First draft of model binding

.space/CODEOWNERS

@@ -1 +0,0 @@
-./space/* "Project Admin"

build.gradle.kts

@@ -7,10 +7,7 @@ plugins {
 
 allprojects {
     group = "space.kscience"
-    version = "0.4.0-dev-3"
+    version = "0.4.0-dev-4"
-    repositories{
-        maven("https://maven.pkg.jetbrains.space/spc/p/sci/dev")
-    }
 }
 
 ksciencePublish {

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/DeviceConstructor.kt

@@ -1,8 +1,5 @@
 package space.kscience.controls.constructor
 
-import kotlinx.coroutines.Job
-import kotlinx.coroutines.flow.launchIn
-import kotlinx.coroutines.flow.onEach
 import space.kscience.controls.api.Device
 import space.kscience.controls.api.PropertyDescriptor
 import space.kscience.controls.spec.DevicePropertySpec
@@ -25,29 +22,24 @@ public abstract class DeviceConstructor(
     context: Context,
     meta: Meta = Meta.EMPTY,
 ) : DeviceGroup(context, meta), StateContainer {
-    private val _stateDescriptors: MutableList<StateDescriptor> = mutableListOf()
+    private val _stateDescriptors: MutableSet<StateDescriptor> = mutableSetOf()
-    override val stateDescriptors: List<StateDescriptor> get() = _stateDescriptors
+    override val stateDescriptors: Set<StateDescriptor> get() = _stateDescriptors
 
     override fun registerState(stateDescriptor: StateDescriptor) {
         _stateDescriptors.add(stateDescriptor)
     }
 
-    override fun registerProperty(descriptor: PropertyDescriptor, state: DeviceState<*>) {
+    override fun unregisterState(stateDescriptor: StateDescriptor) {
-        super.registerProperty(descriptor, state)
+        _stateDescriptors.remove(stateDescriptor)
-        registerState(PropertyStateDescriptor(this, descriptor.name, state))
     }
 
-    /**
+    override fun <T> registerProperty(
-     * Bind an action to a [DeviceState]. [onChange] block is performed on each state change
+        converter: MetaConverter<T>,
-     *
+        descriptor: PropertyDescriptor,
-     * Optionally provide [writes] - a set of states that this change affects.
+        state: DeviceState<T>,
-     */
+    ) {
-    public fun <T> DeviceState<T>.onChange(
+        super.registerProperty(converter, descriptor, state)
-        vararg writes: DeviceState<*>,
+        registerState(StatePropertyDescriptor(this, descriptor.name, state))
-        reads: Collection<DeviceState<*>>,
-        onChange: suspend (T) -> Unit,
-    ): Job = valueFlow.onEach(onChange).launchIn(this@DeviceConstructor).also {
-        registerState(ConnectionStateDescriptor(setOf(this, *reads.toTypedArray()), setOf(*writes)))
     }
 }
 
@@ -84,6 +76,7 @@ public fun <D : Device> DeviceConstructor.device(
  * Register a property and provide a direct reader for it
  */
 public fun <T, S : DeviceState<T>> DeviceConstructor.property(
+    converter: MetaConverter<T>,
     state: S,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     nameOverride: String? = null,
@@ -91,7 +84,7 @@ public fun <T, S : DeviceState<T>> DeviceConstructor.property(
     PropertyDelegateProvider { _: DeviceConstructor, property ->
         val name = nameOverride ?: property.name
         val descriptor = PropertyDescriptor(name).apply(descriptorBuilder)
-        registerProperty(descriptor, state)
+        registerProperty(converter, descriptor, state)
         ReadOnlyProperty { _: DeviceConstructor, _ ->
             state
         }
@@ -108,7 +101,8 @@ public fun <T : Any> DeviceConstructor.property(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     nameOverride: String? = null,
 ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, DeviceState<T>>> = property(
-    DeviceState.external(this, metaConverter, readInterval, initialState, reader),
+    metaConverter,
+    DeviceState.external(this, readInterval, initialState, reader),
     descriptorBuilder,
     nameOverride,
 )
@@ -125,7 +119,8 @@ public fun <T : Any> DeviceConstructor.mutableProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     nameOverride: String? = null,
 ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> = property(
-    DeviceState.external(this, metaConverter, readInterval, initialState, reader, writer),
+    metaConverter,
+    DeviceState.external(this, readInterval, initialState, reader, writer),
     descriptorBuilder,
     nameOverride,
 )
@@ -140,7 +135,8 @@ public fun <T> DeviceConstructor.virtualProperty(
     nameOverride: String? = null,
     callback: (T) -> Unit = {},
 ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> = property(
-    DeviceState.internal(metaConverter, initialState, callback),
+    metaConverter,
+    MutableDeviceState(initialState, callback),
     descriptorBuilder,
     nameOverride,
 )
@@ -153,7 +149,7 @@ public fun <T, D : Device> DeviceConstructor.deviceProperty(
     property: DevicePropertySpec<D, T>,
     initialValue: T,
 ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, DeviceState<T>>> =
-    property(device.propertyAsState(property, initialValue))
+    property(property.converter, device.propertyAsState(property, initialValue))
 
 /**
  * Bind existing property provided by specification to this device
@@ -163,4 +159,4 @@ public fun <T, D : Device> DeviceConstructor.deviceProperty(
     property: MutableDevicePropertySpec<D, T>,
     initialValue: T,
 ): PropertyDelegateProvider<DeviceConstructor, ReadOnlyProperty<DeviceConstructor, MutableDeviceState<T>>> =
-    property(device.mutablePropertyAsState(property, initialValue))
+    property(property.converter, device.mutablePropertyAsState(property, initialValue))

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/DeviceGroup.kt

@@ -1,14 +1,12 @@
 package space.kscience.controls.constructor
 
 import kotlinx.coroutines.*
-import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.*
-import kotlinx.coroutines.flow.MutableSharedFlow
-import kotlinx.coroutines.flow.launchIn
-import kotlinx.coroutines.flow.onEach
 import space.kscience.controls.api.*
 import space.kscience.controls.api.DeviceLifecycleState.*
 import space.kscience.controls.manager.DeviceManager
 import space.kscience.controls.manager.install
+import space.kscience.controls.spec.DevicePropertySpec
 import space.kscience.dataforge.context.*
 import space.kscience.dataforge.meta.Laminate
 import space.kscience.dataforge.meta.Meta
@@ -30,12 +28,21 @@ public open class DeviceGroup(
     override val meta: Meta,
 ) : DeviceHub, CachingDevice {
 
