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Spirodraw
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.metadata.json
{
"origin": "dartlab.org",
"url": "http://dartlab.org/#:gistId",
"history": []
}
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readme.md
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index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Spirodraw</title>
<link rel="stylesheet" href="styles.css">
<script type="application/dart" src="main.dart"></script>
</head>
<body>
<div id="leftnav">
<div class="control">
<select id="in_out" size="1" class="full">
<option selected value="-1">Wheel inside</option>
<option value="1">Wheel outside</option>
</select>
</div>
<div class="control">
<label>Fixed radius</label>
<input id="fixed_radius" type="range" min="10" max="19" value="10">
</div>
<div class="control">
<label>Wheel radius</label>
<input id="wheel_radius" type="range" min="0" max="9" value="3">
</div>
<div class="control">
<label>Pen radius</label>
<input id="pen_radius" type="range" min="0" max="9">
</div>
<div class="control">
<label>Pen thickness</label>
<input id="pen_width" type="range" min="1" max="10">
</div>
<div class="control">
<div class="rangeOption">
<div class="rangeRow">
<label class="minLabel">Smoother</label>
<label class="maxLabel">Faster</label>
</div>
</div>
<input id="speed" type="range" min="1" max="20" value="15">
</div>
<div>
<canvas id="palette" height="160" width="180" />
</div>
<div class="control">
<div class="buttonBar">
<input type="button" id="start" value="Start"></input>
<input type="button" id="stop" value="Stop"></input>
<input type="button" id="clear" value="Clear"></input>
</div>
</div>
</div>
<div id="main">
<canvas id="canvas" />
</div>
</body>
</html>
Raw
main.dart
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. 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:html';
import 'dart:math' as Math;
void main() {
new Spirodraw().go();
}
class Spirodraw {
static double PI2 = Math.pi * 2;
Document doc;
// Scale factor used to scale wheel radius from 1-10 to pixels
int RUnits, rUnits, dUnits;
// Fixed radius, wheel radius, pen distance in pixels
double R, r, d;
InputElement fixedRadiusSlider,
wheelRadiusSlider,
penRadiusSlider,
penWidthSlider,
speedSlider;
SelectElement inOrOut;
DivElement mainDiv;
num lastX, lastY;
int height, width, xc, yc;
int maxTurns;
CanvasElement frontCanvas, backCanvas;
CanvasRenderingContext2D front, back;
CanvasElement paletteElement;
ColorPicker colorPicker;
String penColor = "red";
int penWidth;
double rad = 0.0;
double stepSize;
bool animationEnabled = true;
int numPoints;
double speed;
bool run;
Spirodraw() {
doc = window.document;
inOrOut = doc.querySelector("#in_out");
fixedRadiusSlider = doc.querySelector("#fixed_radius");
wheelRadiusSlider = doc.querySelector("#wheel_radius");
penRadiusSlider = doc.querySelector("#pen_radius");
penWidthSlider = doc.querySelector("#pen_width");
speedSlider = doc.querySelector("#speed");
mainDiv = doc.querySelector("#main");
frontCanvas = doc.querySelector("#canvas");
front = frontCanvas.context2D;
backCanvas = new Element.tag("canvas");
back = backCanvas.context2D;
paletteElement = doc.querySelector("#palette");
initControlPanel();
}
void go() => _setupSize();
void _setupSize() {
height = window.innerHeight;
width = window.innerWidth - 270;
yc = height ~/ 2;
xc = width ~/ 2;
frontCanvas
..height = height
..width = width;
backCanvas
..height = height
..width = width;
clear();
}
void initControlPanel() {
inOrOut.onChange.listen((_) => refresh());
fixedRadiusSlider.onChange.listen((_) => refresh());
wheelRadiusSlider.onChange.listen((_) => refresh());
speedSlider.onChange.listen(onSpeedChange);
penRadiusSlider.onChange.listen((_) => refresh());
penWidthSlider.onChange.listen(onPenWidthChange);
colorPicker = new ColorPicker(paletteElement);
colorPicker.addListener((String color) => onColorChange(color));
doc.querySelector("#start").onClick.listen((_) => start());
doc.querySelector("#stop").onClick.listen((_) => stop());
doc.querySelector("#clear").onClick.listen((_) => clear());
}
void onColorChange(String color) {
penColor = color;
drawFrame(rad);
}
void onSpeedChange(Event event) {
speed = speedSlider.valueAsNumber;
stepSize = calcStepSize();
}
void onPenWidthChange(Event event) {
penWidth = penWidthSlider.valueAsNumber.toInt();
drawFrame(rad);
}
void refresh() {
stop();
// Reset
lastX = lastY = 0;
// Compute fixed radius
// based on starting diameter == min / 2, fixed radius == 10 units
int min = Math.min(height, width);
double pixelsPerUnit = min / 40;
RUnits = fixedRadiusSlider.valueAsNumber.toInt();
R = RUnits * pixelsPerUnit;
// Scale inner radius and pen distance in units of fixed radius
rUnits = wheelRadiusSlider.valueAsNumber.toInt();
r = rUnits * R / RUnits * int.parse(inOrOut.value);
dUnits = penRadiusSlider.valueAsNumber.toInt();
d = dUnits * R / RUnits;
numPoints = calcNumPoints();
maxTurns = calcTurns();
onSpeedChange(null);
penWidth = penWidthSlider.valueAsNumber.toInt();
drawFrame(0.0);
}
int calcNumPoints() {
// Empirically, treat it like an oval.
