--- a/ChengsongTanPhdThesis/main.tex	Fri Aug 12 00:39:23 2022 +0100
+++ b/ChengsongTanPhdThesis/main.tex	Sun Aug 14 09:44:27 2022 +0100
@@ -47,6 +47,11 @@
 \usepackage{hyperref}
 \usepackage{lipsum}
 \usepackage[backend=bibtex]{biblatex} % Use the bibtex backend with the authoryear citation style (which resembles APA)
+
+\usepackage[usestackEOL]{stackengine}
+\usepackage{scalerel}
+\usepackage{graphicx}
+
 %style=authoryear, natbib=true 
 \usepackage{stmaryrd}
 \usepackage{caption}
@@ -61,6 +66,22 @@
 
 %\usepackage{algorithm}
 \usepackage{amsmath}
+\makeatletter
+\newcommand{\xleftrightarrow}[2][]{\ext@arrow 3359\leftrightarrowfill@{#1}{#2}}
+\newcommand{\xdashrightarrow}[2][]{\ext@arrow 0359\rightarrowfill@@{#1}{#2}}
+\newcommand{\xdashleftarrow}[2][]{\ext@arrow 3095\leftarrowfill@@{#1}{#2}}
+\newcommand{\xdashleftrightarrow}[2][]{\ext@arrow 3359\leftrightarrowfill@@{#1}{#2}}
+\def\rightarrowfill@@{\arrowfill@@\relax\relbar\rightarrow}
+\def\leftarrowfill@@{\arrowfill@@\leftarrow\relbar\relax}
+\def\leftrightarrowfill@@{\arrowfill@@\leftarrow\relbar\rightarrow}
+\def\arrowfill@@#1#2#3#4{%
+  $\m@th\thickmuskip0mu\medmuskip\thickmuskip\thinmuskip\thickmuskip
+   \relax#4#1
+   \xleaders\hbox{$#4#2$}\hfill
+   #3$%
+}
+\makeatother
+
 \usepackage{amsthm}
 \usepackage{amssymb}
 \usepackage{cleveref}
@@ -82,6 +103,7 @@
 
 \DeclareCaptionType{mytype}[Illustration][]
 \newenvironment{envForCaption}{\captionsetup{type=mytype} }{}
+
 %----------------------------------------------------------------------------------------
 %	MARGIN SETTINGS
 %----------------------------------------------------------------------------------------