-    internal class Property(
+    private class Property<T>(
-        val state: DeviceState<*>,
+        val state: DeviceState<T>,
+        val converter: MetaConverter<T>,
         val descriptor: PropertyDescriptor,
-    )
+    ) {
+        val valueAsMeta get() = converter.convert(state.value)
 
-    internal class Action(
+        fun setMeta(meta: Meta) {
+            check(state is MutableDeviceState) { "Can't write to read-only property" }
+
+            state.value = converter.read(meta)
+        }
+    }
+
+    private class Action(
         val invoke: suspend (Meta?) -> Meta?,
         val descriptor: ActionDescriptor,
     )
@@ -81,16 +88,20 @@ public open class DeviceGroup(
         return device
     }
 
-    private val properties: MutableMap<Name, Property> = hashMapOf()
+    private val properties: MutableMap<Name, Property<*>> = hashMapOf()
 
     /**
      * Register a new property based on [DeviceState]. Properties could be modified dynamically
      */
-    public open fun registerProperty(descriptor: PropertyDescriptor, state: DeviceState<*>) {
+    public open fun <T> registerProperty(
+        converter: MetaConverter<T>,
+        descriptor: PropertyDescriptor,
+        state: DeviceState<T>,
+    ) {
         val name = descriptor.name.parseAsName()
         require(properties[name] == null) { "Can't add property with name $name. It already exists." }
-        properties[name] = Property(state, descriptor)
+        properties[name] = Property(state, converter, descriptor)
-        state.metaFlow.onEach {
+        state.valueFlow.map(converter::convert).onEach {
             sharedMessageFlow.emit(
                 PropertyChangedMessage(
                     descriptor.name,
@@ -109,19 +120,18 @@ public open class DeviceGroup(
         get() = actions.values.map { it.descriptor }
 
     override suspend fun readProperty(propertyName: String): Meta =
-        properties[propertyName.parseAsName()]?.state?.valueAsMeta
+        properties[propertyName.parseAsName()]?.valueAsMeta
             ?: error("Property with name $propertyName not found")
 
-    override fun getProperty(propertyName: String): Meta? = properties[propertyName.parseAsName()]?.state?.valueAsMeta
+    override fun getProperty(propertyName: String): Meta? = properties[propertyName.parseAsName()]?.valueAsMeta
 
     override suspend fun invalidate(propertyName: String) {
         //does nothing for this implementation
     }
 
     override suspend fun writeProperty(propertyName: String, value: Meta) {
-        val property = (properties[propertyName.parseAsName()]?.state as? MutableDeviceState)
+        val property = properties[propertyName.parseAsName()] ?: error("Property with name $propertyName not found")
-            ?: error("Property with name $propertyName not found")
+        property.setMeta(value)
-        property.valueAsMeta = value
     }
 
 
@@ -164,6 +174,10 @@ public open class DeviceGroup(
     }
 }
 
+public fun <T> DeviceGroup.registerProperty(propertySpec: DevicePropertySpec<*, T>, state: DeviceState<T>) {
+    registerProperty(propertySpec.converter, propertySpec.descriptor, state)
+}
+
 public fun DeviceManager.registerDeviceGroup(
     name: String = "@group",
     meta: Meta = Meta.EMPTY,
@@ -234,10 +248,12 @@ public fun DeviceGroup.registerDeviceGroup(name: String, block: DeviceGroup.() -
  */
 public fun <T : Any> DeviceGroup.registerProperty(
     name: String,
+    converter: MetaConverter<T>,
     state: DeviceState<T>,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
 ) {
     registerProperty(
+        converter,
         PropertyDescriptor(name).apply(descriptorBuilder),
         state
     )
@@ -248,10 +264,12 @@ public fun <T : Any> DeviceGroup.registerProperty(
  */
 public fun <T : Any> DeviceGroup.registerMutableProperty(
     name: String,
+    converter: MetaConverter<T>,
     state: MutableDeviceState<T>,
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
 ) {
     registerProperty(
+        converter,
         PropertyDescriptor(name).apply(descriptorBuilder),
         state
     )
@@ -269,7 +287,7 @@ public fun <T : Any> DeviceGroup.registerVirtualProperty(
     descriptorBuilder: PropertyDescriptor.() -> Unit = {},
     callback: (T) -> Unit = {},
 ): MutableDeviceState<T> {
-    val state = DeviceState.internal<T>(converter, initialValue, callback)
+    val state = MutableDeviceState<T>(initialValue, callback)
-    registerMutableProperty(name, state, descriptorBuilder)
+    registerMutableProperty(name, converter, state, descriptorBuilder)
     return state
 }

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/DeviceModel.kt

@@ -1,14 +1,32 @@
 package space.kscience.controls.constructor
 
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.newCoroutineContext
 import space.kscience.dataforge.context.Context
+import kotlin.coroutines.CoroutineContext
 
-public abstract class DeviceModel(override val context: Context) : StateContainer {
+public abstract class DeviceModel(
+    final override val context: Context,
+    vararg dependencies: DeviceState<*>,
+) : StateContainer, CoroutineScope {
 
-    private val _stateDescriptors: MutableList<StateDescriptor> = mutableListOf()
+    override val coroutineContext: CoroutineContext = context.newCoroutineContext(SupervisorJob())
 
-    override val stateDescriptors: List<StateDescriptor> get() = _stateDescriptors
+
+    private val _stateDescriptors: MutableSet<StateDescriptor> = mutableSetOf<StateDescriptor>().apply {
+        dependencies.forEach {
+            add(StateNodeDescriptor(it))
+        }
+    }
+
+    override val stateDescriptors: Set<StateDescriptor> get() = _stateDescriptors
 
     override fun registerState(stateDescriptor: StateDescriptor) {
         _stateDescriptors.add(stateDescriptor)
     }
+
+    override fun unregisterState(stateDescriptor: StateDescriptor) {
+        _stateDescriptors.remove(stateDescriptor)
+    }
 }

