Support touch events on mobile`s browsers (#850)

* add support for touchscreen events in js for mobile devices

* add touchevents for wasm

---------
Co-authored-by: dmitriy tukhvatullin <tukhvatullin01@gmail.com>

skiko/src/jsMain/kotlin/org/jetbrains/skiko/Convertors.js.kt

 package org.jetbrains.skiko
 
+import org.w3c.dom.TouchEvent
+import org.w3c.dom.asList
 import org.w3c.dom.events.KeyboardEvent
 import org.w3c.dom.events.MouseEvent
 import org.w3c.dom.events.WheelEvent
@@ -35,6 +37,38 @@ internal fun toSkikoDragEvent(
     )
 }
 
+internal fun toSkikoEvent(
+    event: TouchEvent,
+    kind: SkikoPointerEventKind,
+    offsetX: Double,
+    offsetY: Double
+): SkikoPointerEvent {
+    val touches = event.changedTouches.asList()
+    val pointers = touches.map { touch ->
+        val x = touch.clientX.toDouble() - offsetX
+        val y = touch.clientY.toDouble() - offsetY
+        val force = touch.asDynamic().force as Double
+
+        SkikoPointer(
+            x = x,
+            y = y,
+            pressed = kind in listOf(SkikoPointerEventKind.DOWN, SkikoPointerEventKind.MOVE),
+            device = SkikoPointerDevice.TOUCH,
+            id = touch.identifier.toLong(),
+            pressure = force
+        )
+    }
+
+    return SkikoPointerEvent(
+        x = pointers.centroidX,
+        y = pointers.centroidY,
+        kind = kind,
+        timestamp = (currentNanoTime() / 1E6).toLong(),
+        pointers = pointers,
+        platform = event
+    )
+}
+
 internal fun toSkikoTypeEvent(
     character: String,
     event: KeyboardEvent?,

skiko/src/jsMain/kotlin/org/jetbrains/skiko/SkiaLayer.js.kt

@@ -2,15 +2,42 @@ package org.jetbrains.skiko
 
 import kotlinx.browser.window
 import org.jetbrains.skiko.w3c.HTMLCanvasElement
+import org.w3c.dom.TouchEvent
 import org.w3c.dom.events.KeyboardEvent
 import org.w3c.dom.events.MouseEvent
 import org.w3c.dom.events.WheelEvent
+import org.w3c.dom.events.UIEvent
 
 internal actual fun SkiaLayer.bindCanvasEventsToSkikoView(
     canvas: HTMLCanvasElement
 ) {
     val htmlCanvas = canvas.unsafeCast<org.w3c.dom.HTMLCanvasElement>()
-
+    var offsetX = 0.0
+    var offsetY = 0.0
+    htmlCanvas.addEventListener("touchstart", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        htmlCanvas.getBoundingClientRect().apply {
+            offsetX = left
+            offsetY = top
+        }
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.DOWN, offsetX, offsetY))
+    })
+    htmlCanvas.addEventListener("touchmove", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.MOVE, offsetX, offsetY))
+    })
+    htmlCanvas.addEventListener("touchend", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.UP, offsetX, offsetY))
+    })
+    htmlCanvas.addEventListener("touchcancel", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.UP, offsetX, offsetY))
+    })
     htmlCanvas.addEventListener("mousedown", { event ->
         event as MouseEvent
         isPointerPressed = true
@@ -54,7 +81,7 @@ actual typealias SkikoGesturePlatformEvent = Any
 actual typealias SkikoPlatformInputEvent = KeyboardEvent
 actual typealias SkikoPlatformKeyboardEvent = KeyboardEvent
 //  MouseEvent is base class of PointerEvent
-actual typealias SkikoPlatformPointerEvent = MouseEvent
+actual typealias SkikoPlatformPointerEvent = UIEvent
 
 internal actual fun SkiaLayer.setOnChangeScaleNotifier() {
     state?.initCanvas(desiredWidth, desiredHeight, contentScale, this.pixelGeometry)

skiko/src/wasmJsMain/kotlin/org/jetbrains/skiko/Convertors.wasm.kt

 package org.jetbrains.skiko
 
+import org.w3c.dom.TouchEvent
+import org.w3c.dom.asList
 import org.w3c.dom.events.KeyboardEvent
 import org.w3c.dom.events.MouseEvent
 import org.w3c.dom.events.WheelEvent
 
