
+    this.color,
+    Font font,
+    Font fontNormal,
+    Font fontBold,
+    Font fontItalic,
+    Font fontBoldItalic,
+    this.fontSize,
+    this.fontWeight,
+    this.fontStyle,
+    this.letterSpacing,
+    this.wordSpacing,
+    this.lineSpacing,
+    this.height,
+    this.background,
+  })  : assert(inherit || color != null),
+        assert(inherit || font != null),
+        assert(inherit || fontSize != null),
+        assert(inherit || fontWeight != null),
+        assert(inherit || fontStyle != null),
+        assert(inherit || letterSpacing != null),
+        assert(inherit || wordSpacing != null),
+        assert(inherit || lineSpacing != null),
+        assert(inherit || height != null),
+        fontNormal = fontNormal ??
+            (fontStyle != FontStyle.italic && fontWeight != FontWeight.bold
+                ? font
+                : null),
+        fontBold = fontBold ??
+            (fontStyle != FontStyle.italic && fontWeight == FontWeight.bold
+                ? font
+                : null),
+        fontItalic = fontItalic ??
+            (fontStyle == FontStyle.italic && fontWeight != FontWeight.bold
+                ? font
+                : null),
+        fontBoldItalic = fontBoldItalic ??
+            (fontStyle == FontStyle.italic && fontWeight == FontWeight.bold
+                ? font
+                : null);
+
+  factory TextStyle.defaultStyle() {
+    return TextStyle(
+      color: PdfColors.black,
+      fontNormal: Font.helvetica(),
+      fontBold: Font.helveticaBold(),
+      fontItalic: Font.helveticaOblique(),
+      fontBoldItalic: Font.helveticaBoldOblique(),
+      fontSize: _defaultFontSize,
+      fontWeight: FontWeight.normal,
+      fontStyle: FontStyle.normal,
+      letterSpacing: 1.0,
+      wordSpacing: 1.0,
+      lineSpacing: 0.0,
+      height: 1.0,
+    );
+  }
+
+  final bool inherit;
+
+  final PdfColor color;
+
+  final Font fontNormal;
+
+  final Font fontBold;
+
+  final Font fontItalic;
+
+  final Font fontBoldItalic;
+
+  // font height, in pdf unit
+  final double fontSize;
+
+  /// The typeface thickness to use when painting the text (e.g., bold).
+  final FontWeight fontWeight;
+
+  /// The typeface variant to use when drawing the letters (e.g., italics).
+  final FontStyle fontStyle;
+
+  static const double _defaultFontSize = 12.0 * PdfPageFormat.point;
+
+  // spacing between letters, 1.0 being natural spacing
+  final double letterSpacing;
+
+  // spacing between lines, in pdf unit
+  final double lineSpacing;
+
+  // spacing between words, 1.0 being natural spacing
+  final double wordSpacing;
+
+  final double height;
+
+  final PdfColor background;
+
+  TextStyle copyWith({
+    PdfColor color,
+    Font font,
+    Font fontNormal,
+    Font fontBold,
+    Font fontItalic,
+    Font fontBoldItalic,
+    double fontSize,
+    FontWeight fontWeight,
+    FontStyle fontStyle,
+    double letterSpacing,
+    double wordSpacing,
+    double lineSpacing,
+    double height,
+    PdfColor background,
+  }) {
+    return TextStyle(
+      inherit: inherit,
+      color: color ?? this.color,
+      font: font ?? this.font,
+      fontNormal: fontNormal ?? this.fontNormal,
+      fontBold: fontBold ?? this.fontBold,
+      fontItalic: fontItalic ?? this.fontItalic,
+      fontBoldItalic: fontBoldItalic ?? this.fontBoldItalic,
+      fontSize: fontSize ?? this.fontSize,
+      fontWeight: fontWeight ?? this.fontWeight,
+      fontStyle: fontStyle ?? this.fontStyle,
+      letterSpacing: letterSpacing ?? this.letterSpacing,
+      wordSpacing: wordSpacing ?? this.wordSpacing,
+      lineSpacing: lineSpacing ?? this.lineSpacing,
+      height: height ?? this.height,
+      background: background ?? this.background,
+    );
+  }
+
+  /// Creates a copy of this text style replacing or altering the specified
+  /// properties.