if (dUnits == 0 || rUnits == 0) return 2;
int gcf_ = gcf(RUnits, rUnits);
int n = RUnits ~/ gcf_;
int d_ = rUnits ~/ gcf_;
if (n % 2 == 1) return n;
if (d_ % 2 == 1) return n;
return n ~/ 2;
}
double calcStepSize() => speed / 100 * maxTurns / numPoints;
void drawFrame(double theta) {
if (animationEnabled) {
front
..clearRect(0, 0, width, height)
..drawImage(backCanvas, 0, 0);
drawFixed();
}
drawWheel(theta);
}
void animate(num time) {
if (run && rad <= maxTurns * PI2) {
rad += stepSize;
drawFrame(rad);
window.requestAnimationFrame(animate);
} else {
stop();
}
}
void start() {
refresh();
rad = 0.0;
run = true;
window.requestAnimationFrame(animate);
}
int calcTurns() {
// compute ratio of wheel radius to big R then find LCM
if ((dUnits == 0) || (rUnits == 0)) return 1;
int ru = rUnits.abs();
int wrUnits = RUnits + rUnits;
int g = gcf(wrUnits, ru);
return ru ~/ g;
}
void stop() {
run = false;
// Show drawing only
front
..clearRect(0, 0, width, height)
..drawImage(backCanvas, 0, 0);
// Reset angle
rad = 0.0;
}
void clear() {
stop();
back.clearRect(0, 0, width, height);
refresh();
}
void drawFixed() {
if (animationEnabled) {
front
..beginPath()
..lineWidth = 2
..strokeStyle = "gray"
..arc(xc, yc, R, 0, PI2, true)
..closePath()
..stroke();
}
}
/// Draw the wheel with its center at angle theta with respect to the fixed
/// wheel
void drawWheel(double theta) {
double wx = xc + ((R + r) * Math.cos(theta));
double wy = yc - ((R + r) * Math.sin(theta));
if (animationEnabled) {
if (rUnits > 0) {
// Draw ring
front
..beginPath()
..arc(wx, wy, r.abs(), 0, PI2, true)
..closePath()
..stroke();
// Draw center
front
..lineWidth = 1
..beginPath()
..arc(wx, wy, 3, 0, PI2, true)
..fillStyle = "black"
..fill()
..closePath()
..stroke();
}
}
drawTip(wx, wy, theta);
}
/// Draw a rotating line that shows the wheel rolling and leaves the pen trace.
