Fix text input in samples (#591)

samples/SkiaMultiplatformSample/src/awtMain/kotlin/org/jetbrains/skiko/sample/App.awt.kt

@@ -7,7 +7,7 @@ import javax.swing.*
 
 fun main() {
     val skiaLayer = SkiaLayer()
-    skiaLayer.addView( GenericSkikoView(skiaLayer, Clocks(skiaLayer)))
+    skiaLayer.addView(GenericSkikoView(skiaLayer, AwtClocks(skiaLayer)))
     SwingUtilities.invokeLater {
         val window = JFrame("Skiko example").apply {
             defaultCloseOperation = WindowConstants.EXIT_ON_CLOSE

samples/SkiaMultiplatformSample/src/awtMain/kotlin/org/jetbrains/skiko/sample/AwtClocks.kt

+package org.jetbrains.skiko.sample
+
+import org.jetbrains.skiko.SkiaLayer
+import org.jetbrains.skiko.SkikoInputEvent
+
+class AwtClocks(layer: SkiaLayer) : Clocks(layer) {
+    override var inputText: String = "Hello, AwtClocks"
+
+    override fun handleBackspace() {
+        if (inputText.isNotEmpty()) {
+            inputText = inputText.dropLast(1)
+        }
+    }
+
+    override fun onInputEvent(event: SkikoInputEvent) {
+        if (event.input != "\b") {
+            inputText += event.input
+        }
+    }
+
+}
\ No newline at end of file

samples/SkiaMultiplatformSample/src/commonMain/kotlin/org/jetbrains/skiko/sample/Clocks.kt

@@ -10,7 +10,7 @@ import kotlin.math.cos
 import kotlin.math.sin
 import kotlin.math.PI
 
-class Clocks(private val layer: SkiaLayer): SkikoView {
+abstract class Clocks(private val layer: SkiaLayer): SkikoView {
     private val cursorManager = CursorManager()
     private val withFps = true
     private val fpsCounter = FPSCounter()
@@ -26,7 +26,9 @@ class Clocks(private val layer: SkiaLayer): SkikoView {
     private val fontCollection = FontCollection()
         .setDefaultFontManager(FontMgr.default)
     private val style = ParagraphStyle()
-    private var inputText = ""
+
+    abstract val inputText:String
+    abstract fun handleBackspace()
 
     override fun onRender(canvas: Canvas, width: Int, height: Int, nanoTime: Long) {
         if (withFps) fpsCounter.tick()
@@ -159,12 +161,6 @@ class Clocks(private val layer: SkiaLayer): SkikoView {
         }
     }
 
-    override fun onInputEvent(event: SkikoInputEvent) {
-        if (event.input != "\b") {
-            inputText += event.input
-        }
-    }
-
     override fun onKeyboardEvent(event: SkikoKeyboardEvent) {
         if (event.kind == SkikoKeyboardEventKind.DOWN) {
             when (event.key) {
@@ -200,9 +196,7 @@ class Clocks(private val layer: SkiaLayer): SkikoView {
                 SkikoKey.KEY_DOWN -> yOffset += 5.0
                 SkikoKey.KEY_SPACE -> { reset() }
                 SkikoKey.KEY_BACKSPACE -> {
-                    if (inputText.isNotEmpty()) {
-                        inputText = inputText.dropLast(1)
-                    }
+                    handleBackspace()
                 }
                 else -> {}
             }

samples/SkiaMultiplatformSample/src/iosMain/kotlin/org/jetbrains/skiko/sample/IosClocks.kt

+package org.jetbrains.skiko.sample
+
+import org.jetbrains.skiko.SkiaLayer
+import org.jetbrains.skiko.SkikoUIView
+import org.jetbrains.skiko.SkikoInput
+
+class IosClocks(layer: SkiaLayer) : Clocks(layer) {
+    override var inputText: String = "Hello, IosClocks"
+
+    override fun handleBackspace() {
+        if (inputText.isNotEmpty()) {
+            inputText = inputText.dropLast(1)
+        }
+    }
+
+    override val input: SkikoInput = object : SkikoInput by SkikoInput.Empty {
+        override fun insertText(text: String) {
+            inputText += text
+        }
+
+        override fun deleteBackward() {
+            handleBackspace()
+        }
+    }
+}

samples/SkiaMultiplatformSample/src/iosMain/kotlin/org/jetbrains/skiko/sample/getSkikoViewContoller.kt

