Add RTL support to BorderRadius widget

Add RTL support Alignment

@@ -16,15 +16,10 @@
 
 
 import 'dart:math' as math;
 import 'dart:math' as math;
 
 
-import 'package:pdf/widgets.dart';
 import 'package:vector_math/vector_math_64.dart';
 import 'package:vector_math/vector_math_64.dart';
 
 
 import '../../pdf.dart';
 import '../../pdf.dart';
-import 'box_border.dart';
-import 'container.dart';
-import 'decoration.dart';
-import 'geometry.dart';
-import 'widget.dart';
+import '../../widgets.dart';
 
 
 enum BoxFit { fill, contain, cover, fitWidth, fitHeight, none, scaleDown }
 enum BoxFit { fill, contain, cover, fitWidth, fitHeight, none, scaleDown }
 
 
@@ -303,7 +298,7 @@ class Align extends SingleChildWidget {
         super(child: child);
         super(child: child);
 
 
   /// How to align the child.
   /// How to align the child.
-  final Alignment alignment;
+  final AlignmentGeometry alignment;
 
 
   /// If non-null, sets its width to the child's width multiplied by this factor.
   /// If non-null, sets its width to the child's width multiplied by this factor.
   final double? widthFactor;
   final double? widthFactor;
@@ -330,8 +325,8 @@ class Align extends SingleChildWidget {
           height: shrinkWrapHeight
           height: shrinkWrapHeight
               ? child!.box!.height * (heightFactor ?? 1.0)
               ? child!.box!.height * (heightFactor ?? 1.0)
               : double.infinity);
               : double.infinity);
-
-      child!.box = alignment.inscribe(child!.box!.size, box!);
+      final resolvedAlignment = alignment.resolve(Directionality.of(context));
+      child!.box = resolvedAlignment.inscribe(child!.box!.size, box!);
     } else {
     } else {
       box = constraints.constrainRect(
       box = constraints.constrainRect(
           width: shrinkWrapWidth ? 0.0 : double.infinity,
           width: shrinkWrapWidth ? 0.0 : double.infinity,

@@ -14,8 +14,10 @@
  * limitations under the License.
  * limitations under the License.
  */
  */
 
 
+import 'package:meta/meta.dart';
+
 import '../../pdf.dart';
 import '../../pdf.dart';
-import 'widget.dart';
+import '../../widgets.dart';
 
 
 /// A radius for either circular or elliptical shapes.
 /// A radius for either circular or elliptical shapes.
 class Radius {
 class Radius {
@@ -35,8 +37,149 @@ class Radius {
   static const Radius zero = Radius.circular(0.0);
   static const Radius zero = Radius.circular(0.0);
 }
 }
 
