Add tab and shift-tab switching support to oxr-panel

orx-panel/src/main/kotlin/org/openrndr/panel/ControlManager.kt

@@ -6,6 +6,7 @@ import org.openrndr.color.ColorRGBa
 import org.openrndr.draw.*
 import org.openrndr.math.Matrix44
 import org.openrndr.math.Vector2
+import org.openrndr.math.mod_
 import org.openrndr.panel.elements.*
 import org.openrndr.panel.layout.Layouter
 import org.openrndr.panel.style.*
@@ -95,7 +96,11 @@ class ControlManager : Extension {
 
     val dropInput = DropInput()
 
+
+
+
     inner class KeyboardInput {
+        private var lastTarget: Element? = null
         var target: Element? = null
             set(value) {
                 if (value != field) {
@@ -104,6 +109,9 @@ class ControlManager : Extension {
                     value?.keyboard?.focusGained?.trigger(FocusEvent())
                     field = value
                     field?.pseudoClasses?.add(ElementPseudoClass("active"))
+                    value?.let {
+                        lastTarget = it
+                    }
                 }
             }
 
@@ -118,6 +126,26 @@ class ControlManager : Extension {
                 }
                 checkForManualRedraw()
             }
+
+            if (!event.propagationCancelled) {
+                if (event.key == KEY_TAB) {
+                    val focusableControls = body?.findAllVisible { it.handlesKeyboardFocus } ?: emptyList()
+
+                    val index = target?.let { focusableControls.indexOf(it) } ?: lastTarget?.let { focusableControls.indexOf(it) } ?: -1
+                    if (focusableControls.isNotEmpty()) {
+
+                        target = if (target != null) {
+                            if (KeyModifier.SHIFT in event.modifiers) {
+                                focusableControls[(index - 1).mod_(focusableControls.size)]
+                            } else {
+                                focusableControls[(index + 1).mod_(focusableControls.size)]
+                            }
+                        } else {
+                            lastTarget ?: focusableControls[0]
+                        }
+                    }
+                }
+            }
         }
 
         fun release(event: KeyEvent) {
@@ -210,7 +238,6 @@ class ControlManager : Extension {
                     element.children.forEach { traverse(it, depth + 1) }
                 }
 
-
                 if (!event.propagationCancelled && event.position in element.screenArea && element.computedStyle.display != Display.NONE) {
                     candidates.add(Pair(element, depth))
                 }

orx-panel/src/main/kotlin/org/openrndr/panel/elements/Button.kt

@@ -12,6 +12,7 @@ import kotlin.math.round
 
 class Button : Element(ElementType("button")) {
 
+    override val handlesKeyboardFocus = true
     var label: String = "OK"
 
     class ButtonEvent(val source: Button)

orx-panel/src/main/kotlin/org/openrndr/panel/elements/Element.kt

@@ -10,7 +10,9 @@ import org.openrndr.math.Vector2
 import org.openrndr.panel.collections.ObservableCopyOnWriteArrayList
 import org.openrndr.panel.collections.ObservableHashSet
 import org.openrndr.panel.style.CompoundSelector
+import org.openrndr.panel.style.Display
 import org.openrndr.panel.style.StyleSheet
+import org.openrndr.panel.style.display
 import org.openrndr.shape.Rectangle
 
 import java.util.*
@@ -27,6 +29,7 @@ open class Element(val type: ElementType) {
 
     var scrollTop = 0.0
     open val handlesDoubleClick = false
+    open val handlesKeyboardFocus = false
 
     open val widthHint: Double?
         get() {
@@ -223,9 +226,34 @@ open class Element(val type: ElementType) {
                 else -> p.children[index + 1]
             }
         }
-
     }
 
+    fun findNext(premise: (Element) -> Boolean) : Element? {
+        return parent?.let { p ->
+            val index = p.children.indexOf(this)
+            val siblingCount = p.children.size
+            for (i in index + 1 until siblingCount) {
+                if (premise(p.children[i])) {
+                    return p.children[i]
+                }
+            }
+            return null
+        }
+    }
+
+    fun findPrevious(premise: (Element) -> Boolean) : Element? {
+        return parent?.let { p ->
+            val index = p.children.indexOf(this)
+            for (i in index-1 downTo 0) {
+                if (premise(p.children[i])) {
+                    return p.children[i]
+                }
+            }
+            return null
+        }
+    }
+
+
     fun move(steps: Int) {
         parent?.let { p ->
             if (steps != 0) {
@@ -283,7 +311,34 @@ fun Element.enable() {
 
 fun Element.isDisabled(): Boolean = disabled in pseudoClasses
 
+fun Element.findAll(predicate: (Element) -> Boolean) : List<Element> {
+    val results = mutableListOf<Element>()
+    visit {
+        if (predicate(this)) {
+            results.add(this)
+        }
+    }
+    return results
+}
+
+fun Element.findAllVisible(predicate: (Element) -> Boolean) : List<Element> {
+    val results = mutableListOf<Element>()
+    visitVisible {
+        if (predicate(this)) {
+            results.add(this)
+        }
+    }
+    return results
+}
+
 fun Element.visit(function: Element.() -> Unit) {
     this.function()
     children.forEach { it.visit(function) }
+}
+
+fun Element.visitVisible(function: Element.() -> Unit) {
+    if (this.computedStyle.display != Display.NONE) {
+        this.function()
+        children.forEach { it.visitVisible(function) }
+    }
 }

orx-panel/src/main/kotlin/org/openrndr/panel/elements/Slider.kt

@@ -24,6 +24,9 @@ data class Range(val min: Double, val max: Double) {
 }
 
 class Slider : Element(ElementType("slider")) {
+
+    override val handlesKeyboardFocus = true
+
     var label = ""
     var precision = 3
     var value: Double