+  TextStyle apply({
+    PdfColor color,
+    Font font,
+    Font fontNormal,
+    Font fontBold,
+    Font fontItalic,
+    Font fontBoldItalic,
+    double fontSizeFactor = 1.0,
+    double fontSizeDelta = 0.0,
+    double letterSpacingFactor = 1.0,
+    double letterSpacingDelta = 0.0,
+    double wordSpacingFactor = 1.0,
+    double wordSpacingDelta = 0.0,
+    double heightFactor = 1.0,
+    double heightDelta = 0.0,
+  }) {
+    assert(fontSizeFactor != null);
+    assert(fontSizeDelta != null);
+    assert(fontSize != null || (fontSizeFactor == 1.0 && fontSizeDelta == 0.0));
+    assert(letterSpacingFactor != null);
+    assert(letterSpacingDelta != null);
+    assert(letterSpacing != null ||
+        (letterSpacingFactor == 1.0 && letterSpacingDelta == 0.0));
+    assert(wordSpacingFactor != null);
+    assert(wordSpacingDelta != null);
+    assert(wordSpacing != null ||
+        (wordSpacingFactor == 1.0 && wordSpacingDelta == 0.0));
+    assert(heightFactor != null);
+    assert(heightDelta != null);
+    assert(heightFactor != null || (heightFactor == 1.0 && heightDelta == 0.0));
+
+    return TextStyle(
+      inherit: inherit,
+      color: color ?? this.color,
+      font: font ?? this.font,
+      fontNormal: fontNormal ?? this.fontNormal,
+      fontBold: fontBold ?? this.fontBold,
+      fontItalic: fontItalic ?? this.fontItalic,
+      fontBoldItalic: fontBoldItalic ?? this.fontBoldItalic,
+      fontSize:
+          fontSize == null ? null : fontSize * fontSizeFactor + fontSizeDelta,
+      fontWeight: fontWeight,
+      fontStyle: fontStyle,
+      letterSpacing: letterSpacing == null
+          ? null
+          : letterSpacing * letterSpacingFactor + letterSpacingDelta,
+      wordSpacing: wordSpacing == null
+          ? null
+          : wordSpacing * wordSpacingFactor + wordSpacingDelta,
+      height: height == null ? null : height * heightFactor + heightDelta,
+      background: background,
+    );
+  }
+
+  /// Returns a new text style that is a combination of this style and the given
+  /// [other] style.
+  TextStyle merge(TextStyle other) {
+    if (other == null) {
+      return this;
+    }
+
+    if (!other.inherit) {
+      return other;
+    }
+
+    return copyWith(
+      color: other.color,
+      font: other.font,
+      fontNormal: other.fontNormal,
+      fontBold: other.fontBold,
+      fontItalic: other.fontItalic,
+      fontBoldItalic: other.fontBoldItalic,
+      fontSize: other.fontSize,
+      fontWeight: other.fontWeight,
+      fontStyle: other.fontStyle,
+      letterSpacing: other.letterSpacing,
+      wordSpacing: other.wordSpacing,
+      lineSpacing: other.lineSpacing,
+      height: other.height,
+      background: other.background,
+    );
+  }
+
+  @Deprecated('use font instead')
+  Font get paintFont => font;
+
+  Font get font {
+    if (fontWeight != FontWeight.bold) {
+      if (fontStyle != FontStyle.italic) {
+        // normal
+        return fontNormal ?? fontBold ?? fontItalic ?? fontBoldItalic;
+      } else {
+        // italic
+        return fontItalic ?? fontNormal ?? fontBold ?? fontBoldItalic;
+      }
+    } else {
+      if (fontStyle != FontStyle.italic) {
+        // bold
+        return fontBold ?? fontNormal ?? fontItalic ?? fontBoldItalic;
+      } else {
+        // bold + italic
+        return fontBoldItalic ?? fontBold ?? fontItalic ?? fontNormal;
+      }
+    }
+  }
+
+  @override
+  String toString() =>
+      'TextStyle(color:$color font:$font size:$fontSize weight:$fontWeight style:$fontStyle letterSpacing:$letterSpacing wordSpacing:$wordSpacing lineSpacing:$lineSpacing height:$height background:$background)';
+}

@@ -16,255 +16,6 @@
 
 part of widget;
 
-enum FontWeight { normal, bold }
-
-enum FontStyle { normal, italic }
-
-@immutable
-class TextStyle {
-  const TextStyle({
-    this.inherit = true,
-    this.color,
-    Font font,
-    Font fontNormal,
-    Font fontBold,
-    Font fontItalic,
-    Font fontBoldItalic,
-    this.fontSize,
-    this.fontWeight,
-    this.fontStyle,
-    this.letterSpacing,
-    this.wordSpacing,
-    this.lineSpacing,
-    this.height,
-    this.background,
-  })  : assert(inherit || color != null),
-        assert(inherit || font != null),
-        assert(inherit || fontSize != null),
-        assert(inherit || fontWeight != null),
-        assert(inherit || fontStyle != null),
-        assert(inherit || letterSpacing != null),
-        assert(inherit || wordSpacing != null),
-        assert(inherit || lineSpacing != null),
-        assert(inherit || height != null),
-        fontNormal = fontNormal ??