 
+/// Base class for [BorderRadius] that allows for text-direction aware resolution.
+///
+/// A property or argument of this type accepts classes created either with [
+/// BorderRadius.only] and its variants, or [BorderRadiusDirectional.only]
+/// and its variants.
+///
+/// To convert a [BorderRadiusGeometry] object of indeterminate type into a
+/// [BorderRadius] object, call the [resolve] method.
+@immutable
+abstract class BorderRadiusGeometry {
+  /// Abstract const constructor. This constructor enables subclasses to provide
+  /// const constructors so that they can be used in const expressions.
+  const BorderRadiusGeometry();
+
+  Radius get _topLeft;
+
+  Radius get _topRight;
+
+  Radius get _bottomLeft;
+
+  Radius get _bottomRight;
+
+  Radius get _topStart;
+
+  Radius get _topEnd;
+
+  Radius get _bottomStart;
+
+  Radius get _bottomEnd;
+
+  Radius get uniform;
+
+  bool get isUniform;
+
+  /// Convert this instance into a [BorderRadius], so that the radii are
+  /// expressed for specific physical corners (top-left, top-right, etc) rather
+  /// than in a direction-dependent manner.
+  ///
+  /// See also:
+  ///
+  ///  * [BorderRadius], for which this is a no-op (returns itself).
+  ///  * [BorderRadiusDirectional], which flips the horizontal direction
+  ///    based on the `direction` argument.
+  BorderRadius resolve(TextDirection? direction);
+
+  @override
+  String toString() {
+    String? visual, logical;
+    if (_topLeft == _topRight && _topRight == _bottomLeft && _bottomLeft == _bottomRight) {
+      if (_topLeft != Radius.zero) {
+        if (_topLeft.x == _topLeft.y) {
+          visual = 'BorderRadius.circular(${_topLeft.x.toStringAsFixed(1)})';
+        } else {
+          visual = 'BorderRadius.all($_topLeft)';
+        }
+      }
+    } else {
+      // visuals aren't the same and at least one isn't zero
+      final result = StringBuffer();
+      result.write('BorderRadius.only(');
+      var comma = false;
+      if (_topLeft != Radius.zero) {
+        result.write('topLeft: $_topLeft');
+        comma = true;
+      }
+      if (_topRight != Radius.zero) {
+        if (comma) {
+          result.write(', ');
+        }
+        result.write('topRight: $_topRight');
+        comma = true;
+      }
+      if (_bottomLeft != Radius.zero) {
+        if (comma) {
+          result.write(', ');
+        }
+        result.write('bottomLeft: $_bottomLeft');
+        comma = true;
+      }
+      if (_bottomRight != Radius.zero) {
+        if (comma) {
+          result.write(', ');
+        }
+        result.write('bottomRight: $_bottomRight');
+      }
+      result.write(')');
+      visual = result.toString();
+    }
+    if (_topStart == _topEnd && _topEnd == _bottomEnd && _bottomEnd == _bottomStart) {
+      if (_topStart != Radius.zero) {
+        if (_topStart.x == _topStart.y) {
+          logical = 'BorderRadiusDirectional.circular(${_topStart.x.toStringAsFixed(1)})';
+        } else {
+          logical = 'BorderRadiusDirectional.all($_topStart)';
+        }
+      }
+    } else {
+      // logical aren't the same and at least one isn't zero
+      final result = StringBuffer();
+      result.write('BorderRadiusDirectional.only(');
+      var comma = false;
+      if (_topStart != Radius.zero) {
+        result.write('topStart: $_topStart');
+        comma = true;
+      }
+      if (_topEnd != Radius.zero) {
+        if (comma) {
+          result.write(', ');
+        }
+        result.write('topEnd: $_topEnd');
+        comma = true;
+      }
+      if (_bottomStart != Radius.zero) {
+        if (comma) {
+          result.write(', ');
+        }
+        result.write('bottomStart: $_bottomStart');
+        comma = true;
+      }
+      if (_bottomEnd != Radius.zero) {
+        if (comma) {
+          result.write(', ');
+        }
+        result.write('bottomEnd: $_bottomEnd');
+      }
+      result.write(')');
+      logical = result.toString();
+    }
+    if (visual != null && logical != null) {
+      return '$visual + $logical';
+    }
+    if (visual != null) {
+      return visual;
+    }
+    if (logical != null) {
+      return logical;
+    }
+    return 'BorderRadius.zero';
+  }
+}
+
 /// An immutable set of radii for each corner of a rectangle.
 /// An immutable set of radii for each corner of a rectangle.
-class BorderRadius {
+class BorderRadius extends BorderRadiusGeometry {
   /// Creates a border radius where all radii are [radius].
   /// Creates a border radius where all radii are [radius].
   const BorderRadius.all(Radius radius)
   const BorderRadius.all(Radius radius)
       : this.only(
       : this.only(
@@ -85,6 +228,8 @@ class BorderRadius {
     this.bottomRight = Radius.zero,
     this.bottomRight = Radius.zero,
   });
   });
 
 
+
+
   /// A border radius with all zero radii.
   /// A border radius with all zero radii.
   static const BorderRadius zero = BorderRadius.all(Radius.zero);
   static const BorderRadius zero = BorderRadius.all(Radius.zero);
 
 
@@ -100,6 +245,14 @@ class BorderRadius {
   /// The bottom-right [Radius].
   /// The bottom-right [Radius].
   final Radius bottomRight;
   final Radius bottomRight;
 