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/DeviceState.kt

@@ -6,15 +6,12 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
-import space.kscience.dataforge.meta.Meta
-import space.kscience.dataforge.meta.MetaConverter
 import kotlin.reflect.KProperty
 
 /**
  * An observable state of a device
  */
 public interface DeviceState<T> {
-    public val converter: MetaConverter<T>
     public val value: T
 
     public val valueFlow: Flow<T>
@@ -24,9 +21,6 @@ public interface DeviceState<T> {
     public companion object
 }
 
-public val <T> DeviceState<T>.metaFlow: Flow<Meta> get() = valueFlow.map(converter::convert)
-
-public val <T> DeviceState<T>.valueAsMeta: Meta get() = converter.convert(value)
 
 public operator fun <T> DeviceState<T>.getValue(thisRef: Any?, property: KProperty<*>): T = value
 
@@ -47,12 +41,6 @@ public operator fun <T> MutableDeviceState<T>.setValue(thisRef: Any?, property:
     this.value = value
 }
 
-public var <T> MutableDeviceState<T>.valueAsMeta: Meta
-    get() = converter.convert(value)
-    set(arg) {
-        value = converter.read(arg)
-    }
-
 /**
  * Device state with a value that depends on other device states
  */
@@ -65,17 +53,15 @@ public interface DeviceStateWithDependencies<T> : DeviceState<T> {
  */
 public fun <T, R> DeviceState.Companion.map(
     state: DeviceState<T>,
-    converter: MetaConverter<R>, mapper: (T) -> R,
+    mapper: (T) -> R,
 ): DeviceStateWithDependencies<R> = object : DeviceStateWithDependencies<R> {
     override val dependencies = listOf(state)
 
-    override val converter: MetaConverter<R> = converter
-
     override val value: R get() = mapper(state.value)
 
     override val valueFlow: Flow<R> = state.valueFlow.map(mapper)
 
-    override fun toString(): String = "DeviceState.map(arg=${state}, converter=$converter)"
+    override fun toString(): String = "DeviceState.map(arg=${state})"
 }
 
 /**
@@ -84,13 +70,10 @@ public fun <T, R> DeviceState.Companion.map(
 public fun <T1, T2, R> DeviceState.Companion.combine(
     state1: DeviceState<T1>,
     state2: DeviceState<T2>,
-    converter: MetaConverter<R>,
     mapper: (T1, T2) -> R,
 ): DeviceStateWithDependencies<R> = object : DeviceStateWithDependencies<R> {
     override val dependencies = listOf(state1, state2)
 
-    override val converter: MetaConverter<R> = converter
-
     override val value: R get() = mapper(state1.value, state2.value)
 
     override val valueFlow: Flow<R> = kotlinx.coroutines.flow.combine(state1.valueFlow, state2.valueFlow, mapper)

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/StateDescriptor.kt

@@ -1,10 +1,14 @@
 package space.kscience.controls.constructor
 
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.runningFold
 import space.kscience.controls.api.Device
 import space.kscience.controls.manager.ClockManager
 import space.kscience.dataforge.context.ContextAware
 import space.kscience.dataforge.context.request
-import space.kscience.dataforge.meta.MetaConverter
 import kotlin.time.Duration
 
 /**
@@ -15,7 +19,7 @@ public sealed interface StateDescriptor
 /**
  * A binding that exposes device property as read-only state
  */
-public class PropertyStateDescriptor<T>(
+public class StatePropertyDescriptor<T>(
     public val device: Device,
     public val propertyName: String,
     public val state: DeviceState<T>,
@@ -24,51 +28,172 @@ public class PropertyStateDescriptor<T>(
 /**
  * A binding for independent state like a timer
  */
-public class StateBinding<T>(
+public class StateNodeDescriptor<T>(
     public val state: DeviceState<T>,
 ) : StateDescriptor
 
-public class ConnectionStateDescriptor(
+public class StateConnectionDescriptor(
     public val reads: Collection<DeviceState<*>>,
     public val writes: Collection<DeviceState<*>>,
 ) : StateDescriptor
 
 
-public interface StateContainer : ContextAware {
+public interface StateContainer : ContextAware, CoroutineScope {
-    public val stateDescriptors: List<StateDescriptor>
+    public val stateDescriptors: Set<StateDescriptor>
     public fun registerState(stateDescriptor: StateDescriptor)
+    public fun unregisterState(stateDescriptor: StateDescriptor)
+
+
+    /**
+     * Bind an action to a [DeviceState]. [onChange] block is performed on each state change
+     *
+     * Optionally provide [writes] - a set of states that this change affects.
+     */
+    public fun <T> DeviceState<T>.onNext(
+        vararg writes: DeviceState<*>,
+        alsoReads: Collection<DeviceState<*>> = emptySet(),
+        onChange: suspend (T) -> Unit,
+    ): Job = valueFlow.onEach(onChange).launchIn(this@StateContainer).also {
+        registerState(StateConnectionDescriptor(setOf(this, *alsoReads.toTypedArray()), setOf(*writes)))
+    }
+
+    public fun <T> DeviceState<T>.onChange(
+        vararg writes: DeviceState<*>,
+        alsoReads: Collection<DeviceState<*>> = emptySet(),
+        onChange: suspend (prev: T, next: T) -> Unit,
+    ): Job = valueFlow.runningFold(Pair(value, value)) { pair, next ->
+        Pair(pair.second, next)
+    }.onEach { pair ->
+        if (pair.first != pair.second) {
+            onChange(pair.first, pair.second)
+        }
+    }.launchIn(this@StateContainer).also {
+        registerState(StateConnectionDescriptor(setOf(this, *alsoReads.toTypedArray()), setOf(*writes)))
+    }
 }
 
 /**
  * Register a [state] in this container. The state is not registered as a device property if [this] is a [DeviceConstructor]
  */
 public fun <T, D : DeviceState<T>> StateContainer.state(state: D): D {
-    registerState(StateBinding(state))
+    registerState(StateNodeDescriptor(state))
     return state
 }
 