-            (fontStyle != FontStyle.italic && fontWeight != FontWeight.bold
-                ? font
-                : null),
-        fontBold = fontBold ??
-            (fontStyle != FontStyle.italic && fontWeight == FontWeight.bold
-                ? font
-                : null),
-        fontItalic = fontItalic ??
-            (fontStyle == FontStyle.italic && fontWeight != FontWeight.bold
-                ? font
-                : null),
-        fontBoldItalic = fontBoldItalic ??
-            (fontStyle == FontStyle.italic && fontWeight == FontWeight.bold
-                ? font
-                : null);
-
-  factory TextStyle.defaultStyle() {
-    return TextStyle(
-      color: PdfColors.black,
-      fontNormal: Font.helvetica(),
-      fontBold: Font.helveticaBold(),
-      fontItalic: Font.helveticaOblique(),
-      fontBoldItalic: Font.helveticaBoldOblique(),
-      fontSize: _defaultFontSize,
-      fontWeight: FontWeight.normal,
-      fontStyle: FontStyle.normal,
-      letterSpacing: 1.0,
-      wordSpacing: 1.0,
-      lineSpacing: 0.0,
-      height: 1.0,
-    );
-  }
-
-  final bool inherit;
-
-  final PdfColor color;
-
-  final Font fontNormal;
-
-  final Font fontBold;
-
-  final Font fontItalic;
-
-  final Font fontBoldItalic;
-
-  // font height, in pdf unit
-  final double fontSize;
-
-  /// The typeface thickness to use when painting the text (e.g., bold).
-  final FontWeight fontWeight;
-
-  /// The typeface variant to use when drawing the letters (e.g., italics).
-  final FontStyle fontStyle;
-
-  static const double _defaultFontSize = 12.0 * PdfPageFormat.point;
-
-  // spacing between letters, 1.0 being natural spacing
-  final double letterSpacing;
-
-  // spacing between lines, in pdf unit
-  final double lineSpacing;
-
-  // spacing between words, 1.0 being natural spacing
-  final double wordSpacing;
-
-  final double height;
-
-  final PdfColor background;
-
-  TextStyle copyWith({
-    PdfColor color,
-    Font font,
-    Font fontNormal,
-    Font fontBold,
-    Font fontItalic,
-    Font fontBoldItalic,
-    double fontSize,
-    FontWeight fontWeight,
-    FontStyle fontStyle,
-    double letterSpacing,
-    double wordSpacing,
-    double lineSpacing,
-    double height,
-    PdfColor background,
-  }) {
-    return TextStyle(
-      inherit: inherit,
-      color: color ?? this.color,
-      font: font ?? this.font,
-      fontNormal: fontNormal ?? this.fontNormal,
-      fontBold: fontBold ?? this.fontBold,
-      fontItalic: fontItalic ?? this.fontItalic,
-      fontBoldItalic: fontBoldItalic ?? this.fontBoldItalic,
-      fontSize: fontSize ?? this.fontSize,
-      fontWeight: fontWeight ?? this.fontWeight,
-      fontStyle: fontStyle ?? this.fontStyle,
-      letterSpacing: letterSpacing ?? this.letterSpacing,
-      wordSpacing: wordSpacing ?? this.wordSpacing,
-      lineSpacing: lineSpacing ?? this.lineSpacing,
-      height: height ?? this.height,
-      background: background ?? this.background,
-    );
-  }
-
-  /// Creates a copy of this text style replacing or altering the specified
-  /// properties.