 
+
+  @override
+  bool get isUniform => topLeft == topRight && topLeft == bottomLeft && topLeft == bottomRight;
+
+  @override
+  Radius get uniform => isUniform ? topLeft : Radius.zero;
+
+
   void paint(Context context, PdfRect box) {
   void paint(Context context, PdfRect box) {
     // Ellipse 4-spline magic number
     // Ellipse 4-spline magic number
     const _m4 = 0.551784;
     const _m4 = 0.551784;
@@ -108,23 +261,13 @@ class BorderRadius {
       // Start
       // Start
       ..moveTo(box.x, box.y + bottomLeft.y)
       ..moveTo(box.x, box.y + bottomLeft.y)
       // bottomLeft
       // bottomLeft
-      ..curveTo(
-          box.x,
-          box.y - _m4 * bottomLeft.y + bottomLeft.y,
-          box.x - _m4 * bottomLeft.x + bottomLeft.x,
-          box.y,
-          box.x + bottomLeft.x,
-          box.y)
+      ..curveTo(box.x, box.y - _m4 * bottomLeft.y + bottomLeft.y, box.x - _m4 * bottomLeft.x + bottomLeft.x, box.y,
+          box.x + bottomLeft.x, box.y)
       // bottom
       // bottom
       ..lineTo(box.x + box.width - bottomRight.x, box.y)
       ..lineTo(box.x + box.width - bottomRight.x, box.y)
       // bottomRight
       // bottomRight
-      ..curveTo(
-          box.x + _m4 * bottomRight.x + box.width - bottomRight.x,
-          box.y,
-          box.x + box.width,
-          box.y - _m4 * bottomRight.y + bottomRight.y,
-          box.x + box.width,
-          box.y + bottomRight.y)
+      ..curveTo(box.x + _m4 * bottomRight.x + box.width - bottomRight.x, box.y, box.x + box.width,
+          box.y - _m4 * bottomRight.y + bottomRight.y, box.x + box.width, box.y + bottomRight.y)
       // right
       // right
       ..lineTo(box.x + box.width, box.y + box.height - topRight.y)
       ..lineTo(box.x + box.width, box.y + box.height - topRight.y)
       // topRight
       // topRight
@@ -138,14 +281,165 @@ class BorderRadius {
       // top
       // top
       ..lineTo(box.x + topLeft.x, box.y + box.height)
       ..lineTo(box.x + topLeft.x, box.y + box.height)
       // topLeft
       // topLeft
-      ..curveTo(
-          box.x - _m4 * topLeft.x + topLeft.x,
-          box.y + box.height,
-          box.x,
-          box.y + _m4 * topLeft.y + box.height - topLeft.y,
-          box.x,
-          box.y + box.height - topLeft.y)
+      ..curveTo(box.x - _m4 * topLeft.x + topLeft.x, box.y + box.height, box.x,
+          box.y + _m4 * topLeft.y + box.height - topLeft.y, box.x, box.y + box.height - topLeft.y)
       // left
       // left
       ..lineTo(box.x, box.y + bottomLeft.y);
       ..lineTo(box.x, box.y + bottomLeft.y);
   }
   }
+
+  @override
+  Radius get _topLeft => topLeft;
+
+  @override
+  Radius get _topRight => topRight;
+
+  @override
+  Radius get _bottomLeft => bottomLeft;
+
+  @override
+  Radius get _bottomRight => bottomRight;
+
+  @override
+  Radius get _topStart => Radius.zero;
+
+  @override
+  Radius get _topEnd => Radius.zero;
+
+  @override
+  Radius get _bottomStart => Radius.zero;
+
+  @override
+  Radius get _bottomEnd => Radius.zero;
+
+  @override
+  BorderRadius resolve(TextDirection? direction) => this;
+}
+
+/// An immutable set of radii for each corner of a rectangle, but with the
+/// corners specified in a manner dependent on the writing direction.
+///
+/// This can be used to specify a corner radius on the leading or trailing edge
+/// of a box, so that it flips to the other side when the text alignment flips
