ScrollComponent: Add a minimum scrollbar grip size

api/Elementa.api

@@ -6,6 +6,7 @@ public final class gg/essential/elementa/ElementaVersion : java/lang/Enum {
 	public static final field V3 Lgg/essential/elementa/ElementaVersion;
 	public static final field V4 Lgg/essential/elementa/ElementaVersion;
 	public static final field V5 Lgg/essential/elementa/ElementaVersion;
+	public static final field V6 Lgg/essential/elementa/ElementaVersion;
 	public final fun enableFor (Lkotlin/jvm/functions/Function0;)Ljava/lang/Object;
 	public static fun valueOf (Ljava/lang/String;)Lgg/essential/elementa/ElementaVersion;
 	public static fun values ()[Lgg/essential/elementa/ElementaVersion;

src/main/kotlin/gg/essential/elementa/ElementaVersion.kt

@@ -84,8 +84,14 @@ enum class ElementaVersion {
     /**
      * Change the behavior of scroll components to no longer require holding down shift when horizontal is the only possible scrolling direction.
      */
+    @Deprecated(DEPRECATION_MESSAGE)
     V5,
 
+    /**
+     * [gg.essential.elementa.components.ScrollComponent] now has a minimum size for scrollbar grips.
+     */
+    V6,
+
     ;
 
     /**
@@ -126,7 +132,9 @@ Be sure to read through all the changes between your current version and your ne
         internal val v3 = V3
         @Suppress("DEPRECATION")
         internal val v4 = V4
+        @Suppress("DEPRECATION")
         internal val v5 = V5
+        internal val v6 = V6
 
 
         @PublishedApi

src/main/kotlin/gg/essential/elementa/components/ScrollComponent.kt

@@ -32,7 +32,7 @@ class ScrollComponent constructor(
     private val pixelsPerScroll: Float = 15f,
     private val scrollAcceleration: Float = 1.0f,
     customScissorBoundingBox: UIComponent? = null,
-    private val passthroughScroll: Boolean = true
+    private val passthroughScroll: Boolean = true,
 ) : UIContainer() {
     @JvmOverloads constructor(
         emptyString: String = "",
@@ -44,7 +44,7 @@ class ScrollComponent constructor(
         verticalScrollOpposite: Boolean = false,
         pixelsPerScroll: Float = 15f,
         scrollAcceleration: Float = 1.0f,
-        customScissorBoundingBox: UIComponent? = null
+        customScissorBoundingBox: UIComponent? = null,
     ) : this (
         emptyString,
         innerPadding,
@@ -59,7 +59,7 @@ class ScrollComponent constructor(
         verticalScrollOpposite,
         pixelsPerScroll,
         scrollAcceleration,
-        customScissorBoundingBox
+        customScissorBoundingBox,
     )
 
     private val primaryScrollDirection
@@ -466,10 +466,17 @@ class ScrollComponent constructor(
             }
         }
 
+        val relativeConstraint = RelativeConstraint(clampedPercentage)
+        val desiredSizeConstraint = if (Window.of(this).version >= ElementaVersion.v6) {
+            ScrollBarGripMinSizeConstraint(relativeConstraint)
+        } else {
+            relativeConstraint
+        }
+
         if (isHorizontal) {
-            component.setWidth(RelativeConstraint(clampedPercentage))
+            component.setWidth(desiredSizeConstraint)
         } else {
-            component.setHeight(RelativeConstraint(clampedPercentage))
+            component.setHeight(desiredSizeConstraint)
         }
 
         component.animate {
@@ -800,6 +807,48 @@ class ScrollComponent constructor(
 
     }
 
+    /**
+     * Constraints the scrollbar grip's size to be a certain minimum size, or the [desiredSize].
+     * This is the default constraint for horizontal scrollbar grips if [ElementaVersion.V6] is used.
+     *
+     * @param desiredSize The intended size for the scrollbar grip.
+     */
+    private class ScrollBarGripMinSizeConstraint(
+        private val desiredSize: SizeConstraint
+    ) : SizeConstraint {
+        override var cachedValue: Float = 0f
+        override var recalculate: Boolean = true
+        override var constrainTo: UIComponent? = null
+
+        override fun animationFrame() {
+            super.animationFrame()
+            desiredSize.animationFrame()
+        }
+
+        override fun getWidthImpl(component: UIComponent): Float {
+            val parent = component.parent
+            val minimumWidthPercentage = if (parent.getWidth() < 200) { 0.15f } else { 0.10f }
+            val minimumWidth = parent.getWidth() * minimumWidthPercentage
+
+            return desiredSize.getWidth(component).coerceAtLeast(minimumWidth)
+        }
+
+        override fun getHeightImpl(component: UIComponent): Float {
+            val parent = component.parent
+            val minimumHeightPercentage = if (parent.getHeight() < 200) { 0.15f } else { 0.10f }
+            val minimumHeight = parent.getHeight() * minimumHeightPercentage
+
+            return desiredSize.getHeight(component).coerceAtLeast(minimumHeight)
+        }
+
+        override fun visitImpl(visitor: ConstraintVisitor, type: ConstraintType) {
+        }
+
+        override fun getRadiusImpl(component: UIComponent): Float {
+            throw IllegalStateException("`ScrollBarGripMinSizeConstraint` does not support `getRadiusImpl`.")
+        }
+    }
+
     enum class Direction {
         Vertical,
         Horizontal,