From 03923f91f6ae778a3807a4f6301568f7b2baea49 Mon Sep 17 00:00:00 2001
From: Ellpeck <megamaximal@gmail.com>
Date: Fri, 13 Sep 2019 11:53:28 +0200
Subject: [PATCH] some exception handling

---
 MLEM.Ui/Elements/Element.cs   | 10 ++++++----
 MLEM.Ui/Elements/Image.cs     |  3 ++-
 MLEM.Ui/Elements/Paragraph.cs |  1 +
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/MLEM.Ui/Elements/Element.cs b/MLEM.Ui/Elements/Element.cs
index 8c1c901..30e42dd 100644
--- a/MLEM.Ui/Elements/Element.cs
+++ b/MLEM.Ui/Elements/Element.cs
@@ -305,10 +305,12 @@ namespace MLEM.Ui.Elements {
 
             if (this.SetHeightBasedOnChildren && this.Children.Count > 0) {
                 var lowest = this.GetLowestChild(e => !e.IsHidden);
-                var newHeight = (lowest.UnscrolledArea.Bottom - pos.Y + this.ScaledChildPadding.Y) / this.Scale;
-                if (newHeight != this.size.Y) {
-                    this.size.Y = newHeight;
-                    this.ForceUpdateArea();
+                if (lowest != null) {
+                    var newHeight = (lowest.UnscrolledArea.Bottom - pos.Y + this.ScaledChildPadding.Y) / this.Scale;
+                    if (newHeight != this.size.Y) {
+                        this.size.Y = newHeight;
+                        this.ForceUpdateArea();
+                    }
                 }
             }
         }
diff --git a/MLEM.Ui/Elements/Image.cs b/MLEM.Ui/Elements/Image.cs
index 38ce989..c1d2036 100644
--- a/MLEM.Ui/Elements/Image.cs
+++ b/MLEM.Ui/Elements/Image.cs
@@ -14,6 +14,7 @@ namespace MLEM.Ui.Elements {
             set {
                 if (this.texture != value) {
                     this.texture = value;
+                    this.IsHidden = this.texture == null;
                     if (this.scaleToImage)
                         this.SetAreaDirty();
                 }
@@ -42,7 +43,7 @@ namespace MLEM.Ui.Elements {
         }
 
         protected override Point CalcActualSize(Rectangle parentArea) {
-            return this.scaleToImage ? this.texture.Size : base.CalcActualSize(parentArea);
+            return this.texture != null && this.scaleToImage ? this.texture.Size : base.CalcActualSize(parentArea);
         }
 
         public override void Draw(GameTime time, SpriteBatch batch, float alpha) {
diff --git a/MLEM.Ui/Elements/Paragraph.cs b/MLEM.Ui/Elements/Paragraph.cs
index 0fcda97..0fac150 100644
--- a/MLEM.Ui/Elements/Paragraph.cs
+++ b/MLEM.Ui/Elements/Paragraph.cs
@@ -29,6 +29,7 @@ namespace MLEM.Ui.Elements {
             set {
                 if (this.text != value) {
                     this.text = value;
+                    this.IsHidden = string.IsNullOrWhiteSpace(this.text);
                     this.SetAreaDirty();
                 }
             }