+/// (e.g. being on the top right in English text but the top left in Arabic
+/// text).
+///
+/// See also:
+///
+///  * [BorderRadius], a variant that uses physical labels (`topLeft` and
+///    `topRight` instead of `topStart` and `topEnd`).
+class BorderRadiusDirectional extends BorderRadiusGeometry {
+  /// Creates a border radius where all radii are [radius].
+  const BorderRadiusDirectional.all(Radius radius) : this.only(
+    topStart: radius,
+    topEnd: radius,
+    bottomStart: radius,
+    bottomEnd: radius,
+  );
+
+  /// Creates a border radius where all radii are [Radius.circular(radius)].
+  BorderRadiusDirectional.circular(double radius) : this.all(
+    Radius.circular(radius),
+  );
+
+  /// Creates a vertically symmetric border radius where the top and bottom
+  /// sides of the rectangle have the same radii.
+  const BorderRadiusDirectional.vertical({
+    Radius top = Radius.zero,
+    Radius bottom = Radius.zero,
+  }) : this.only(
+    topStart: top,
+    topEnd: top,
+    bottomStart: bottom,
+    bottomEnd: bottom,
+  );
+
+  /// Creates a horizontally symmetrical border radius where the start and end
+  /// sides of the rectangle have the same radii.
+  const BorderRadiusDirectional.horizontal({
+    Radius start = Radius.zero,
+    Radius end = Radius.zero,
+  }) : this.only(
+    topStart: start,
+    topEnd: end,
+    bottomStart: start,
+    bottomEnd: end,
+  );
+
+  /// Creates a border radius with only the given non-zero values. The other
+  /// corners will be right angles.
+  const BorderRadiusDirectional.only({
+    this.topStart = Radius.zero,
+    this.topEnd = Radius.zero,
+    this.bottomStart = Radius.zero,
+    this.bottomEnd = Radius.zero,
+  });
+
+  /// A border radius with all zero radii.
+  ///
+  /// Consider using [BorderRadius.zero] instead, since that object has the same
+  /// effect, but will be cheaper to [resolve].
+  static const BorderRadiusDirectional zero = BorderRadiusDirectional.all(Radius.zero);
+
+  /// The top-start [Radius].
+  final Radius topStart;
+
+  @override
+  Radius get _topStart => topStart;
+
+  /// The top-end [Radius].
+  final Radius topEnd;
+
+  @override
+  Radius get _topEnd => topEnd;
+
+  /// The bottom-start [Radius].
+  final Radius bottomStart;
+
+  @override
+  Radius get _bottomStart => bottomStart;
+
+  /// The bottom-end [Radius].
+  final Radius bottomEnd;
+
+  @override
+  Radius get _bottomEnd => bottomEnd;
+
+  @override
+  Radius get _topLeft => Radius.zero;
+
+  @override
+  Radius get _topRight => Radius.zero;
+
+  @override
+  Radius get _bottomLeft => Radius.zero;
+
+  @override
+  Radius get _bottomRight => Radius.zero;
+
+  @override
+  bool get isUniform => topStart == topEnd && topStart == bottomStart && topStart == bottomEnd;
+
+  @override
+  Radius get uniform => isUniform ? topStart : Radius.zero;
+
+  @override
+  BorderRadius resolve(TextDirection? direction) {
+    assert(direction != null);
+    switch (direction!) {
+      case TextDirection.rtl:
+        return BorderRadius.only(
+          topLeft: topEnd,
+          topRight: topStart,
+          bottomLeft: bottomEnd,
+          bottomRight: bottomStart,
+        );
+      case TextDirection.ltr:
+        return BorderRadius.only(
+          topLeft: topStart,
+          topRight: topEnd,
+          bottomLeft: bottomStart,
+          bottomRight: bottomEnd,
+        );
+    }
+  }
 }
 }

