Implemented RadarView to show the selected pass trajectory and the current sat position if overhead

app/src/main/java/com/rtbishop/lookingsat/ui/RadarFragment.kt

@@ -1,5 +1,7 @@
 package com.rtbishop.lookingsat.ui
 
+import android.content.Context
+import android.graphics.*
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
@@ -7,14 +9,23 @@ import android.view.ViewGroup
 import android.widget.FrameLayout
 import androidx.fragment.app.Fragment
 import androidx.recyclerview.widget.RecyclerView
+import com.github.amsacode.predict4java.SatPos
 import com.rtbishop.lookingsat.R
 import com.rtbishop.lookingsat.repo.SatPass
+import java.util.*
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+import kotlin.math.cos
+import kotlin.math.sin
 
 class RadarFragment : Fragment() {
 
     private lateinit var satPass: SatPass
+    private lateinit var radarView: RadarView
     private lateinit var radarSkyFrame: FrameLayout
     private lateinit var radarRecycler: RecyclerView
+    private val service = Executors.newSingleThreadScheduledExecutor()
+    private val delay = 5000L
 
     override fun onCreateView(
         inflater: LayoutInflater,
@@ -29,5 +40,113 @@ class RadarFragment : Fragment() {
         satPass = arguments?.get("satPass") as SatPass
         radarSkyFrame = view.findViewById(R.id.radar_sky_frame)
         radarRecycler = view.findViewById(R.id.radar_recycler)
+
+        radarView = RadarView(activity as MainActivity)
+        radarSkyFrame.addView(radarView)
+
+        service.scheduleAtFixedRate({ radarView.invalidate() }, delay, delay, TimeUnit.MILLISECONDS)
+    }
+
+    inner class RadarView(context: Context) : View(context) {
+
+        private val radarSize = resources.displayMetrics.widthPixels
+        private val scale = resources.displayMetrics.density
+        private val startTime = satPass.pass.startTime
+        private val endTime = satPass.pass.endTime
+        private val radius = radarSize * 0.45f
+        private val piDiv2 = Math.PI / 2.0
+        private val txtSize = scale * 15
+        private val center = 0f
+
+        private val bmp: Bitmap = Bitmap.createBitmap(radarSize, radarSize, Bitmap.Config.ARGB_8888)
+        private val mtrx: Matrix = Matrix().apply {
+            postTranslate(radarSize / 2f, radarSize / 2f)
+        }
+        private val cvs: Canvas = Canvas().apply {
+            setBitmap(bmp)
+            setMatrix(mtrx)
+        }
+        private val linePaint = Paint().apply {
+            isAntiAlias = true
+            color = Color.parseColor("#C0C0C0")
+            style = Paint.Style.STROKE
+            strokeWidth = scale
+        }
+        private val txtPaint = Paint().apply {
+            isAntiAlias = true
+            color = Color.parseColor("#FFE082")
+            textSize = txtSize
+        }
+        private val passPaint = Paint().apply {
+            isAntiAlias = true
+            color = Color.RED
+            style = Paint.Style.STROKE
+            strokeWidth = scale
+        }
+        private val satPaint = Paint().apply {
+            isAntiAlias = true
+            color = Color.parseColor("#FFE082")
+            style = Paint.Style.FILL
+        }
+        private val path: Path = Path()
+
+        override fun onDraw(canvas: Canvas) {
+            var satPos: SatPos
+            var satPassX: Float
+            var satPassY: Float
+
+            bmp.eraseColor(Color.TRANSPARENT)
+
+            cvs.drawLine(center - radius, center, center + radius, center, linePaint)
+            cvs.drawLine(center, center - radius, center, center + radius, linePaint)
+            cvs.drawCircle(center, center, radius, linePaint)
+            cvs.drawCircle(center, center, (radius / 3) * 2, linePaint)
+            cvs.drawCircle(center, center, radius / 3, linePaint)
+
+            cvs.drawText("N", center - txtSize / 3, center - radius - scale * 2, txtPaint)
+            cvs.drawText("E", center + radius + scale * 2, center + txtSize / 3, txtPaint)
+            cvs.drawText("S", center - txtSize / 3, center + radius + txtSize, txtPaint)
+            cvs.drawText("W", center - radius - txtSize, center + txtSize / 3, txtPaint)
+            cvs.drawText("0°", center + scale, center - scale * 2, txtPaint)
+            cvs.drawText("30°", center + scale, center - (radius / 3) - scale * 2, txtPaint)
+            cvs.drawText("60°", center + scale, center - ((radius / 3) * 2) - scale * 2, txtPaint)
+
+            while (startTime.before(endTime)) {
+                satPos = satPass.predictor.getSatPos(startTime)
+                satPassX = center + sph2CartX(satPos.azimuth, satPos.elevation, radius.toDouble())
+                satPassY = center - sph2CartY(satPos.azimuth, satPos.elevation, radius.toDouble())
+                if (startTime.compareTo(satPass.pass.startTime) == 0) {
+                    path.moveTo(satPassX, satPassY)
+                } else {
+                    path.lineTo(satPassX, satPassY)
+                }
+                startTime.time += delay
+            }
+            cvs.drawPath(path, passPaint)
+
+            satPos = satPass.predictor.getSatPos(getCurrentDate())
+            if (satPos.elevation > 0) {
+                cvs.drawCircle(
+                    center + sph2CartX(satPos.azimuth, satPos.elevation, radius.toDouble()),
+                    center - sph2CartY(satPos.azimuth, satPos.elevation, radius.toDouble()),
+                    txtSize / 3, satPaint
+                )
+            }
+            canvas.drawBitmap(bmp, left.toFloat(), top.toFloat(), null)
+        }
+
+        private fun sph2CartX(azimuth: Double, elevation: Double, r: Double): Float {
+            val radius = r * (piDiv2 - elevation) / piDiv2
+            return (radius * cos(piDiv2 - azimuth)).toFloat()
+        }
+
+        private fun sph2CartY(azimuth: Double, elevation: Double, r: Double): Float {
+            val radius = r * (piDiv2 - elevation) / piDiv2
+            return (radius * sin(piDiv2 - azimuth)).toFloat()
+        }
+
+        private fun getCurrentDate(): Date {
+            return Date()
+        }
     }
 }