Jacob Richman
9484ac8bdf
BUG= R=vsm@google.com Review-Url: https://codereview.chromium.org/2752163002 .
54 lines
1.5 KiB
Dart
54 lines
1.5 KiB
Dart
// Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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library sunflower;
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import 'dart:html';
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import 'dart:math';
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import 'circle.dart';
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import 'painter.dart';
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const SEED_RADIUS = 2;
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const SCALE_FACTOR = 4;
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const MAX_D = 300;
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const centerX = MAX_D / 2;
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const centerY = centerX;
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Element querySelector(String selector) => document.querySelector(selector);
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final canvas = querySelector("#canvas") as CanvasElement;
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final context = canvas.getContext('2d') as CanvasRenderingContext2D;
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final slider = querySelector("#slider") as InputElement;
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final notes = querySelector("#notes");
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final PHI = (sqrt(5) + 1) / 2;
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int seeds = 0;
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void main() {
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slider.addEventListener('change', (e) => draw());
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draw();
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}
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/// Draw the complete figure for the current number of seeds.
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void draw() {
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seeds = int.parse(slider.value);
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context.clearRect(0, 0, MAX_D, MAX_D);
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for (var i = 0; i < seeds; i++) {
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final theta = i * TAU / PHI;
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final r = sqrt(i) * SCALE_FACTOR;
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final x = centerX + r * cos(theta);
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final y = centerY - r * sin(theta);
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new SunflowerSeed(x, y, SEED_RADIUS).draw(context);
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}
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notes.text = "$seeds seeds";
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}
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// This example was modified to use classes and mixins.
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class SunflowerSeed extends Circle with CirclePainter {
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SunflowerSeed(num x, num y, num radius, [String color])
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: super(x, y, radius) {
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if (color != null) this.color = color;
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}
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}
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