@@ -20,12 +20,7 @@ import 'package:meta/meta.dart';
 import 'package:vector_math/vector_math_64.dart';
 import 'package:vector_math/vector_math_64.dart';
 
 
 import '../../pdf.dart';
 import '../../pdf.dart';
-import 'basic.dart';
-import 'border_radius.dart';
-import 'box_border.dart';
-import 'geometry.dart';
-import 'image_provider.dart';
-import 'widget.dart';
+import '../../widgets.dart';
 
 
 enum DecorationPosition { background, foreground }
 enum DecorationPosition { background, foreground }
 
 
@@ -271,7 +266,7 @@ class BoxDecoration {
   /// The color to fill in the background of the box.
   /// The color to fill in the background of the box.
   final PdfColor? color;
   final PdfColor? color;
   final BoxBorder? border;
   final BoxBorder? border;
-  final BorderRadius? borderRadius;
+  final BorderRadiusGeometry? borderRadius;
   final BoxShape shape;
   final BoxShape shape;
   final DecorationGraphic? image;
   final DecorationGraphic? image;
   final Gradient? gradient;
   final Gradient? gradient;
@@ -282,11 +277,12 @@ class BoxDecoration {
     PdfRect box, [
     PdfRect box, [
     PaintPhase phase = PaintPhase.all,
     PaintPhase phase = PaintPhase.all,
   ]) {
   ]) {
+    final resolvedBorderRadius = borderRadius?.resolve(Directionality.of(context));
     if (phase == PaintPhase.all || phase == PaintPhase.background) {
     if (phase == PaintPhase.all || phase == PaintPhase.background) {
       if (color != null) {
       if (color != null) {
         switch (shape) {
         switch (shape) {
           case BoxShape.rectangle:
           case BoxShape.rectangle:
-            if (borderRadius == null) {
+            if (resolvedBorderRadius == null) {
               if (boxShadow != null) {
               if (boxShadow != null) {
                 for (final s in boxShadow!) {
                 for (final s in boxShadow!) {
                   final i = PdfRasterBase.shadowRect(box.width, box.height,
                   final i = PdfRasterBase.shadowRect(box.width, box.height,
@@ -313,7 +309,7 @@ class BoxDecoration {
                   );
                   );
                 }
                 }
               }
               }
-              borderRadius!.paint(context, box);
+              resolvedBorderRadius.paint(context, box);
             }
             }
             break;
             break;
           case BoxShape.circle:
           case BoxShape.circle:
@@ -341,10 +337,10 @@ class BoxDecoration {
       if (gradient != null) {
       if (gradient != null) {
         switch (shape) {
         switch (shape) {
           case BoxShape.rectangle:
           case BoxShape.rectangle:
-            if (borderRadius == null) {
+            if (resolvedBorderRadius == null) {
               context.canvas.drawBox(box);
               context.canvas.drawBox(box);
             } else {
             } else {
-              borderRadius!.paint(context, box);
+              resolvedBorderRadius.paint(context, box);
             }
             }
             break;
             break;
           case BoxShape.circle:
           case BoxShape.circle:
@@ -367,8 +363,8 @@ class BoxDecoration {
 
 
             break;
             break;
           case BoxShape.rectangle:
           case BoxShape.rectangle:
-            if (borderRadius != null) {
-              borderRadius!.paint(context, box);
+            if (resolvedBorderRadius!= null) {
+              resolvedBorderRadius.paint(context, box);
               context.canvas.clipPath();
               context.canvas.clipPath();
             }
             }
             break;
             break;
@@ -384,7 +380,7 @@ class BoxDecoration {
           context,
           context,
           box,
           box,
           shape: shape,
           shape: shape,
-          borderRadius: borderRadius,
+          borderRadius: resolvedBorderRadius,
         );
         );
       }
       }
     }
     }

@@ -16,14 +16,10 @@
 
 
 import 'dart:math' as math;
 import 'dart:math' as math;
 
 
-import 'package:pdf/widgets.dart';
 import 'package:vector_math/vector_math_64.dart';
 import 'package:vector_math/vector_math_64.dart';
 
 
 import '../../pdf.dart';
 import '../../pdf.dart';
-import 'basic.dart';
-import 'geometry.dart';
-import 'multi_page.dart';
-import 'widget.dart';
+import '../../widgets.dart';
 
 
 enum FlexFit {
 enum FlexFit {
   tight,
   tight,

@@ -146,7 +146,7 @@ class Checkbox extends SingleChildWidget with AnnotationAppearance {
     BoxDecoration? decoration,
     BoxDecoration? decoration,
   })  : radius = decoration?.shape == BoxShape.circle
   })  : radius = decoration?.shape == BoxShape.circle
             ? Radius.circular(math.max(height, width) / 2)
             ? Radius.circular(math.max(height, width) / 2)
-            : decoration?.borderRadius?.topLeft ?? Radius.zero,
+            : decoration?.borderRadius?.uniform ?? Radius.zero,
         super(
         super(
             child: Container(
             child: Container(
                 width: width,
                 width: width,