 /**
  * Create a register a [MutableDeviceState] with a given [converter]
  */
-public fun <T> StateContainer.state(converter: MetaConverter<T>, initialValue: T): MutableDeviceState<T> = state(
+public fun <T> StateContainer.mutableState(initialValue: T): MutableDeviceState<T> = state(
-    DeviceState.internal(converter, initialValue)
+    MutableDeviceState(initialValue)
 )
 
-/**
+public fun <T : DeviceModel> StateContainer.model(model: T): T {
- * Create a register a mutable [Double] state
+    model.stateDescriptors.forEach {
- */
+        registerState(it)
-public fun StateContainer.doubleState(initialValue: Double): MutableDeviceState<Double> = state(
+    }
-    MetaConverter.double, initialValue
+    return model
-)
+}
-
-/**
- * Create a register a mutable [String] state
- */
-public fun StateContainer.stringState(initialValue: String): MutableDeviceState<String> = state(
-    MetaConverter.string, initialValue
-)
 
 /**
  * Create and register a timer state.
  */
 public fun StateContainer.timer(tick: Duration): TimerState = state(TimerState(context.request(ClockManager), tick))
+
+
+public fun <T, R> StateContainer.mapState(
+    state: DeviceState<T>,
+    transformation: (T) -> R,
+): DeviceStateWithDependencies<R> = state(DeviceState.map(state, transformation))
+
+/**
+ * Create a new state by combining two existing ones
+ */
+public fun <T1, T2, R> StateContainer.combineState(
+    first: DeviceState<T1>,
+    second: DeviceState<T2>,
+    transformation: (T1, T2) -> R,
+): DeviceState<R> = state(DeviceState.combine(first, second, transformation))
+
+
+/**
+ * Create and start binding between [sourceState] and [targetState]. Changes made to [sourceState] are automatically
+ * transferred onto [targetState], but not vise versa.
+ *
+ * On resulting [Job] cancel the binding is unregistered
+ */
+public fun <T> StateContainer.bindTo(sourceState: DeviceState<T>, targetState: MutableDeviceState<T>): Job {
+    val descriptor = StateConnectionDescriptor(setOf(sourceState), setOf(targetState))
+    registerState(descriptor)
+    return sourceState.valueFlow.onEach {
+        targetState.value = it
+    }.launchIn(this).apply {
+        invokeOnCompletion {
+            unregisterState(descriptor)
+        }
+    }
+}
+
+/**
+ * Create and start binding between [sourceState] and [targetState]. Changes made to [sourceState] are automatically
+ * transferred onto [targetState] via [transformation], but not vise versa.
+ *
+ * On resulting [Job] cancel the binding is unregistered
+ */
+public fun <T, R> StateContainer.transformTo(
+    sourceState: DeviceState<T>,
+    targetState: MutableDeviceState<R>,
+    transformation: suspend (T) -> R,
+): Job {
+    val descriptor = StateConnectionDescriptor(setOf(sourceState), setOf(targetState))
+    registerState(descriptor)
+    return sourceState.valueFlow.onEach {
+        targetState.value = transformation(it)
+    }.launchIn(this).apply {
+        invokeOnCompletion {
+            unregisterState(descriptor)
+        }
+    }
+}
+
+/**
+ * Register [StateDescriptor] that combines values from [sourceState1] and [sourceState2] using [transformation].
+ *
+ * On resulting [Job] cancel the binding is unregistered
+ */
+public fun <T1, T2, R> StateContainer.combineTo(
+    sourceState1: DeviceState<T1>,
+    sourceState2: DeviceState<T2>,
+    targetState: MutableDeviceState<R>,
+    transformation: suspend (T1, T2) -> R,
+): Job {
+    val descriptor = StateConnectionDescriptor(setOf(sourceState1, sourceState2), setOf(targetState))
+    registerState(descriptor)
+    return kotlinx.coroutines.flow.combine(sourceState1.valueFlow, sourceState2.valueFlow, transformation).onEach {
+        targetState.value = it
+    }.launchIn(this).apply {
+        invokeOnCompletion {
+            unregisterState(descriptor)
+        }
+    }
+}
+
+/**
+ * Register [StateDescriptor] that combines values from [sourceStates] using [transformation].
+ *
+ * On resulting [Job] cancel the binding is unregistered
+ */
+public inline fun <reified T, R> StateContainer.combineTo(
+    sourceStates: Collection<DeviceState<T>>,
+    targetState: MutableDeviceState<R>,
+    noinline transformation: suspend (Array<T>) -> R,
+): Job {
+    val descriptor = StateConnectionDescriptor(sourceStates, setOf(targetState))
+    registerState(descriptor)
+    return kotlinx.coroutines.flow.combine(sourceStates.map { it.valueFlow }, transformation).onEach {
+        targetState.value = it
+    }.launchIn(this).apply {
+        invokeOnCompletion {
+            unregisterState(descriptor)
+        }
+    }
+}

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/TimerState.kt

@@ -7,8 +7,6 @@ import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import kotlinx.datetime.Instant
 import space.kscience.controls.manager.ClockManager
-import space.kscience.controls.spec.instant
-import space.kscience.dataforge.meta.MetaConverter
 import kotlin.time.Duration
 
 /**
@@ -23,7 +21,6 @@ public class TimerState(
     public val clockManager: ClockManager,
     public val tick: Duration,
 ) : DeviceState<Instant> {
-    override val converter: MetaConverter<Instant> get() = MetaConverter.instant
 
     private val clock = MutableStateFlow(clockManager.clock.now())
 

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/boundState.kt

@@ -15,7 +15,7 @@ import space.kscience.dataforge.meta.MetaConverter
  * A copy-free [DeviceState] bound to a device property
  */
 private open class BoundDeviceState<T>(
-    override val converter: MetaConverter<T>,
+    val converter: MetaConverter<T>,
     val device: Device,
     val propertyName: String,
     initialValue: T,

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/exoticState.kt

@@ -2,7 +2,6 @@ package space.kscience.controls.constructor
 
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
-import space.kscience.dataforge.meta.MetaConverter
 
 
 /**
@@ -17,7 +16,6 @@ public class DoubleInRangeState(
         require(initialValue in range) { "Initial value should be in range" }
     }
 
