Hack together a "Hello, world" in Scala with Laminar

This commit is contained in:
Aaron Fenyes 2024-08-07 13:32:12 -07:00
parent 244f222eb0
commit c376fcdad8
7 changed files with 329 additions and 0 deletions

2
lang-trials/scala/.gitignore vendored Normal file
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target
sbt.json

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enablePlugins(ScalaJSPlugin)
name := "Lattice Circle"
scalaVersion := "3.4.2"
// This is an application with a main method
scalaJSUseMainModuleInitializer := true
libraryDependencies += "com.raquo" %%% "laminar" % "17.0.0"
/*libraryDependencies += "org.scalanlp" %% "breeze" % "2.1.0"*/
libraryDependencies += "ai.dragonfly" %%% "slash" % "0.3.1"
libraryDependencies += "org.scala-js" %%% "scalajs-dom" % "2.8.0"

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<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Lattice circle</title>
<script type="text/javascript" src="./target/scala-3.4.2/lattice-circle-fastopt/main.js"></script>
<link rel="stylesheet" href="main.css"/>
</head>
<body></body>
</html>

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body {
margin-left: 20px;
margin-top: 20px;
color: #fcfcfc;
background-color: #202020;
}
input {
color: inherit;
background-color: #020202;
border: 1px solid #606060;
min-width: 40px;
border-radius: 4px;
}
input.point-1 {
border-color: #ba5d09;
}
input.point-2 {
border-color: #0e8a06;
}
input.point-3 {
border-color: #8951fb;
}
#data-panel {
float: left;
margin-left: 20px;
display: grid;
grid-template-columns: auto auto;
gap: 10px 10px;
width: 120px;
}
#data-panel > div {
text-align: center;
}
#result-display {
margin-top: 10px;
font-weight: bold;
}
canvas {
float: left;
background-color: #020202;
border-radius: 10px;
}

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sbt.version=1.10.1

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addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.16.0")

