From d231386f861de98b03d30cc5ad29bfbcc5b8fa65 Mon Sep 17 00:00:00 2001
From: Ellpeck <megamaximal@gmail.com>
Date: Sat, 24 Aug 2019 15:12:11 +0200
Subject: [PATCH] made auto-anchored elements look for the lowest older sibling

---
 Demos/UiDemo.cs                   |  2 +-
 MLEM.Ui/Elements/Element.cs       | 21 ++++++++++++---------
 MLEM.Ui/Elements/ElementHelper.cs |  8 +++-----
 MLEM.Ui/Elements/Panel.cs         |  2 +-
 4 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/Demos/UiDemo.cs b/Demos/UiDemo.cs
index 3a3fa11..190628f 100644
--- a/Demos/UiDemo.cs
+++ b/Demos/UiDemo.cs
@@ -160,7 +160,7 @@ namespace Demos {
             root.AddChild(ElementHelper.NumberField(Anchor.AutoLeft, new Vector2(1, 10))).PositionOffset = new Vector2(0, 1);
 
             root.AddChild(new Paragraph(Anchor.AutoLeft, 1, "There is an easy helper method to make any amount of same-sized columns:") {PositionOffset = new Vector2(0, 1)});
-            var cols = ElementHelper.MakeColumns(root, Anchor.AutoLeft, new Vector2(1), 3);
+            var cols = ElementHelper.MakeColumns(root, new Vector2(1), 3);
             cols[0].AddChild(new Paragraph(Anchor.AutoLeft, 1, "This is the first column"));
             cols[1].AddChild(new Paragraph(Anchor.AutoLeft, 1, "This is the second column"));
             cols[2].AddChild(new Paragraph(Anchor.AutoLeft, 1, "This is the third column"));
diff --git a/MLEM.Ui/Elements/Element.cs b/MLEM.Ui/Elements/Element.cs
index 9f96c72..11ffd41 100644
--- a/MLEM.Ui/Elements/Element.cs
+++ b/MLEM.Ui/Elements/Element.cs
@@ -263,7 +263,7 @@ namespace MLEM.Ui.Elements {
             }
 
             if (this.Anchor >= Anchor.AutoLeft) {
-                var previousChild = this.GetPreviousChild(false, false);
+                var previousChild = this.GetLowestOlderSibling(false, false);
                 if (previousChild != null) {
                     var prevArea = previousChild.GetAreaForAutoAnchors();
                     switch (this.Anchor) {
@@ -296,7 +296,7 @@ namespace MLEM.Ui.Elements {
                 child.ForceUpdateArea();
 
             if (this.SetHeightBasedOnChildren && this.Children.Count > 0) {
-                var lowest = this.GetLowestReachingChild(false, true);
+                var lowest = this.GetLowestChild(false, true);
                 var newHeight = (lowest.area.Bottom - pos.Y + this.ScaledChildPadding.Y) / this.Scale;
                 if (newHeight != this.size.Y) {
                     this.size.Y = newHeight;
@@ -316,7 +316,7 @@ namespace MLEM.Ui.Elements {
             return this.Area;
         }
 
-        public Element GetLowestReachingChild(bool hiddenAlso, bool unattachableAlso) {
+        public Element GetLowestChild(bool hiddenAlso, bool unattachableAlso) {
             Element lowest = null;
             // the lowest child is expected to be towards the back, so search is usually faster if done backwards
             for (var i = this.Children.Count - 1; i >= 0; i--) {
@@ -331,19 +331,22 @@ namespace MLEM.Ui.Elements {
             return lowest;
         }
 
-        public Element GetPreviousChild(bool hiddenAlso, bool unattachableAlso) {
+        public Element GetLowestOlderSibling(bool hiddenAlso, bool unattachableAlso) {
             if (this.Parent == null)
                 return null;
 
-            Element lastChild = null;
+            Element lowest = null;
             foreach (var child in this.Parent.Children) {
-                if (!hiddenAlso && child.IsHidden || !unattachableAlso && !child.CanAutoAnchorsAttach)
-                    continue;
                 if (child == this)
                     break;
-                lastChild = child;
+                if (!hiddenAlso && child.IsHidden || !unattachableAlso && !child.CanAutoAnchorsAttach)
+                    continue;
+                if (child.Anchor > Anchor.TopRight && child.Anchor < Anchor.AutoLeft)
+                    continue;
+                if (lowest == null || child.Area.Bottom > lowest.Area.Bottom)
+                    lowest = child;
             }
-            return lastChild;
+            return lowest;
         }
 
         public IEnumerable<Element> GetSiblings(bool hiddenAlso) {
diff --git a/MLEM.Ui/Elements/ElementHelper.cs b/MLEM.Ui/Elements/ElementHelper.cs
index 7963e64..2559d84 100644
--- a/MLEM.Ui/Elements/ElementHelper.cs
+++ b/MLEM.Ui/Elements/ElementHelper.cs
@@ -18,15 +18,13 @@ namespace MLEM.Ui.Elements {
             return box;
         }
 
-        public static Group[] MakeColumns(Element parent, Anchor anchor, Vector2 totalSize, int amount, bool setHeightBasedOnChildren = true) {
-            var group = new Group(anchor, totalSize, setHeightBasedOnChildren);
+        public static Group[] MakeColumns(Element parent, Vector2 totalSize, int amount, bool setHeightBasedOnChildren = true) {
             var cols = new Group[amount];
             for (var i = 0; i < amount; i++) {
                 cols[i] = new Group(Anchor.AutoInline, new Vector2(totalSize.X / amount, totalSize.Y), setHeightBasedOnChildren);
-                group.AddChild(cols[i]);
+                if (parent != null)
+                    parent.AddChild(cols[i]);
             }
-            if (parent != null)
-                parent.AddChild(group);
             return cols;
         }
 
diff --git a/MLEM.Ui/Elements/Panel.cs b/MLEM.Ui/Elements/Panel.cs
index 7349c34..3ef523c 100644
--- a/MLEM.Ui/Elements/Panel.cs
+++ b/MLEM.Ui/Elements/Panel.cs
@@ -65,7 +65,7 @@ namespace MLEM.Ui.Elements {
                     return;
                 // the "real" first child is the scroll bar, which we want to ignore
                 var firstChild = this.Children[1];
-                var lowestChild = this.GetLowestReachingChild(false, true);
+                var lowestChild = this.GetLowestChild(false, true);
                 // the max value of the scrollbar is the amount of non-scaled pixels taken up by overflowing components
                 var childrenHeight = lowestChild.Area.Bottom - firstChild.Area.Top;
                 this.ScrollBar.MaxValue = (childrenHeight - this.Area.Height) / this.Scale + this.ChildPadding.Y * 2;