From b46975391b65083313c50fb066bf2192101bcd7f Mon Sep 17 00:00:00 2001
From: Ellpeck <me@ellpeck.de>
Date: Thu, 6 Jan 2022 23:26:14 +0100
Subject: [PATCH] Only set a paragraph's area dirty when a text change would
 cause it to change size

---
 CHANGELOG.md                  |  1 +
 MLEM.Ui/Elements/Element.cs   |  7 ++++++-
 MLEM.Ui/Elements/Paragraph.cs | 21 +++++++++++++++------
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6374973..d836072 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@ Fixes
 ### MLEM.Ui
 Improvements
 - Allow for checkboxes and radio buttons to be disabled
+- Only set a paragraph's area dirty when a text change would cause it to change size
 
 ### MLEM.Data
 Improvements
diff --git a/MLEM.Ui/Elements/Element.cs b/MLEM.Ui/Elements/Element.cs
index ef289a7..f386e39 100644
--- a/MLEM.Ui/Elements/Element.cs
+++ b/MLEM.Ui/Elements/Element.cs
@@ -398,6 +398,11 @@ namespace MLEM.Ui.Elements {
         /// The input handler that this element's <see cref="Controls"/> use
         /// </summary>
         protected InputHandler Input => this.Controls.Input;
+        /// <summary>
+        /// The <see cref="ChildPaddedArea"/> of this element's <see cref="Parent"/>, or the <see cref="UiSystem.Viewport"/> if this element has no parent.
+        /// This value is the one that is passed to <see cref="CalcActualSize"/> during <see cref="ForceUpdateArea"/>.
+        /// </summary>
+        protected RectangleF ParentArea => this.Parent?.ChildPaddedArea ?? (RectangleF) this.system.Viewport;
 
         private readonly List<Element> children = new List<Element>();
         private bool sortedChildrenDirty;
@@ -554,7 +559,7 @@ namespace MLEM.Ui.Elements {
                 return;
             this.System.Stopwatch.Restart();
 
-            var parentArea = this.Parent != null ? this.Parent.ChildPaddedArea : (RectangleF) this.system.Viewport;
+            var parentArea = this.ParentArea;
             var parentCenterX = parentArea.X + parentArea.Width / 2;
             var parentCenterY = parentArea.Y + parentArea.Height / 2;
             var actualSize = this.CalcActualSize(parentArea);
diff --git a/MLEM.Ui/Elements/Paragraph.cs b/MLEM.Ui/Elements/Paragraph.cs
index 9511c3b..48ff87d 100644
--- a/MLEM.Ui/Elements/Paragraph.cs
+++ b/MLEM.Ui/Elements/Paragraph.cs
@@ -2,6 +2,7 @@ using System;
 using System.Linq;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
+using MLEM.Extensions;
 using MLEM.Font;
 using MLEM.Formatting;
 using MLEM.Formatting.Codes;
@@ -24,8 +25,7 @@ namespace MLEM.Ui.Elements {
             get => this.regularFont;
             set {
                 this.regularFont = value;
-                this.SetAreaDirty();
-                this.TokenizedText = null;
+                this.SetTextDirty();
             }
         }
         /// <summary>
@@ -59,8 +59,7 @@ namespace MLEM.Ui.Elements {
                 if (this.text != value) {
                     this.text = value;
                     this.IsHidden = string.IsNullOrWhiteSpace(this.text);
-                    this.SetAreaDirty();
-                    this.TokenizedText = null;
+                    this.SetTextDirty();
                 }
             }
         }
@@ -95,8 +94,7 @@ namespace MLEM.Ui.Elements {
             get => this.alignment;
             set {
                 this.alignment = value;
-                this.SetAreaDirty();
-                this.TokenizedText = null;
+                this.SetTextDirty();
             }
         }
 
@@ -187,6 +185,17 @@ namespace MLEM.Ui.Elements {
             }
         }
 
+        /// <summary>
+        /// A helper method that causes the <see cref="TokenizedText"/> to be reset.
+        /// Additionally, <see cref="Element.SetAreaDirty"/> if this paragraph's area has changed enough to warrant it, or if it has any <see cref="Link"/> children.
+        /// </summary>
+        protected void SetTextDirty() {
+            this.TokenizedText = null;
+            // only set our area dirty if our size changed as a result of this action or if we have link children we need to update
+            if (!this.AreaDirty && (this.Children.Count > 0 || !this.CalcActualSize(this.ParentArea).Equals(this.DisplayArea.Size, Epsilon)))
+                this.SetAreaDirty();
+        }
+
         private void QueryTextCallback() {
             if (this.GetTextCallback != null)
                 this.Text = this.GetTextCallback(this);