-    override val converter: MetaConverter<Double> = MetaConverter.double
 
     private val _valueFlow = MutableStateFlow(initialValue)
 
@@ -32,18 +30,18 @@ public class DoubleInRangeState(
     /**
      * A state showing that the range is on its lower boundary
      */
-    public val atStart: DeviceState<Boolean> = DeviceState.map(this, MetaConverter.boolean) {
+    public val atStart: DeviceState<Boolean> = DeviceState.map(this) {
         it <= range.start
     }
 
     /**
      * A state showing that the range is on its higher boundary
      */
-    public val atEnd: DeviceState<Boolean> = DeviceState.map(this, MetaConverter.boolean) {
+    public val atEnd: DeviceState<Boolean> = DeviceState.map(this) {
         it >= range.endInclusive
     }
 
-    override fun toString(): String = "DoubleRangeState(range=$range, converter=$converter)"
+    override fun toString(): String = "DoubleRangeState(range=$range)"
 
 
 }
@@ -55,5 +53,5 @@ public fun StateContainer.doubleInRangeState(
     initialValue: Double,
     range: ClosedFloatingPointRange<Double>,
 ): DoubleInRangeState = DoubleInRangeState(initialValue, range).also {
-    registerState(StateBinding(it))
+    registerState(StateNodeDescriptor(it))
 }

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/externalState.kt

@@ -4,13 +4,11 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.launch
-import space.kscience.dataforge.meta.MetaConverter
 import kotlin.time.Duration
 
 
 private open class ExternalState<T>(
     val scope: CoroutineScope,
-    override val converter: MetaConverter<T>,
     val readInterval: Duration,
     initialValue: T,
     val reader: suspend () -> T,
@@ -26,7 +24,7 @@ private open class ExternalState<T>(
     override val value: T get() = flow.value
     override val valueFlow: Flow<T> get() = flow
 
-    override fun toString(): String  = "ExternalState(converter=$converter)"
+    override fun toString(): String  = "ExternalState()"
 }
 
 /**
@@ -34,20 +32,18 @@ private open class ExternalState<T>(
  */
 public fun <T> DeviceState.Companion.external(
     scope: CoroutineScope,
-    converter: MetaConverter<T>,
     readInterval: Duration,
     initialValue: T,
     reader: suspend () -> T,
-): DeviceState<T> = ExternalState(scope, converter, readInterval, initialValue, reader)
+): DeviceState<T> = ExternalState(scope,  readInterval, initialValue, reader)
 
 private class MutableExternalState<T>(
     scope: CoroutineScope,
-    converter: MetaConverter<T>,
     readInterval: Duration,
     initialValue: T,
     reader: suspend () -> T,
     val writer: suspend (T) -> Unit,
-) : ExternalState<T>(scope, converter, readInterval, initialValue, reader), MutableDeviceState<T> {
+) : ExternalState<T>(scope, readInterval, initialValue, reader), MutableDeviceState<T> {
     override var value: T
         get() = super.value
         set(value) {
@@ -62,9 +58,8 @@ private class MutableExternalState<T>(
  */
 public fun <T> DeviceState.Companion.external(
     scope: CoroutineScope,
-    converter: MetaConverter<T>,
     readInterval: Duration,
     initialValue: T,
     reader: suspend () -> T,
     writer: suspend (T) -> Unit,
-): MutableDeviceState<T> = MutableExternalState(scope, converter, readInterval, initialValue, reader, writer)
+): MutableDeviceState<T> = MutableExternalState(scope, readInterval, initialValue, reader, writer)

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/flowState.kt

@@ -2,22 +2,19 @@ package space.kscience.controls.constructor
 
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
-import space.kscience.dataforge.meta.MetaConverter
 
 
 private class StateFlowAsState<T>(
-    override val converter: MetaConverter<T>,
     val flow: MutableStateFlow<T>,
 ) : MutableDeviceState<T> {
     override var value: T by flow::value
     override val valueFlow: Flow<T> get() = flow
 
-    override fun toString(): String = "FlowAsState(converter=$converter)"
+    override fun toString(): String = "FlowAsState()"
 }
 
 /**
  * Create a read-only [DeviceState] that wraps [MutableStateFlow].
  * No data copy is performed.
  */
-public fun <T> MutableStateFlow<T>.asDeviceState(converter: MetaConverter<T>): DeviceState<T> =
+public fun <T> MutableStateFlow<T>.asDeviceState(): MutableDeviceState<T> = StateFlowAsState(this)
-    StateFlowAsState(converter, this)

controls-constructor/src/commonMain/kotlin/space/kscience/controls/constructor/internalState.kt

@@ -2,7 +2,6 @@ package space.kscience.controls.constructor
 
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
-import space.kscience.dataforge.meta.MetaConverter
 
 /**
  * A [MutableDeviceState] that does not correspond to a physical state
@@ -10,7 +9,6 @@ import space.kscience.dataforge.meta.MetaConverter
  * @param callback a synchronous callback that could be used without a scope
  */
 private class VirtualDeviceState<T>(
-    override val converter: MetaConverter<T>,
     initialValue: T,
     private val callback: (T) -> Unit = {},
 ) : MutableDeviceState<T> {
@@ -24,7 +22,7 @@ private class VirtualDeviceState<T>(
             callback(value)
         }
 
-    override fun toString(): String = "VirtualDeviceState(converter=$converter)"
+    override fun toString(): String = "VirtualDeviceState()"
 }
 
 
@@ -33,8 +31,7 @@ private class VirtualDeviceState<T>(
  *
  * @param callback a synchronous callback that could be used without a scope
  */
-public fun <T> DeviceState.Companion.internal(
+public fun <T> MutableDeviceState(
-    converter: MetaConverter<T>,
     initialValue: T,
     callback: (T) -> Unit = {},
-): MutableDeviceState<T> = VirtualDeviceState(converter, initialValue, callback)
+): MutableDeviceState<T> = VirtualDeviceState(initialValue, callback)

controls-core/src/commonMain/kotlin/space/kscience/controls/api/DeviceHub.kt

@@ -22,6 +22,7 @@ public interface DeviceHub : Provider {
     } else {
         emptyMap()
     }
+    //TODO send message on device change
 
     public companion object
 }

controls-core/src/commonMain/kotlin/space/kscience/controls/misc/converters.kt

@@ -1,4 +1,4 @@
-package space.kscience.controls.spec
+package space.kscience.controls.misc
 
 import kotlinx.datetime.Instant
 import space.kscience.dataforge.meta.*
@@ -12,9 +12,9 @@ public fun Double.asMeta(): Meta = Meta(asValue())
  * Generate a nullable [MetaConverter] from non-nullable one
  */
 public fun <T : Any> MetaConverter<T>.nullable(): MetaConverter<T?> = object : MetaConverter<T?> {
-    override fun convert(obj: T?): Meta  = obj?.let { this@nullable.convert(it) }?: Meta(Null)
+    override fun convert(obj: T?): Meta = obj?.let { this@nullable.convert(it) } ?: Meta(Null)
 