-  TextStyle apply({
-    PdfColor color,
-    Font font,
-    Font fontNormal,
-    Font fontBold,
-    Font fontItalic,
-    Font fontBoldItalic,
-    double fontSizeFactor = 1.0,
-    double fontSizeDelta = 0.0,
-    double letterSpacingFactor = 1.0,
-    double letterSpacingDelta = 0.0,
-    double wordSpacingFactor = 1.0,
-    double wordSpacingDelta = 0.0,
-    double heightFactor = 1.0,
-    double heightDelta = 0.0,
-  }) {
-    assert(fontSizeFactor != null);
-    assert(fontSizeDelta != null);
-    assert(fontSize != null || (fontSizeFactor == 1.0 && fontSizeDelta == 0.0));
-    assert(letterSpacingFactor != null);
-    assert(letterSpacingDelta != null);
-    assert(letterSpacing != null ||
-        (letterSpacingFactor == 1.0 && letterSpacingDelta == 0.0));
-    assert(wordSpacingFactor != null);
-    assert(wordSpacingDelta != null);
-    assert(wordSpacing != null ||
-        (wordSpacingFactor == 1.0 && wordSpacingDelta == 0.0));
-    assert(heightFactor != null);
-    assert(heightDelta != null);
-    assert(heightFactor != null || (heightFactor == 1.0 && heightDelta == 0.0));
-
-    return TextStyle(
-      inherit: inherit,
-      color: color ?? this.color,
-      font: font ?? this.font,
-      fontNormal: fontNormal ?? this.fontNormal,
-      fontBold: fontBold ?? this.fontBold,
-      fontItalic: fontItalic ?? this.fontItalic,
-      fontBoldItalic: fontBoldItalic ?? this.fontBoldItalic,
-      fontSize:
-          fontSize == null ? null : fontSize * fontSizeFactor + fontSizeDelta,
-      fontWeight: fontWeight,
-      fontStyle: fontStyle,
-      letterSpacing: letterSpacing == null
-          ? null
-          : letterSpacing * letterSpacingFactor + letterSpacingDelta,
-      wordSpacing: wordSpacing == null
-          ? null
-          : wordSpacing * wordSpacingFactor + wordSpacingDelta,
-      height: height == null ? null : height * heightFactor + heightDelta,
-      background: background,
-    );
-  }
-
-  /// Returns a new text style that is a combination of this style and the given
-  /// [other] style.
-  TextStyle merge(TextStyle other) {
-    if (other == null) {
-      return this;
-    }
-
-    if (!other.inherit) {
-      return other;
-    }
-
-    return copyWith(
-      color: other.color,
-      font: other.font,
-      fontNormal: other.fontNormal,
-      fontBold: other.fontBold,
-      fontItalic: other.fontItalic,
-      fontBoldItalic: other.fontBoldItalic,
-      fontSize: other.fontSize,
-      fontWeight: other.fontWeight,
-      fontStyle: other.fontStyle,
-      letterSpacing: other.letterSpacing,
-      wordSpacing: other.wordSpacing,
-      lineSpacing: other.lineSpacing,
-      height: other.height,
-      background: other.background,
-    );
-  }
-
-  @Deprecated('use font instead')
-  Font get paintFont => font;
-
-  Font get font {
-    if (fontWeight != FontWeight.bold) {
-      if (fontStyle != FontStyle.italic) {
-        // normal
-        return fontNormal ?? fontBold ?? fontItalic ?? fontBoldItalic;
-      } else {
-        // italic
-        return fontItalic ?? fontNormal ?? fontBold ?? fontBoldItalic;
-      }
-    } else {
-      if (fontStyle != FontStyle.italic) {
-        // bold
-        return fontBold ?? fontNormal ?? fontItalic ?? fontBoldItalic;
-      } else {
-        // bold + italic
-        return fontBoldItalic ?? fontBold ?? fontItalic ?? fontNormal;
-      }
-    }
-  }
-
-  @override
-  String toString() =>
-      'TextStyle(color:$color font:$font size:$fontSize weight:$fontWeight style:$fontStyle letterSpacing:$letterSpacing wordSpacing:$wordSpacing lineSpacing:$lineSpacing height:$height background:$background)';
-}
-
 @immutable
 class Theme extends Inherited {
   const Theme({