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// based on the Laminar example app
//
// https://github.com/raquo/laminar-examples/blob/master/src/main/scala/App.scala
//
// and Li Haoyi's example canvas app
//
// http://www.lihaoyi.com/hands-on-scala-js/#MakingaCanvasApp
//
import com.raquo.laminar.api.L.{*, given}
/*import breeze.linalg._*/
import narr.*
import org.scalajs.dom
import org.scalajs.dom.document
import scala.math
import slash.matrix.*
class Circle(var centerX: Double, var centerY: Double, var radius: Double)
object LatticeCircleApp:
val canvas = canvasTag(widthAttr := 600, heightAttr := 600)
val ctx = canvas.ref.getContext("2d").asInstanceOf[dom.CanvasRenderingContext2D]
val dataBusList = List.tabulate(6)(_ => new EventBus[Double])
val dataStream = dataBusList(0).events
.combineWith(dataBusList(1).events)
.combineWith(dataBusList(2).events)
.combineWith(dataBusList(3).events)
.combineWith(dataBusList(4).events)
.combineWith(dataBusList(5).events)
.map(dataTuple => NArray(dataTuple(0), dataTuple(1), dataTuple(2), dataTuple(3), dataTuple(4), dataTuple(5)))
.filter(data => data.forall(!_.isNaN()))
/*
val dataList = List(-1.0, 0.0, 0.0, -1.0, 1.0, 0.0).map(Var(_))
val dataStream = dataList(0).signal
.combineWith(dataList(1).signal)
.combineWith(dataList(2).signal)
.combineWith(dataList(3).signal)
.combineWith(dataList(4).signal)
.combineWith(dataList(5).signal)
.map(dataTuple => NArray(dataTuple(0), dataTuple(1), dataTuple(2), dataTuple(3), dataTuple(4), dataTuple(5)))
*/
val pointStream = dataStream.map(data => Matrix[3, 2](data))
/* Breeze version */
/*
val pointStream = dataStream.map(data => new DenseMatrix(2, 3, Array(data(0), data(1), data(2), data(3), data(4), data(5))))
*/
/* Breeze version */
/*
def circThru(points: DenseMatrix[Double]): Circle =
// build the matrix that maps the circle's coefficient vector to the
// negative of the linear part of the circle's equation, evaluated at the
// given points
val negLinPart = DenseMatrix.horzcat(
2.0*points.t,
DenseMatrix.ones[Double](3, 1)
)
// find the quadrdatic part of the circle's equation, evaluated at the given
// points
val quadPart = points(::, *).map(v => v dot v)
// find the circle's coefficient vector, and from there its center and
// radius
val coeffs = negLinPart \ quadPart
val centerX = coeffs(0, 0)
val centerY = coeffs(1, 0)
Circle(
centerX,
centerY,
math.sqrt(coeffs(2, 0) + centerX*centerX + centerY*centerY)
)
*/
def circThru(points: Matrix[3, 2]): Option[Circle] =
// build the matrix that maps the circle's coefficient vector to the
// negative of the linear part of the circle's equation, evaluated at the
// given points
val negLinPart = Matrix.ones[3, 3]
negLinPart.setMatrix(0, 0, points * 2.0)
println("built neg lin part")
println(negLinPart)
// find the quadrdatic part of the circle's equation, evaluated at the given
// points
val quadPart = Matrix[3, 1](
NArray.tabulate[Double](3)(
k => points(k, 0)*points(k, 0) + points(k, 1)*points(k, 1)
)
)
println("build quad part")
println(quadPart)
// find the circle's coefficient vector, and from there its center and
// radius
try
val coeffs = negLinPart.solve(quadPart)
val centerX = coeffs(0, 0)
val centerY = coeffs(1, 0)
Some(Circle(
centerX,
centerY,
math.sqrt(coeffs(2, 0) + centerX*centerX + centerY*centerY)
))
catch
_ => return None
def draw(points: Matrix[3, 2]): Unit =
// center and normalize the coordinate system
val width = canvas.ref.width
val height = canvas.ref.height
ctx.setTransform(1.0, 0.0, 0.0, -1.0, 0.5*width, 0.5*height)
// clear the previous frame
ctx.clearRect(-0.5*width, -0.5*width, width, height)
// find the resolution
val rDisp = 5.0
val res = width / (2.0*rDisp)
// set colors
val highlightStyle = "white"
val gridStyle = "#404040"
val pointFillStyles = List("#ba5d09", "#0e8a06", "#8951fb")
val pointStrokeStyles = List("#f89142", "#58c145", "#c396fc")
// draw the grid
val rGrid = (rDisp - 0.01).floor.toInt
val edgeScr = res * rDisp
ctx.strokeStyle = gridStyle
for t <- -rGrid to rGrid do
val tScr = res * t
// draw horizontal grid line
ctx.beginPath();
ctx.moveTo(-edgeScr, tScr)
ctx.lineTo(edgeScr, tScr)
ctx.stroke()
// draw vertical grid line
ctx.beginPath();
ctx.moveTo(tScr, -edgeScr)
ctx.lineTo(tScr, edgeScr)
ctx.stroke()
// find and draw the circle through the given points
circThru(points) match
case Some(circ) =>
ctx.beginPath()
ctx.strokeStyle = highlightStyle
ctx.arc(
res * circ.centerX,
res * circ.centerY,
res * circ.radius,
0.0, 2.0*math.Pi
)
ctx.stroke()
case None =>
// draw the data points
for n <- 0 to 2 do
ctx.beginPath()
ctx.fillStyle = pointFillStyles(n)
ctx.strokeStyle = pointStrokeStyles(n)
ctx.arc(
res * points(n, 0),
res * points(n, 1),
3.0,
0.0, 2.0*math.Pi
)
ctx.fill()
ctx.stroke()
def main(args: Array[String]): Unit =
lazy val app = div(
canvas,
div(
pointStream --> draw,
idAttr := "data-panel",
div("x"),
div("y"),
input(typ := "number", cls := "point-1", inContext(thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataBusList(0))),
input(typ := "number", cls := "point-1", inContext(thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataBusList(1))),
input(typ := "number", cls := "point-2", inContext(thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataBusList(2))),
input(typ := "number", cls := "point-2", inContext(thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataBusList(3))),
input(typ := "number", cls := "point-3", inContext(thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataBusList(4))),
input(typ := "number", cls := "point-3", inContext(thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataBusList(5)))
/* attempt to use controlled inputs */
/*
input(
typ := "number",
cls := "point-1",
controlled(
value <-- dataList(0).signal,
inContext(
thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataList(0).writer
)
)
),
input(
typ := "number",
cls := "point-1",
controlled(
value <-- dataList(1).signal,
inContext(
thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataList(1).writer
)
)
),
input(
typ := "number",
cls := "point-2",
controlled(
value <-- dataList(2).signal,
inContext(
thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataList(2).writer
)
)
),
input(
typ := "number",
cls := "point-2",
controlled(
value <-- dataList(3).signal,
inContext(
thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataList(3).writer
)
)
),
input(
typ := "number",
cls := "point-3",
controlled(
value <-- dataList(4).signal,
inContext(
thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataList(4).writer
)
)
),
input(
typ := "number",
cls := "point-3",
controlled(
value <-- dataList(5).signal,
inContext(
thisNode => onInput.mapTo(thisNode.ref.valueAsNumber) --> dataList(5).writer
)
)
)
*/
)
)
renderOnDomContentLoaded(document.body, app)