progress.dart
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/*
* 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.
*/
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(
{@required this.value,
this.color,
this.strokeWidth = 4.0,
this.backgroundColor})
: assert(value != null),
assert(strokeWidth != null);
final double value;
final PdfColor color;
final PdfColor backgroundColor;
final double strokeWidth;
@override
void layout(Context context, BoxConstraints constraints,
{bool parentUsesSize = false}) {
box = PdfRect.fromPoints(PdfPoint.zero, constraints.biggest);
}
@override
void paint(Context context) {
super.paint(context);
final double adjustedValue = value.clamp(0.00001, .99999);
final rx = box.width / 2;
final ry = box.height / 2;
const angleStart = math.pi / 2;
final angleEnd = angleStart - math.pi * 2 * adjustedValue;
final startTop = PdfPoint(
box.x + rx + math.cos(angleStart) * rx,
box.y + ry + math.sin(angleStart) * ry,
);
final endTop = PdfPoint(
box.x + rx + math.cos(angleEnd) * rx,
box.y + ry + math.sin(angleEnd) * ry,
);
final startBottom = PdfPoint(
box.x + rx + math.cos(angleStart) * (rx - strokeWidth),
box.y + ry + math.sin(angleStart) * (ry - strokeWidth),
);
final endBottom = PdfPoint(
box.x + rx + math.cos(angleEnd) * (rx - strokeWidth),
box.y + ry + math.sin(angleEnd) * (ry - strokeWidth),
);
if (backgroundColor != null && value < 1) {
context.canvas
..moveTo(startTop.x, startTop.y)
..bezierArc(startTop.x, startTop.y, rx, ry, endTop.x, endTop.y,
large: adjustedValue < .5, sweep: true)
..lineTo(endBottom.x, endBottom.y)
..bezierArc(endBottom.x, endBottom.y, rx - strokeWidth,
ry - strokeWidth, startBottom.x, startBottom.y,
large: adjustedValue < .5)
..lineTo(startTop.x, startTop.y)
..setFillColor(backgroundColor)
..fillPath();
}
if (value > 0) {
context.canvas
..moveTo(startTop.x, startTop.y)
..bezierArc(startTop.x, startTop.y, rx, ry, endTop.x, endTop.y,
large: adjustedValue > .5)
..lineTo(endBottom.x, endBottom.y)
..bezierArc(endBottom.x, endBottom.y, rx - strokeWidth,
ry - strokeWidth, startBottom.x, startBottom.y,
large: adjustedValue > .5, sweep: true)
..lineTo(startTop.x, startTop.y)
..setFillColor(color ?? PdfColors.indigo)
..fillPath();
}
}
}