-    override fun readOrNull(source: Meta): T? = if(source.value == Null) null else this@nullable.readOrNull(source)
+    override fun readOrNull(source: Meta): T? = if (source.value == Null) null else this@nullable.readOrNull(source)
 
 }
 
@@ -38,4 +38,16 @@ private object InstantConverter : MetaConverter<Instant> {
     override fun convert(obj: Instant): Meta = Meta(obj.toString())
 }
 
-public val MetaConverter.Companion.instant: MetaConverter<Instant> get() = InstantConverter
+public val MetaConverter.Companion.instant: MetaConverter<Instant> get() = InstantConverter
+
+private object DoubleRangeConverter : MetaConverter<ClosedFloatingPointRange<Double>> {
+    override fun readOrNull(source: Meta): ClosedFloatingPointRange<Double>? = source.value?.doubleArray?.let { (start, end)->
+        start..end
+    }
+
+    override fun convert(
+        obj: ClosedFloatingPointRange<Double>,
+    ): Meta = Meta(doubleArrayOf(obj.start, obj.endInclusive).asValue())
+}
+
+public val MetaConverter.Companion.doubleRange: MetaConverter<ClosedFloatingPointRange<Double>> get() = DoubleRangeConverter

controls-core/src/commonTest/kotlin/space/kscience/controls/api/MessageTest.kt

@@ -1,9 +1,8 @@
 package space.kscience.controls.api
 
-import kotlinx.serialization.decodeFromString
 import kotlinx.serialization.encodeToString
 import kotlinx.serialization.json.Json
-import space.kscience.controls.spec.asMeta
+import space.kscience.controls.misc.asMeta
 import kotlin.test.Test
 import kotlin.test.assertEquals
 

controls-magix/src/commonMain/kotlin/space/kscience/controls/client/DeviceClient.kt

@@ -16,8 +16,6 @@ import space.kscience.dataforge.context.Context
 import space.kscience.dataforge.meta.Meta
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.Name
-import space.kscience.dataforge.names.length
-import space.kscience.dataforge.names.startsWith
 import space.kscience.magix.api.MagixEndpoint
 import space.kscience.magix.api.send
 import space.kscience.magix.api.subscribe
@@ -121,12 +119,18 @@ public suspend fun MagixEndpoint.remoteDevice(
     deviceEndpoint: String,
     deviceName: Name,
 ): DeviceClient = coroutineScope {
-    val subscription = subscribe(DeviceManager.magixFormat, originFilter = listOf(deviceEndpoint)).map { it.second }
+    val subscription = subscribe(DeviceManager.magixFormat, originFilter = listOf(deviceEndpoint))
+        .map { it.second }
+        .filter {
+            it.sourceDevice == null || it.sourceDevice == deviceName
+        }
 
     val deferredDescriptorMessage = CompletableDeferred<DescriptionMessage>()
 
     launch {
-        deferredDescriptorMessage.complete(subscription.filterIsInstance<DescriptionMessage>().first())
+        deferredDescriptorMessage.complete(
+            subscription.filterIsInstance<DescriptionMessage>().first()
+        )
     }
 
     send(
@@ -157,12 +161,6 @@ public suspend fun MagixEndpoint.remoteDevice(
     }
 }
 
-private class MapBasedDeviceHub(val deviceMap: Map<Name, Device>, val prefix: Name) : DeviceHub {
-    override val devices: Map<Name, Device>
-        get() = deviceMap.filterKeys { name: Name -> name == prefix || (name.startsWith(prefix) && name.length == prefix.length + 1) }
-
-}
-
 /**
  * Create a dynamic [DeviceHub] from incoming messages
  */

controls-magix/src/commonMain/kotlin/space/kscience/controls/client/controlsMagix.kt

@@ -1,6 +1,7 @@
 package space.kscience.controls.client
 
 import com.benasher44.uuid.uuid4
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.launchIn
@@ -56,7 +57,7 @@ public fun DeviceManager.launchMagixService(
             )
         }
     }.catch { error ->
-        logger.error(error) { "Error while responding to message: ${error.message}" }
+        if (error !is CancellationException) logger.error(error) { "Error while responding to message: ${error.message}" }
     }.launchIn(this)
 
     hubMessageFlow().onEach { payload ->

controls-vision/src/commonMain/kotlin/BooleanIndicatorVision.kt

@@ -1,24 +0,0 @@
-package space.kscience.controls.vision
-
-import kotlinx.serialization.SerialName
-import kotlinx.serialization.Serializable
-import space.kscience.dataforge.meta.boolean
-import space.kscience.visionforge.AbstractVision
-import space.kscience.visionforge.Vision
-import space.kscience.visionforge.html.VisionOfHtml
-
-/**
- * A [Vision] that shows an indicator
- */
-@Serializable
-@SerialName("controls.indicator")
-public class BooleanIndicatorVision : AbstractVision(), VisionOfHtml {
-    public val isOn: Boolean by properties.boolean(false)
-}
-
-///**
-// * A [Vision] that allows both showing the value and changing it
-// */
-//public interface RegulatorVision: IndicatorVision{
-//
-//}

controls-vision/src/commonMain/kotlin/ControlVisionPlugin.kt

@@ -13,6 +13,7 @@ public expect class ControlVisionPlugin: VisionPlugin{
 
 internal val controlsVisionSerializersModule = SerializersModule {
     polymorphic(Vision::class) {
-        subclass(BooleanIndicatorVision.serializer())
+        subclass(IndicatorVision.serializer())
+        subclass(SliderVision.serializer())
     }
 }