@@ -566,7 +566,35 @@ class EdgeInsetsDirectional extends EdgeInsetsGeometry {
   }
   }
 }
 }
 
 
-class Alignment {
+/// Base class for [Alignment] that allows for text-direction aware
+/// resolution.
+///
+/// A property or argument of this type accepts classes created either with [
+/// Alignment] and its variants, or [AlignmentDirectional.new].
+///
+/// To convert an [AlignmentGeometry] object of indeterminate type into an
+/// [Alignment] object, call the [resolve] method.
+@immutable
+abstract class AlignmentGeometry {
+  /// Abstract const constructor. This constructor enables subclasses to provide
+  /// const constructors so that they can be used in const expressions.
+  const AlignmentGeometry();
+
+
+  /// Convert this instance into an [Alignment], which uses literal
+  /// coordinates (the `x` coordinate being explicitly a distance from the
+  /// left).
+  ///
+  /// See also:
+  ///
+  ///  * [Alignment], for which this is a no-op (returns itself).
+  ///  * [AlignmentDirectional], which flips the horizontal direction
+  ///    based on the `direction` argument.
+  Alignment resolve(TextDirection? direction);
+
+}
+
+class Alignment extends AlignmentGeometry {
   const Alignment(this.x, this.y);
   const Alignment(this.x, this.y);
 
 
   /// The distance fraction in the horizontal direction.
   /// The distance fraction in the horizontal direction.
@@ -633,9 +661,169 @@ class Alignment {
   }
   }
 
