More progress

src/UI/Widgets/AutoSliderScrollbar.cs

@@ -0,0 +1,138 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using UnityEngine;
+using UnityEngine.Events;
+using UnityEngine.UI;
+using UnityExplorer;
+using UnityExplorer.Core;
+using UnityExplorer.UI;
+using UnityExplorer.UI.Models;
+
+namespace UnityExplorer.UI.Utility
+{
+    // A Slider Scrollbar which automatically resizes for the content size (no pooling).
+    // Currently just used for the C# Console input field.
+
+    public class AutoSliderScrollbar : UIBehaviourModel
+    {
+        public override GameObject UIRoot
+        {
+            get
+            {
+                if (Slider)
+                    return Slider.gameObject;
+                return null;
+            }
+        }
+
+        //public event Action<float> OnValueChanged;
+
+        internal readonly Scrollbar Scrollbar;
+        internal readonly Slider Slider;
+        internal RectTransform ContentRect;
+        internal RectTransform ViewportRect;
+
+        //internal InputFieldScroller m_parentInputScroller;
+
+        public AutoSliderScrollbar(Scrollbar scrollbar, Slider slider, RectTransform contentRect, RectTransform viewportRect)
+        {
+            this.Scrollbar = scrollbar;
+            this.Slider = slider;
+            this.ContentRect = contentRect;
+            this.ViewportRect = viewportRect;
+
+            this.Scrollbar.onValueChanged.AddListener(this.OnScrollbarValueChanged);
+            this.Slider.onValueChanged.AddListener(this.OnSliderValueChanged);
+
+            //this.RefreshVisibility();
+            this.Slider.Set(0f, false);
+        }
+
+        private float lastAnchorPosition;
+        private float lastContentHeight;
+        private float lastViewportHeight;
+        private bool _refreshWanted;
+
+        public override void Update()
+        {
+            if (!Enabled)
+                return;
+
+            _refreshWanted = false;
+            if (ContentRect.localPosition.y != lastAnchorPosition)
+            {
+                lastAnchorPosition = ContentRect.localPosition.y;
+                _refreshWanted = true;
+            }
+            if (ContentRect.rect.height != lastContentHeight)
+            {
+                lastContentHeight = ContentRect.rect.height;
+                _refreshWanted = true;
+            }
+            if (ViewportRect.rect.height != lastViewportHeight)
+            {
+                lastViewportHeight = ViewportRect.rect.height;
+                _refreshWanted = true;
+            }
+
+            if (_refreshWanted)
+                UpdateSliderHandle();
+        }
+
+        public void UpdateSliderHandle()
+        {
+            // calculate handle size based on viewport / total data height
+            var totalHeight = ContentRect.rect.height;
+            var viewportHeight = ViewportRect.rect.height;
+
+            if (totalHeight <= viewportHeight)
+            {
+                Slider.value = 0f;
+                Slider.interactable = false;
+                return;
+            }
+            
+            var handleHeight = viewportHeight * Math.Min(1, viewportHeight / totalHeight);
+            handleHeight = Math.Max(15f, handleHeight);
+
+            // resize the handle container area for the size of the handle (bigger handle = smaller container)
+            var container = Slider.m_HandleContainerRect;
+            container.offsetMax = new Vector2(container.offsetMax.x, -(handleHeight * 0.5f));
+            container.offsetMin = new Vector2(container.offsetMin.x, handleHeight * 0.5f);
+
+            // set handle size
+            Slider.handleRect.SetSizeWithCurrentAnchors(RectTransform.Axis.Vertical, handleHeight);
+
+            // if slider is 100% height then make it not interactable
+            Slider.interactable = !Mathf.Approximately(handleHeight, viewportHeight);
+
+            float val = 0f;
+            if (totalHeight > 0f)
+                val = (float)((decimal)ContentRect.localPosition.y / (decimal)(totalHeight - ViewportRect.rect.height));
+
+            Slider.value = val;
+        }
+
+        public void OnScrollbarValueChanged(float value)
+        {
+            value = 1f - value;
+            if (this.Slider.value != value)
+                this.Slider.Set(value, false);
+            //OnValueChanged?.Invoke(value);
+        }
+
+        public void OnSliderValueChanged(float value)
+        {
+            value = 1f - value;
+            this.Scrollbar.value = value;
+            //OnValueChanged?.Invoke(value);
+        }
+
+        public override void ConstructUI(GameObject parent)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}