controls-vision/src/commonMain/kotlin/controlsVisions.kt

@@ -0,0 +1,35 @@
+package space.kscience.controls.vision
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import space.kscience.controls.misc.doubleRange
+import space.kscience.dataforge.meta.MetaConverter
+import space.kscience.dataforge.meta.convertable
+import space.kscience.dataforge.meta.double
+import space.kscience.dataforge.meta.string
+import space.kscience.visionforge.AbstractControlVision
+import space.kscience.visionforge.AbstractVision
+import space.kscience.visionforge.Vision
+
+/**
+ * A [Vision] that shows a colored indicator
+ */
+@Serializable
+@SerialName("controls.indicator")
+public class IndicatorVision : AbstractVision() {
+    public val color: String? by properties.string()
+}
+
+@Serializable
+@SerialName("controls.slider")
+public class SliderVision : AbstractControlVision() {
+    public var position: Double? by properties.double()
+    public var range: ClosedFloatingPointRange<Double>? by properties.convertable(MetaConverter.doubleRange)
+}
+
+///**
+// * A [Vision] that allows both showing the value and changing it
+// */
+//public interface RegulatorVision: IndicatorVision{
+//
+//}

controls-vision/src/commonMain/kotlin/plotExtensions.kt

@@ -145,7 +145,7 @@ private fun <T> Trace.updateFromState(
 public fun <T> Plot.plotDeviceState(
     context: Context,
     state: DeviceState<T>,
-    extractValue: T.() -> Value = { state.converter.convert(this).value ?: Null },
+    extractValue: (T) -> Value = { Value.of(it) },
     maxAge: Duration = defaultMaxAge,
     maxPoints: Int = defaultMaxPoints,
     minPoints: Int = defaultMinPoints,

controls-vision/src/jsMain/kotlin/ControlsVisionPlugin.js.kt

@@ -10,7 +10,34 @@ import space.kscience.dataforge.names.asName
 import space.kscience.visionforge.VisionPlugin
 import space.kscience.visionforge.html.ElementVisionRenderer
 
-private val indicatorRenderer = ElementVisionRenderer<BooleanIndicatorVision> { name, vision: BooleanIndicatorVision, meta ->
+
+private val indicatorRenderer = ElementVisionRenderer<IndicatorVision> { name, vision: IndicatorVision, meta ->
+//    val ledSize = vision.properties["size"].int ?: 15
+//    val color = vision.color ?: "LightGray"
+//    div("controls-indicator") {
+//        style = """
+//
+//            @keyframes blink {
+//              0%   { box-shadow: 0 0 10px; }
+//              50%  { box-shadow: 0 0 30px; }
+//              100% { box-shadow: 0 0 10px; }
+//            }
+//
+//            display: inline-block;
+//            margin: ${ledSize}px;
+//            width: ${ledSize}px;
+//            height: ${ledSize}px;
+//            border-radius: 50%;
+//
+//            background: $color;
+//            border: 1px solid darken($color,5%);
+//            color: $color;
+//            animation: blink 3s infinite;
+//        """.trimIndent()
+//    }
+}
+
+private val sliderRenderer = ElementVisionRenderer<SliderVision> { name, vision: SliderVision, meta ->
 
 }
 
@@ -22,7 +49,8 @@ public actual class ControlVisionPlugin : VisionPlugin() {
 
     override fun content(target: String): Map<Name, Any> = when (target) {
         ElementVisionRenderer.TYPE -> mapOf(
-            "indicator".asName() to indicatorRenderer
+            "indicator".asName() to indicatorRenderer,
+            "slider".asName() to sliderRenderer
         )
 
         else -> super.content(target)

demo/car/src/main/kotlin/space/kscience/controls/demo/car/VirtualCarController.kt

@@ -64,7 +64,7 @@ class VirtualCarController : Controller(), ContextAware {
             //mongoStorageJob = deviceManager.storeMessages(DefaultAsynchronousMongoClientFactory)
             //Launch device client and connect it to the server
             val deviceEndpoint = MagixEndpoint.rSocketWithTcp("localhost")
-            deviceManager.launchMagixService(deviceEndpoint)
+            deviceManager.launchMagixService(deviceEndpoint, "car")
         }
     }
 

demo/constructor/build.gradle.kts

@@ -1,3 +1,4 @@
+import org.jetbrains.compose.ExperimentalComposeLibrary
 import org.jetbrains.compose.desktop.application.dsl.TargetFormat
 import org.jetbrains.kotlin.gradle.dsl.ExplicitApiMode
 
@@ -11,12 +12,15 @@ kscience {
         withJava()
     }
     useKtor()
+    useSerialization()
     useContextReceivers()
-    dependencies {
+    commonMain {
-        api(projects.controlsVision)
+        implementation(projects.controlsVision)
+        implementation(projects.controlsConstructor)
+//        implementation("io.github.koalaplot:koalaplot-core:0.6.0")
     }
     jvmMain {
-        implementation("io.ktor:ktor-server-cio")
+//        implementation("io.ktor:ktor-server-cio")
         implementation(spclibs.logback.classic)
     }
 }
@@ -26,6 +30,8 @@ kotlin {
         jvmMain {
             dependencies {
                 implementation(compose.desktop.currentOs)
+                @OptIn(ExperimentalComposeLibrary::class)
+                implementation(compose.desktop.components.splitPane)
             }
         }
     }