 
   @override
   @override
-  String toString() => '($x, $y)';
+  String toString() => _stringify(x, y);
+
+  static String _stringify(double x, double y) {
+    if (x == -1.0 && y == -1.0) {
+      return 'Alignment.topLeft';
+    }
+    if (x == 0.0 && y == -1.0) {
+      return 'Alignment.topCenter';
+    }
+    if (x == 1.0 && y == -1.0) {
+      return 'Alignment.topRight';
+    }
+    if (x == -1.0 && y == 0.0) {
+      return 'Alignment.centerLeft';
+    }
+    if (x == 0.0 && y == 0.0) {
+      return 'Alignment.center';
+    }
+    if (x == 1.0 && y == 0.0) {
+      return 'Alignment.centerRight';
+    }
+    if (x == -1.0 && y == 1.0) {
+      return 'Alignment.bottomLeft';
+    }
+    if (x == 0.0 && y == 1.0) {
+      return 'Alignment.bottomCenter';
+    }
+    if (x == 1.0 && y == 1.0) {
+      return 'Alignment.bottomRight';
+    }
+    return 'Alignment(${x.toStringAsFixed(1)}, '
+        '${y.toStringAsFixed(1)})';
+  }
+
+  @override
+  Alignment resolve(TextDirection? direction) => this;
+}
+
+/// An offset that's expressed as a fraction of a [Size], but whose horizontal
+/// component is dependent on the writing direction.
+///
+/// This can be used to indicate an offset from the left in [TextDirection.ltr]
+/// text and an offset from the right in [TextDirection.rtl] text without having
+/// to be aware of the current text direction.
+///
+/// See also:
+///
+///  * [Alignment], a variant that is defined in physical terms (i.e.
+///    whose horizontal component does not depend on the text direction).
+class AlignmentDirectional extends AlignmentGeometry {
+  /// Creates a directional alignment.
+  ///
+  /// The [start] and [y] arguments must not be null.
+  const AlignmentDirectional(this.start, this.y);
+
+  /// The distance fraction in the horizontal direction.
+  ///
+  /// A value of -1.0 corresponds to the edge on the "start" side, which is the
+  /// left side in [TextDirection.ltr] contexts and the right side in
+  /// [TextDirection.rtl] contexts. A value of 1.0 corresponds to the opposite
+  /// edge, the "end" side. Values are not limited to that range; values less
+  /// than -1.0 represent positions beyond the start edge, and values greater than
+  /// 1.0 represent positions beyond the end edge.
+  ///
+  /// This value is normalized into an [Alignment.x] value by the [resolve]
+  /// method.
+  final double start;
+
+  /// The distance fraction in the vertical direction.
+  ///
+  /// A value of -1.0 corresponds to the topmost edge. A value of 1.0
+  /// corresponds to the bottommost edge. Values are not limited to that range;
+  /// values less than -1.0 represent positions above the top, and values
+  /// greater than 1.0 represent positions below the bottom.
+  ///
+  /// This value is passed through to [Alignment.y] unmodified by the
+  /// [resolve] method.
+  final double y;
+
+  /// The top corner on the "start" side.
+  static const AlignmentDirectional topStart = AlignmentDirectional(-1.0, -1.0);
+
+  /// The center point along the top edge.
+  ///
+  /// Consider using [Alignment.topCenter] instead, as it does not need
+  /// to be [resolve]d to be used.
+  static const AlignmentDirectional topCenter = AlignmentDirectional(0.0, -1.0);
+
+  /// The top corner on the "end" side.
+  static const AlignmentDirectional topEnd = AlignmentDirectional(1.0, -1.0);
+
+  /// The center point along the "start" edge.
+  static const AlignmentDirectional centerStart = AlignmentDirectional(-1.0, 0.0);
+
+  /// The center point, both horizontally and vertically.
+  ///
+  /// Consider using [Alignment.center] instead, as it does not need to
+  /// be [resolve]d to be used.
+  static const AlignmentDirectional center = AlignmentDirectional(0.0, 0.0);
+
+  /// The center point along the "end" edge.
+  static const AlignmentDirectional centerEnd = AlignmentDirectional(1.0, 0.0);
+
+  /// The bottom corner on the "start" side.
+  static const AlignmentDirectional bottomStart = AlignmentDirectional(-1.0, 1.0);
+
+  /// The center point along the bottom edge.
+  ///
+  /// Consider using [Alignment.bottomCenter] instead, as it does not
+  /// need to be [resolve]d to be used.
+  static const AlignmentDirectional bottomCenter = AlignmentDirectional(0.0, 1.0);
+
+  /// The bottom corner on the "end" side.
+  static const AlignmentDirectional bottomEnd = AlignmentDirectional(1.0, 1.0);
+
+  static String _stringify(double start, double y) {
+    if (start == -1.0 && y == -1.0) {
+      return 'AlignmentDirectional.topStart';
+    }
+    if (start == 0.0 && y == -1.0) {
+      return 'AlignmentDirectional.topCenter';
+    }
+    if (start == 1.0 && y == -1.0) {
+      return 'AlignmentDirectional.topEnd';
+    }
+    if (start == -1.0 && y == 0.0) {
+      return 'AlignmentDirectional.centerStart';
+    }
+    if (start == 0.0 && y == 0.0) {
+      return 'AlignmentDirectional.center';
+    }
+    if (start == 1.0 && y == 0.0) {
+      return 'AlignmentDirectional.centerEnd';
+    }
+    if (start == -1.0 && y == 1.0) {
+      return 'AlignmentDirectional.bottomStart';
+    }
+    if (start == 0.0 && y == 1.0) {
+      return 'AlignmentDirectional.bottomCenter';
+    }
+    if (start == 1.0 && y == 1.0) {
+      return 'AlignmentDirectional.bottomEnd';
+    }
+    return 'AlignmentDirectional(${start.toStringAsFixed(1)}, '
+        '${y.toStringAsFixed(1)})';
+  }
+
+  @override
+  String toString() => _stringify(start, y);
+
+  @override
+  Alignment resolve(TextDirection? direction) {
+    assert(direction != null, 'Cannot resolve $runtimeType without a TextDirection.');
+    switch (direction!) {
+      case TextDirection.rtl:
+        return Alignment(-start, y);
+      case TextDirection.ltr:
+        return Alignment(start, y);
+    }
+  }
 }
 }
 