///
/// [wx] - X coordinate of wheel center
/// [wy] - Y coordinate of wheel center
/// [theta] - Angle of wheel center with respect to fixed circle
void drawTip(double wx, double wy, double theta) {
// Calc wheel rotation angle
double rot = (r == 0) ? theta : theta * (R + r) / r;
// Find tip of line
double tx = wx + d * Math.cos(rot);
double ty = wy - d * Math.sin(rot);
if (animationEnabled) {
front
..beginPath()
..fillStyle = penColor
..arc(tx, ty, penWidth / 2 + 2, 0, PI2, true)
..fill()
..moveTo(wx, wy)
..strokeStyle = "black"
..lineTo(tx, ty)
..closePath()
..stroke();
}
drawSegmentTo(tx, ty);
}
void drawSegmentTo(double tx, double ty) {
if (lastX > 0) {
back
..beginPath()
..strokeStyle = penColor
..lineWidth = penWidth
..moveTo(lastX, lastY)
..lineTo(tx, ty)
..closePath()
..stroke();
}
lastX = tx;
lastY = ty;
}
}
int gcf(int n, int d) {
if (n == d) return n;
int max = Math.max(n, d);
for (int i = max ~/ 2; i > 1; i--) {
if ((n % i == 0) && (d % i == 0)) return i;
}
return 1;
}
typedef void PickerListener(String selectedColor);
class ColorPicker {
static const hexValues = const ['00', '33', '66', '99', 'CC', 'FF'];
static const COLS = 18;
// Block height, width, padding
static const BH = 10;
static const BW = 10;
static const BP = 1;
final List<PickerListener> _listeners;
CanvasElement canvasElement;
String _selectedColor = 'red';
final height = 160;
final width = 180;
CanvasRenderingContext2D ctx;
ColorPicker(this.canvasElement) : _listeners = [] {
ctx = canvasElement.context2D;
drawPalette();
addHandlers();
showSelected();
}
String get selectedColor => _selectedColor;
void set selectedColor(String color) {
_selectedColor = color;
showSelected();
fireSelected();
}
void onMouseMove(MouseEvent event) {
int x = event.offset.x;
int y = event.offset.y - 40;
if ((y < 0) || (x >= width)) {
return;
}
ctx.fillStyle = getHexString(getColorIndex(x, y));
ctx.fillRect(0, 0, width / 2, 30);
}
void onMouseDown(MouseEvent event) {
event.stopPropagation();
int x = event.offset.x;
int y = event.offset.y - 40;
if ((y < 0) || (x >= width)) {
return;
}
selectedColor = getHexString(getColorIndex(x, y));
}
/**
* Adds a [PickerListener] to receive updates.
*/
void addListener(PickerListener listener) {
_listeners.add(listener);
}
void addHandlers() {
canvasElement.onMouseMove.listen(onMouseMove);
canvasElement.onMouseDown.listen(onMouseDown);
}
void drawPalette() {
int i = 0;
for (int r = 0; r < 256; r += 51) {
for (int g = 0; g < 256; g += 51) {
for (int b = 0; b < 256; b += 51) {
String color = getHexString(i);
ctx.fillStyle = color;
int x = BW * (i % COLS);
int y = BH * (i ~/ COLS) + 40;
ctx.fillRect(x + BP, y + BP, BW - 2 * BP, BH - 2 * BP);
i++;
}
}
}
}
void fireSelected() {
for (final listener in _listeners) {
listener(_selectedColor);
}
}
int getColorIndex(int x, int y) {
// Get color index 0-215 using row, col
int i = y ~/ BH * COLS + x ~/ BW;
return i;
}
void showSelected() {
ctx.fillStyle = _selectedColor;
ctx.fillRect(width / 2, 0, width / 2, 30);
ctx.fillStyle = "white";
ctx.fillRect(0, 0, width / 2, 30);
}
String getHexString(num value) {
int i = value.floor().toInt();
int r = (i ~/ 36) % 6;
int g = (i % 36) ~/ 6;
int b = i % 6;
return '#${hexValues[r]}${hexValues[g]}${hexValues[b]}';
}
}
Raw
styles.css
/* Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file */
/* for details. All rights reserved. Use of this source code is governed by a */
/* BSD-style license that can be found in the LICENSE file. */
body {
font-style: normal;
font-family: sans-serif;
font-size: 0.9em;
margin-top: 0;
margin-bottom: 0;
margin-left: auto;
margin-right: auto;
text-align: center;
display: block;
color: #666;
min-width: 450px;
}
.centered {
text-align: center;
}
.full {
width: 100%;
}
div.control {
text-align: left;
margin-top: 10px;
margin-bottom: 10px;
}
select, input[type='range'] {
width: 100%;
}
div.rangeOption {
display: table;
width: 100%;
}
div.rangeRow {
display: table-row;
width: 100%;
}
.rangeOption label {
display: table-cell;
text-align: center;
}
.rangeOption input[type='range'] {
display: block;
width: 100%;
}
.rangeRow .minLabel {
text-align: left;
}
.rangeRow .maxLabel {
text-align: right;
}
.buttonBar {
text-align: center;
width: 100%;
margin-top: 10px;
margin-bottom: 10px;
}
.buttonBar input[type='button'] {
min-width: 4em;
}
#wrapper {
display: table;
}
#leftnav {
float: left;
width: 200px;
margin: 10px;
background-color: #EEEEEE;
border: 1px solid #CCCCCC;
border-radius: 25px 25px 25px 25px;
padding: 1em;
}
#palette {
cursor: pointer;
}
#lucky {
width: 90%;
}
#main {
float: right;
}
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