demo/constructor/src/jvmMain/kotlin/BodyOnSprings.kt

@@ -0,0 +1,185 @@
+package space.kscience.controls.demo.constructor
+
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.size
+import androidx.compose.material.MaterialTheme
+import androidx.compose.runtime.*
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.window.Window
+import androidx.compose.ui.window.application
+import kotlinx.serialization.Serializable
+import space.kscience.controls.constructor.*
+import space.kscience.dataforge.context.Context
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
+import kotlin.math.pow
+import kotlin.math.sqrt
+import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.DurationUnit
+
+@Serializable
+data class XY(val x: Double, val y: Double) {
+    companion object {
+        val ZERO = XY(0.0, 0.0)
+    }
+}
+
+operator fun XY.plus(other: XY): XY = XY(x + other.x, y + other.y)
+operator fun XY.times(c: Double): XY = XY(x * c, y * c)
+operator fun XY.div(c: Double): XY = XY(x / c, y / c)
+//
+//class XYPosition(context: Context, x0: Double, y0: Double) : DeviceModel(context) {
+//    val x: MutableDeviceState<Double> = mutableState(x0)
+//    val y: MutableDeviceState<Double> = mutableState(y0)
+//
+//    val xy = combineState(x, y) { x, y -> XY(x, y) }
+//}
+
+class Spring(
+    context: Context,
+    val k: Double,
+    val l0: Double,
+    val begin: DeviceState<XY>,
+    val end: DeviceState<XY>,
+) : DeviceConstructor(context) {
+
+    val length = combineState(begin, end) { begin, end ->
+        sqrt((end.y - begin.y).pow(2) + (end.x - begin.x).pow(2))
+    }
+
+    val tension: DeviceState<Double> = mapState(length) { l ->
+        val delta = l - l0
+        k * delta
+    }
+
+    /**
+     * direction from start to end
+     */
+    val direction = combineState(begin, end) { begin, end ->
+        val dx = end.x - begin.x
+        val dy = end.y - begin.y
+        val l = sqrt((end.y - begin.y).pow(2) + (end.x - begin.x).pow(2))
+        XY(dx / l, dy / l)
+    }
+
+    val beginForce = combineState(direction, tension) { direction: XY, tension: Double ->
+        direction * (tension)
+    }
+
+
+    val endForce = combineState(direction, tension) { direction: XY, tension: Double ->
+        direction * (-tension)
+    }
+}
+
+class MaterialPoint(
+    context: Context,
+    val mass: Double,
+    val force: DeviceState<XY>,
+    val position: MutableDeviceState<XY>,
+    val velocity: MutableDeviceState<XY> = MutableDeviceState(XY.ZERO),
+) : DeviceModel(context, force) {
+
+    private val timer: TimerState = timer(2.milliseconds)
+
+    private val movement = timer.onChange(
+        position, velocity,
+        alsoReads = setOf(force, velocity, position)
+    ) { prev, next ->
+        val dt = (next - prev).toDouble(DurationUnit.SECONDS)
+        val a = force.value / mass
+        position.value += a * (dt * dt / 2) + velocity.value * dt
+        velocity.value += a * dt
+    }
+}
+
+
+class BodyOnSprings(
+    context: Context,
+    mass: Double,
+    k: Double,
+    startPosition: XY,
+    l0: Double = 1.0,
+    val xLeft: Double = 0.0,
+    val xRight: Double = 2.0,
+    val yBottom: Double = 0.0,
+    val yTop: Double = 2.0,
+) : DeviceConstructor(context) {
+
+    val width = xRight - xLeft
+    val height = yTop - yBottom
+
+    val position = mutableState(startPosition)
+
+    private val leftAnchor = mutableState(XY(xLeft, yTop + yBottom / 2))
+
+    val leftSpring by device(
+        Spring(context, k, l0, leftAnchor, position)
+    )
+
+    private val rightAnchor = mutableState(XY(xRight, yTop + yBottom / 2))
+
+    val rightSpring by device(
+        Spring(context, k, l0, rightAnchor, position)
+    )
+
+    val force: DeviceState<XY> = combineState(leftSpring.endForce, rightSpring.endForce) { left, rignt ->
+        left + rignt
+    }
+
+
+    val body = model(
+        MaterialPoint(
+            context = context,
+            mass = mass,
+            force = force,
+            position = position
+        )
+    )
+}
+
+@Composable
+fun <T> DeviceState<T>.collect(
+    coroutineContext: CoroutineContext = EmptyCoroutineContext,
+): State<T> = valueFlow.collectAsState(value, coroutineContext)
+
+fun main() = application {
+    val initialState = XY(1.1, 1.1)
+
+    Window(title = "Ball on springs", onCloseRequest = ::exitApplication) {
+        MaterialTheme {
+            val context = remember {
+                Context("simulation")
+            }
+
+            val model = remember {
+                BodyOnSprings(context, 100.0, 1000.0, initialState)
+            }
+
+            val position: XY by model.body.position.collect()
+            Box(Modifier.size(400.dp)) {
+                Canvas(modifier = Modifier.fillMaxSize()) {
+                    fun XY.toOffset() = Offset(
+                        (x / model.width * size.width).toFloat(),
+                        (y / model.height * size.height).toFloat()
+                    )
+
+                    drawCircle(
+                        Color.Red, 10f, center = position.toOffset()
+                    )
+                    drawLine(Color.Blue, model.leftSpring.begin.value.toOffset(), model.leftSpring.end.value.toOffset())
+                    drawLine(
+                        Color.Blue,
+                        model.rightSpring.begin.value.toOffset(),
+                        model.rightSpring.end.value.toOffset()
+                    )
+                }
+            }
+        }
+    }
+}

demo/motors/src/main/kotlin/ru/mipt/npm/devices/pimotionmaster/PiMotionMasterDevice.kt

@@ -12,6 +12,8 @@ import kotlinx.coroutines.sync.withLock
 import kotlinx.coroutines.withTimeout
 import space.kscience.controls.api.DeviceHub
 import space.kscience.controls.api.PropertyDescriptor
+import space.kscience.controls.misc.asMeta
+import space.kscience.controls.misc.duration
 import space.kscience.controls.ports.AsynchronousPort
 import space.kscience.controls.ports.KtorTcpPort
 import space.kscience.controls.ports.send

gradle/libs.versions.toml

@@ -79,6 +79,7 @@ visionforge-jupiter = { module = "space.kscience:visionforge-jupyter", version.r
 visionforge-plotly = { module = "space.kscience:visionforge-plotly", version.ref = "visionforge" }
 visionforge-markdown = { module = "space.kscience:visionforge-markdown", version.ref = "visionforge" }
 visionforge-server = { module = "space.kscience:visionforge-server", version.ref = "visionforge" }
+visionforge-compose-html = { module = "space.kscience:visionforge-compose-html", version.ref = "visionforge" }
 
 # Buildscript