Added checkbox option for wrapping with align, and a spinner indicator

app.js

@@ -142,9 +142,7 @@ function getLatexTemplate(equation) {
     \\usepackage[utf8]{inputenc}
     \\thispagestyle{empty}
     \\begin{document}
-    \\begin{align*}
     ${equation}
-    \\end{align*}
     \\end{document}`;
 }
 

static/index.html

@@ -5,9 +5,8 @@
         <meta charset="utf-8">
         <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
         <meta name="description" content="Convert LaTeX math equations to PNG/JPG/SVG images, with transparent backgrounds and perfect LaTeX rendering">
-        <meta name="author" content="Joseph Rautenbach">
         <!-- Bootstrap CSS -->
-        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
+        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
         <link rel="stylesheet" href="custom.css">
         <script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
         <script src="latex2image-client.js"></script>
@@ -27,20 +26,24 @@
         </div>
         <div class="container">
             <div class="card">
+                <form>
                     <div class="card-body">
                         <div class="form-group">
                             <textarea class="form-control" id="latexInputTextArea" placeholder="Enter LaTeX math equation" rows="5"></textarea>
                         </div>
                         <div class="form-row">
-                        <div class="form-group col-sm-6">
+                            <div class="col-sm-6">
+                                <div class="form-group">
                                     <label for="outputFormatSelect">Image format</label>
                                     <select class="form-control" id="outputFormatSelect">
                                         <option selected>PNG</option>
-                                <option>SVG</option>
                                         <option>JPG</option>
+                                        <option>SVG</option>
                                     </select>
                                 </div>
-                        <div class="form-group col-sm-6">
+                            </div>
+                            <div class="col-sm-6">
+                                <div class="form-group">
                                     <label for="outputScaleSelect">Scale</label>
                                     <select class="form-control" id="outputScaleSelect">
                                         <option>10%</option>
@@ -56,10 +59,25 @@
                                     </select>
                                 </div>
                             </div>
-                    <input type='submit' class="btn btn-primary" id="convertButton" value="Convert">
-                    &nbsp;&nbsp;
-                    <input type='submit' class="btn btn-info" id="exampleButton" value="Show Example">
                         </div>
+                        <div class="form-group">
+                            <div class="form-check">
+                                <input class="form-check-input" type="checkbox" id="autoAlignCheckbox" checked>
+                                <label class="form-check-label" for="autoAlignCheckbox">
+                                    Wrap input with <code>\begin{align*}</code> and <code>\end{align*}</code> automatically
+                                </label>
+                            </div>
+                        </div>
+                        <button class="btn btn-primary" type="button" id="convertButton">
+                            <span class="spinner-grow spinner-grow-sm d-none" role="status" aria-hidden="true" id="convertSpinner"></span>
+                            <span id="convertButtonText">Convert</span>
+                        </button>
+                        &nbsp;&nbsp;
+                        <button class="btn btn-info" type="button" id="exampleButton">
+                            Show Example
+                        </button>
+                    </div>
+                </form>
             </div>
         </div>
         <br>
@@ -68,7 +86,7 @@
                 <div class="card-body">
                     <img id="resultImage" />
                     <br><br>
-                    <a href="#" class="btn btn-primary" role="button" id="downloadButton" download>Save Image</a>
+                    <a href="#" class="btn btn-primary" role="button" id="downloadButton" target="_blank" download>Save Image</a>
                 </div>
             </div>
             <div class="alert alert-danger initiallyHidden" id="errorAlert"></div>

static/latex2image-client.js

@@ -1,6 +1,8 @@
 var sampleEquation = '\\frac{\\pi}{2} = \\int_{-1}^{1} \\sqrt{1-x^2}\\ dx';
 var hasShownBefore = false;
 
+var ENDPOINT = '/convert';
+
 $(document).ready(function() {
   function show(resultData) {
     function afterSlideUp() {
@@ -30,38 +32,45 @@ $(document).ready(function() {
   }
 
   $('#convertButton').click(function() {
-    if (!$('#latexInputTextArea').val()) {
+    var latexInput = $('#latexInputTextArea').val();
-      show(JSON.stringify({
+
-        error: 'No LaTeX input provided'
+    if (!latexInput) {
-      }));
+      show({ error: 'No LaTeX input provided.' });
       return;
     }
 
+    if ($('#autoAlignCheckbox').prop('checked')) {
+      latexInput = '\\begin{align*}\n' + latexInput + '\\end{align*}\n';
+    }
+
     $('#result').slideUp(hasShownBefore ? 330 : 0, function() {
       $('#resultImage').attr('src', '');
     });
 
     $('#convertButton').prop('disabled', true);
     $('#exampleButton').prop('disabled', true);
-    $('#convertButton').prop('value', 'Converting...');
+    $('#convertButtonText').html('Converting...');
+    $('#convertSpinner').removeClass('d-none');
     $.ajax({
-      url: '/convert',
+      url: ENDPOINT,
       type: 'POST',
       data: {
-        latexInput: $('#latexInputTextArea').val(),
+        latexInput: latexInput,
         outputFormat: $('#outputFormatSelect').val(),
         outputScale: $('#outputScaleSelect').val()
       },
       success: function(data) {
         $('#convertButton').prop('disabled', false);
         $('#exampleButton').prop('disabled', false);
-        $('#convertButton').prop('value', 'Convert');
+        $('#convertButtonText').html('Convert');
+        $('#convertSpinner').addClass('d-none');
         show(data);
       },
       error: function() {
         $('#convertButton').prop('disabled', false);
         $('#exampleButton').prop('disabled', false);
-        $('#convertButton').prop('value', 'Convert');
+        $('#convertButtonText').html('Convert');
+        $('#convertSpinner').addClass('d-none');
         alert('Error communicating with server');
       }
     });
@@ -70,6 +79,7 @@ $(document).ready(function() {
   // Show and convert a sample equation
   $('#exampleButton').click(function() {
     $('#latexInputTextArea').val(sampleEquation);
+    $('#autoAlignCheckbox').prop('checked', true);
     $('#convertButton').click();
   });
 });