+internal external abstract class ExtendedTouchEvent: TouchEvent {
+    val force: Double
+}
+
+internal fun toSkikoEvent(
+    event: TouchEvent,
+    kind: SkikoPointerEventKind,
+    offsetX: Double,
+    offsetY: Double
+): SkikoPointerEvent {
+    val touches = event.changedTouches.asList()
+    val pointers = touches.map { touch ->
+        val x = touch.clientX.toDouble() - offsetX
+        val y = touch.clientY.toDouble() - offsetY
+        val force = touch.unsafeCast<ExtendedTouchEvent>().force
+
+        SkikoPointer(
+            x = x,
+            y = y,
+            pressed = kind in listOf(SkikoPointerEventKind.DOWN, SkikoPointerEventKind.MOVE),
+            device = SkikoPointerDevice.TOUCH,
+            id = touch.identifier.toLong(),
+            pressure = force
+        )
+    }
+
+    return SkikoPointerEvent(
+        x = pointers.centroidX,
+        y = pointers.centroidY,
+        kind = kind,
+        timestamp = (currentNanoTime() / 1E6).toLong(),
+        pointers = pointers,
+        platform = event
+    )
+}
+
 internal fun toSkikoEvent(
     event: MouseEvent,
     kind: SkikoPointerEventKind

skiko/src/wasmJsMain/kotlin/org/jetbrains/skiko/SkiaLayer.js.wasmJs.kt

@@ -2,16 +2,43 @@ package org.jetbrains.skiko
 
 import kotlinx.browser.window
 import org.jetbrains.skiko.w3c.HTMLCanvasElement
+import org.w3c.dom.TouchEvent
 
 import org.w3c.dom.events.KeyboardEvent
 import org.w3c.dom.events.MouseEvent
+import org.w3c.dom.events.UIEvent
 import org.w3c.dom.events.WheelEvent
 
 internal actual fun SkiaLayer.bindCanvasEventsToSkikoView(
     canvas: HTMLCanvasElement
 ) {
     val htmlCanvas = canvas as org.w3c.dom.HTMLCanvasElement
-
+    var offsetX = 0.0
+    var offsetY = 0.0
+    htmlCanvas.addEventListener("touchstart", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        htmlCanvas.getBoundingClientRect().apply {
+            offsetX = left
+            offsetY = top
+        }
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.DOWN, offsetX, offsetY))
+    })
+    htmlCanvas.addEventListener("touchmove", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.MOVE, offsetX, offsetY))
+    })
+    htmlCanvas.addEventListener("touchend", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.UP, offsetX, offsetY))
+    })
+    htmlCanvas.addEventListener("touchcancel", { event ->
+        event.preventDefault()
+        event as TouchEvent
+        skikoView?.onPointerEvent(toSkikoEvent(event, SkikoPointerEventKind.UP, offsetX, offsetY))
+    })
     htmlCanvas.addEventListener("mousedown", { event ->
         event as MouseEvent
         isPointerPressed = true
@@ -55,7 +82,7 @@ actual typealias SkikoGesturePlatformEvent = Any
 actual typealias SkikoPlatformInputEvent = KeyboardEvent
 actual typealias SkikoPlatformKeyboardEvent = KeyboardEvent
 //  MouseEvent is base class of PointerEvent
-actual typealias SkikoPlatformPointerEvent = MouseEvent
+actual typealias SkikoPlatformPointerEvent = UIEvent
 
 internal actual fun SkiaLayer.setOnChangeScaleNotifier() {
     state?.initCanvas(desiredWidth, desiredHeight, contentScale, this.pixelGeometry)