Underbrace rendering tests

Author: Happypig375

CSharpMath.Maui.Example/ExamplesPage.xaml.cs

@@ -8,7 +8,6 @@ public partial class ExamplesPage : ContentPage {
     static Dictionary<byte, MathView> labels { get; } = new();
     public ExamplesPage() {
       InitializeComponent();
-      //TODO: uncomment, before merging this branch with master
       var mathViews = demoLabels.Concat(labels).Select(p => p.Value);
       foreach (var view in mathViews) {
         view.ErrorFontSize = view.FontSize * 0.8f;

CSharpMath.Rendering.Tests/MathDisplay/Underbrace.png

@@ -128,7 +128,9 @@ public sealed class TestRenderingMathData : TestRenderingSharedData<TestRenderin
     public const string TangentPeriodShift = @"\tan(\theta\pm\frac\pi4)=\frac{\tan\theta\pm1}{1\mp\tan\theta}";
     public const string Taylor = @"\begin{eqnarray} e^x  &=&  \sum_{n=0}^{\infty}\frac{x^n}{n!} \\ \\ \sin(x) &=& \sum_{n=0}^{\infty}(-1)^n\frac{x^{2n+1}}{(2n+1)!}  \\ \\ -\ln(1-x)   &=& \sum_{n=1}^{\infty}\frac{x^n}{n}  \ \ \ \ \ (-1 \leq x < 1) \end{eqnarray}";
     public const string TwoSin = @"2 \sin";
-
+    public const string Underbrace = @"\underbrace{abcd}";
+    public const string UnderbraceSubscript = @"\underbrace{abcdefghklmnopqrst} _{eee}";
+    public const string UnderbraceSubscriptIntegral = @"\underbrace{\frac{abcd}{efgh} \int \limits _a^b f(x)dx} _{\frac{abcd}{efgh} \int \limits _a^b f(x)dx}";
     public const string Underline = @"\underline{Underline}";
 
     public const string VectorProjection = @"Proj_\vec{v}\vec{u}=|\vec u|\cos\theta\times\frac\vec v{|\vec v|}=|\vec u|\frac{\vec u \cdot \vec v}{|\vec u||\vec v|}\times\frac\vec v{|\vec v|}\\\text{Suppose \mathit{u} and \mathit v are unit vectors, }Proj_\vec v\vec u = (\vec u\cdot\vec v)\vec v";