 
+
 /// An offset that's expressed as a fraction of a [PdfPoint].
 /// An offset that's expressed as a fraction of a [PdfPoint].
 @immutable
 @immutable
 class FractionalOffset extends Alignment {
 class FractionalOffset extends Alignment {

@@ -16,14 +16,10 @@
 
 
 import 'dart:math' as math;
 import 'dart:math' as math;
 
 
-import 'package:pdf/widgets.dart';
 import 'package:vector_math/vector_math_64.dart';
 import 'package:vector_math/vector_math_64.dart';
 
 
 import '../../pdf.dart';
 import '../../pdf.dart';
-import 'flex.dart';
-import 'geometry.dart';
-import 'multi_page.dart';
-import 'widget.dart';
+import '../../widgets.dart';
 
 
 /// How [Wrap] should align objects.
 /// How [Wrap] should align objects.
 enum WrapAlignment {
 enum WrapAlignment {

@@ -284,6 +284,120 @@ void main() {
     );
     );
   });
   });
 
 
+  test('Should render a blue box aligned center right', () {
+    pdf.addPage(
+      Page(
+        textDirection: TextDirection.rtl,
+        pageFormat: const PdfPageFormat(150, 150),
+        build: (Context context) {
+          return Align(
+             alignment: AlignmentDirectional.centerStart,
+            child: _blueBox,
+          );
+        },
+      ),
+    );
+  });
+
+  test('Should render a blue box aligned center left', () {
+    pdf.addPage(
+      Page(
+        textDirection: TextDirection.ltr,
+        pageFormat: const PdfPageFormat(150, 150),
+        build: (Context context) {
+          return Align(
+            alignment: AlignmentDirectional.centerStart,
+            child: _blueBox,
+          );
+        },
+      ),
+    );
+  });
+
+  test('Should render a box with top-right curved corner', () {
+    pdf.addPage(
+      Page(
+        textDirection: TextDirection.rtl,
+        pageFormat: const PdfPageFormat(150, 150),
+        build: (Context context) {
+          return Container(
+            decoration: const BoxDecoration(
+              color: PdfColors.blue,
+              borderRadius: BorderRadiusDirectional.only(
+                topStart: Radius.circular(20),
+              ),
+            ),
+            width: 150,
+            height: 150,
+          );
+        },
+      ),
+    );
+  });
+
+  test('Should render a box with right curved corners', () {
+    pdf.addPage(
+      Page(
+        textDirection: TextDirection.rtl,
+        pageFormat: const PdfPageFormat(150, 150),
+        build: (Context context) {
+          return Container(
+            decoration: const BoxDecoration(
+              color: PdfColors.blue,
+              borderRadius: BorderRadiusDirectional.horizontal(
+                start: Radius.circular(20),
+              ),
+            ),
+            width: 150,
+            height: 150,
+          );
+        },
+      ),
+    );
+  });
+
+  test('Should render a box with left curved corners', () {
+    pdf.addPage(
+      Page(
+        textDirection: TextDirection.ltr,
+        pageFormat: const PdfPageFormat(150, 150),
+        build: (Context context) {
+          return Container(
+            decoration: const BoxDecoration(
+              color: PdfColors.blue,
+              borderRadius: BorderRadiusDirectional.horizontal(
+                start: Radius.circular(20),
+              ),
+            ),
+            width: 150,
+            height: 150,
+          );
+        },
+      ),
+    );
+  });
+
+  test('Should render a box with top-left curved corner', () {
+    pdf.addPage(
+      Page(
+        textDirection: TextDirection.ltr,
+        pageFormat: const PdfPageFormat(150, 150),
+        build: (Context context) {
+          return Container(
+            decoration: const BoxDecoration(
+              color: PdfColors.blue,
+              borderRadius: BorderRadiusDirectional.only(
+                topStart: Radius.circular(20),
+              ),
+            ),
+            width: 150,
+            height: 150,
+          );
+        },
+      ),
+    );
+  });
+
   tearDownAll(() async {
   tearDownAll(() async {
     final file = File('rtl-layout.pdf');
     final file = File('rtl-layout.pdf');
     await file.writeAsBytes(await pdf.save());
     await file.writeAsBytes(await pdf.save());