@@ -6,7 +6,7 @@ import org.jetbrains.skiko.sample.*
 import platform.Foundation.*
 import platform.UIKit.*
 
-fun makeApp(skiaLayer: SkiaLayer) = Clocks(skiaLayer)
+fun makeApp(skiaLayer: SkiaLayer) = IosClocks(skiaLayer)
 
 fun getSkikoViewContoller(): UIViewController = SkikoViewController(
     SkikoUIView(

samples/SkiaMultiplatformSample/src/jsMain/kotlin/org/jetbrains/skiko/sample/App.js.kt

 package org.jetbrains.skiko.sample
 
 import kotlinx.browser.document
-import org.jetbrains.skiko.GenericSkikoView
-import org.jetbrains.skiko.SkiaLayer
-import org.jetbrains.skiko.onContentScaleChanged
+import org.jetbrains.skiko.*
 import org.jetbrains.skiko.wasm.onWasmReady
 import org.w3c.dom.HTMLCanvasElement
 
@@ -11,7 +9,7 @@ fun main() {
     onWasmReady {
         val skiaLayer = SkiaLayer()
         onContentScaleChanged = { scale -> println(scale) }
-        val game = Clocks(skiaLayer)
+        val game = JsClocks(skiaLayer)
         skiaLayer.skikoView = GenericSkikoView(skiaLayer, game)
         val canvas = document.getElementById("SkikoTarget") as HTMLCanvasElement
         canvas.setAttribute("tabindex", "0")

samples/SkiaMultiplatformSample/src/jsMain/kotlin/org/jetbrains/skiko/sample/JsClocks.kt

+package org.jetbrains.skiko.sample
+
+import org.jetbrains.skiko.SkiaLayer
+import org.jetbrains.skiko.SkikoInput
+import org.jetbrains.skiko.SkikoInputEvent
+
+class JsClocks(layer: SkiaLayer) : Clocks(layer) {
+    override var inputText: String = "Hello, JsClocks"
+
+    override fun handleBackspace() {
+        if (inputText.isNotEmpty()) {
+            inputText = inputText.dropLast(1)
+        }
+    }
+
+    override val input: SkikoInput = object : SkikoInput {
+        override fun onInputEvent(event: SkikoInputEvent) {
+            inputText += event.input
+        }
+    }
+
+}

samples/SkiaMultiplatformSample/src/macosMain/kotlin/org/jetbrains/skiko/sample/App.macos.kt

@@ -7,7 +7,7 @@ import platform.Foundation.NSMakeRect
 import platform.Foundation.NSSelectorFromString
 import platform.darwin.NSObject
 
-fun makeApp(skiaLayer: SkiaLayer) = Clocks(skiaLayer)
+fun makeApp(skiaLayer: SkiaLayer) = MacosClocks(skiaLayer)
 
 fun main() {
     val app = NSApplication.sharedApplication()

samples/SkiaMultiplatformSample/src/macosMain/kotlin/org/jetbrains/skiko/sample/MacosClocks.kt

+package org.jetbrains.skiko.sample
+
+import org.jetbrains.skiko.SkiaLayer
+import org.jetbrains.skiko.SkikoInputEvent
+
+class MacosClocks(layer: SkiaLayer): Clocks(layer) {
+    override var inputText: String = ""
+
+    override fun handleBackspace() {
+        if (inputText.isNotEmpty()) {
+            inputText = inputText.dropLast(1)
+        }
+    }
+
+    override fun onInputEvent(event: SkikoInputEvent) {
+        inputText += event.input
+    }
+}

skiko/src/iosMain/kotlin/org/jetbrains/skiko/SkikoUIView.kt

@@ -250,8 +250,11 @@ class SkikoUIView : UIView, UIKeyInputProtocol, UITextInputProtocol, UITextPaste
         )
     }
 
+    /**
+     * Attention! position may be null
+     */
     override fun positionFromPosition(position: UITextPosition, offset: NSInteger): UITextPosition? {
-        val p = (position as IntermediateTextPosition).position
+        val p = (position as? IntermediateTextPosition)?.position ?: return null
         val endOfDocument = skiaLayer?.skikoView?.input?.endOfDocument()
         return if (endOfDocument != null) {
             IntermediateTextPosition(max(min(p + offset, endOfDocument), 0))