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// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:math' as math;
import 'basic_types.dart';
import 'borders.dart';
import 'edge_insets.dart';
/// A border that fits a circle within the available space.
///
/// Typically used with [ShapeDecoration] to draw a circle.
///
/// The [dimensions] assume that the border is being used in a square space.
/// When applied to a rectangular space, the border paints in the center of the
/// rectangle.
///
/// See also:
///
/// * [BorderSide], which is used to describe each side of the box.
/// * [Border], which, when used with [BoxDecoration], can also
/// describe a circle.
class CircleBorder extends ShapeBorder {
/// Create a circle border.
///
/// The [side] argument must not be null.
const CircleBorder({ this.side = BorderSide.none }) : assert(side != null);
/// The style of this border.
final BorderSide side;
@override
EdgeInsetsGeometry get dimensions {
return EdgeInsets.all(side.width);
}
@override
ShapeBorder scale(double t) => CircleBorder(side: side.scale(t));
@override
ShapeBorder lerpFrom(ShapeBorder a, double t) {
if (a is CircleBorder)
return CircleBorder(side: BorderSide.lerp(a.side, side, t));
return super.lerpFrom(a, t);
}
@override
ShapeBorder lerpTo(ShapeBorder b, double t) {
if (b is CircleBorder)
return CircleBorder(side: BorderSide.lerp(side, b.side, t));
return super.lerpTo(b, t);
}
@override
Path getInnerPath(Rect rect, { TextDirection textDirection }) {
return Path()
..addOval(Rect.fromCircle(
center: rect.center,
radius: math.max(0.0, rect.shortestSide / 2.0 - side.width),
));
}
@override
Path getOuterPath(Rect rect, { TextDirection textDirection }) {
return Path()
..addOval(Rect.fromCircle(
center: rect.center,
radius: rect.shortestSide / 2.0,
));
}
@override
void paint(Canvas canvas, Rect rect, { TextDirection textDirection }) {
switch (side.style) {
case BorderStyle.none:
break;
case BorderStyle.solid:
canvas.drawCircle(rect.center, (rect.shortestSide - side.width) / 2.0, side.toPaint());
}
}
@override
bool operator ==(dynamic other) {
if (runtimeType != other.runtimeType)
return false;
final CircleBorder typedOther = other;
return side == typedOther.side;
}
@override
int get hashCode => side.hashCode;
@override
String toString() {
return '$runtimeType($side)';
}
}